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/* Copyright (C) 2000-2006 MySQL AB
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   This program is free software; you can redistribute it and/or modify
   it under the terms of the GNU General Public License as published by
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   the Free Software Foundation; version 2 of the License.
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   This program is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   GNU General Public License for more details.
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   You should have received a copy of the GNU General Public License
   along with this program; if not, write to the Free Software
   Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA */


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#ifdef USE_PRAGMA_IMPLEMENTATION
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#pragma implementation				// gcc: Class implementation
#endif
#include "mysql_priv.h"
#include <m_ctype.h>
#include "my_dir.h"
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#include "sp_rcontext.h"
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#include "sp_head.h"
#include "sql_trigger.h"
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#include "sql_select.h"
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const String my_null_string("NULL", 4, default_charset_info);

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/****************************************************************************/

/* Hybrid_type_traits {_real} */

void Hybrid_type_traits::fix_length_and_dec(Item *item, Item *arg) const
{
  item->decimals= NOT_FIXED_DEC;
  item->max_length= item->float_length(arg->decimals);
}

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static const Hybrid_type_traits real_traits_instance;
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const Hybrid_type_traits *Hybrid_type_traits::instance()
{
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  return &real_traits_instance;
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}


my_decimal *
Hybrid_type_traits::val_decimal(Hybrid_type *val, my_decimal *to) const
{
  double2my_decimal(E_DEC_FATAL_ERROR, val->real, val->dec_buf);
  return val->dec_buf;
}


String *
Hybrid_type_traits::val_str(Hybrid_type *val, String *to, uint8 decimals) const
{
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  to->set_real(val->real, decimals, &my_charset_bin);
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  return to;
}

/* Hybrid_type_traits_decimal */
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static const Hybrid_type_traits_decimal decimal_traits_instance;
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const Hybrid_type_traits_decimal *Hybrid_type_traits_decimal::instance()
{
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  return &decimal_traits_instance;
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}


void
Hybrid_type_traits_decimal::fix_length_and_dec(Item *item, Item *arg) const
{
  item->decimals= arg->decimals;
  item->max_length= min(arg->max_length + DECIMAL_LONGLONG_DIGITS,
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                        DECIMAL_MAX_STR_LENGTH);
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}


void Hybrid_type_traits_decimal::set_zero(Hybrid_type *val) const
{
  my_decimal_set_zero(&val->dec_buf[0]);
  val->used_dec_buf_no= 0;
}


void Hybrid_type_traits_decimal::add(Hybrid_type *val, Field *f) const
{
  my_decimal_add(E_DEC_FATAL_ERROR,
                 &val->dec_buf[val->used_dec_buf_no ^ 1],
                 &val->dec_buf[val->used_dec_buf_no],
                 f->val_decimal(&val->dec_buf[2]));
  val->used_dec_buf_no^= 1;
}


void Hybrid_type_traits_decimal::div(Hybrid_type *val, ulonglong u) const
{
  int2my_decimal(E_DEC_FATAL_ERROR, u, TRUE, &val->dec_buf[2]);
  /* XXX: what is '4' for scale? */
  my_decimal_div(E_DEC_FATAL_ERROR,
                 &val->dec_buf[val->used_dec_buf_no ^ 1],
                 &val->dec_buf[val->used_dec_buf_no],
                 &val->dec_buf[2], 4);
  val->used_dec_buf_no^= 1;
}


longlong
Hybrid_type_traits_decimal::val_int(Hybrid_type *val, bool unsigned_flag) const
{
  longlong result;
  my_decimal2int(E_DEC_FATAL_ERROR, &val->dec_buf[val->used_dec_buf_no],
                 unsigned_flag, &result);
  return result;
}


double
Hybrid_type_traits_decimal::val_real(Hybrid_type *val) const
{
  my_decimal2double(E_DEC_FATAL_ERROR, &val->dec_buf[val->used_dec_buf_no],
                    &val->real);
  return val->real;
}


String *
Hybrid_type_traits_decimal::val_str(Hybrid_type *val, String *to,
                                    uint8 decimals) const
{
  my_decimal_round(E_DEC_FATAL_ERROR, &val->dec_buf[val->used_dec_buf_no],
                   decimals, FALSE, &val->dec_buf[2]);
  my_decimal2string(E_DEC_FATAL_ERROR, &val->dec_buf[2], 0, 0, 0, to);
  return to;
}

/* Hybrid_type_traits_integer */
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static const Hybrid_type_traits_integer integer_traits_instance;
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const Hybrid_type_traits_integer *Hybrid_type_traits_integer::instance()
{
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  return &integer_traits_instance;
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}

void
Hybrid_type_traits_integer::fix_length_and_dec(Item *item, Item *arg) const
{
  item->decimals= 0;
  item->max_length= 21;
  item->unsigned_flag= 0;
}

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/*****************************************************************************
** Item functions
*****************************************************************************/

/* Init all special items */

void item_init(void)
{
  item_user_lock_init();
}

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/*
TODO: make this functions class dependent
*/
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bool Item::val_bool()
{
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  switch(result_type()) {
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  case INT_RESULT:
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    return val_int() != 0;
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  case DECIMAL_RESULT:
  {
    my_decimal decimal_value;
    my_decimal *val= val_decimal(&decimal_value);
    if (val)
      return !my_decimal_is_zero(val);
    return 0;
  }
  case REAL_RESULT:
  case STRING_RESULT:
    return val_real() != 0.0;
  case ROW_RESULT:
  default:
    DBUG_ASSERT(0);
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    return 0;                                   // Wrong (but safe)
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  }
}


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String *Item::val_string_from_real(String *str)
{
  double nr= val_real();
  if (null_value)
    return 0;					/* purecov: inspected */
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  str->set_real(nr,decimals, &my_charset_bin);
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  return str;
}


String *Item::val_string_from_int(String *str)
{
  longlong nr= val_int();
  if (null_value)
    return 0;
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  str->set_int(nr, unsigned_flag, &my_charset_bin);
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  return str;
}


String *Item::val_string_from_decimal(String *str)
{
  my_decimal dec_buf, *dec= val_decimal(&dec_buf);
  if (null_value)
    return 0;
  my_decimal_round(E_DEC_FATAL_ERROR, dec, decimals, FALSE, &dec_buf);
  my_decimal2string(E_DEC_FATAL_ERROR, &dec_buf, 0, 0, 0, str);
  return str;
}


my_decimal *Item::val_decimal_from_real(my_decimal *decimal_value)
{
  double nr= val_real();
  if (null_value)
    return 0;
  double2my_decimal(E_DEC_FATAL_ERROR, nr, decimal_value);
  return (decimal_value);
}


my_decimal *Item::val_decimal_from_int(my_decimal *decimal_value)
{
  longlong nr= val_int();
  if (null_value)
    return 0;
  int2my_decimal(E_DEC_FATAL_ERROR, nr, unsigned_flag, decimal_value);
  return decimal_value;
}


my_decimal *Item::val_decimal_from_string(my_decimal *decimal_value)
{
  String *res;
  char *end_ptr;
  if (!(res= val_str(&str_value)))
    return 0;                                   // NULL or EOM

  end_ptr= (char*) res->ptr()+ res->length();
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  if (str2my_decimal(E_DEC_FATAL_ERROR & ~E_DEC_BAD_NUM,
                     res->ptr(), res->length(), res->charset(),
                     decimal_value) & E_DEC_BAD_NUM)
  {
    push_warning_printf(current_thd, MYSQL_ERROR::WARN_LEVEL_WARN,
                        ER_TRUNCATED_WRONG_VALUE,
                        ER(ER_TRUNCATED_WRONG_VALUE), "DECIMAL",
                        str_value.c_ptr());
  }
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  return decimal_value;
}


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my_decimal *Item::val_decimal_from_date(my_decimal *decimal_value)
{
  DBUG_ASSERT(fixed == 1);
  TIME ltime;
  if (get_date(&ltime, TIME_FUZZY_DATE))
  {
    my_decimal_set_zero(decimal_value);
    return 0;
  }
  return date2my_decimal(&ltime, decimal_value);
}


my_decimal *Item::val_decimal_from_time(my_decimal *decimal_value)
{
  DBUG_ASSERT(fixed == 1);
  TIME ltime;
  if (get_time(&ltime))
  {
    my_decimal_set_zero(decimal_value);
    return 0;
  }
  return date2my_decimal(&ltime, decimal_value);
}


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double Item::val_real_from_decimal()
{
  /* Note that fix_fields may not be called for Item_avg_field items */
  double result;
  my_decimal value_buff, *dec_val= val_decimal(&value_buff);
  if (null_value)
    return 0.0;
  my_decimal2double(E_DEC_FATAL_ERROR, dec_val, &result);
  return result;
}


longlong Item::val_int_from_decimal()
{
  /* Note that fix_fields may not be called for Item_avg_field items */
  longlong result;
  my_decimal value, *dec_val= val_decimal(&value);
  if (null_value)
    return 0;
  my_decimal2int(E_DEC_FATAL_ERROR, dec_val, unsigned_flag, &result);
  return result;
}

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int Item::save_time_in_field(Field *field)
{
  TIME ltime;
  if (get_time(&ltime))
    return set_field_to_null(field);
  field->set_notnull();
  return field->store_time(&ltime, MYSQL_TIMESTAMP_TIME);
}


int Item::save_date_in_field(Field *field)
{
  TIME ltime;
  if (get_date(&ltime, TIME_FUZZY_DATE))
    return set_field_to_null(field);
  field->set_notnull();
  return field->store_time(&ltime, MYSQL_TIMESTAMP_DATETIME);
}

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Item::Item():
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  rsize(0), name(0), orig_name(0), name_length(0), fixed(0),
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  is_autogenerated_name(TRUE),
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  collation(&my_charset_bin, DERIVATION_COERCIBLE)
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{
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  marker= 0;
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  maybe_null=null_value=with_sum_func=unsigned_flag=0;
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  decimals= 0; max_length= 0;
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  with_subselect= 0;
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  cmp_context= (Item_result)-1;
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  /* Put item in free list so that we can free all items at end */
  THD *thd= current_thd;
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  next= thd->free_list;
  thd->free_list= this;
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  /*
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    Item constructor can be called during execution other then SQL_COM
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    command => we should check thd->lex->current_select on zero (thd->lex
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    can be uninitialised)
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  */
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  if (thd->lex->current_select)
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  {
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    enum_parsing_place place= 
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      thd->lex->current_select->parsing_place;
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    if (place == SELECT_LIST ||
	place == IN_HAVING)
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      thd->lex->current_select->select_n_having_items++;
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  }
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}

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/*
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  Constructor used by Item_field, Item_*_ref & aggregate (sum) functions.
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  Used for duplicating lists in processing queries with temporary
  tables
*/
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Item::Item(THD *thd, Item *item):
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  rsize(0),
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  str_value(item->str_value),
  name(item->name),
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  orig_name(item->orig_name),
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  max_length(item->max_length),
  marker(item->marker),
  decimals(item->decimals),
  maybe_null(item->maybe_null),
  null_value(item->null_value),
  unsigned_flag(item->unsigned_flag),
  with_sum_func(item->with_sum_func),
  fixed(item->fixed),
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  collation(item->collation),
  cmp_context(item->cmp_context)
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{
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  next= thd->free_list;				// Put in free list
  thd->free_list= this;
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}

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uint Item::decimal_precision() const
{
  Item_result restype= result_type();

  if ((restype == DECIMAL_RESULT) || (restype == INT_RESULT))
    return min(my_decimal_length_to_precision(max_length, decimals, unsigned_flag),
               DECIMAL_MAX_PRECISION);
  return min(max_length, DECIMAL_MAX_PRECISION);
}


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void Item::print_item_w_name(String *str)
{
  print(str);
  if (name)
  {
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    THD *thd= current_thd;
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    str->append(STRING_WITH_LEN(" AS "));
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    append_identifier(thd, str, name, (uint) strlen(name));
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  }
}


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void Item::cleanup()
{
  DBUG_ENTER("Item::cleanup");
  fixed=0;
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  marker= 0;
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  if (orig_name)
    name= orig_name;
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  DBUG_VOID_RETURN;
}

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/*
  cleanup() item if it is 'fixed'

  SYNOPSIS
    cleanup_processor()
    arg - a dummy parameter, is not used here
*/

bool Item::cleanup_processor(byte *arg)
{
  if (fixed)
    cleanup();
  return FALSE;
}


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/*
  rename item (used for views, cleanup() return original name)

  SYNOPSIS
    Item::rename()
    new_name	new name of item;
*/

void Item::rename(char *new_name)
{
  /*
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    we can compare pointers to names here, because if name was not changed,
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    pointer will be same
  */
  if (!orig_name && new_name != name)
    orig_name= name;
  name= new_name;
}


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/*
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  Traverse item tree possibly transforming it (replacing items).
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  SYNOPSIS
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    Item::transform()
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      transformer    functor that performs transformation of a subtree
      arg            opaque argument passed to the functor

  DESCRIPTION
    This function is designed to ease transformation of Item trees.

    Re-execution note: every such transformation is registered for
    rollback by THD::change_item_tree() and is rolled back at the end
    of execution by THD::rollback_item_tree_changes().

    Therefore:

      - this function can not be used at prepared statement prepare
        (in particular, in fix_fields!), as only permanent
        transformation of Item trees are allowed at prepare.

      - the transformer function shall allocate new Items in execution
        memory root (thd->mem_root) and not anywhere else: allocated
        items will be gone in the end of execution.

    If you don't need to transform an item tree, but only traverse
    it, please use Item::walk() instead.


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  RETURN VALUE
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    Returns pointer to the new subtree root.  THD::change_item_tree()
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    should be called for it if transformation took place, i.e. if a
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    pointer to newly allocated item is returned.
*/

Item* Item::transform(Item_transformer transformer, byte *arg)
{
  DBUG_ASSERT(!current_thd->is_stmt_prepare());

  return (this->*transformer)(arg);
}


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Item_ident::Item_ident(Name_resolution_context *context_arg,
                       const char *db_name_arg,const char *table_name_arg,
		       const char *field_name_arg)
  :orig_db_name(db_name_arg), orig_table_name(table_name_arg),
   orig_field_name(field_name_arg), context(context_arg),
   db_name(db_name_arg), table_name(table_name_arg),
   field_name(field_name_arg),
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   alias_name_used(FALSE), cached_field_index(NO_CACHED_FIELD_INDEX),
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   cached_table(0), depended_from(0)
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{
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  name = (char*) field_name_arg;
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}

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/* Constructor used by Item_field & Item_*_ref (see Item comment) */
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Item_ident::Item_ident(THD *thd, Item_ident *item)
  :Item(thd, item),
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   orig_db_name(item->orig_db_name),
   orig_table_name(item->orig_table_name), 
   orig_field_name(item->orig_field_name),
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   context(item->context),
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   db_name(item->db_name),
   table_name(item->table_name),
   field_name(item->field_name),
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   alias_name_used(item->alias_name_used),
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   cached_field_index(item->cached_field_index),
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   cached_table(item->cached_table),
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   depended_from(item->depended_from)
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{}
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void Item_ident::cleanup()
{
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  DBUG_ENTER("Item_ident::cleanup");
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#ifdef CANT_BE_USED_AS_MEMORY_IS_FREED
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		       db_name ? db_name : "(null)",
                       orig_db_name ? orig_db_name : "(null)",
		       table_name ? table_name : "(null)",
                       orig_table_name ? orig_table_name : "(null)",
		       field_name ? field_name : "(null)",
                       orig_field_name ? orig_field_name : "(null)"));
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#endif
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  Item::cleanup();
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  db_name= orig_db_name; 
  table_name= orig_table_name;
  field_name= orig_field_name;
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  depended_from= 0;
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  DBUG_VOID_RETURN;
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}

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bool Item_ident::remove_dependence_processor(byte * arg)
{
  DBUG_ENTER("Item_ident::remove_dependence_processor");
  if (depended_from == (st_select_lex *) arg)
    depended_from= 0;
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  DBUG_RETURN(0);
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}


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/*
  Store the pointer to this item field into a list if not already there.

  SYNOPSIS
    Item_field::collect_item_field_processor()
    arg  pointer to a List<Item_field>

  DESCRIPTION
    The method is used by Item::walk to collect all unique Item_field objects
    from a tree of Items into a set of items represented as a list.

  IMPLEMENTATION
    Item_cond::walk() and Item_func::walk() stop the evaluation of the
    processor function for its arguments once the processor returns
    true.Therefore in order to force this method being called for all item
    arguments in a condition the method must return false.

  RETURN
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    FALSE to force the evaluation of collect_item_field_processor
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          for the subsequent items.
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*/

bool Item_field::collect_item_field_processor(byte *arg)
{
  DBUG_ENTER("Item_field::collect_item_field_processor");
  DBUG_PRINT("info", ("%s", field->field_name ? field->field_name : "noname"));
  List<Item_field> *item_list= (List<Item_field>*) arg;
  List_iterator<Item_field> item_list_it(*item_list);
  Item_field *curr_item;
  while ((curr_item= item_list_it++))
  {
    if (curr_item->eq(this, 1))
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      DBUG_RETURN(FALSE); /* Already in the set. */
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  }
  item_list->push_back(this);
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  DBUG_RETURN(FALSE);
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}


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/*
  Check if an Item_field references some field from a list of fields.

  SYNOPSIS
    Item_field::find_item_in_field_list_processor
    arg   Field being compared, arg must be of type Field

  DESCRIPTION
    Check whether the Item_field represented by 'this' references any
    of the fields in the keyparts passed via 'arg'. Used with the
    method Item::walk() to test whether any keypart in a sequence of
    keyparts is referenced in an expression.

  RETURN
    TRUE  if 'this' references the field 'arg'
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    FALSE otherwise
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*/
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bool Item_field::find_item_in_field_list_processor(byte *arg)
{
  KEY_PART_INFO *first_non_group_part= *((KEY_PART_INFO **) arg);
  KEY_PART_INFO *last_part= *(((KEY_PART_INFO **) arg) + 1);
  KEY_PART_INFO *cur_part;

  for (cur_part= first_non_group_part; cur_part != last_part; cur_part++)
  {
    if (field->eq(cur_part->field))
      return TRUE;
  }
  return FALSE;
}


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/*
  Mark field in read_map

  NOTES
    This is used by filesort to register used fields in a a temporary
    column read set or to register used fields in a view
*/

bool Item_field::register_field_in_read_map(byte *arg)
{
  TABLE *table= (TABLE *) arg;
  if (field->table == table || !table)
    bitmap_set_bit(field->table->read_set, field->field_index);
  return 0;
}


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bool Item::check_cols(uint c)
{
  if (c != 1)
  {
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    my_error(ER_OPERAND_COLUMNS, MYF(0), c);
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    return 1;
  }
  return 0;
}

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void Item::set_name(const char *str, uint length, CHARSET_INFO *cs)
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{
  if (!length)
  {
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    /* Empty string, used by AS or internal function like last_insert_id() */
    name= (char*) str;
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    name_length= 0;
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    return;
  }
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  if (cs->ctype)
  {
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    uint orig_len= length;
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    /*
      This will probably need a better implementation in the future:
      a function in CHARSET_INFO structure.
    */
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    while (length && !my_isgraph(cs,*str))
    {						// Fix problem with yacc
      length--;
      str++;
    }
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    if (orig_len != length && !is_autogenerated_name)
      push_warning_printf(current_thd, MYSQL_ERROR::WARN_LEVEL_WARN,
                          ER_REMOVED_SPACES, ER(ER_REMOVED_SPACES),
                          str + length - orig_len);

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  }
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  if (!my_charset_same(cs, system_charset_info))
  {
    uint32 res_length;
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    name= sql_strmake_with_convert(str, name_length= length, cs,
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				   MAX_ALIAS_NAME, system_charset_info,
				   &res_length);
  }
  else
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    name= sql_strmake(str, (name_length= min(length,MAX_ALIAS_NAME)));
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}

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/*
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  This function is called when:
  - Comparing items in the WHERE clause (when doing where optimization)
  - When trying to find an ORDER BY/GROUP BY item in the SELECT part
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*/

bool Item::eq(const Item *item, bool binary_cmp) const
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{
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  /*
    Note, that this is never TRUE if item is a Item_param:
    for all basic constants we have special checks, and Item_param's
    type() can be only among basic constant types.
  */
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  return type() == item->type() && name && item->name &&
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    !my_strcasecmp(system_charset_info,name,item->name);
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}

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Item *Item::safe_charset_converter(CHARSET_INFO *tocs)
{
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  Item_func_conv_charset *conv= new Item_func_conv_charset(this, tocs, 1);
  return conv->safe ? conv : NULL;
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}


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/*
  Created mostly for mysql_prepare_table(). Important
  when a string ENUM/SET column is described with a numeric default value:

  CREATE TABLE t1(a SET('a') DEFAULT 1);

  We cannot use generic Item::safe_charset_converter(), because
  the latter returns a non-fixed Item, so val_str() crashes afterwards.
  Override Item_num method, to return a fixed item.
*/
Item *Item_num::safe_charset_converter(CHARSET_INFO *tocs)
{
  Item_string *conv;
  char buf[64];
  String *s, tmp(buf, sizeof(buf), &my_charset_bin);
  s= val_str(&tmp);
  if ((conv= new Item_string(s->ptr(), s->length(), s->charset())))
  {
    conv->str_value.copy();
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    conv->str_value.mark_as_const();
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  }
  return conv;
}


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Item *Item_static_float_func::safe_charset_converter(CHARSET_INFO *tocs)
{
  Item_string *conv;
  char buf[64];
  String *s, tmp(buf, sizeof(buf), &my_charset_bin);
  s= val_str(&tmp);
  if ((conv= new Item_static_string_func(func_name, s->ptr(), s->length(),
                                         s->charset())))
  {
    conv->str_value.copy();
    conv->str_value.mark_as_const();
  }
  return conv;
}


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Item *Item_string::safe_charset_converter(CHARSET_INFO *tocs)
{
  Item_string *conv;
  uint conv_errors;
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  char *ptr;
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  String tmp, cstr, *ostr= val_str(&tmp);
  cstr.copy(ostr->ptr(), ostr->length(), ostr->charset(), tocs, &conv_errors);
  if (conv_errors || !(conv= new Item_string(cstr.ptr(), cstr.length(),
                                             cstr.charset(),
                                             collation.derivation)))
  {
    /*
      Safe conversion is not possible (or EOM).
      We could not convert a string into the requested character set
      without data loss. The target charset does not cover all the
      characters from the string. Operation cannot be done correctly.
    */
    return NULL;
  }
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  if (!(ptr= current_thd->memdup(cstr.ptr(), cstr.length() + 1 )))
    return NULL;
  conv->str_value.set(ptr, cstr.length(), cstr.charset());
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  /* Ensure that no one is going to change the result string */
  conv->str_value.mark_as_const();
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  return conv;
}


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Item *Item_param::safe_charset_converter(CHARSET_INFO *tocs)
{
  if (const_item())
  {
    uint cnv_errors;
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    String *ostr= val_str(&cnvstr);
    cnvitem->str_value.copy(ostr->ptr(), ostr->length(),
                            ostr->charset(), tocs, &cnv_errors);
    if (cnv_errors)
       return NULL;
    cnvitem->str_value.mark_as_const();
    cnvitem->max_length= cnvitem->str_value.numchars() * tocs->mbmaxlen;
    return cnvitem;
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  }
  return NULL;
}


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Item *Item_static_string_func::safe_charset_converter(CHARSET_INFO *tocs)
{
  Item_string *conv;
  uint conv_errors;
  String tmp, cstr, *ostr= val_str(&tmp);
  cstr.copy(ostr->ptr(), ostr->length(), ostr->charset(), tocs, &conv_errors);
  if (conv_errors ||
      !(conv= new Item_static_string_func(func_name,
                                          cstr.ptr(), cstr.length(),
                                          cstr.charset(),
                                          collation.derivation)))
  {
    /*
      Safe conversion is not possible (or EOM).
      We could not convert a string into the requested character set
      without data loss. The target charset does not cover all the
      characters from the string. Operation cannot be done correctly.
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    */
    return NULL;
  }
  conv->str_value.copy();
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  /* Ensure that no one is going to change the result string */
  conv->str_value.mark_as_const();
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  return conv;
}


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bool Item_string::eq(const Item *item, bool binary_cmp) const
{
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  if (type() == item->type() && item->basic_const_item())
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  {
    if (binary_cmp)
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      return !stringcmp(&str_value, &item->str_value);
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    return (collation.collation == item->collation.collation &&
	    !sortcmp(&str_value, &item->str_value, collation.collation));
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  }
  return 0;
}


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/*
  Get the value of the function as a TIME structure.
  As a extra convenience the time structure is reset on error!
 */

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bool Item::get_date(TIME *ltime,uint fuzzydate)
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{
  char buff[40];
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  String tmp(buff,sizeof(buff), &my_charset_bin),*res;
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  if (!(res=val_str(&tmp)) ||
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      str_to_datetime_with_warn(res->ptr(), res->length(),
                                ltime, fuzzydate) <= MYSQL_TIMESTAMP_ERROR)
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  {
    bzero((char*) ltime,sizeof(*ltime));
    return 1;
  }
  return 0;
}

/*
  Get time of first argument.
  As a extra convenience the time structure is reset on error!
 */

bool Item::get_time(TIME *ltime)
{
  char buff[40];
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  String tmp(buff,sizeof(buff),&my_charset_bin),*res;
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  if (!(res=val_str(&tmp)) ||
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      str_to_time_with_warn(res->ptr(), res->length(), ltime))
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  {
    bzero((char*) ltime,sizeof(*ltime));
    return 1;
  }
  return 0;
}

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CHARSET_INFO *Item::default_charset()
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{
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  return current_thd->variables.collation_connection;
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}

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/*
  Save value in field, but don't give any warnings

  NOTES
   This is used to temporary store and retrieve a value in a column,
   for example in opt_range to adjust the key value to fit the column.
*/

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int Item::save_in_field_no_warnings(Field *field, bool no_conversions)
{
  int res;
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  TABLE *table= field->table;
  THD *thd= table->in_use;
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  enum_check_fields tmp= thd->count_cuted_fields;
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  my_bitmap_map *old_map= dbug_tmp_use_all_columns(table, table->write_set);
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  thd->count_cuted_fields= CHECK_FIELD_IGNORE;
  res= save_in_field(field, no_conversions);
  thd->count_cuted_fields= tmp;
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  dbug_tmp_restore_column_map(table->write_set, old_map);
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  return res;
}


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/*****************************************************************************
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  Item_sp_variable methods
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*****************************************************************************/
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Item_sp_variable::Item_sp_variable(char *sp_var_name_str,
                                   uint sp_var_name_length)
  :m_thd(0)
#ifndef DBUG_OFF
   , m_sp(0)
#endif
{
  m_name.str= sp_var_name_str;
  m_name.length= sp_var_name_length;
}


bool Item_sp_variable::fix_fields(THD *thd, Item **)
{
  Item *it;

  m_thd= thd; /* NOTE: this must be set before any this_xxx() */
  it= this_item();

  DBUG_ASSERT(it->fixed);

  max_length= it->max_length;
  decimals= it->decimals;
  unsigned_flag= it->unsigned_flag;
  fixed= 1;
  collation.set(it->collation.collation, it->collation.derivation);

  return FALSE;
}


double Item_sp_variable::val_real()
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{
  DBUG_ASSERT(fixed);
  Item *it= this_item();
  double ret= it->val_real();
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  null_value= it->null_value;
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  return ret;
}


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longlong Item_sp_variable::val_int()
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{
  DBUG_ASSERT(fixed);
  Item *it= this_item();
  longlong ret= it->val_int();
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  null_value= it->null_value;
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  return ret;
}


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String *Item_sp_variable::val_str(String *sp)
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{
  DBUG_ASSERT(fixed);
  Item *it= this_item();
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  String *res= it->val_str(sp);
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  null_value= it->null_value;
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  if (!res)
    return NULL;

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  /*
    This way we mark returned value of val_str as const,
    so that various functions (e.g. CONCAT) won't try to
    modify the value of the Item. Analogous mechanism is
    implemented for Item_param.
    Without this trick Item_splocal could be changed as a
    side-effect of expression computation. Here is an example
    of what happens without it: suppose x is varchar local
    variable in a SP with initial value 'ab' Then
      select concat(x,'c');
    would change x's value to 'abc', as Item_func_concat::val_str()
    would use x's internal buffer to compute the result.
    This is intended behaviour of Item_func_concat. Comments to
    Item_param class contain some more details on the topic.
  */
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  if (res != &str_value)
    str_value.set(res->ptr(), res->length(), res->charset());
  else
    res->mark_as_const();
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  return &str_value;
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}


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my_decimal *Item_sp_variable::val_decimal(my_decimal *decimal_value)
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{
  DBUG_ASSERT(fixed);
  Item *it= this_item();
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  my_decimal *val= it->val_decimal(decimal_value);
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  null_value= it->null_value;
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  return val;
}


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bool Item_sp_variable::is_null()
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{
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  return this_item()->is_null();
}


/*****************************************************************************
  Item_splocal methods
*****************************************************************************/

Item_splocal::Item_splocal(const LEX_STRING &sp_var_name,
                           uint sp_var_idx,
                           enum_field_types sp_var_type,
                           uint pos_in_q)
  :Item_sp_variable(sp_var_name.str, sp_var_name.length),
   m_var_idx(sp_var_idx), pos_in_query(pos_in_q)
{
  maybe_null= TRUE;

  m_type= sp_map_item_type(sp_var_type);
  m_result_type= sp_map_result_type(sp_var_type);
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}


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Item *
Item_splocal::this_item()
{
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  DBUG_ASSERT(m_sp == m_thd->spcont->sp);

  return m_thd->spcont->get_item(m_var_idx);
}

const Item *
Item_splocal::this_item() const
{
  DBUG_ASSERT(m_sp == m_thd->spcont->sp);

  return m_thd->spcont->get_item(m_var_idx);
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}

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Item **
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Item_splocal::this_item_addr(THD *thd, Item **)
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{
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  DBUG_ASSERT(m_sp == thd->spcont->sp);

  return thd->spcont->get_item_addr(m_var_idx);
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}

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void Item_splocal::print(String *str)
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{
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  str->reserve(m_name.length+8);
  str->append(m_name.str, m_name.length);
  str->append('@');
  str->qs_append(m_var_idx);
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}

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bool Item_splocal::set_value(THD *thd, sp_rcontext *ctx, Item **it)
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{
  return ctx->set_variable(thd, get_var_idx(), it);
}


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/*****************************************************************************
  Item_case_expr methods
*****************************************************************************/

Item_case_expr::Item_case_expr(int case_expr_id)
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  :Item_sp_variable( C_STRING_WITH_LEN("case_expr")),
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   m_case_expr_id(case_expr_id)
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{
}


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Item *
Item_case_expr::this_item()
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{
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  DBUG_ASSERT(m_sp == m_thd->spcont->sp);

  return m_thd->spcont->get_case_expr(m_case_expr_id);
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}


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const Item *
Item_case_expr::this_item() const
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{
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  DBUG_ASSERT(m_sp == m_thd->spcont->sp);

  return m_thd->spcont->get_case_expr(m_case_expr_id);
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}


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Item **
Item_case_expr::this_item_addr(THD *thd, Item **)
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{
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  DBUG_ASSERT(m_sp == thd->spcont->sp);

  return thd->spcont->get_case_expr_addr(m_case_expr_id);
}


void Item_case_expr::print(String *str)
{
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  VOID(str->append(STRING_WITH_LEN("case_expr@")));
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  str->qs_append(m_case_expr_id);
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}


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/*****************************************************************************
  Item_name_const methods
*****************************************************************************/
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double Item_name_const::val_real()
{
  DBUG_ASSERT(fixed);
  double ret= value_item->val_real();
  null_value= value_item->null_value;
  return ret;
}


longlong Item_name_const::val_int()
{
  DBUG_ASSERT(fixed);
  longlong ret= value_item->val_int();
  null_value= value_item->null_value;
  return ret;
}


String *Item_name_const::val_str(String *sp)
{
  DBUG_ASSERT(fixed);
  String *ret= value_item->val_str(sp);
  null_value= value_item->null_value;
  return ret;
}


my_decimal *Item_name_const::val_decimal(my_decimal *decimal_value)
{
  DBUG_ASSERT(fixed);
  my_decimal *val= value_item->val_decimal(decimal_value);
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  null_value= value_item->null_value;
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  return val;
}


bool Item_name_const::is_null()
{
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  return value_item->is_null();
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}

Item::Type Item_name_const::type() const
{
  return value_item->type();
}


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bool Item_name_const::fix_fields(THD *thd, Item **ref)
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{
  char buf[128];
  String *item_name;
  String s(buf, sizeof(buf), &my_charset_bin);
  s.length(0);

  if (value_item->fix_fields(thd, &value_item) ||
      name_item->fix_fields(thd, &name_item))
    return TRUE;
  if (!(value_item->const_item() && name_item->const_item()))
    return TRUE;

  if (!(item_name= name_item->val_str(&s)))
    return TRUE; /* Can't have a NULL name */

  set_name(item_name->ptr(), (uint) item_name->length(), system_charset_info);
  max_length= value_item->max_length;
  decimals= value_item->decimals;
  fixed= 1;
  return FALSE;
}


void Item_name_const::print(String *str)
{
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  str->append(STRING_WITH_LEN("NAME_CONST("));
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  name_item->print(str);
  str->append(',');
  value_item->print(str);
  str->append(')');
}

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/*
 need a special class to adjust printing : references to aggregate functions 
 must not be printed as refs because the aggregate functions that are added to
 the front of select list are not printed as well.
*/
class Item_aggregate_ref : public Item_ref
{
public:
  Item_aggregate_ref(Name_resolution_context *context_arg, Item **item,
                  const char *table_name_arg, const char *field_name_arg)
    :Item_ref(context_arg, item, table_name_arg, field_name_arg) {}

  void print (String *str)
  {
    if (ref)
      (*ref)->print(str);
    else
      Item_ident::print(str);
  }
};


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/*
  Move SUM items out from item tree and replace with reference

  SYNOPSIS
    split_sum_func2()
    thd			Thread handler
    ref_pointer_array	Pointer to array of reference fields
    fields		All fields in select
    ref			Pointer to item
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    skip_registered     <=> function be must skipped for registered SUM items
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  NOTES
   This is from split_sum_func2() for items that should be split

   All found SUM items are added FIRST in the fields list and
   we replace the item with a reference.

   thd->fatal_error() may be called if we are out of memory
*/


void Item::split_sum_func2(THD *thd, Item **ref_pointer_array,
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                           List<Item> &fields, Item **ref, 
                           bool skip_registered)
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{
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  /* An item of type Item_sum  is registered <=> ref_by != 0 */ 
  if (type() == SUM_FUNC_ITEM && skip_registered && 
      ((Item_sum *) this)->ref_by)
    return;                                                 
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  if ((type() != SUM_FUNC_ITEM && with_sum_func) ||
      (type() == FUNC_ITEM &&
       (((Item_func *) this)->functype() == Item_func::ISNOTNULLTEST_FUNC ||
        ((Item_func *) this)->functype() == Item_func::TRIG_COND_FUNC)))
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  {
    /* Will split complicated items and ignore simple ones */
    split_sum_func(thd, ref_pointer_array, fields);
  }
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  else if ((type() == SUM_FUNC_ITEM || (used_tables() & ~PARAM_TABLE_BIT)) &&
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           type() != SUBSELECT_ITEM &&
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           (type() != REF_ITEM ||
           ((Item_ref*)this)->ref_type() == Item_ref::VIEW_REF))
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  {
    /*
      Replace item with a reference so that we can easily calculate
      it (in case of sum functions) or copy it (in case of fields)

      The test above is to ensure we don't do a reference for things
      that are constants (PARAM_TABLE_BIT is in effect a constant)
      or already referenced (for example an item in HAVING)
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      Exception is Item_direct_view_ref which we need to convert to
      Item_ref to allow fields from view being stored in tmp table.
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    */
    uint el= fields.elements;
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    Item *new_item, *real_itm= real_item();
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    ref_pointer_array[el]= real_itm;
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    if (!(new_item= new Item_aggregate_ref(&thd->lex->current_select->context,
                                           ref_pointer_array + el, 0, name)))
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      return;                                   // fatal_error is set
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    fields.push_front(real_itm);
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    thd->change_item_tree(ref, new_item);
  }
}


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/*
   Aggregate two collations together taking
   into account their coercibility (aka derivation):

1309
   0 == DERIVATION_EXPLICIT  - an explicitly written COLLATE clause
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   1 == DERIVATION_NONE      - a mix of two different collations
   2 == DERIVATION_IMPLICIT  - a column
   3 == DERIVATION_COERCIBLE - a string constant

   The most important rules are:

   1. If collations are the same:
      chose this collation, and the strongest derivation.

   2. If collations are different:
     - Character sets may differ, but only if conversion without
       data loss is possible. The caller provides flags whether
       character set conversion attempts should be done. If no
       flags are substituted, then the character sets must be the same.
       Currently processed flags are:
         MY_COLL_ALLOW_SUPERSET_CONV  - allow conversion to a superset
         MY_COLL_ALLOW_COERCIBLE_CONV - allow conversion of a coercible value
     - two EXPLICIT collations produce an error, e.g. this is wrong:
       CONCAT(expr1 collate latin1_swedish_ci, expr2 collate latin1_german_ci)
     - the side with smaller derivation value wins,
       i.e. a column is stronger than a string constant,
       an explicit COLLATE clause is stronger than a column.
     - if derivations are the same, we have DERIVATION_NONE,
       we'll wait for an explicit COLLATE clause which possibly can
       come from another argument later: for example, this is valid,
       but we don't know yet when collecting the first two arguments:
         CONCAT(latin1_swedish_ci_column,
                latin1_german1_ci_column,
                expr COLLATE latin1_german2_ci)
*/
bool DTCollation::aggregate(DTCollation &dt, uint flags)
1341
{
1342
  if (!my_charset_same(collation, dt.collation))
1343
  {
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    /* 
       We do allow to use binary strings (like BLOBS)
       together with character strings.
1347
       Binaries have more precedence than a character
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       string of the same derivation.
1349
    */
1350
    if (collation == &my_charset_bin)
1351
    {
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      if (derivation <= dt.derivation)
	; // Do nothing
      else
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      {
	set(dt); 
      }
1358
    }
1359
    else if (dt.collation == &my_charset_bin)
1360
    {
1361
      if (dt.derivation <= derivation)
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      {
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        set(dt);
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      }
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      else
       ; // Do nothing
1367
    }
1368
    else if ((flags & MY_COLL_ALLOW_SUPERSET_CONV) &&
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             collation->state & MY_CS_UNICODE &&
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             (derivation < dt.derivation ||
             (derivation == dt.derivation &&
             !(dt.collation->state & MY_CS_UNICODE))))
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    {
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      // Do nothing
    }
    else if ((flags & MY_COLL_ALLOW_SUPERSET_CONV) &&
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             dt.collation->state & MY_CS_UNICODE &&
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             (dt.derivation < derivation ||
              (dt.derivation == derivation &&
             !(collation->state & MY_CS_UNICODE))))
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    {
      set(dt);
    }
    else if ((flags & MY_COLL_ALLOW_COERCIBLE_CONV) &&
             derivation < dt.derivation &&
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             dt.derivation >= DERIVATION_SYSCONST)
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    {
      // Do nothing;
    }
    else if ((flags & MY_COLL_ALLOW_COERCIBLE_CONV) &&
             dt.derivation < derivation &&
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             derivation >= DERIVATION_SYSCONST)
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    {
      set(dt);
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    }
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    else
    {
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      // Cannot apply conversion
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      set(0, DERIVATION_NONE);
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      return 1;
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    }
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  }
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  else if (derivation < dt.derivation)
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  {
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    // Do nothing
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  }
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  else if (dt.derivation < derivation)
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  {
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    set(dt);
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  }
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  else
  { 
    if (collation == dt.collation)
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    {
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      // Do nothing
    }
    else 
    {
      if (derivation == DERIVATION_EXPLICIT)
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      {
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	set(0, DERIVATION_NONE);
	return 1;
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      }
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      if (collation->state & MY_CS_BINSORT)
        return 0;
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      if (dt.collation->state & MY_CS_BINSORT)
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      {
        set(dt);
        return 0;
      }
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      CHARSET_INFO *bin= get_charset_by_csname(collation->csname, 
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                                               MY_CS_BINSORT,MYF(0));
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      set(bin, DERIVATION_NONE);
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    }
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  }
  return 0;
}

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/******************************/
static
void my_coll_agg_error(DTCollation &c1, DTCollation &c2, const char *fname)
{
  my_error(ER_CANT_AGGREGATE_2COLLATIONS,MYF(0),
           c1.collation->name,c1.derivation_name(),
           c2.collation->name,c2.derivation_name(),
           fname);
}


static
void my_coll_agg_error(DTCollation &c1, DTCollation &c2, DTCollation &c3,
                       const char *fname)
{
  my_error(ER_CANT_AGGREGATE_3COLLATIONS,MYF(0),
  	   c1.collation->name,c1.derivation_name(),
	   c2.collation->name,c2.derivation_name(),
	   c3.collation->name,c3.derivation_name(),
	   fname);
}


static
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void my_coll_agg_error(Item** args, uint count, const char *fname,
                       int item_sep)
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{
  if (count == 2)
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    my_coll_agg_error(args[0]->collation, args[item_sep]->collation, fname);
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  else if (count == 3)
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    my_coll_agg_error(args[0]->collation, args[item_sep]->collation,
                      args[2*item_sep]->collation, fname);
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  else
    my_error(ER_CANT_AGGREGATE_NCOLLATIONS,MYF(0),fname);
}


bool agg_item_collations(DTCollation &c, const char *fname,
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                         Item **av, uint count, uint flags, int item_sep)
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{
  uint i;
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  Item **arg;
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  c.set(av[0]->collation);
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  for (i= 1, arg= &av[item_sep]; i < count; i++, arg++)
1483
  {
1484
    if (c.aggregate((*arg)->collation, flags))
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    {
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      my_coll_agg_error(av, count, fname, item_sep);
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      return TRUE;
    }
  }
  if ((flags & MY_COLL_DISALLOW_NONE) &&
      c.derivation == DERIVATION_NONE)
  {
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    my_coll_agg_error(av, count, fname, item_sep);
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    return TRUE;
  }
  return FALSE;
}


bool agg_item_collations_for_comparison(DTCollation &c, const char *fname,
                                        Item **av, uint count, uint flags)
{
  return (agg_item_collations(c, fname, av, count,
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                              flags | MY_COLL_DISALLOW_NONE, 1));
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}


/* 
  Collect arguments' character sets together.
  We allow to apply automatic character set conversion in some cases.
  The conditions when conversion is possible are:
  - arguments A and B have different charsets
  - A wins according to coercibility rules
    (i.e. a column is stronger than a string constant,
     an explicit COLLATE clause is stronger than a column)
  - character set of A is either superset for character set of B,
    or B is a string constant which can be converted into the
    character set of A without data loss.
    
  If all of the above is true, then it's possible to convert
  B into the character set of A, and then compare according
  to the collation of A.
  
  For functions with more than two arguments:

    collect(A,B,C) ::= collect(collect(A,B),C)
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  Since this function calls THD::change_item_tree() on the passed Item **
  pointers, it is necessary to pass the original Item **'s, not copies.
  Otherwise their values will not be properly restored (see BUG#20769).
  If the items are not consecutive (eg. args[2] and args[5]), use the
  item_sep argument, ie.

    agg_item_charsets(coll, fname, &args[2], 2, flags, 3)

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*/

bool agg_item_charsets(DTCollation &coll, const char *fname,
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                       Item **args, uint nargs, uint flags, int item_sep)
1540
{
1541
  Item **arg, *safe_args[2];
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  LINT_INIT(safe_args[0]);
  LINT_INIT(safe_args[1]);
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  if (agg_item_collations(coll, fname, args, nargs, flags, item_sep))
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    return TRUE;

  /*
    For better error reporting: save the first and the second argument.
    We need this only if the the number of args is 3 or 2:
    - for a longer argument list, "Illegal mix of collations"
      doesn't display each argument's characteristics.
    - if nargs is 1, then this error cannot happen.
  */
  if (nargs >=2 && nargs <= 3)
  {
    safe_args[0]= args[0];
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    safe_args[1]= args[item_sep];
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  }

  THD *thd= current_thd;
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  Query_arena *arena, backup;
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  bool res= FALSE;
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  uint i;
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  /*
    In case we're in statement prepare, create conversion item
    in its memory: it will be reused on each execute.
  */
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  arena= thd->is_stmt_prepare() ? thd->activate_stmt_arena_if_needed(&backup)
                                : NULL;
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  for (i= 0, arg= args; i < nargs; i++, arg+= item_sep)
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  {
    Item* conv;
    uint32 dummy_offset;
    if (!String::needs_conversion(0, coll.collation,
                                  (*arg)->collation.collation,
                                  &dummy_offset))
      continue;

    if (!(conv= (*arg)->safe_charset_converter(coll.collation)))
    {
      if (nargs >=2 && nargs <= 3)
      {
        /* restore the original arguments for better error message */
        args[0]= safe_args[0];
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        args[item_sep]= safe_args[1];
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      }
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      my_coll_agg_error(args, nargs, fname, item_sep);
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      res= TRUE;
      break; // we cannot return here, we need to restore "arena".
    }
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    if ((*arg)->type() == Item::FIELD_ITEM)
      ((Item_field *)(*arg))->no_const_subst= 1;
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    /*
      If in statement prepare, then we create a converter for two
      constant items, do it once and then reuse it.
      If we're in execution of a prepared statement, arena is NULL,
      and the conv was created in runtime memory. This can be
      the case only if the argument is a parameter marker ('?'),
      because for all true constants the charset converter has already
      been created in prepare. In this case register the change for
      rollback.
    */
1606
    if (thd->is_stmt_prepare())
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      *arg= conv;
    else
      thd->change_item_tree(arg, conv);
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    /*
      We do not check conv->fixed, because Item_func_conv_charset which can
      be return by safe_charset_converter can't be fixed at creation
    */
    conv->fix_fields(thd, arg);
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  }
  if (arena)
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    thd->restore_active_arena(arena, &backup);
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  return res;
}


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void Item_ident_for_show::make_field(Send_field *tmp_field)
{
  tmp_field->table_name= tmp_field->org_table_name= table_name;
  tmp_field->db_name= db_name;
  tmp_field->col_name= tmp_field->org_col_name= field->field_name;
  tmp_field->charsetnr= field->charset()->number;
  tmp_field->length=field->field_length;
  tmp_field->type=field->type();
  tmp_field->flags= field->table->maybe_null ? 
    (field->flags & ~NOT_NULL_FLAG) : field->flags;
  tmp_field->decimals= 0;
}
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/**********************************************/

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Item_field::Item_field(Field *f)
1638
  :Item_ident(0, NullS, *f->table_name, f->field_name),
1639
   item_equal(0), no_const_subst(0),
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   have_privileges(0), any_privileges(0)
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{
  set_field(f);
1643
  /*
1644
    field_name and table_name should not point to garbage
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    if this item is to be reused
  */
  orig_table_name= orig_field_name= "";
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}

1650

1651 1652
Item_field::Item_field(THD *thd, Name_resolution_context *context_arg,
                       Field *f)
1653
  :Item_ident(context_arg, f->table->s->db.str, *f->table_name, f->field_name),
1654
   item_equal(0), no_const_subst(0),
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   have_privileges(0), any_privileges(0)
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{
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  /*
    We always need to provide Item_field with a fully qualified field
    name to avoid ambiguity when executing prepared statements like
    SELECT * from d1.t1, d2.t1; (assuming d1.t1 and d2.t1 have columns
    with same names).
    This is because prepared statements never deal with wildcards in
    select list ('*') and always fix fields using fully specified path
    (i.e. db.table.column).
    No check for OOM: if db_name is NULL, we'll just get
    "Field not found" error.
    We need to copy db_name, table_name and field_name because they must
    be allocated in the statement memory, not in table memory (the table
    structure can go away and pop up again between subsequent executions
    of a prepared statement).
  */
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  if (thd->stmt_arena->is_stmt_prepare_or_first_sp_execute())
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  {
    if (db_name)
      orig_db_name= thd->strdup(db_name);
    orig_table_name= thd->strdup(table_name);
    orig_field_name= thd->strdup(field_name);
    /*
      We don't restore 'name' in cleanup because it's not changed
      during execution. Still we need it to point to persistent
      memory if this item is to be reused.
    */
    name= (char*) orig_field_name;
  }
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  set_field(f);
}

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Item_field::Item_field(Name_resolution_context *context_arg,
                       const char *db_arg,const char *table_name_arg,
                       const char *field_name_arg)
  :Item_ident(context_arg, db_arg,table_name_arg,field_name_arg),
   field(0), result_field(0), item_equal(0), no_const_subst(0),
   have_privileges(0), any_privileges(0)
{
  collation.set(DERIVATION_IMPLICIT);
}

1699
// Constructor need to process subselect with temporary tables (see Item)
1700
Item_field::Item_field(THD *thd, Item_field *item)
1701
  :Item_ident(thd, item),
1702
   field(item->field),
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   result_field(item->result_field),
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   item_equal(item->item_equal),
   no_const_subst(item->no_const_subst),
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   have_privileges(item->have_privileges),
   any_privileges(item->any_privileges)
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{
  collation.set(DERIVATION_IMPLICIT);
}
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void Item_field::set_field(Field *field_par)
{
  field=result_field=field_par;			// for easy coding with fields
  maybe_null=field->maybe_null();
  decimals= field->decimals();
1717
  max_length= field_par->max_display_length();
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  table_name= *field_par->table_name;
  field_name= field_par->field_name;
1720
  db_name= field_par->table->s->db.str;
1721
  alias_name_used= field_par->table->alias_name_used;
1722
  unsigned_flag=test(field_par->flags & UNSIGNED_FLAG);
1723
  collation.set(field_par->charset(), field_par->derivation());
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  fixed= 1;
}


/*
  Reset this item to point to a field from the new temporary table.
  This is used when we create a new temporary table for each execution
  of prepared statement.
*/

void Item_field::reset_field(Field *f)
{
  set_field(f);
  /* 'name' is pointing at field->field_name of old field */
  name= (char*) f->field_name;
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}

const char *Item_ident::full_name() const
{
  char *tmp;
1744
  if (!table_name || !field_name)
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    return field_name ? field_name : name ? name : "tmp_field";
1746
  if (db_name && db_name[0])
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  {
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    tmp=(char*) sql_alloc((uint) strlen(db_name)+(uint) strlen(table_name)+
			  (uint) strlen(field_name)+3);
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    strxmov(tmp,db_name,".",table_name,".",field_name,NullS);
  }
  else
  {
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    if (table_name[0])
    {
      tmp= (char*) sql_alloc((uint) strlen(table_name) +
			     (uint) strlen(field_name) + 2);
      strxmov(tmp, table_name, ".", field_name, NullS);
    }
    else
      tmp= (char*) field_name;
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  }
  return tmp;
}

1766 1767
void Item_ident::print(String *str)
{
1768
  THD *thd= current_thd;
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  char d_name_buff[MAX_ALIAS_NAME], t_name_buff[MAX_ALIAS_NAME];
  const char *d_name= db_name, *t_name= table_name;
1771 1772
  if (lower_case_table_names== 1 ||
      (lower_case_table_names == 2 && !alias_name_used))
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  {
    if (table_name && table_name[0])
    {
      strmov(t_name_buff, table_name);
      my_casedn_str(files_charset_info, t_name_buff);
      t_name= t_name_buff;
    }
    if (db_name && db_name[0])
    {
      strmov(d_name_buff, db_name);
      my_casedn_str(files_charset_info, d_name_buff);
      d_name= d_name_buff;
    }
  }

1788 1789
  if (!table_name || !field_name)
  {
1790
    const char *nm= field_name ? field_name : name ? name : "tmp_field";
1791
    append_identifier(thd, str, nm, (uint) strlen(nm));
1792 1793
    return;
  }
1794
  if (db_name && db_name[0] && !alias_name_used)
1795
  {
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    if (!(cached_table && cached_table->belong_to_view &&
          cached_table->belong_to_view->compact_view_format))
    {
1799
      append_identifier(thd, str, d_name, (uint)strlen(d_name));
1800 1801
      str->append('.');
    }
1802
    append_identifier(thd, str, t_name, (uint)strlen(t_name));
1803
    str->append('.');
1804
    append_identifier(thd, str, field_name, (uint)strlen(field_name));
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  }
  else
  {
    if (table_name[0])
    {
1810
      append_identifier(thd, str, t_name, (uint) strlen(t_name));
1811
      str->append('.');
1812
      append_identifier(thd, str, field_name, (uint) strlen(field_name));
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    }
    else
1815
      append_identifier(thd, str, field_name, (uint) strlen(field_name));
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  }
}

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/* ARGSUSED */
String *Item_field::val_str(String *str)
{
1822
  DBUG_ASSERT(fixed == 1);
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  if ((null_value=field->is_null()))
    return 0;
1825
  str->set_charset(str_value.charset());
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  return field->val_str(str,&str_value);
}

1829

1830
double Item_field::val_real()
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{
1832
  DBUG_ASSERT(fixed == 1);
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  if ((null_value=field->is_null()))
    return 0.0;
  return field->val_real();
}

1838

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longlong Item_field::val_int()
{
1841
  DBUG_ASSERT(fixed == 1);
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  if ((null_value=field->is_null()))
    return 0;
  return field->val_int();
}


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my_decimal *Item_field::val_decimal(my_decimal *decimal_value)
{
  if ((null_value= field->is_null()))
    return 0;
  return field->val_decimal(decimal_value);
}


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String *Item_field::str_result(String *str)
{
  if ((null_value=result_field->is_null()))
    return 0;
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  str->set_charset(str_value.charset());
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  return result_field->val_str(str,&str_value);
}

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bool Item_field::get_date(TIME *ltime,uint fuzzydate)
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{
  if ((null_value=field->is_null()) || field->get_date(ltime,fuzzydate))
  {
    bzero((char*) ltime,sizeof(*ltime));
    return 1;
  }
  return 0;
}

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bool Item_field::get_date_result(TIME *ltime,uint fuzzydate)
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{
  if ((null_value=result_field->is_null()) ||
      result_field->get_date(ltime,fuzzydate))
  {
    bzero((char*) ltime,sizeof(*ltime));
    return 1;
  }
  return 0;
}

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bool Item_field::get_time(TIME *ltime)
{
  if ((null_value=field->is_null()) || field->get_time(ltime))
  {
    bzero((char*) ltime,sizeof(*ltime));
    return 1;
  }
  return 0;
}

double Item_field::val_result()
{
  if ((null_value=result_field->is_null()))
    return 0.0;
  return result_field->val_real();
}

longlong Item_field::val_int_result()
{
  if ((null_value=result_field->is_null()))
    return 0;
  return result_field->val_int();
}

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my_decimal *Item_field::val_decimal_result(my_decimal *decimal_value)
{
  if ((null_value= result_field->is_null()))
    return 0;
  return result_field->val_decimal(decimal_value);
}


bool Item_field::val_bool_result()
{
  if ((null_value= result_field->is_null()))
    return FALSE;
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  switch (result_field->result_type()) {
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  case INT_RESULT:
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    return result_field->val_int() != 0;
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  case DECIMAL_RESULT:
  {
    my_decimal decimal_value;
    my_decimal *val= result_field->val_decimal(&decimal_value);
    if (val)
      return !my_decimal_is_zero(val);
    return 0;
  }
  case REAL_RESULT:
  case STRING_RESULT:
    return result_field->val_real() != 0.0;
  case ROW_RESULT:
  default:
    DBUG_ASSERT(0);
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    return 0;                                   // Shut up compiler
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  }
}


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bool Item_field::eq(const Item *item, bool binary_cmp) const
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{
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  if (item->type() != FIELD_ITEM)
    return 0;
  
  Item_field *item_field= (Item_field*) item;
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  if (item_field->field && field)
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    return item_field->field == field;
  /*
    We may come here when we are trying to find a function in a GROUP BY
    clause from the select list.
    In this case the '100 % correct' way to do this would be to first
    run fix_fields() on the GROUP BY item and then retry this function, but
    I think it's better to relax the checking a bit as we will in
    most cases do the correct thing by just checking the field name.
    (In cases where we would choose wrong we would have to generate a
    ER_NON_UNIQ_ERROR).
  */
  return (!my_strcasecmp(system_charset_info, item_field->name,
			 field_name) &&
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	  (!item_field->table_name || !table_name ||
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	   (!my_strcasecmp(table_alias_charset, item_field->table_name,
			   table_name) &&
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	    (!item_field->db_name || !db_name ||
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	     (item_field->db_name && !strcmp(item_field->db_name,
					     db_name))))));
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}

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table_map Item_field::used_tables() const
{
  if (field->table->const_table)
    return 0;					// const item
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  return (depended_from ? OUTER_REF_TABLE_BIT : field->table->map);
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}

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Item *Item_field::get_tmp_table_item(THD *thd)
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{
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  Item_field *new_item= new Item_field(thd, this);
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  if (new_item)
    new_item->field= new_item->result_field;
  return new_item;
}
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/*
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  Create an item from a string we KNOW points to a valid longlong
  end \0 terminated number string.
  This is always 'signed'. Unsigned values are created with Item_uint()
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*/

Item_int::Item_int(const char *str_arg, uint length)
{
  char *end_ptr= (char*) str_arg + length;
  int error;
  value= my_strtoll10(str_arg, &end_ptr, &error);
  max_length= (uint) (end_ptr - str_arg);
  name= (char*) str_arg;
  fixed= 1;
}


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my_decimal *Item_int::val_decimal(my_decimal *decimal_value)
{
  int2my_decimal(E_DEC_FATAL_ERROR, value, unsigned_flag, decimal_value);
  return decimal_value;
}

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String *Item_int::val_str(String *str)
{
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  // following assert is redundant, because fixed=1 assigned in constructor
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  DBUG_ASSERT(fixed == 1);
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  str->set(value, &my_charset_bin);
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  return str;
}

void Item_int::print(String *str)
{
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  // my_charset_bin is good enough for numbers
  str_value.set(value, &my_charset_bin);
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  str->append(str_value);
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}

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Item_uint::Item_uint(const char *str_arg, uint length):
  Item_int(str_arg, length)
{
  unsigned_flag= 1;
}


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Item_uint::Item_uint(const char *str_arg, longlong i, uint length):
  Item_int(str_arg, i, length)
{
  unsigned_flag= 1;
}


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String *Item_uint::val_str(String *str)
{
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  // following assert is redundant, because fixed=1 assigned in constructor
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  DBUG_ASSERT(fixed == 1);
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  str->set((ulonglong) value, &my_charset_bin);
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  return str;
}

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void Item_uint::print(String *str)
{
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  // latin1 is good enough for numbers
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  str_value.set((ulonglong) value, default_charset());
  str->append(str_value);
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}

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Item_decimal::Item_decimal(const char *str_arg, uint length,
                           CHARSET_INFO *charset)
{
  str2my_decimal(E_DEC_FATAL_ERROR, str_arg, length, charset, &decimal_value);
  name= (char*) str_arg;
  decimals= (uint8) decimal_value.frac;
  fixed= 1;
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  max_length= my_decimal_precision_to_length(decimal_value.intg + decimals,
                                             decimals, unsigned_flag);
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}

Item_decimal::Item_decimal(longlong val, bool unsig)
{
  int2my_decimal(E_DEC_FATAL_ERROR, val, unsig, &decimal_value);
  decimals= (uint8) decimal_value.frac;
  fixed= 1;
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  max_length= my_decimal_precision_to_length(decimal_value.intg + decimals,
                                             decimals, unsigned_flag);
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}


Item_decimal::Item_decimal(double val, int precision, int scale)
{
  double2my_decimal(E_DEC_FATAL_ERROR, val, &decimal_value);
  decimals= (uint8) decimal_value.frac;
  fixed= 1;
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  max_length= my_decimal_precision_to_length(decimal_value.intg + decimals,
                                             decimals, unsigned_flag);
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}


Item_decimal::Item_decimal(const char *str, const my_decimal *val_arg,
                           uint decimal_par, uint length)
{
  my_decimal2decimal(val_arg, &decimal_value);
  name= (char*) str;
  decimals= (uint8) decimal_par;
  max_length= length;
  fixed= 1;
}


Item_decimal::Item_decimal(my_decimal *value_par)
{
  my_decimal2decimal(value_par, &decimal_value);
  decimals= (uint8) decimal_value.frac;
  fixed= 1;
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  max_length= my_decimal_precision_to_length(decimal_value.intg + decimals,
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                                             decimals, unsigned_flag);
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}


Item_decimal::Item_decimal(const char *bin, int precision, int scale)
{
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  binary2my_decimal(E_DEC_FATAL_ERROR, bin,
                    &decimal_value, precision, scale);
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  decimals= (uint8) decimal_value.frac;
  fixed= 1;
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  max_length= my_decimal_precision_to_length(precision, decimals,
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                                             unsigned_flag);
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}


longlong Item_decimal::val_int()
{
  longlong result;
  my_decimal2int(E_DEC_FATAL_ERROR, &decimal_value, unsigned_flag, &result);
  return result;
}

double Item_decimal::val_real()
{
  double result;
  my_decimal2double(E_DEC_FATAL_ERROR, &decimal_value, &result);
  return result;
}

String *Item_decimal::val_str(String *result)
{
  result->set_charset(&my_charset_bin);
  my_decimal2string(E_DEC_FATAL_ERROR, &decimal_value, 0, 0, 0, result);
  return result;
}

void Item_decimal::print(String *str)
{
  my_decimal2string(E_DEC_FATAL_ERROR, &decimal_value, 0, 0, 0, &str_value);
  str->append(str_value);
}


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bool Item_decimal::eq(const Item *item, bool binary_cmp) const
{
  if (type() == item->type() && item->basic_const_item())
  {
    /*
      We need to cast off const to call val_decimal(). This should
      be OK for a basic constant. Additionally, we can pass 0 as
      a true decimal constant will return its internal decimal
      storage and ignore the argument.
    */
    Item *arg= (Item*) item;
    my_decimal *value= arg->val_decimal(0);
    return !my_decimal_cmp(&decimal_value, value);
  }
  return 0;
}


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void Item_decimal::set_decimal_value(my_decimal *value_par)
{
  my_decimal2decimal(value_par, &decimal_value);
  decimals= (uint8) decimal_value.frac;
  unsigned_flag= !decimal_value.sign();
  max_length= my_decimal_precision_to_length(decimal_value.intg + decimals,
                                             decimals, unsigned_flag);
}


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String *Item_float::val_str(String *str)
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{
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  // following assert is redundant, because fixed=1 assigned in constructor
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  DBUG_ASSERT(fixed == 1);
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  str->set_real(value,decimals,&my_charset_bin);
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  return str;
}

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my_decimal *Item_float::val_decimal(my_decimal *decimal_value)
{
  // following assert is redundant, because fixed=1 assigned in constructor
  DBUG_ASSERT(fixed == 1);
  double2my_decimal(E_DEC_FATAL_ERROR, value, decimal_value);
  return (decimal_value);
}


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void Item_string::print(String *str)
{
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  str->append('_');
  str->append(collation.collation->csname);
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  str->append('\'');
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  str_value.print(str);
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  str->append('\'');
}

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double Item_string::val_real()
{
  DBUG_ASSERT(fixed == 1);
  int error;
  char *end, *org_end;
  double tmp;
  CHARSET_INFO *cs= str_value.charset();

  org_end= (char*) str_value.ptr() + str_value.length();
  tmp= my_strntod(cs, (char*) str_value.ptr(), str_value.length(), &end,
                  &error);
  if (error || (end != org_end && !check_if_only_end_space(cs, end, org_end)))
  {
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    /*
      We can use str_value.ptr() here as Item_string is gurantee to put an
      end \0 here.
    */
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    push_warning_printf(current_thd, MYSQL_ERROR::WARN_LEVEL_WARN,
                        ER_TRUNCATED_WRONG_VALUE,
                        ER(ER_TRUNCATED_WRONG_VALUE), "DOUBLE",
                        str_value.ptr());
  }
  return tmp;
}


longlong Item_string::val_int()
{
  DBUG_ASSERT(fixed == 1);
  int err;
  longlong tmp;
  char *end= (char*) str_value.ptr()+ str_value.length();
  char *org_end= end;
  CHARSET_INFO *cs= str_value.charset();

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  tmp= (*(cs->cset->strtoll10))(cs, str_value.ptr(), &end, &err);
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  /*
    TODO: Give error if we wanted a signed integer and we got an unsigned
    one
  */
  if (err > 0 ||
      (end != org_end && !check_if_only_end_space(cs, end, org_end)))
  {
    push_warning_printf(current_thd, MYSQL_ERROR::WARN_LEVEL_WARN,
                        ER_TRUNCATED_WRONG_VALUE,
                        ER(ER_TRUNCATED_WRONG_VALUE), "INTEGER",
                        str_value.ptr());
  }
  return tmp;
}


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my_decimal *Item_string::val_decimal(my_decimal *decimal_value)
{
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  return val_decimal_from_string(decimal_value);
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}


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bool Item_null::eq(const Item *item, bool binary_cmp) const
{ return item->type() == type(); }
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double Item_null::val_real()
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{
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  // following assert is redundant, because fixed=1 assigned in constructor
  DBUG_ASSERT(fixed == 1);
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  null_value=1;
  return 0.0;
}
longlong Item_null::val_int()
{
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  // following assert is redundant, because fixed=1 assigned in constructor
  DBUG_ASSERT(fixed == 1);
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  null_value=1;
  return 0;
}
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/* ARGSUSED */
String *Item_null::val_str(String *str)
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{
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  // following assert is redundant, because fixed=1 assigned in constructor
  DBUG_ASSERT(fixed == 1);
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  null_value=1;
  return 0;
}
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my_decimal *Item_null::val_decimal(my_decimal *decimal_value)
{
  return 0;
}

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Item *Item_null::safe_charset_converter(CHARSET_INFO *tocs)
{
  collation.set(tocs);
  return this;
}

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/*********************** Item_param related ******************************/

/* 
  Default function of Item_param::set_param_func, so in case
  of malformed packet the server won't SIGSEGV
*/

static void
default_set_param_func(Item_param *param,
                       uchar **pos __attribute__((unused)),
                       ulong len __attribute__((unused)))
{
  param->set_null();
}

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Item_param::Item_param(unsigned pos_in_query_arg) :
  state(NO_VALUE),
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  item_result_type(STRING_RESULT),
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  /* Don't pretend to be a literal unless value for this item is set. */
  item_type(PARAM_ITEM),
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  param_type(MYSQL_TYPE_VARCHAR),
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  pos_in_query(pos_in_query_arg),
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  set_param_func(default_set_param_func)
{
  name= (char*) "?";
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  /* 
    Since we can't say whenever this item can be NULL or cannot be NULL
    before mysql_stmt_execute(), so we assuming that it can be NULL until
    value is set.
  */
  maybe_null= 1;
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  cnvitem= new Item_string("", 0, &my_charset_bin, DERIVATION_COERCIBLE);
  cnvstr.set(cnvbuf, sizeof(cnvbuf), &my_charset_bin);
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}
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void Item_param::set_null()
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{
  DBUG_ENTER("Item_param::set_null");
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  /* These are cleared after each execution by reset() method */
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  null_value= 1;
  /* 
    Because of NULL and string values we need to set max_length for each new
    placeholder value: user can submit NULL for any placeholder type, and 
    string length can be different in each execution.
  */
  max_length= 0;
  decimals= 0;
  state= NULL_VALUE;
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  item_type= Item::NULL_ITEM;
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  DBUG_VOID_RETURN;
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}

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void Item_param::set_int(longlong i, uint32 max_length_arg)
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{
  DBUG_ENTER("Item_param::set_int");
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  value.integer= (longlong) i;
  state= INT_VALUE;
  max_length= max_length_arg;
  decimals= 0;
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  maybe_null= 0;
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  DBUG_VOID_RETURN;
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}

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void Item_param::set_double(double d)
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{
  DBUG_ENTER("Item_param::set_double");
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  value.real= d;
  state= REAL_VALUE;
  max_length= DBL_DIG + 8;
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  decimals= NOT_FIXED_DEC;
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  maybe_null= 0;
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  DBUG_VOID_RETURN;
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}


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/*
  Set decimal parameter value from string.

  SYNOPSIS
    set_decimal()
      str    - character string
      length - string length

  NOTE
    as we use character strings to send decimal values in
    binary protocol, we use str2my_decimal to convert it to
    internal decimal value.
*/
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void Item_param::set_decimal(const char *str, ulong length)
{
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  char *end;
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  DBUG_ENTER("Item_param::set_decimal");

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  end= (char*) str+length;
  str2my_decimal(E_DEC_FATAL_ERROR, str, &decimal_value, &end);
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  state= DECIMAL_VALUE;
  decimals= decimal_value.frac;
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  max_length= my_decimal_precision_to_length(decimal_value.precision(),
                                             decimals, unsigned_flag);
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  maybe_null= 0;
  DBUG_VOID_RETURN;
}


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/*
  Set parameter value from TIME value.

  SYNOPSIS
    set_time()
      tm             - datetime value to set (time_type is ignored)
      type           - type of datetime value
      max_length_arg - max length of datetime value as string

  NOTE
    If we value to be stored is not normalized, zero value will be stored
    instead and proper warning will be produced. This function relies on
    the fact that even wrong value sent over binary protocol fits into
    MAX_DATE_STRING_REP_LENGTH buffer.
*/
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void Item_param::set_time(TIME *tm, timestamp_type time_type,
                          uint32 max_length_arg)
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{ 
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  DBUG_ENTER("Item_param::set_time");
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  value.time= *tm;
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  value.time.time_type= time_type;
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  if (value.time.year > 9999 || value.time.month > 12 ||
      value.time.day > 31 ||
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      time_type != MYSQL_TIMESTAMP_TIME && value.time.hour > 23 ||
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      value.time.minute > 59 || value.time.second > 59)
  {
    char buff[MAX_DATE_STRING_REP_LENGTH];
    uint length= my_TIME_to_str(&value.time, buff);
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    make_truncated_value_warning(current_thd, buff, length, time_type, 0);
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    set_zero_time(&value.time, MYSQL_TIMESTAMP_ERROR);
  }

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  state= TIME_VALUE;
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  maybe_null= 0;
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  max_length= max_length_arg;
  decimals= 0;
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  DBUG_VOID_RETURN;
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}

2452

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bool Item_param::set_str(const char *str, ulong length)
{
  DBUG_ENTER("Item_param::set_str");
  /*
    Assign string with no conversion: data is converted only after it's
    been written to the binary log.
  */
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  uint dummy_errors;
  if (str_value.copy(str, length, &my_charset_bin, &my_charset_bin,
                     &dummy_errors))
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    DBUG_RETURN(TRUE);
  state= STRING_VALUE;
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  max_length= length;
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  maybe_null= 0;
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  /* max_length and decimals are set after charset conversion */
  /* sic: str may be not null-terminated, don't add DBUG_PRINT here */
  DBUG_RETURN(FALSE);
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}


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bool Item_param::set_longdata(const char *str, ulong length)
{
  DBUG_ENTER("Item_param::set_longdata");

  /*
    If client character set is multibyte, end of long data packet
    may hit at the middle of a multibyte character.  Additionally,
    if binary log is open we must write long data value to the
    binary log in character set of client. This is why we can't
    convert long data to connection character set as it comes
    (here), and first have to concatenate all pieces together,
    write query to the binary log and only then perform conversion.
  */
  if (str_value.append(str, length, &my_charset_bin))
    DBUG_RETURN(TRUE);
  state= LONG_DATA_VALUE;
2489
  maybe_null= 0;
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  DBUG_RETURN(FALSE);
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}


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/*
  Set parameter value from user variable value.

  SYNOPSIS
   set_from_user_var
     thd   Current thread
     entry User variable structure (NULL means use NULL value)

  RETURN
    0 OK
2505
    1 Out of memory
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*/

bool Item_param::set_from_user_var(THD *thd, const user_var_entry *entry)
{
  DBUG_ENTER("Item_param::set_from_user_var");
  if (entry && entry->value)
  {
    item_result_type= entry->type;
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    switch (entry->type) {
    case REAL_RESULT:
      set_double(*(double*)entry->value);
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      item_type= Item::REAL_ITEM;
      item_result_type= REAL_RESULT;
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      break;
    case INT_RESULT:
      set_int(*(longlong*)entry->value, 21);
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      item_type= Item::INT_ITEM;
      item_result_type= INT_RESULT;
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      break;
    case STRING_RESULT:
2526
    {
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      CHARSET_INFO *fromcs= entry->collation.collation;
      CHARSET_INFO *tocs= thd->variables.collation_connection;
      uint32 dummy_offset;

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      value.cs_info.character_set_of_placeholder= 
        value.cs_info.character_set_client= fromcs;
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      /*
        Setup source and destination character sets so that they
        are different only if conversion is necessary: this will
        make later checks easier.
      */
      value.cs_info.final_character_set_of_str_value=
        String::needs_conversion(0, fromcs, tocs, &dummy_offset) ?
        tocs : fromcs;
      /*
        Exact value of max_length is not known unless data is converted to
        charset of connection, so we have to set it later.
      */
      item_type= Item::STRING_ITEM;
      item_result_type= STRING_RESULT;

      if (set_str((const char *)entry->value, entry->length))
        DBUG_RETURN(1);
      break;
    }
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    case DECIMAL_RESULT:
    {
      const my_decimal *ent_value= (const my_decimal *)entry->value;
      my_decimal2decimal(ent_value, &decimal_value);
      state= DECIMAL_VALUE;
      decimals= ent_value->frac;
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      max_length= my_decimal_precision_to_length(ent_value->precision(),
                                                 decimals, unsigned_flag);
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      break;
    }
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    default:
      DBUG_ASSERT(0);
      set_null();
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    }
  }
  else
    set_null();

  DBUG_RETURN(0);
}

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/*
    Resets parameter after execution.
  
  SYNOPSIS
     Item_param::reset()
 
  NOTES
    We clear null_value here instead of setting it in set_* methods, 
    because we want more easily handle case for long data.
*/

void Item_param::reset()
2585
{
2586
  DBUG_ENTER("Item_param::reset");
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  /* Shrink string buffer if it's bigger than max possible CHAR column */
  if (str_value.alloced_length() > MAX_CHAR_WIDTH)
    str_value.free();
  else
    str_value.length(0);
2592
  str_value_ptr.length(0);
2593
  /*
2594
    We must prevent all charset conversions until data has been written
2595
    to the binary log.
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  */
  str_value.set_charset(&my_charset_bin);
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  collation.set(&my_charset_bin, DERIVATION_COERCIBLE);
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  state= NO_VALUE;
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  maybe_null= 1;
  null_value= 0;
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  /*
    Don't reset item_type to PARAM_ITEM: it's only needed to guard
    us from item optimizations at prepare stage, when item doesn't yet
    contain a literal of some kind.
    In all other cases when this object is accessed its value is
    set (this assumption is guarded by 'state' and
    DBUG_ASSERTS(state != NO_VALUE) in all Item_param::get_*
    methods).
  */
2611
  DBUG_VOID_RETURN;
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}


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int Item_param::save_in_field(Field *field, bool no_conversions)
2616 2617
{
  field->set_notnull();
2618 2619 2620

  switch (state) {
  case INT_VALUE:
2621
    return field->store(value.integer, unsigned_flag);
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  case REAL_VALUE:
    return field->store(value.real);
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  case DECIMAL_VALUE:
    return field->store_decimal(&decimal_value);
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  case TIME_VALUE:
    field->store_time(&value.time, value.time.time_type);
2628
    return 0;
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  case STRING_VALUE:
  case LONG_DATA_VALUE:
    return field->store(str_value.ptr(), str_value.length(),
                        str_value.charset());
  case NULL_VALUE:
2634
    return set_field_to_null_with_conversions(field, no_conversions);
2635 2636 2637
  case NO_VALUE:
  default:
    DBUG_ASSERT(0);
2638
  }
2639
  return 1;
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}

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2643 2644
bool Item_param::get_time(TIME *res)
{
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  if (state == TIME_VALUE)
  {
    *res= value.time;
    return 0;
  }
  /*
    If parameter value isn't supplied assertion will fire in val_str()
    which is called from Item::get_time().
  */
  return Item::get_time(res);
2655
}
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bool Item_param::get_date(TIME *res, uint fuzzydate)
{
  if (state == TIME_VALUE)
  {
    *res= value.time;
    return 0;
  }
  return Item::get_date(res, fuzzydate);
}


2669
double Item_param::val_real()
2670
{
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  switch (state) {
  case REAL_VALUE:
    return value.real;
  case INT_VALUE:
    return (double) value.integer;
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  case DECIMAL_VALUE:
  {
    double result;
    my_decimal2double(E_DEC_FATAL_ERROR, &decimal_value, &result);
    return result;
  }
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  case STRING_VALUE:
  case LONG_DATA_VALUE:
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  {
    int dummy_err;
    char *end_not_used;
    return my_strntod(str_value.charset(), (char*) str_value.ptr(),
                      str_value.length(), &end_not_used, &dummy_err);
  }
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  case TIME_VALUE:
    /*
      This works for example when user says SELECT ?+0.0 and supplies
      time value for the placeholder.
    */
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    return ulonglong2double(TIME_to_ulonglong(&value.time));
2696
  case NULL_VALUE:
2697
    return 0.0;
2698
  default:
2699
    DBUG_ASSERT(0);
2700
  }
2701
  return 0.0;
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} 

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2705 2706
longlong Item_param::val_int() 
{ 
2707 2708
  switch (state) {
  case REAL_VALUE:
2709
    return (longlong) rint(value.real);
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  case INT_VALUE:
    return value.integer;
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  case DECIMAL_VALUE:
  {
    longlong i;
    my_decimal2int(E_DEC_FATAL_ERROR, &decimal_value, unsigned_flag, &i);
    return i;
  }
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  case STRING_VALUE:
  case LONG_DATA_VALUE:
    {
      int dummy_err;
      return my_strntoll(str_value.charset(), str_value.ptr(),
                         str_value.length(), 10, (char**) 0, &dummy_err);
    }
  case TIME_VALUE:
    return (longlong) TIME_to_ulonglong(&value.time);
  case NULL_VALUE:
    return 0; 
2729
  default:
2730
    DBUG_ASSERT(0);
2731
  }
2732
  return 0;
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}

2735

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my_decimal *Item_param::val_decimal(my_decimal *dec)
{
  switch (state) {
  case DECIMAL_VALUE:
    return &decimal_value;
  case REAL_VALUE:
    double2my_decimal(E_DEC_FATAL_ERROR, value.real, dec);
    return dec;
  case INT_VALUE:
    int2my_decimal(E_DEC_FATAL_ERROR, value.integer, unsigned_flag, dec);
    return dec;
  case STRING_VALUE:
  case LONG_DATA_VALUE:
    string2my_decimal(E_DEC_FATAL_ERROR, &str_value, dec);
    return dec;
  case TIME_VALUE:
  {
    longlong i= (longlong) TIME_to_ulonglong(&value.time);
    int2my_decimal(E_DEC_FATAL_ERROR, i, 0, dec);
    return dec;
  }
  case NULL_VALUE:
    return 0; 
  default:
    DBUG_ASSERT(0);
  }
  return 0;
}


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String *Item_param::val_str(String* str) 
{ 
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  switch (state) {
  case STRING_VALUE:
  case LONG_DATA_VALUE:
2771
    return &str_value_ptr;
2772
  case REAL_VALUE:
2773
    str->set_real(value.real, NOT_FIXED_DEC, &my_charset_bin);
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    return str;
  case INT_VALUE:
    str->set(value.integer, &my_charset_bin);
2777
    return str;
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  case DECIMAL_VALUE:
    if (my_decimal2string(E_DEC_FATAL_ERROR, &decimal_value,
                          0, 0, 0, str) <= 1)
      return str;
    return NULL;
2783 2784
  case TIME_VALUE:
  {
2785
    if (str->reserve(MAX_DATE_STRING_REP_LENGTH))
2786
      break;
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    str->length((uint) my_TIME_to_str(&value.time, (char*) str->ptr()));
    str->set_charset(&my_charset_bin);
2789
    return str;
2790 2791 2792
  }
  case NULL_VALUE:
    return NULL; 
2793
  default:
2794
    DBUG_ASSERT(0);
2795
  }
2796
  return str;
2797
}
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/*
  Return Param item values in string format, for generating the dynamic 
  query used in update/binary logs
2802 2803
  TODO: change interface and implementation to fill log data in place
  and avoid one more memcpy/alloc between str and log string.
2804 2805
*/

2806
const String *Item_param::query_val_str(String* str) const
2807
{
2808 2809 2810 2811 2812
  switch (state) {
  case INT_VALUE:
    str->set(value.integer, &my_charset_bin);
    break;
  case REAL_VALUE:
2813
    str->set_real(value.real, NOT_FIXED_DEC, &my_charset_bin);
2814
    break;
2815 2816 2817 2818 2819
  case DECIMAL_VALUE:
    if (my_decimal2string(E_DEC_FATAL_ERROR, &decimal_value,
                          0, 0, 0, str) > 1)
      return &my_null_string;
    break;
2820
  case TIME_VALUE:
2821
    {
2822 2823 2824 2825 2826 2827
      char *buf, *ptr;
      str->length(0);
      /*
        TODO: in case of error we need to notify replication
        that binary log contains wrong statement 
      */
2828
      if (str->reserve(MAX_DATE_STRING_REP_LENGTH+3))
2829 2830 2831 2832 2833 2834
        break; 

      /* Create date string inplace */
      buf= str->c_ptr_quick();
      ptr= buf;
      *ptr++= '\'';
2835
      ptr+= (uint) my_TIME_to_str(&value.time, ptr);
2836 2837 2838
      *ptr++= '\'';
      str->length((uint32) (ptr - buf));
      break;
2839
    }
2840 2841
  case STRING_VALUE:
  case LONG_DATA_VALUE:
2842
    {
2843
      str->length(0);
2844
      append_query_string(value.cs_info.character_set_client, &str_value, str);
2845
      break;
2846
    }
2847 2848 2849 2850
  case NULL_VALUE:
    return &my_null_string;
  default:
    DBUG_ASSERT(0);
2851 2852 2853
  }
  return str;
}
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/*
  Convert string from client character set to the character set of
  connection.
*/

bool Item_param::convert_str_value(THD *thd)
{
  bool rc= FALSE;
  if (state == STRING_VALUE || state == LONG_DATA_VALUE)
  {
    /*
      Check is so simple because all charsets were set up properly
      in setup_one_conversion_function, where typecode of
      placeholder was also taken into account: the variables are different
      here only if conversion is really necessary.
    */
    if (value.cs_info.final_character_set_of_str_value !=
2873
        value.cs_info.character_set_of_placeholder)
2874 2875
    {
      rc= thd->convert_string(&str_value,
2876
                              value.cs_info.character_set_of_placeholder,
2877 2878
                              value.cs_info.final_character_set_of_str_value);
    }
2879 2880 2881 2882
    else
      str_value.set_charset(value.cs_info.final_character_set_of_str_value);
    /* Here str_value is guaranteed to be in final_character_set_of_str_value */

2883 2884
    max_length= str_value.length();
    decimals= 0;
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    /*
      str_value_ptr is returned from val_str(). It must be not alloced
      to prevent it's modification by val_str() invoker.
    */
    str_value_ptr.set(str_value.ptr(), str_value.length(),
                      str_value.charset());
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    /* Synchronize item charset with value charset */
    collation.set(str_value.charset(), DERIVATION_COERCIBLE);
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  }
  return rc;
}

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bool Item_param::basic_const_item() const
{
  if (state == NO_VALUE || state == TIME_VALUE)
    return FALSE;
  return TRUE;
}

2905

2906
Item *
2907
Item_param::clone_item()
2908 2909 2910 2911 2912 2913
{
  /* see comments in the header file */
  switch (state) {
  case NULL_VALUE:
    return new Item_null(name);
  case INT_VALUE:
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    return (unsigned_flag ?
            new Item_uint(name, value.integer, max_length) :
            new Item_int(name, value.integer, max_length));
2917
  case REAL_VALUE:
2918
    return new Item_float(name, value.real, decimals, max_length);
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  case STRING_VALUE:
  case LONG_DATA_VALUE:
    return new Item_string(name, str_value.c_ptr_quick(), str_value.length(),
                           str_value.charset());
  case TIME_VALUE:
    break;
  case NO_VALUE:
  default:
    DBUG_ASSERT(0);
  };
  return 0;
}


bool
Item_param::eq(const Item *arg, bool binary_cmp) const
{
  Item *item;
  if (!basic_const_item() || !arg->basic_const_item() || arg->type() != type())
    return FALSE;
  /*
    We need to cast off const to call val_int(). This should be OK for
    a basic constant.
  */
  item= (Item*) arg;

  switch (state) {
  case NULL_VALUE:
    return TRUE;
  case INT_VALUE:
    return value.integer == item->val_int() &&
           unsigned_flag == item->unsigned_flag;
  case REAL_VALUE:
2952
    return value.real == item->val_real();
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  case STRING_VALUE:
  case LONG_DATA_VALUE:
    if (binary_cmp)
      return !stringcmp(&str_value, &item->str_value);
    return !sortcmp(&str_value, &item->str_value, collation.collation);
  default:
    break;
  }
  return FALSE;
}

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/* End of Item_param related */

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void Item_param::print(String *str)
{
  if (state == NO_VALUE)
  {
    str->append('?');
  }
  else
  {
2974
    char buffer[STRING_BUFFER_USUAL_SIZE];
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    String tmp(buffer, sizeof(buffer), &my_charset_bin);
    const String *res;
    res= query_val_str(&tmp);
    str->append(*res);
  }
}


/****************************************************************************
  Item_copy_string
****************************************************************************/
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void Item_copy_string::copy()
{
  String *res=item->val_str(&str_value);
  if (res && res != &str_value)
    str_value.copy(*res);
  null_value=item->null_value;
}

/* ARGSUSED */
String *Item_copy_string::val_str(String *str)
{
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  // Item_copy_string is used without fix_fields call
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  if (null_value)
    return (String*) 0;
  return &str_value;
}

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my_decimal *Item_copy_string::val_decimal(my_decimal *decimal_value)
{
  // Item_copy_string is used without fix_fields call
  if (null_value)
    return 0;
  string2my_decimal(E_DEC_FATAL_ERROR, &str_value, decimal_value);
  return (decimal_value);
}



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int Item_copy_string::save_in_field(Field *field, bool no_conversions)
{
  if (null_value)
    return set_field_to_null(field);
  field->set_notnull();
  return field->store(str_value.ptr(),str_value.length(),
		      collation.collation);
}

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/*
3026
  Functions to convert item to field (for send_fields)
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*/

/* ARGSUSED */
3030
bool Item::fix_fields(THD *thd, Item **ref)
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{
3032 3033

  // We do not check fields which are fixed during construction
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  DBUG_ASSERT(fixed == 0 || basic_const_item());
3035
  fixed= 1;
3036
  return FALSE;
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}

3039
double Item_ref_null_helper::val_real()
3040
{
3041
  DBUG_ASSERT(fixed == 1);
3042
  double tmp= (*ref)->val_result();
3043
  owner->was_null|= null_value= (*ref)->null_value;
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  return tmp;
}
3046 3047


3048 3049
longlong Item_ref_null_helper::val_int()
{
3050
  DBUG_ASSERT(fixed == 1);
3051
  longlong tmp= (*ref)->val_int_result();
3052
  owner->was_null|= null_value= (*ref)->null_value;
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  return tmp;
}
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my_decimal *Item_ref_null_helper::val_decimal(my_decimal *decimal_value)
{
  DBUG_ASSERT(fixed == 1);
  my_decimal *val= (*ref)->val_decimal_result(decimal_value);
  owner->was_null|= null_value= (*ref)->null_value;
  return val;
}


bool Item_ref_null_helper::val_bool()
{
  DBUG_ASSERT(fixed == 1);
  bool val= (*ref)->val_bool_result();
  owner->was_null|= null_value= (*ref)->null_value;
  return val;
}


3075 3076
String* Item_ref_null_helper::val_str(String* s)
{
3077
  DBUG_ASSERT(fixed == 1);
3078
  String* tmp= (*ref)->str_result(s);
3079
  owner->was_null|= null_value= (*ref)->null_value;
3080 3081
  return tmp;
}
3082 3083


3084
bool Item_ref_null_helper::get_date(TIME *ltime, uint fuzzydate)
3085 3086 3087
{  
  return (owner->was_null|= null_value= (*ref)->get_date(ltime, fuzzydate));
}
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/*
3091
  Mark item and SELECT_LEXs as dependent if item was resolved in outer SELECT
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  SYNOPSIS
    mark_as_dependent()
3095
    thd - thread handler
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    last - select from which current item depend
    current  - current select
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    resolved_item - item which was resolved in outer SELECT(for warning)
    mark_item - item which should be marked (can be differ in case of
                substitution)
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*/

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static void mark_as_dependent(THD *thd, SELECT_LEX *last, SELECT_LEX *current,
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                              Item_ident *resolved_item,
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                              Item_ident *mark_item)
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{
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  const char *db_name= (resolved_item->db_name ?
                        resolved_item->db_name : "");
  const char *table_name= (resolved_item->table_name ?
                           resolved_item->table_name : "");
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  /* store pointer on SELECT_LEX from which item is dependent */
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  if (mark_item)
    mark_item->depended_from= last;
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  current->mark_as_dependent(last);
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  if (thd->lex->describe & DESCRIBE_EXTENDED)
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  {
    char warn_buff[MYSQL_ERRMSG_SIZE];
    sprintf(warn_buff, ER(ER_WARN_FIELD_RESOLVED),
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            db_name, (db_name[0] ? "." : ""),
            table_name, (table_name [0] ? "." : ""),
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            resolved_item->field_name,
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	    current->select_number, last->select_number);
    push_warning(thd, MYSQL_ERROR::WARN_LEVEL_NOTE,
		 ER_WARN_FIELD_RESOLVED, warn_buff);
  }
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}


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/*
  Mark range of selects and resolved identifier (field/reference) item as
  dependent

  SYNOPSIS
    mark_select_range_as_dependent()
    thd           - thread handler
    last_select   - select where resolved_item was resolved
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    current_sel   - current select (select where resolved_item was placed)
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    found_field   - field which was found during resolving
    found_item    - Item which was found during resolving (if resolved
                    identifier belongs to VIEW)
    resolved_item - Identifier which was resolved

  NOTE:
    We have to mark all items between current_sel (including) and
    last_select (excluding) as dependend (select before last_select should
    be marked with actual table mask used by resolved item, all other with
    OUTER_REF_TABLE_BIT) and also write dependence information to Item of
    resolved identifier.
*/

void mark_select_range_as_dependent(THD *thd,
                                    SELECT_LEX *last_select,
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                                    SELECT_LEX *current_sel,
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                                    Field *found_field, Item *found_item,
                                    Item_ident *resolved_item)
{
  /*
    Go from current SELECT to SELECT where field was resolved (it
    have to be reachable from current SELECT, because it was already
    done once when we resolved this field and cached result of
    resolving)
  */
  SELECT_LEX *previous_select= current_sel;
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  for (; previous_select->outer_select() != last_select;
       previous_select= previous_select->outer_select())
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  {
    Item_subselect *prev_subselect_item=
      previous_select->master_unit()->item;
    prev_subselect_item->used_tables_cache|= OUTER_REF_TABLE_BIT;
    prev_subselect_item->const_item_cache= 0;
  }
  {
    Item_subselect *prev_subselect_item=
      previous_select->master_unit()->item;
    Item_ident *dependent= resolved_item;
    if (found_field == view_ref_found)
    {
      Item::Type type= found_item->type();
      prev_subselect_item->used_tables_cache|=
        found_item->used_tables();
      dependent= ((type == Item::REF_ITEM || type == Item::FIELD_ITEM) ?
                  (Item_ident*) found_item :
                  0);
    }
    else
      prev_subselect_item->used_tables_cache|=
        found_field->table->map;
    prev_subselect_item->const_item_cache= 0;
    mark_as_dependent(thd, last_select, current_sel, resolved_item,
                      dependent);
  }
}
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/*
  Search a GROUP BY clause for a field with a certain name.

  SYNOPSIS
    find_field_in_group_list()
    find_item  the item being searched for
    group_list GROUP BY clause

  DESCRIPTION
    Search the GROUP BY list for a column named as find_item. When searching
    preference is given to columns that are qualified with the same table (and
    database) name as the one being searched for.

  RETURN
    - the found item on success
    - NULL if find_item is not in group_list
*/

static Item** find_field_in_group_list(Item *find_item, ORDER *group_list)
{
  const char *db_name;
  const char *table_name;
  const char *field_name;
  ORDER      *found_group= NULL;
  int         found_match_degree= 0;
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  Item_ident *cur_field;
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  int         cur_match_degree= 0;
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  char        name_buff[NAME_LEN+1];
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  if (find_item->type() == Item::FIELD_ITEM ||
      find_item->type() == Item::REF_ITEM)
  {
    db_name=    ((Item_ident*) find_item)->db_name;
    table_name= ((Item_ident*) find_item)->table_name;
    field_name= ((Item_ident*) find_item)->field_name;
  }
  else
    return NULL;

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  if (db_name && lower_case_table_names)
  {
    /* Convert database to lower case for comparison */
    strmake(name_buff, db_name, sizeof(name_buff)-1);
    my_casedn_str(files_charset_info, name_buff);
    db_name= name_buff;
  }

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  DBUG_ASSERT(field_name != 0);
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  for (ORDER *cur_group= group_list ; cur_group ; cur_group= cur_group->next)
  {
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    if ((*(cur_group->item))->real_item()->type() == Item::FIELD_ITEM)
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    {
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      cur_field= (Item_ident*) *cur_group->item;
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      cur_match_degree= 0;
      
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      DBUG_ASSERT(cur_field->field_name != 0);
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      if (!my_strcasecmp(system_charset_info,
                         cur_field->field_name, field_name))
        ++cur_match_degree;
      else
        continue;

      if (cur_field->table_name && table_name)
      {
        /* If field_name is qualified by a table name. */
        if (strcmp(cur_field->table_name, table_name))
          /* Same field names, different tables. */
          return NULL;

        ++cur_match_degree;
        if (cur_field->db_name && db_name)
        {
          /* If field_name is also qualified by a database name. */
          if (strcmp(cur_field->db_name, db_name))
            /* Same field names, different databases. */
            return NULL;
          ++cur_match_degree;
        }
      }

      if (cur_match_degree > found_match_degree)
      {
        found_match_degree= cur_match_degree;
        found_group= cur_group;
      }
      else if (found_group && (cur_match_degree == found_match_degree) &&
               ! (*(found_group->item))->eq(cur_field, 0))
      {
        /*
          If the current resolve candidate matches equally well as the current
          best match, they must reference the same column, otherwise the field
          is ambiguous.
        */
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        my_error(ER_NON_UNIQ_ERROR, MYF(0),
                 find_item->full_name(), current_thd->where);
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        return NULL;
      }
    }
  }

  if (found_group)
    return found_group->item;
  else
    return NULL;
}


/*
  Resolve a column reference in a sub-select.

  SYNOPSIS
    resolve_ref_in_select_and_group()
    thd     current thread
    ref     column reference being resolved
    select  the sub-select that ref is resolved against

  DESCRIPTION
    Resolve a column reference (usually inside a HAVING clause) against the
    SELECT and GROUP BY clauses of the query described by 'select'. The name
    resolution algorithm searches both the SELECT and GROUP BY clauses, and in
    case of a name conflict prefers GROUP BY column names over SELECT names. If
    both clauses contain different fields with the same names, a warning is
    issued that name of 'ref' is ambiguous. We extend ANSI SQL in that when no
    GROUP BY column is found, then a HAVING name is resolved as a possibly
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    derived SELECT column. This extension is allowed only if the
    MODE_ONLY_FULL_GROUP_BY sql mode isn't enabled.
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  NOTES
    The resolution procedure is:
    - Search for a column or derived column named col_ref_i [in table T_j]
      in the SELECT clause of Q.
    - Search for a column named col_ref_i [in table T_j]
      in the GROUP BY clause of Q.
    - If found different columns with the same name in GROUP BY and SELECT
      - issue a warning and return the GROUP BY column,
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      - otherwise
        - if the MODE_ONLY_FULL_GROUP_BY mode is enabled return error
        - else return the found SELECT column.
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  RETURN
    NULL - there was an error, and the error was already reported
    not_found_item - the item was not resolved, no error was reported
    resolved item - if the item was resolved
*/

static Item**
resolve_ref_in_select_and_group(THD *thd, Item_ident *ref, SELECT_LEX *select)
{
  Item **group_by_ref= NULL;
  Item **select_ref= NULL;
  ORDER *group_list= (ORDER*) select->group_list.first;
  bool ambiguous_fields= FALSE;
  uint counter;
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  bool not_used;
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  /*
    Search for a column or derived column named as 'ref' in the SELECT
    clause of the current select.
  */
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  if (!(select_ref= find_item_in_list(ref, *(select->get_item_list()),
                                      &counter, REPORT_EXCEPT_NOT_FOUND,
                                      &not_used)))
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    return NULL; /* Some error occurred. */

  /* If this is a non-aggregated field inside HAVING, search in GROUP BY. */
  if (select->having_fix_field && !ref->with_sum_func && group_list)
  {
    group_by_ref= find_field_in_group_list(ref, group_list);
    
    /* Check if the fields found in SELECT and GROUP BY are the same field. */
    if (group_by_ref && (select_ref != not_found_item) &&
        !((*group_by_ref)->eq(*select_ref, 0)))
    {
      ambiguous_fields= TRUE;
      push_warning_printf(thd, MYSQL_ERROR::WARN_LEVEL_WARN, ER_NON_UNIQ_ERROR,
                          ER(ER_NON_UNIQ_ERROR), ref->full_name(),
                          current_thd->where);

    }
  }

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  if (thd->variables.sql_mode & MODE_ONLY_FULL_GROUP_BY &&
      select_ref != not_found_item && !group_by_ref)
  {
    /*
      Report the error if fields was found only in the SELECT item list and
      the strict mode is enabled.
    */
    my_error(ER_NON_GROUPING_FIELD_USED, MYF(0),
             ref->name, "HAVING");
    return NULL;
  }
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  if (select_ref != not_found_item || group_by_ref)
  {
    if (select_ref != not_found_item && !ambiguous_fields)
    {
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      DBUG_ASSERT(*select_ref != 0);
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      if (!select->ref_pointer_array[counter])
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      {
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        my_error(ER_ILLEGAL_REFERENCE, MYF(0),
                 ref->name, "forward reference in item list");
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        return NULL;
      }
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      DBUG_ASSERT((*select_ref)->fixed);
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      return (select->ref_pointer_array + counter);
    }
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    if (group_by_ref)
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      return group_by_ref;
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    DBUG_ASSERT(FALSE);
    return NULL; /* So there is no compiler warning. */
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  }
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  return (Item**) not_found_item;
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}


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/*
  Resolve the name of an outer select column reference.

  SYNOPSIS
    Item_field::fix_outer_field()
    thd        [in]      current thread
    from_field [in/out]  found field reference or (Field*)not_found_field
    reference  [in/out]  view column if this item was resolved to a view column

  DESCRIPTION
    The method resolves the column reference represented by 'this' as a column
    present in outer selects that contain current select.

  NOTES
    This is the inner loop of Item_field::fix_fields:

      for each outer query Q_k beginning from the inner-most one
      {
        search for a column or derived column named col_ref_i
        [in table T_j] in the FROM clause of Q_k;

        if such a column is not found
          Search for a column or derived column named col_ref_i
          [in table T_j] in the SELECT and GROUP clauses of Q_k.
      }

  IMPLEMENTATION
    In prepared statements, because of cache, find_field_in_tables()
    can resolve fields even if they don't belong to current context.
    In this case this method only finds appropriate context and marks
    current select as dependent. The found reference of field should be
    provided in 'from_field'.

  RETURN
     1 - column succefully resolved and fix_fields() should continue.
     0 - column fully fixed and fix_fields() should return FALSE
    -1 - error occured
*/
int
Item_field::fix_outer_field(THD *thd, Field **from_field, Item **reference)
{
  enum_parsing_place place= NO_MATTER;
  bool field_found= (*from_field != not_found_field);
  bool upward_lookup= FALSE;

  /*
    If there are outer contexts (outer selects, but current select is
    not derived table or view) try to resolve this reference in the
    outer contexts.

    We treat each subselect as a separate namespace, so that different
    subselects may contain columns with the same names. The subselects
    are searched starting from the innermost.
  */
  Name_resolution_context *last_checked_context= context;
  Item **ref= (Item **) not_found_item;
  Name_resolution_context *outer_context= context->outer_context;
  for (;
       outer_context;
       outer_context= outer_context->outer_context)
  {
    SELECT_LEX *select= outer_context->select_lex;
    Item_subselect *prev_subselect_item=
      last_checked_context->select_lex->master_unit()->item;
    last_checked_context= outer_context;
    upward_lookup= TRUE;

    place= prev_subselect_item->parsing_place;
    /*
      If outer_field is set, field was already found by first call
      to find_field_in_tables(). Only need to find appropriate context.
    */
    if (field_found && outer_context->select_lex !=
        cached_table->select_lex)
      continue;
    /*
      In case of a view, find_field_in_tables() writes the pointer to
      the found view field into '*reference', in other words, it
      substitutes this Item_field with the found expression.
    */
    if (field_found || (*from_field= find_field_in_tables(thd, this,
                                          outer_context->
                                            first_name_resolution_table,
                                          outer_context->
                                            last_name_resolution_table,
                                          reference,
                                          IGNORE_EXCEPT_NON_UNIQUE,
                                          TRUE, TRUE)) !=
        not_found_field)
    {
      if (*from_field)
      {
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        if (thd->variables.sql_mode & MODE_ONLY_FULL_GROUP_BY &&
            select->cur_pos_in_select_list != UNDEF_POS)
        {
          /*
            As this is an outer field it should be added to the list of
            non aggregated fields of the outer select.
          */
          marker= select->cur_pos_in_select_list;
          select->non_agg_fields.push_back(this);
        }
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        if (*from_field != view_ref_found)
        {
          prev_subselect_item->used_tables_cache|= (*from_field)->table->map;
          prev_subselect_item->const_item_cache= 0;
          if (thd->lex->in_sum_func &&
              thd->lex->in_sum_func->nest_level == 
              thd->lex->current_select->nest_level)
          {
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            Item::Type ref_type= (*reference)->type();
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            set_if_bigger(thd->lex->in_sum_func->max_arg_level,
                          select->nest_level);
            set_field(*from_field);
            fixed= 1;
            mark_as_dependent(thd, last_checked_context->select_lex,
                              context->select_lex, this,
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                              ((ref_type == REF_ITEM ||
                                ref_type == FIELD_ITEM) ?
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                               (Item_ident*) (*reference) : 0));
            return 0;
          }
        }
        else
        {
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          Item::Type ref_type= (*reference)->type();
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          prev_subselect_item->used_tables_cache|=
            (*reference)->used_tables();
          prev_subselect_item->const_item_cache&=
            (*reference)->const_item();
          mark_as_dependent(thd, last_checked_context->select_lex,
                            context->select_lex, this,
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                            ((ref_type == REF_ITEM || ref_type == FIELD_ITEM) ?
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                             (Item_ident*) (*reference) :
                             0));
          /*
            A reference to a view field had been found and we
            substituted it instead of this Item (find_field_in_tables
            does it by assigning the new value to *reference), so now
            we can return from this function.
          */
          return 0;
        }
      }
      break;
    }

    /* Search in SELECT and GROUP lists of the outer select. */
    if (outer_context->resolve_in_select_list)
    {
      if (!(ref= resolve_ref_in_select_and_group(thd, this, select)))
        return -1; /* Some error occurred (e.g. ambiguous names). */
      if (ref != not_found_item)
      {
        DBUG_ASSERT(*ref && (*ref)->fixed);
        prev_subselect_item->used_tables_cache|= (*ref)->used_tables();
        prev_subselect_item->const_item_cache&= (*ref)->const_item();
        break;
      }
    }

    /*
      Reference is not found in this select => this subquery depend on
      outer select (or we just trying to find wrong identifier, in this
      case it does not matter which used tables bits we set)
    */
    prev_subselect_item->used_tables_cache|= OUTER_REF_TABLE_BIT;
    prev_subselect_item->const_item_cache= 0;
  }

  DBUG_ASSERT(ref != 0);
  if (!*from_field)
    return -1;
  if (ref == not_found_item && *from_field == not_found_field)
  {
    if (upward_lookup)
    {
      // We can't say exactly what absent table or field
      my_error(ER_BAD_FIELD_ERROR, MYF(0), full_name(), thd->where);
    }
    else
    {
      /* Call find_field_in_tables only to report the error */
      find_field_in_tables(thd, this,
                           context->first_name_resolution_table,
                           context->last_name_resolution_table,
                           reference, REPORT_ALL_ERRORS,
                           !any_privileges &&
                           TRUE, TRUE);
    }
    return -1;
  }
  else if (ref != not_found_item)
  {
    Item *save;
    Item_ref *rf;

    /* Should have been checked in resolve_ref_in_select_and_group(). */
    DBUG_ASSERT(*ref && (*ref)->fixed);
    /*
      Here, a subset of actions performed by Item_ref::set_properties
      is not enough. So we pass ptr to NULL into Item_[direct]_ref
      constructor, so no initialization is performed, and call 
      fix_fields() below.
    */
    save= *ref;
    *ref= NULL;                             // Don't call set_properties()
    rf= (place == IN_HAVING ?
         new Item_ref(context, ref, (char*) table_name,
                      (char*) field_name) :
         new Item_direct_ref(context, ref, (char*) table_name,
                             (char*) field_name));
    *ref= save;
    if (!rf)
      return -1;
    thd->change_item_tree(reference, rf);
    /*
      rf is Item_ref => never substitute other items (in this case)
      during fix_fields() => we can use rf after fix_fields()
    */
    DBUG_ASSERT(!rf->fixed);                // Assured by Item_ref()
    if (rf->fix_fields(thd, reference) || rf->check_cols(1))
      return -1;

    mark_as_dependent(thd, last_checked_context->select_lex,
                      context->select_lex, this,
                      rf);
    return 0;
  }
  else
  {
    mark_as_dependent(thd, last_checked_context->select_lex,
                      context->select_lex,
                      this, this);
    if (last_checked_context->select_lex->having_fix_field)
    {
      Item_ref *rf;
      rf= new Item_ref(context,
                       (cached_table->db[0] ? cached_table->db : 0),
                       (char*) cached_table->alias, (char*) field_name);
      if (!rf)
        return -1;
      thd->change_item_tree(reference, rf);
      /*
        rf is Item_ref => never substitute other items (in this case)
        during fix_fields() => we can use rf after fix_fields()
      */
      DBUG_ASSERT(!rf->fixed);                // Assured by Item_ref()
      if (rf->fix_fields(thd, reference) || rf->check_cols(1))
        return -1;
      return 0;
    }
  }
  return 1;
}


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/*
  Resolve the name of a column reference.

  SYNOPSIS
    Item_field::fix_fields()
    thd       [in]      current thread
    reference [in/out]  view column if this item was resolved to a view column

  DESCRIPTION
    The method resolves the column reference represented by 'this' as a column
    present in one of: FROM clause, SELECT clause, GROUP BY clause of a query
    Q, or in outer queries that contain Q.

  NOTES
    The name resolution algorithm used is (where [T_j] is an optional table
    name that qualifies the column name):

      resolve_column_reference([T_j].col_ref_i)
      {
        search for a column or derived column named col_ref_i
        [in table T_j] in the FROM clause of Q;

        if such a column is NOT found AND    // Lookup in outer queries.
           there are outer queries
        {
          for each outer query Q_k beginning from the inner-most one
          {
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igor@rurik.mysql.com committed
3698 3699
            search for a column or derived column named col_ref_i
            [in table T_j] in the FROM clause of Q_k;
3700 3701 3702 3703 3704 3705 3706 3707 3708 3709 3710 3711 3712 3713 3714 3715

            if such a column is not found
              Search for a column or derived column named col_ref_i
              [in table T_j] in the SELECT and GROUP clauses of Q_k.
          }
        }
      }

    Notice that compared to Item_ref::fix_fields, here we first search the FROM
    clause, and then we search the SELECT and GROUP BY clauses.

  RETURN
    TRUE  if error
    FALSE on success
*/

3716
bool Item_field::fix_fields(THD *thd, Item **reference)
bk@work.mysql.com's avatar
bk@work.mysql.com committed
3717
{
bell@sanja.is.com.ua's avatar
bell@sanja.is.com.ua committed
3718
  DBUG_ASSERT(fixed == 0);
3719 3720 3721
  Field *from_field= (Field *)not_found_field;
  bool outer_fixed= false;

3722
  if (!field)					// If field is not checked
bk@work.mysql.com's avatar
bk@work.mysql.com committed
3723
  {
3724 3725 3726 3727 3728
    /*
      In case of view, find_field_in_tables() write pointer to view field
      expression to 'reference', i.e. it substitute that expression instead
      of this Item_field
    */
3729 3730 3731
    if ((from_field= find_field_in_tables(thd, this,
                                          context->first_name_resolution_table,
                                          context->last_name_resolution_table,
3732 3733
                                          reference,
                                          IGNORE_EXCEPT_NON_UNIQUE,
3734
                                          !any_privileges,
3735
                                          TRUE)) ==
3736
	not_found_field)
3737
    {
3738
      int ret;
3739 3740 3741 3742 3743 3744 3745 3746
      /* Look up in current select's item_list to find aliased fields */
      if (thd->lex->current_select->is_item_list_lookup)
      {
        uint counter;
        bool not_used;
        Item** res= find_item_in_list(this, thd->lex->current_select->item_list,
                                      &counter, REPORT_EXCEPT_NOT_FOUND,
                                      &not_used);
3747 3748
        if (!res)
          return 1;
3749
        if (res != (Item **)not_found_item)
3750
        {
3751 3752 3753 3754 3755 3756 3757 3758 3759 3760 3761 3762 3763 3764 3765 3766 3767 3768
          if ((*res)->type() == Item::FIELD_ITEM)
          {
            /*
             It's an Item_field referencing another Item_field in the select
             list.
             use the field from the Item_field in the select list and leave
             the Item_field instance in place.
            */
            set_field((*((Item_field**)res))->field);
            return 0;
          }
          else
          {
            /*
              It's not an Item_field in the select list so we must make a new
              Item_ref to point to the Item in the select list and replace the
              Item_field created by the parser with the new Item_ref.
            */
gkodinov@dl145s.mysql.com's avatar
gkodinov@dl145s.mysql.com committed
3769
            Item_ref *rf= new Item_ref(context, db_name,table_name,field_name);
3770 3771
            if (!rf)
              return 1;
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gkodinov@dl145s.mysql.com committed
3772
            thd->change_item_tree(reference, rf);
3773 3774 3775 3776 3777
            /*
              Because Item_ref never substitutes itself with other items 
              in Item_ref::fix_fields(), we can safely use the original 
              pointer to it even after fix_fields()
             */
gkodinov@dl145s.mysql.com's avatar
gkodinov@dl145s.mysql.com committed
3778
            return rf->fix_fields(thd, reference) ||  rf->check_cols(1);
3779
          }
3780 3781
        }
      }
3782 3783 3784 3785 3786
      if ((ret= fix_outer_field(thd, &from_field, reference)) < 0)
        goto error;
      else if (!ret)
        return FALSE;
      outer_fixed= TRUE;
3787
    }
3788
    else if (!from_field)
3789
      goto error;
3790

bell@sanja.is.com.ua's avatar
VIEW  
bell@sanja.is.com.ua committed
3791 3792 3793 3794
    /*
      if it is not expression from merged VIEW we will set this field.

      We can leave expression substituted from view for next PS/SP rexecution
3795
      (i.e. do not register this substitution for reverting on cleanup()
bell@sanja.is.com.ua's avatar
VIEW  
bell@sanja.is.com.ua committed
3796
      (register_item_tree_changing())), because this subtree will be
3797
      fix_field'ed during setup_tables()->setup_underlying() (i.e. before
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VIEW  
bell@sanja.is.com.ua committed
3798 3799 3800 3801 3802
      all other expressions of query, and references on tables which do
      not present in query will not make problems.

      Also we suppose that view can't be changed during PS/SP life.
    */
3803 3804 3805
    if (from_field == view_ref_found)
      return FALSE;

3806
    if (!outer_fixed && cached_table && cached_table->select_lex &&
3807 3808
        context->select_lex &&
        cached_table->select_lex != context->select_lex)
3809 3810 3811 3812
    {
      int ret;
      if ((ret= fix_outer_field(thd, &from_field, reference)) < 0)
        goto error;
3813
      if (!ret)
3814
        return FALSE;
3815
      outer_fixed= 1;
3816 3817
    }

3818
    set_field(from_field);
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3819 3820 3821 3822 3823
    if (thd->lex->in_sum_func &&
        thd->lex->in_sum_func->nest_level == 
        thd->lex->current_select->nest_level)
      set_if_bigger(thd->lex->in_sum_func->max_arg_level,
                    thd->lex->current_select->nest_level);
bk@work.mysql.com's avatar
bk@work.mysql.com committed
3824
  }
3825
  else if (thd->mark_used_columns != MARK_COLUMNS_NONE)
3826
  {
3827
    TABLE *table= field->table;
3828 3829
    MY_BITMAP *current_bitmap, *other_bitmap;
    if (thd->mark_used_columns == MARK_COLUMNS_READ)
3830
    {
3831 3832 3833 3834 3835 3836 3837 3838 3839 3840 3841 3842 3843 3844 3845 3846
      current_bitmap= table->read_set;
      other_bitmap=   table->write_set;
    }
    else
    {
      current_bitmap= table->write_set;
      other_bitmap=   table->read_set;
    }
    if (!bitmap_fast_test_and_set(current_bitmap, field->field_index))
    {
      if (!bitmap_is_set(other_bitmap, field->field_index))
      {
        /* First usage of column */
        table->used_fields++;                     // Used to optimize loops
        table->used_keys.intersect(field->part_of_key);
      }
3847
    }
3848
  }
bell@sanja.is.com.ua's avatar
VIEW  
bell@sanja.is.com.ua committed
3849 3850 3851 3852 3853 3854 3855 3856 3857 3858 3859 3860
#ifndef NO_EMBEDDED_ACCESS_CHECKS
  if (any_privileges)
  {
    char *db, *tab;
    if (cached_table->view)
    {
      db= cached_table->view_db.str;
      tab= cached_table->view_name.str;
    }
    else
    {
      db= cached_table->db;
3861
      tab= cached_table->table_name;
bell@sanja.is.com.ua's avatar
VIEW  
bell@sanja.is.com.ua committed
3862 3863 3864 3865 3866
    }
    if (!(have_privileges= (get_column_grant(thd, &field->table->grant,
                                             db, tab, field_name) &
                            VIEW_ANY_ACL)))
    {
3867
      my_error(ER_COLUMNACCESS_DENIED_ERROR, MYF(0),
3868 3869
               "ANY", thd->security_ctx->priv_user,
               thd->security_ctx->host_or_ip, field_name, tab);
3870
      goto error;
bell@sanja.is.com.ua's avatar
VIEW  
bell@sanja.is.com.ua committed
3871 3872 3873
    }
  }
#endif
3874
  fixed= 1;
3875 3876 3877 3878 3879 3880 3881
  if (thd->variables.sql_mode & MODE_ONLY_FULL_GROUP_BY &&
      !outer_fixed && !thd->lex->in_sum_func &&
      thd->lex->current_select->cur_pos_in_select_list != UNDEF_POS)
  {
    thd->lex->current_select->non_agg_fields.push_back(this);
    marker= thd->lex->current_select->cur_pos_in_select_list;
  }
3882
  return FALSE;
3883 3884 3885 3886

error:
  context->process_error(thd);
  return TRUE;
bk@work.mysql.com's avatar
bk@work.mysql.com committed
3887 3888
}

3889 3890 3891 3892 3893 3894 3895 3896

Item *Item_field::safe_charset_converter(CHARSET_INFO *tocs)
{
  no_const_subst= 1;
  return Item::safe_charset_converter(tocs);
}


hf@deer.(none)'s avatar
hf@deer.(none) committed
3897 3898
void Item_field::cleanup()
{
3899
  DBUG_ENTER("Item_field::cleanup");
hf@deer.(none)'s avatar
hf@deer.(none) committed
3900
  Item_ident::cleanup();
3901 3902
  /*
    Even if this object was created by direct link to field in setup_wild()
3903
    it will be linked correctly next time by name of field and table alias.
3904 3905
    I.e. we can drop 'field'.
   */
3906
  field= result_field= 0;
3907
  null_value= FALSE;
3908
  DBUG_VOID_RETURN;
3909
}
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igor@rurik.mysql.com committed
3910 3911 3912 3913 3914 3915 3916 3917 3918 3919 3920 3921 3922 3923 3924 3925 3926 3927 3928 3929 3930

/*
  Find a field among specified multiple equalities 

  SYNOPSIS
    find_item_equal()
    cond_equal   reference to list of multiple equalities where
                 the field (this object) is to be looked for
  
  DESCRIPTION
    The function first searches the field among multiple equalities
    of the current level (in the cond_equal->current_level list).
    If it fails, it continues searching in upper levels accessed
    through a pointer cond_equal->upper_levels.
    The search terminates as soon as a multiple equality containing 
    the field is found. 

  RETURN VALUES
    First Item_equal containing the field, if success
    0, otherwise
*/
3931 3932 3933 3934 3935 3936 3937 3938 3939 3940 3941 3942 3943 3944 3945 3946 3947 3948 3949 3950 3951
Item_equal *Item_field::find_item_equal(COND_EQUAL *cond_equal)
{
  Item_equal *item= 0;
  while (cond_equal)
  {
    List_iterator_fast<Item_equal> li(cond_equal->current_level);
    while ((item= li++))
    {
      if (item->contains(field))
        return item;
    }
    /* 
      The field is not found in any of the multiple equalities
      of the current level. Look for it in upper levels
    */
    cond_equal= cond_equal->upper_levels;
  }
  return 0;
}


3952 3953 3954 3955 3956 3957 3958 3959 3960 3961 3962 3963 3964 3965 3966 3967 3968 3969 3970 3971 3972 3973 3974 3975 3976 3977 3978 3979 3980 3981 3982 3983 3984 3985 3986
/*
  Check whether a field can be substituted by an equal item

  SYNOPSIS
    equal_fields_propagator()
      arg - *arg != NULL <-> the field is in the context where
            substitution for an equal item is valid
   
  DESCRIPTION
    The function checks whether a substitution of the field
    occurrence for an equal item is valid.

  NOTES
    The following statement is not always true:
    x=y => F(x)=F(x/y).
    This means substitution of an item for an equal item not always
    yields an equavalent condition.
    Here's an example:
      'a'='a '
      (LENGTH('a')=1) != (LENGTH('a ')=2)
    Such a substitution is surely valid if either the substituted
    field is not of a STRING type or if it is an argument of
    a comparison  predicate.  

  RETURN
    TRUE   substitution is valid
    FALSE  otherwise
*/

bool Item_field::subst_argument_checker(byte **arg)
{
  return (result_type() != STRING_RESULT) || (*arg);
}


3987
/*
3988 3989
  Set a pointer to the multiple equality the field reference belongs to
  (if any)
3990 3991 3992
   
  SYNOPSIS
    equal_fields_propagator()
3993 3994
      arg - reference to list of multiple equalities where
            the field (this object) is to be looked for
3995 3996 3997 3998 3999 4000 4001 4002 4003 4004 4005
  
  DESCRIPTION
    The function looks for a multiple equality containing the field item
    among those referenced by arg.
    In the case such equality exists the function does the following.
    If the found multiple equality contains a constant, then the field
    reference is substituted for this constant, otherwise it sets a pointer
    to the multiple equality in the field item.

  NOTES
    This function is supposed to be called as a callback parameter in calls
4006
    of the compile method.  
4007 4008 4009 4010 4011

  RETURN VALUES
    pointer to the replacing constant item, if the field item was substituted 
    pointer to the field item, otherwise.
*/
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4012

4013 4014 4015 4016 4017 4018 4019 4020
Item *Item_field::equal_fields_propagator(byte *arg)
{
  if (no_const_subst)
    return this;
  item_equal= find_item_equal((COND_EQUAL *) arg);
  Item *item= 0;
  if (item_equal)
    item= item_equal->get_const();
4021 4022 4023 4024 4025 4026 4027 4028 4029 4030 4031
  /*
    Disable const propagation for items used in different comparison contexts.
    This must be done because, for example, Item_hex_string->val_int() is not
    the same as (Item_hex_string->val_str() in BINARY column)->val_int().
    We cannot simply disable the replacement in a particular context (
    e.g. <bin_col> = <int_col> AND <bin_col> = <hex_string>) since
    Items don't know the context they are in and there are functions like 
    IF (<hex_string>, 'yes', 'no').
    The same problem occurs when comparing a DATE/TIME field with a
    DATE/TIME represented as an int and as a string.
  */
4032 4033
  if (!item ||
      (cmp_context != (Item_result)-1 && item->cmp_context != cmp_context))
4034 4035 4036 4037 4038 4039
    item= this;
  return item;
}


/*
4040 4041 4042 4043
  Mark the item to not be part of substitution if it's not a binary item
  See comments in Arg_comparator::set_compare_func() for details
*/

4044
bool Item_field::set_no_const_sub(byte *arg)
4045 4046 4047
{
  if (field->charset() != &my_charset_bin)
    no_const_subst=1;
4048
  return FALSE;
4049 4050 4051 4052
}


/*
4053
  Replace an Item_field for an equal Item_field that evaluated earlier
4054
  (if any)
4055 4056
   
  SYNOPSIS
4057
    replace_equal_field_()
4058 4059 4060
    arg - a dummy parameter, is not used here
  
  DESCRIPTION
4061 4062 4063 4064 4065
    The function returns a pointer to an item that is taken from
    the very beginning of the item_equal list which the Item_field
    object refers to (belongs to).  
    If the Item_field object does not refer any Item_equal object
    'this' is returned 
4066 4067 4068

  NOTES
    This function is supposed to be called as a callback parameter in calls
4069
    of the thransformer method.  
4070 4071

  RETURN VALUES
4072 4073
    pointer to a replacement Item_field if there is a better equal item;
    this - otherwise.
4074 4075
*/

4076
Item *Item_field::replace_equal_field(byte *arg)
4077 4078 4079 4080
{
  if (item_equal)
  {
    Item_field *subst= item_equal->get_first();
igor@rurik.mysql.com's avatar
igor@rurik.mysql.com committed
4081
    if (subst && !field->eq(subst->field))
4082
      return subst;
4083
  }
4084
  return this;
hf@deer.(none)'s avatar
hf@deer.(none) committed
4085
}
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bk@work.mysql.com committed
4086

4087

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bk@work.mysql.com committed
4088
void Item::init_make_field(Send_field *tmp_field,
4089
			   enum enum_field_types field_type_arg)
4090
{
4091
  char *empty_name= (char*) "";
4092
  tmp_field->db_name=		empty_name;
4093 4094 4095 4096
  tmp_field->org_table_name=	empty_name;
  tmp_field->org_col_name=	empty_name;
  tmp_field->table_name=	empty_name;
  tmp_field->col_name=		name;
4097
  tmp_field->charsetnr=         collation.collation->number;
4098 4099 4100
  tmp_field->flags=             (maybe_null ? 0 : NOT_NULL_FLAG) | 
                                (my_binary_compare(collation.collation) ?
                                 BINARY_FLAG : 0);
4101
  tmp_field->type=              field_type_arg;
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4102 4103
  tmp_field->length=max_length;
  tmp_field->decimals=decimals;
4104 4105
  if (unsigned_flag)
    tmp_field->flags |= UNSIGNED_FLAG;
bk@work.mysql.com's avatar
bk@work.mysql.com committed
4106 4107
}

4108
void Item::make_field(Send_field *tmp_field)
bk@work.mysql.com's avatar
bk@work.mysql.com committed
4109
{
4110
  init_make_field(tmp_field, field_type());
bk@work.mysql.com's avatar
bk@work.mysql.com committed
4111 4112 4113
}


4114
enum_field_types Item::string_field_type() const
4115
{
4116
  enum_field_types f_type= MYSQL_TYPE_VAR_STRING;
4117
  if (max_length >= 16777216)
4118
    f_type= MYSQL_TYPE_LONG_BLOB;
4119
  else if (max_length >= 65536)
4120
    f_type= MYSQL_TYPE_MEDIUM_BLOB;
4121
  return f_type;
4122 4123 4124 4125 4126 4127
}


void Item_empty_string::make_field(Send_field *tmp_field)
{
  init_make_field(tmp_field, string_field_type());
4128 4129
}

4130

4131
enum_field_types Item::field_type() const
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bk@work.mysql.com committed
4132
{
4133
  switch (result_type()) {
4134
  case STRING_RESULT:  return string_field_type();
4135 4136 4137
  case INT_RESULT:     return MYSQL_TYPE_LONGLONG;
  case DECIMAL_RESULT: return MYSQL_TYPE_NEWDECIMAL;
  case REAL_RESULT:    return MYSQL_TYPE_DOUBLE;
4138 4139 4140
  case ROW_RESULT:
  default:
    DBUG_ASSERT(0);
4141 4142
    return MYSQL_TYPE_VARCHAR;
  }
bk@work.mysql.com's avatar
bk@work.mysql.com committed
4143 4144
}

4145

4146 4147 4148 4149 4150 4151 4152 4153 4154 4155 4156 4157 4158 4159 4160 4161
/*
  Create a field to hold a string value from an item

  SYNOPSIS
    make_string_field()
    table		Table for which the field is created

  IMPLEMENTATION
    If max_length > CONVERT_IF_BIGGER_TO_BLOB create a blob
    If max_length > 0 create a varchar
    If max_length == 0 create a CHAR(0) 
*/


Field *Item::make_string_field(TABLE *table)
{
4162
  Field *field;
4163 4164
  DBUG_ASSERT(collation.collation);
  if (max_length/collation.collation->mbmaxlen > CONVERT_IF_BIGGER_TO_BLOB)
4165
    field= new Field_blob(max_length, maybe_null, name,
4166
                          collation.collation);
4167
  /* Item_type_holder holds the exact type, do not change it */
4168
  else if (max_length > 0 &&
4169
      (type() != Item::TYPE_HOLDER || field_type() != MYSQL_TYPE_STRING))
4170
    field= new Field_varstring(max_length, maybe_null, name, table->s,
4171
                               collation.collation);
4172 4173 4174 4175 4176 4177
  else
    field= new Field_string(max_length, maybe_null, name,
                            collation.collation);
  if (field)
    field->init(table);
  return field;
4178 4179 4180
}


4181 4182 4183 4184
/*
  Create a field based on field_type of argument

  For now, this is only used to create a field for
4185
  IFNULL(x,something) and time functions
4186 4187 4188 4189 4190 4191

  RETURN
    0  error
    #  Created field
*/

4192
Field *Item::tmp_table_field_from_field_type(TABLE *table, bool fixed_length)
4193
{
4194 4195 4196 4197
  /*
    The field functions defines a field to be not null if null_ptr is not 0
  */
  uchar *null_ptr= maybe_null ? (uchar*) "" : 0;
4198
  Field *field;
4199 4200

  switch (field_type()) {
4201
  case MYSQL_TYPE_DECIMAL:
4202
  case MYSQL_TYPE_NEWDECIMAL:
4203 4204
    field= new Field_new_decimal((char*) 0, max_length, null_ptr, 0,
                                 Field::NONE, name, decimals, 0,
4205
                                 unsigned_flag);
4206
    break;
4207
  case MYSQL_TYPE_TINY:
4208 4209 4210
    field= new Field_tiny((char*) 0, max_length, null_ptr, 0, Field::NONE,
			  name, 0, unsigned_flag);
    break;
4211
  case MYSQL_TYPE_SHORT:
4212 4213 4214
    field= new Field_short((char*) 0, max_length, null_ptr, 0, Field::NONE,
			   name, 0, unsigned_flag);
    break;
4215
  case MYSQL_TYPE_LONG:
4216 4217 4218
    field= new Field_long((char*) 0, max_length, null_ptr, 0, Field::NONE,
			  name, 0, unsigned_flag);
    break;
4219 4220
#ifdef HAVE_LONG_LONG
  case MYSQL_TYPE_LONGLONG:
4221 4222 4223
    field= new Field_longlong((char*) 0, max_length, null_ptr, 0, Field::NONE,
			      name, 0, unsigned_flag);
    break;
4224
#endif
4225
  case MYSQL_TYPE_FLOAT:
4226 4227 4228
    field= new Field_float((char*) 0, max_length, null_ptr, 0, Field::NONE,
			   name, decimals, 0, unsigned_flag);
    break;
4229
  case MYSQL_TYPE_DOUBLE:
4230 4231 4232
    field= new Field_double((char*) 0, max_length, null_ptr, 0, Field::NONE,
			    name, decimals, 0, unsigned_flag);
    break;
4233
  case MYSQL_TYPE_NULL:
4234 4235 4236
    field= new Field_null((char*) 0, max_length, Field::NONE,
			  name, &my_charset_bin);
    break;
4237
  case MYSQL_TYPE_INT24:
4238 4239 4240
    field= new Field_medium((char*) 0, max_length, null_ptr, 0, Field::NONE,
			    name, 0, unsigned_flag);
    break;
4241
  case MYSQL_TYPE_NEWDATE:
4242
  case MYSQL_TYPE_DATE:
4243 4244
    field= new Field_date(maybe_null, name, &my_charset_bin);
    break;
4245
  case MYSQL_TYPE_TIME:
4246 4247
    field= new Field_time(maybe_null, name, &my_charset_bin);
    break;
4248
  case MYSQL_TYPE_TIMESTAMP:
evgen@sunlight.local's avatar
evgen@sunlight.local committed
4249 4250
    field= new Field_timestamp(maybe_null, name, &my_charset_bin);
    break;
4251
  case MYSQL_TYPE_DATETIME:
4252 4253
    field= new Field_datetime(maybe_null, name, &my_charset_bin);
    break;
4254
  case MYSQL_TYPE_YEAR:
4255 4256 4257
    field= new Field_year((char*) 0, max_length, null_ptr, 0, Field::NONE,
			  name);
    break;
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ramil@mysql.com committed
4258
  case MYSQL_TYPE_BIT:
4259
    field= new Field_bit_as_char(NULL, max_length, null_ptr, 0,
4260 4261
                                 Field::NONE, name);
    break;
4262
  default:
4263
    /* This case should never be chosen */
4264 4265
    DBUG_ASSERT(0);
    /* If something goes awfully wrong, it's better to get a string than die */
4266 4267 4268 4269 4270 4271 4272 4273
  case MYSQL_TYPE_STRING:
    if (fixed_length && max_length < CONVERT_IF_BIGGER_TO_BLOB)
    {
      field= new Field_string(max_length, maybe_null, name,
                              collation.collation);
      break;
    }
    /* Fall through to make_string_field() */
4274 4275
  case MYSQL_TYPE_ENUM:
  case MYSQL_TYPE_SET:
4276
  case MYSQL_TYPE_VAR_STRING:
4277
  case MYSQL_TYPE_VARCHAR:
4278
    return make_string_field(table);
4279 4280 4281 4282 4283
  case MYSQL_TYPE_TINY_BLOB:
  case MYSQL_TYPE_MEDIUM_BLOB:
  case MYSQL_TYPE_LONG_BLOB:
  case MYSQL_TYPE_BLOB:
  case MYSQL_TYPE_GEOMETRY:
4284
    if (this->type() == Item::TYPE_HOLDER)
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4285 4286
      field= new Field_blob(max_length, maybe_null, name, collation.collation,
                            1);
4287
    else
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4288
      field= new Field_blob(max_length, maybe_null, name, collation.collation);
4289
    break;					// Blob handled outside of case
4290
  }
4291 4292 4293
  if (field)
    field->init(table);
  return field;
4294 4295
}

4296

4297 4298
/* ARGSUSED */
void Item_field::make_field(Send_field *tmp_field)
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4299
{
4300
  field->make_field(tmp_field);
4301
  DBUG_ASSERT(tmp_field->table_name != 0);
4302 4303
  if (name)
    tmp_field->col_name=name;			// Use user supplied name
4304 4305 4306 4307
  if (table_name)
    tmp_field->table_name= table_name;
  if (db_name)
    tmp_field->db_name= db_name;
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}

4310

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4311
/*
4312
  Set a field:s value from a item
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4313 4314 4315 4316 4317 4318 4319
*/

void Item_field::save_org_in_field(Field *to)
{
  if (field->is_null())
  {
    null_value=1;
4320
    set_field_to_null_with_conversions(to, 1);
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  }
  else
  {
    to->set_notnull();
    field_conv(to,field);
    null_value=0;
  }
}

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4330
int Item_field::save_in_field(Field *to, bool no_conversions)
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{
  if (result_field->is_null())
  {
    null_value=1;
4335
    return set_field_to_null_with_conversions(to, no_conversions);
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  }
  else
  {
    to->set_notnull();
    field_conv(to,result_field);
    null_value=0;
  }
  return 0;
}

4346

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4347 4348 4349 4350 4351 4352 4353 4354 4355 4356 4357 4358 4359 4360 4361 4362
/*
  Store null in field

  SYNOPSIS
    save_in_field()
    field		Field where we want to store NULL

  DESCRIPTION
    This is used on INSERT.
    Allow NULL to be inserted in timestamp and auto_increment values

  RETURN VALUES
    0	 ok
    1	 Field doesn't support NULL values and can't handle 'field = NULL'
*/   

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4363
int Item_null::save_in_field(Field *field, bool no_conversions)
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4364
{
4365
  return set_field_to_null_with_conversions(field, no_conversions);
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}


4369 4370 4371 4372 4373 4374 4375 4376
/*
  Store null in field

  SYNOPSIS
    save_safe_in_field()
    field		Field where we want to store NULL

  RETURN VALUES
4377
    0	 OK
4378 4379 4380
    1	 Field doesn't support NULL values
*/   

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4381
int Item_null::save_safe_in_field(Field *field)
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{
  return set_field_to_null(field);
}


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4387
int Item::save_in_field(Field *field, bool no_conversions)
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4388
{
4389
  int error;
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4390 4391 4392 4393 4394
  if (result_type() == STRING_RESULT ||
      result_type() == REAL_RESULT &&
      field->result_type() == STRING_RESULT)
  {
    String *result;
4395
    CHARSET_INFO *cs= collation.collation;
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4396
    char buff[MAX_FIELD_WIDTH];		// Alloc buffer for small columns
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4397
    str_value.set_quick(buff, sizeof(buff), cs);
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4398 4399
    result=val_str(&str_value);
    if (null_value)
4400
    {
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4401
      str_value.set_quick(0, 0, cs);
4402
      return set_field_to_null_with_conversions(field, no_conversions);
4403
    }
4404 4405 4406

    /* NOTE: If null_value == FALSE, "result" must be not NULL.  */

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4407
    field->set_notnull();
4408
    error=field->store(result->ptr(),result->length(),cs);
4409
    str_value.set_quick(0, 0, cs);
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4410 4411 4412
  }
  else if (result_type() == REAL_RESULT)
  {
4413
    double nr= val_real();
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4414 4415 4416
    if (null_value)
      return set_field_to_null(field);
    field->set_notnull();
4417
    error=field->store(nr);
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4418
  }
4419 4420 4421 4422 4423 4424 4425 4426 4427
  else if (result_type() == DECIMAL_RESULT)
  {
    my_decimal decimal_value;
    my_decimal *value= val_decimal(&decimal_value);
    if (null_value)
      return set_field_to_null(field);
    field->set_notnull();
    error=field->store_decimal(value);
  }
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4428 4429 4430 4431
  else
  {
    longlong nr=val_int();
    if (null_value)
4432
      return set_field_to_null_with_conversions(field, no_conversions);
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4433
    field->set_notnull();
4434
    error=field->store(nr, unsigned_flag);
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4435
  }
4436
  return error;
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}

4439

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4440
int Item_string::save_in_field(Field *field, bool no_conversions)
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4441 4442 4443 4444 4445 4446
{
  String *result;
  result=val_str(&str_value);
  if (null_value)
    return set_field_to_null(field);
  field->set_notnull();
4447
  return field->store(result->ptr(),result->length(),collation.collation);
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4448 4449
}

4450

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4451
int Item_uint::save_in_field(Field *field, bool no_conversions)
4452
{
4453
  /* Item_int::save_in_field handles both signed and unsigned. */
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4454
  return Item_int::save_in_field(field, no_conversions);
4455 4456
}

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4457 4458

int Item_int::save_in_field(Field *field, bool no_conversions)
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4459 4460 4461 4462 4463
{
  longlong nr=val_int();
  if (null_value)
    return set_field_to_null(field);
  field->set_notnull();
4464
  return field->store(nr, unsigned_flag);
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4465 4466
}

4467 4468 4469 4470 4471 4472 4473 4474

int Item_decimal::save_in_field(Field *field, bool no_conversions)
{
  field->set_notnull();
  return field->store_decimal(&decimal_value);
}


4475 4476 4477 4478 4479 4480 4481 4482 4483 4484 4485 4486 4487 4488 4489 4490
bool Item_int::eq(const Item *arg, bool binary_cmp) const
{
  /* No need to check for null value as basic constant can't be NULL */
  if (arg->basic_const_item() && arg->type() == type())
  {
    /*
      We need to cast off const to call val_int(). This should be OK for
      a basic constant.
    */
    Item *item= (Item*) arg;
    return item->val_int() == value && item->unsigned_flag == unsigned_flag;
  }
  return FALSE;
}


4491
Item *Item_int_with_ref::clone_item()
4492
{
4493
  DBUG_ASSERT(ref->const_item());
4494 4495 4496 4497 4498 4499 4500 4501 4502 4503
  /*
    We need to evaluate the constant to make sure it works with
    parameter markers.
  */
  return (ref->unsigned_flag ?
          new Item_uint(ref->name, ref->val_int(), ref->max_length) :
          new Item_int(ref->name, ref->val_int(), ref->max_length));
}


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4504 4505
Item_num *Item_uint::neg()
{
4506
  Item_decimal *item= new Item_decimal(value, 1);
4507
  return item->neg();
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4508
}
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4509

4510

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static uint nr_of_decimals(const char *str, const char *end)
{
  const char *decimal_point;

  /* Find position for '.' */
  for (;;)
  {
    if (str == end)
      return 0;
    if (*str == 'e' || *str == 'E')
      return NOT_FIXED_DEC;    
    if (*str++ == '.')
      break;
  }
  decimal_point= str;
  for (; my_isdigit(system_charset_info, *str) ; str++)
    ;
  if (*str == 'e' || *str == 'E')
    return NOT_FIXED_DEC;
  return (uint) (str - decimal_point);
}


4534 4535 4536 4537 4538
/*
  This function is only called during parsing. We will signal an error if
  value is not a true double value (overflow)
*/

4539
Item_float::Item_float(const char *str_arg, uint length)
4540 4541
{
  int error;
4542 4543 4544
  char *end_not_used;
  value= my_strntod(&my_charset_bin, (char*) str_arg, length, &end_not_used,
                    &error);
4545 4546 4547 4548 4549 4550 4551
  if (error)
  {
    /*
      Note that we depend on that str_arg is null terminated, which is true
      when we are in the parser
    */
    DBUG_ASSERT(str_arg[length] == 0);
4552
    my_error(ER_ILLEGAL_VALUE_FOR_TYPE, MYF(0), "double", (char*) str_arg);
4553 4554
  }
  presentation= name=(char*) str_arg;
4555
  decimals=(uint8) nr_of_decimals(str_arg, str_arg+length);
4556 4557 4558 4559 4560
  max_length=length;
  fixed= 1;
}


4561
int Item_float::save_in_field(Field *field, bool no_conversions)
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4562
{
4563
  double nr= val_real();
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4564 4565 4566
  if (null_value)
    return set_field_to_null(field);
  field->set_notnull();
4567
  return field->store(nr);
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4568 4569
}

4570

4571
void Item_float::print(String *str)
4572 4573 4574 4575 4576 4577 4578 4579
{
  if (presentation)
  {
    str->append(presentation);
    return;
  }
  char buffer[20];
  String num(buffer, sizeof(buffer), &my_charset_bin);
4580
  num.set_real(value, decimals, &my_charset_bin);
4581 4582 4583 4584
  str->append(num);
}


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/*
  hex item
  In string context this is a binary string.
  In number context this is a longlong value.
*/
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4590

4591
bool Item_float::eq(const Item *arg, bool binary_cmp) const
4592 4593 4594 4595 4596 4597 4598 4599
{
  if (arg->basic_const_item() && arg->type() == type())
  {
    /*
      We need to cast off const to call val_int(). This should be OK for
      a basic constant.
    */
    Item *item= (Item*) arg;
4600
    return item->val_real() == value;
4601 4602 4603 4604
  }
  return FALSE;
}

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4605

4606
inline uint char_val(char X)
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4607 4608 4609 4610 4611 4612
{
  return (uint) (X >= '0' && X <= '9' ? X-'0' :
		 X >= 'A' && X <= 'Z' ? X-'A'+10 :
		 X-'a'+10);
}

4613

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4614
Item_hex_string::Item_hex_string(const char *str, uint str_length)
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4615 4616 4617 4618 4619 4620
{
  name=(char*) str-2;				// Lex makes this start with 0x
  max_length=(str_length+1)/2;
  char *ptr=(char*) sql_alloc(max_length+1);
  if (!ptr)
    return;
4621
  str_value.set(ptr,max_length,&my_charset_bin);
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4622 4623 4624 4625 4626 4627 4628 4629 4630
  char *end=ptr+max_length;
  if (max_length*2 != str_length)
    *ptr++=char_val(*str++);			// Not even, assume 0 prefix
  while (ptr != end)
  {
    *ptr++= (char) (char_val(str[0])*16+char_val(str[1]));
    str+=2;
  }
  *ptr=0;					// Keep purify happy
4631
  collation.set(&my_charset_bin, DERIVATION_COERCIBLE);
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4632
  fixed= 1;
4633
  unsigned_flag= 1;
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4634 4635
}

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4636
longlong Item_hex_string::val_int()
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4637
{
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4638
  // following assert is redundant, because fixed=1 assigned in constructor
4639
  DBUG_ASSERT(fixed == 1);
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4640 4641 4642 4643 4644 4645 4646 4647 4648 4649
  char *end=(char*) str_value.ptr()+str_value.length(),
       *ptr=end-min(str_value.length(),sizeof(longlong));

  ulonglong value=0;
  for (; ptr != end ; ptr++)
    value=(value << 8)+ (ulonglong) (uchar) *ptr;
  return (longlong) value;
}


4650 4651 4652 4653 4654 4655 4656 4657 4658 4659
my_decimal *Item_hex_string::val_decimal(my_decimal *decimal_value)
{
  // following assert is redundant, because fixed=1 assigned in constructor
  DBUG_ASSERT(fixed == 1);
  ulonglong value= (ulonglong)val_int();
  int2my_decimal(E_DEC_FATAL_ERROR, value, TRUE, decimal_value);
  return (decimal_value);
}


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4660
int Item_hex_string::save_in_field(Field *field, bool no_conversions)
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4661 4662 4663
{
  field->set_notnull();
  if (field->result_type() == STRING_RESULT)
4664 4665 4666 4667 4668 4669
    return field->store(str_value.ptr(), str_value.length(), 
                        collation.collation);

  ulonglong nr;
  uint32 length= str_value.length();
  if (length > 8)
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4670
  {
4671 4672
    nr= field->flags & UNSIGNED_FLAG ? ULONGLONG_MAX : LONGLONG_MAX;
    goto warn;
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4673
  }
4674 4675
  nr= (ulonglong) val_int();
  if ((length == 8) && !(field->flags & UNSIGNED_FLAG) && (nr > LONGLONG_MAX))
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4676
  {
4677 4678
    nr= LONGLONG_MAX;
    goto warn;
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4679
  }
4680
  return field->store((longlong) nr, TRUE);  // Assume hex numbers are unsigned
4681 4682

warn:
4683
  if (!field->store((longlong) nr, TRUE))
4684 4685 4686
    field->set_warning(MYSQL_ERROR::WARN_LEVEL_WARN, ER_WARN_DATA_OUT_OF_RANGE,
                       1);
  return 1;
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4687 4688 4689
}


4690
bool Item_hex_string::eq(const Item *arg, bool binary_cmp) const
4691 4692 4693 4694 4695 4696 4697 4698 4699 4700
{
  if (arg->basic_const_item() && arg->type() == type())
  {
    if (binary_cmp)
      return !stringcmp(&str_value, &arg->str_value);
    return !sortcmp(&str_value, &arg->str_value, collation.collation);
  }
  return FALSE;
}

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4701

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4702
Item *Item_hex_string::safe_charset_converter(CHARSET_INFO *tocs)
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{
  Item_string *conv;
  String tmp, *str= val_str(&tmp);

  if (!(conv= new Item_string(str->ptr(), str->length(), tocs)))
    return NULL;
  conv->str_value.copy();
4710
  conv->str_value.mark_as_const();
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  return conv;
}


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/*
  bin item.
  In string context this is a binary string.
  In number context this is a longlong value.
*/
  
Item_bin_string::Item_bin_string(const char *str, uint str_length)
{
  const char *end= str + str_length - 1;
  uchar bits= 0;
  uint power= 1;

  name= (char*) str - 2;
  max_length= (str_length + 7) >> 3;
  char *ptr= (char*) sql_alloc(max_length + 1);
  if (!ptr)
    return;
  str_value.set(ptr, max_length, &my_charset_bin);
  ptr+= max_length - 1;
  ptr[1]= 0;                     // Set end null for string
  for (; end >= str; end--)
  {
    if (power == 256)
    {
      power= 1;
      *ptr--= bits;
      bits= 0;     
    }
    if (*end == '1')
      bits|= power; 
    power<<= 1;
  }
  *ptr= (char) bits;
  collation.set(&my_charset_bin, DERIVATION_COERCIBLE);
  fixed= 1;
}


4753 4754 4755 4756 4757
/*
  Pack data in buffer for sending
*/

bool Item_null::send(Protocol *protocol, String *packet)
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4758
{
4759
  return protocol->store_null();
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}

/*
4763
  This is only called from items that is not of type item_field
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*/

4766
bool Item::send(Protocol *protocol, String *buffer)
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4767
{
4768
  bool result;
4769
  enum_field_types f_type;
4770
  LINT_INIT(result);                     // Will be set if null_value == 0
4771

4772
  switch ((f_type=field_type())) {
4773
  default:
4774 4775 4776 4777 4778 4779 4780 4781 4782
  case MYSQL_TYPE_NULL:
  case MYSQL_TYPE_DECIMAL:
  case MYSQL_TYPE_ENUM:
  case MYSQL_TYPE_SET:
  case MYSQL_TYPE_TINY_BLOB:
  case MYSQL_TYPE_MEDIUM_BLOB:
  case MYSQL_TYPE_LONG_BLOB:
  case MYSQL_TYPE_BLOB:
  case MYSQL_TYPE_GEOMETRY:
4783 4784
  case MYSQL_TYPE_STRING:
  case MYSQL_TYPE_VAR_STRING:
4785
  case MYSQL_TYPE_VARCHAR:
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  case MYSQL_TYPE_BIT:
4787
  case MYSQL_TYPE_NEWDECIMAL:
4788 4789 4790
  {
    String *res;
    if ((res=val_str(buffer)))
4791
      result= protocol->store(res->ptr(),res->length(),res->charset());
4792 4793 4794 4795 4796 4797 4798 4799 4800 4801 4802
    break;
  }
  case MYSQL_TYPE_TINY:
  {
    longlong nr;
    nr= val_int();
    if (!null_value)
      result= protocol->store_tiny(nr);
    break;
  }
  case MYSQL_TYPE_SHORT:
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4803
  case MYSQL_TYPE_YEAR:
4804 4805 4806 4807 4808 4809 4810
  {
    longlong nr;
    nr= val_int();
    if (!null_value)
      result= protocol->store_short(nr);
    break;
  }
4811
  case MYSQL_TYPE_INT24:
4812 4813 4814 4815 4816 4817 4818 4819 4820 4821 4822 4823 4824 4825 4826 4827
  case MYSQL_TYPE_LONG:
  {
    longlong nr;
    nr= val_int();
    if (!null_value)
      result= protocol->store_long(nr);
    break;
  }
  case MYSQL_TYPE_LONGLONG:
  {
    longlong nr;
    nr= val_int();
    if (!null_value)
      result= protocol->store_longlong(nr, unsigned_flag);
    break;
  }
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4828 4829 4830
  case MYSQL_TYPE_FLOAT:
  {
    float nr;
4831
    nr= (float) val_real();
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4832 4833 4834 4835
    if (!null_value)
      result= protocol->store(nr, decimals, buffer);
    break;
  }
4836 4837
  case MYSQL_TYPE_DOUBLE:
  {
4838
    double nr= val_real();
4839 4840 4841 4842 4843 4844
    if (!null_value)
      result= protocol->store(nr, decimals, buffer);
    break;
  }
  case MYSQL_TYPE_DATETIME:
  case MYSQL_TYPE_DATE:
4845
  case MYSQL_TYPE_TIMESTAMP:
4846 4847
  {
    TIME tm;
4848
    get_date(&tm, TIME_FUZZY_DATE);
4849 4850
    if (!null_value)
    {
4851
      if (f_type == MYSQL_TYPE_DATE)
4852 4853 4854 4855 4856 4857 4858 4859 4860 4861 4862 4863 4864 4865 4866 4867 4868 4869
	return protocol->store_date(&tm);
      else
	result= protocol->store(&tm);
    }
    break;
  }
  case MYSQL_TYPE_TIME:
  {
    TIME tm;
    get_time(&tm);
    if (!null_value)
      result= protocol->store_time(&tm);
    break;
  }
  }
  if (null_value)
    result= protocol->store_null();
  return result;
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4870 4871
}

4872 4873

bool Item_field::send(Protocol *protocol, String *buffer)
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4874
{
4875
  return protocol->store(result_field);
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4876 4877
}

4878

4879 4880 4881 4882 4883 4884 4885 4886 4887 4888 4889 4890 4891 4892 4893 4894
void Item_field::update_null_value() 
{ 
  /* 
    need to set no_errors to prevent warnings about type conversion 
    popping up.
  */
  THD *thd= field->table->in_use;
  int no_errors;

  no_errors= thd->no_errors;
  thd->no_errors= 1;
  Item::update_null_value();
  thd->no_errors= no_errors;
}


4895 4896 4897 4898 4899
Item_ref::Item_ref(Name_resolution_context *context_arg,
                   Item **item, const char *table_name_arg,
                   const char *field_name_arg)
  :Item_ident(context_arg, NullS, table_name_arg, field_name_arg),
   result_field(0), ref(item)
4900 4901 4902 4903
{
  /*
    This constructor used to create some internals references over fixed items
  */
4904
  DBUG_ASSERT(ref != 0);
4905
  if (*ref && (*ref)->fixed)
4906 4907 4908 4909
    set_properties();
}


4910
/*
4911
  Resolve the name of a reference to a column reference.
4912 4913 4914

  SYNOPSIS
    Item_ref::fix_fields()
4915 4916
    thd       [in]      current thread
    reference [in/out]  view column if this item was resolved to a view column
4917 4918

  DESCRIPTION
4919 4920
    The method resolves the column reference represented by 'this' as a column
    present in one of: GROUP BY clause, SELECT clause, outer queries. It is
4921 4922
    used typically for columns in the HAVING clause which are not under
    aggregate functions.
4923 4924

  NOTES
4925 4926
    The name resolution algorithm used is (where [T_j] is an optional table
    name that qualifies the column name):
4927

4928 4929 4930
      resolve_extended([T_j].col_ref_i)
      {
        Search for a column or derived column named col_ref_i [in table T_j]
4931
        in the SELECT and GROUP clauses of Q.
4932

4933 4934
        if such a column is NOT found AND    // Lookup in outer queries.
           there are outer queries
4935 4936 4937
        {
          for each outer query Q_k beginning from the inner-most one
         {
4938 4939 4940 4941 4942 4943 4944 4945
            Search for a column or derived column named col_ref_i
            [in table T_j] in the SELECT and GROUP clauses of Q_k.

            if such a column is not found AND
               - Q_k is not a group query AND
               - Q_k is not inside an aggregate function
               OR
               - Q_(k-1) is not in a HAVING or SELECT clause of Q_k
4946 4947 4948 4949 4950 4951 4952
            {
              search for a column or derived column named col_ref_i
              [in table T_j] in the FROM clause of Q_k;
            }
          }
        }
      }
4953 4954

    This procedure treats GROUP BY and SELECT clauses as one namespace for
4955 4956 4957
    column references in HAVING. Notice that compared to
    Item_field::fix_fields, here we first search the SELECT and GROUP BY
    clauses, and then we search the FROM clause.
4958

4959 4960 4961
  POSTCONDITION
    Item_ref::ref is 0 or points to a valid item

4962 4963 4964 4965
  RETURN
    TRUE  if error
    FALSE on success
*/
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4966

4967
bool Item_ref::fix_fields(THD *thd, Item **reference)
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4968
{
4969
  enum_parsing_place place= NO_MATTER;
4970
  DBUG_ASSERT(fixed == 0);
4971 4972
  SELECT_LEX *current_sel= thd->lex->current_select;

4973
  if (!ref || ref == not_found_item)
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4974
  {
4975 4976 4977
    if (!(ref= resolve_ref_in_select_and_group(thd, this,
                                               context->select_lex)))
      goto error;             /* Some error occurred (e.g. ambiguous names). */
4978

4979
    if (ref == not_found_item) /* This reference was not resolved. */
4980
    {
4981 4982
      Name_resolution_context *last_checked_context= context;
      Name_resolution_context *outer_context= context->outer_context;
4983 4984 4985
      Field *from_field;
      ref= 0;

4986
      if (!outer_context)
4987 4988 4989 4990
      {
        /* The current reference cannot be resolved in this query. */
        my_error(ER_BAD_FIELD_ERROR,MYF(0),
                 this->full_name(), current_thd->where);
4991
        goto error;
4992
      }
4993

4994
      /*
4995 4996 4997
        If there is an outer context (select), and it is not a derived table
        (which do not support the use of outer fields for now), try to
        resolve this reference in the outer select(s).
4998

4999 5000 5001
        We treat each subselect as a separate namespace, so that different
        subselects may contain columns with the same names. The subselects are
        searched starting from the innermost.
5002
      */
5003 5004
      from_field= (Field*) not_found_field;

5005
      do
5006
      {
5007 5008 5009 5010
        SELECT_LEX *select= outer_context->select_lex;
        Item_subselect *prev_subselect_item=
          last_checked_context->select_lex->master_unit()->item;
        last_checked_context= outer_context;
5011

5012
        /* Search in the SELECT and GROUP lists of the outer select. */
5013
        if (outer_context->resolve_in_select_list)
5014
        {
5015 5016
          if (!(ref= resolve_ref_in_select_and_group(thd, this, select)))
            goto error; /* Some error occurred (e.g. ambiguous names). */
5017
          if (ref != not_found_item)
5018
          {
5019 5020 5021 5022
            DBUG_ASSERT(*ref && (*ref)->fixed);
            prev_subselect_item->used_tables_cache|= (*ref)->used_tables();
            prev_subselect_item->const_item_cache&= (*ref)->const_item();
            break;
5023 5024
          }
          /*
5025 5026 5027
            Set ref to 0 to ensure that we get an error in case we replaced
            this item with another item and still use this item in some
            other place of the parse tree.
5028
          */
5029
          ref= 0;
5030
        }
5031

5032 5033 5034 5035 5036
        place= prev_subselect_item->parsing_place;
        /*
          Check table fields only if the subquery is used somewhere out of
          HAVING or the outer SELECT does not use grouping (i.e. tables are
          accessible).
5037
          TODO:
5038 5039 5040 5041 5042 5043
          Here we could first find the field anyway, and then test this
          condition, so that we can give a better error message -
          ER_WRONG_FIELD_WITH_GROUP, instead of the less informative
          ER_BAD_FIELD_ERROR which we produce now.
        */
        if ((place != IN_HAVING ||
5044 5045
             (!select->with_sum_func &&
              select->group_list.elements == 0)))
5046
        {
5047
          /*
5048 5049 5050
            In case of view, find_field_in_tables() write pointer to view
            field expression to 'reference', i.e. it substitute that
            expression instead of this Item_ref
5051
          */
5052
          from_field= find_field_in_tables(thd, this,
5053 5054 5055 5056
                                           outer_context->
                                             first_name_resolution_table,
                                           outer_context->
                                             last_name_resolution_table,
5057 5058
                                           reference,
                                           IGNORE_EXCEPT_NON_UNIQUE,
5059
                                           TRUE, TRUE);
5060
          if (! from_field)
5061
            goto error;
5062
          if (from_field == view_ref_found)
5063
          {
5064
            Item::Type refer_type= (*reference)->type();
5065 5066 5067 5068 5069
            prev_subselect_item->used_tables_cache|=
              (*reference)->used_tables();
            prev_subselect_item->const_item_cache&=
              (*reference)->const_item();
            DBUG_ASSERT((*reference)->type() == REF_ITEM);
5070 5071
            mark_as_dependent(thd, last_checked_context->select_lex,
                              context->select_lex, this,
5072 5073
                              ((refer_type == REF_ITEM ||
                                refer_type == FIELD_ITEM) ?
5074 5075 5076 5077 5078 5079
                               (Item_ident*) (*reference) :
                               0));
            /*
              view reference found, we substituted it instead of this
              Item, so can quit
            */
5080 5081
            return FALSE;
          }
5082 5083
          if (from_field != not_found_field)
          {
5084 5085 5086 5087 5088 5089 5090 5091 5092 5093 5094 5095 5096 5097 5098 5099 5100 5101 5102
            if (cached_table && cached_table->select_lex &&
                outer_context->select_lex &&
                cached_table->select_lex != outer_context->select_lex)
            {
              /*
                Due to cache, find_field_in_tables() can return field which
                doesn't belong to provided outer_context. In this case we have
                to find proper field context in order to fix field correcly.
              */
              do
              {
                outer_context= outer_context->outer_context;
                select= outer_context->select_lex;
                prev_subselect_item=
                  last_checked_context->select_lex->master_unit()->item;
                last_checked_context= outer_context;
              } while (outer_context && outer_context->select_lex &&
                       cached_table->select_lex != outer_context->select_lex);
            }
5103 5104 5105 5106
            prev_subselect_item->used_tables_cache|= from_field->table->map;
            prev_subselect_item->const_item_cache= 0;
            break;
          }
5107
        }
5108 5109 5110 5111 5112 5113
        DBUG_ASSERT(from_field == not_found_field);

        /* Reference is not found => depend on outer (or just error). */
        prev_subselect_item->used_tables_cache|= OUTER_REF_TABLE_BIT;
        prev_subselect_item->const_item_cache= 0;

5114 5115
        outer_context= outer_context->outer_context;
      } while (outer_context);
5116 5117 5118

      DBUG_ASSERT(from_field != 0 && from_field != view_ref_found);
      if (from_field != not_found_field)
5119
      {
5120 5121
        Item_field* fld;
        if (!(fld= new Item_field(from_field)))
5122
          goto error;
5123
        thd->change_item_tree(reference, fld);
5124 5125
        mark_as_dependent(thd, last_checked_context->select_lex,
                          thd->lex->current_select, this, fld);
5126 5127 5128 5129 5130 5131
        return FALSE;
      }
      if (ref == 0)
      {
        /* The item was not a table field and not a reference */
        my_error(ER_BAD_FIELD_ERROR, MYF(0),
5132
                 this->full_name(), current_thd->where);
5133
        goto error;
5134
      }
5135 5136
      /* Should be checked in resolve_ref_in_select_and_group(). */
      DBUG_ASSERT(*ref && (*ref)->fixed);
5137 5138
      mark_as_dependent(thd, last_checked_context->select_lex,
                        context->select_lex, this, this);
5139
    }
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5140
  }
5141

5142
  DBUG_ASSERT(*ref);
5143
  /*
5144 5145 5146
    Check if this is an incorrect reference in a group function or forward
    reference. Do not issue an error if this is an unnamed reference inside an
    aggregate function.
5147
  */
5148
  if (((*ref)->with_sum_func && name &&
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5149 5150
       !(current_sel->linkage != GLOBAL_OPTIONS_TYPE &&
         current_sel->having_fix_field)) ||
5151 5152
      !(*ref)->fixed)
  {
5153 5154 5155 5156
    my_error(ER_ILLEGAL_REFERENCE, MYF(0),
             name, ((*ref)->with_sum_func?
                    "reference to group function":
                    "forward reference in item list"));
5157
    goto error;
5158
  }
5159 5160 5161

  set_properties();

5162
  if ((*ref)->check_cols(1))
5163
    goto error;
5164
  return FALSE;
5165 5166 5167 5168

error:
  context->process_error(thd);
  return TRUE;
5169 5170
}

5171

5172 5173
void Item_ref::set_properties()
{
5174 5175 5176
  max_length= (*ref)->max_length;
  maybe_null= (*ref)->maybe_null;
  decimals=   (*ref)->decimals;
5177
  collation.set((*ref)->collation);
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5178 5179 5180 5181
  /*
    We have to remember if we refer to a sum function, to ensure that
    split_sum_func() doesn't try to change the reference.
  */
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5182
  with_sum_func= (*ref)->with_sum_func;
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Merge  
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5183
  unsigned_flag= (*ref)->unsigned_flag;
5184 5185 5186 5187
  if ((*ref)->type() == FIELD_ITEM)
    alias_name_used= ((Item_ident *) (*ref))->alias_name_used;
  else
    alias_name_used= TRUE; // it is not field, so it is was resolved by alias
5188
  fixed= 1;
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5189 5190
}

5191

hf@deer.(none)'s avatar
hf@deer.(none) committed
5192 5193
void Item_ref::cleanup()
{
5194
  DBUG_ENTER("Item_ref::cleanup");
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hf@deer.(none) committed
5195
  Item_ident::cleanup();
5196
  result_field= 0;
5197
  DBUG_VOID_RETURN;
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hf@deer.(none) committed
5198 5199 5200
}


5201 5202
void Item_ref::print(String *str)
{
5203
  if (ref)
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5204 5205 5206 5207 5208 5209 5210 5211 5212 5213
  {
    if ((*ref)->type() != Item::CACHE_ITEM && ref_type() != VIEW_REF &&
        name && alias_name_used)
    {
      THD *thd= current_thd;
      append_identifier(thd, str, name, (uint) strlen(name));
    }
    else
      (*ref)->print(str);
  }
5214 5215 5216 5217 5218
  else
    Item_ident::print(str);
}


5219 5220 5221 5222 5223 5224 5225 5226
bool Item_ref::send(Protocol *prot, String *tmp)
{
  if (result_field)
    return prot->store(result_field);
  return (*ref)->send(prot, tmp);
}


5227 5228 5229 5230 5231 5232 5233 5234
double Item_ref::val_result()
{
  if (result_field)
  {
    if ((null_value= result_field->is_null()))
      return 0.0;
    return result_field->val_real();
  }
5235
  return val_real();
5236 5237 5238 5239 5240 5241 5242 5243
}


longlong Item_ref::val_int_result()
{
  if (result_field)
  {
    if ((null_value= result_field->is_null()))
5244
      return 0;
5245 5246 5247 5248 5249 5250 5251 5252 5253 5254 5255 5256 5257 5258 5259 5260 5261 5262 5263
    return result_field->val_int();
  }
  return val_int();
}


String *Item_ref::str_result(String* str)
{
  if (result_field)
  {
    if ((null_value= result_field->is_null()))
      return 0;
    str->set_charset(str_value.charset());
    return result_field->val_str(str, &str_value);
  }
  return val_str(str);
}


5264 5265 5266 5267 5268 5269 5270 5271 5272 5273 5274 5275 5276 5277 5278 5279 5280 5281
my_decimal *Item_ref::val_decimal_result(my_decimal *decimal_value)
{
  if (result_field)
  {
    if ((null_value= result_field->is_null()))
      return 0;
    return result_field->val_decimal(decimal_value);
  }
  return val_decimal(decimal_value);
}


bool Item_ref::val_bool_result()
{
  if (result_field)
  {
    if ((null_value= result_field->is_null()))
      return 0;
5282
    switch (result_field->result_type()) {
5283
    case INT_RESULT:
5284
      return result_field->val_int() != 0;
5285
    case DECIMAL_RESULT:
5286 5287 5288 5289 5290 5291 5292
    {
      my_decimal decimal_value;
      my_decimal *val= result_field->val_decimal(&decimal_value);
      if (val)
        return !my_decimal_is_zero(val);
      return 0;
    }
5293 5294 5295 5296 5297 5298 5299 5300 5301 5302 5303 5304 5305 5306 5307 5308 5309 5310 5311 5312 5313 5314 5315 5316 5317 5318 5319 5320 5321 5322 5323 5324 5325 5326 5327 5328 5329 5330 5331 5332 5333 5334 5335 5336 5337 5338 5339 5340 5341 5342 5343
    case REAL_RESULT:
    case STRING_RESULT:
      return result_field->val_real() != 0.0;
    case ROW_RESULT:
    default:
      DBUG_ASSERT(0);
    }
  }
  return val_bool();
}


double Item_ref::val_real()
{
  DBUG_ASSERT(fixed);
  double tmp=(*ref)->val_result();
  null_value=(*ref)->null_value;
  return tmp;
}


longlong Item_ref::val_int()
{
  DBUG_ASSERT(fixed);
  longlong tmp=(*ref)->val_int_result();
  null_value=(*ref)->null_value;
  return tmp;
}


bool Item_ref::val_bool()
{
  DBUG_ASSERT(fixed);
  bool tmp= (*ref)->val_bool_result();
  null_value= (*ref)->null_value;
  return tmp;
}


String *Item_ref::val_str(String* tmp)
{
  DBUG_ASSERT(fixed);
  tmp=(*ref)->str_result(tmp);
  null_value=(*ref)->null_value;
  return tmp;
}


bool Item_ref::is_null()
{
  DBUG_ASSERT(fixed);
5344
  return (*ref)->is_null();
5345 5346 5347 5348 5349 5350 5351 5352 5353 5354 5355
}


bool Item_ref::get_date(TIME *ltime,uint fuzzydate)
{
  return (null_value=(*ref)->get_date_result(ltime,fuzzydate));
}


my_decimal *Item_ref::val_decimal(my_decimal *decimal_value)
{
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5356
  my_decimal *val= (*ref)->val_decimal_result(decimal_value);
5357 5358 5359 5360
  null_value= (*ref)->null_value;
  return val;
}

5361 5362 5363
int Item_ref::save_in_field(Field *to, bool no_conversions)
{
  int res;
5364 5365
  if (result_field)
  {
5366 5367 5368 5369 5370
    if (result_field->is_null())
    {
      null_value= 1;
      return set_field_to_null_with_conversions(to, no_conversions);
    }
5371 5372 5373
    to->set_notnull();
    field_conv(to, result_field);
    null_value= 0;
5374 5375 5376 5377 5378 5379 5380
    return 0;
  }
  res= (*ref)->save_in_field(to, no_conversions);
  null_value= (*ref)->null_value;
  return res;
}

5381

5382 5383 5384 5385 5386 5387
void Item_ref::save_org_in_field(Field *field)
{
  (*ref)->save_org_in_field(field);
}


5388 5389 5390 5391 5392 5393 5394 5395 5396 5397
void Item_ref::make_field(Send_field *field)
{
  (*ref)->make_field(field);
  /* Non-zero in case of a view */
  if (name)
    field->col_name= name;
  if (table_name)
    field->table_name= table_name;
  if (db_name)
    field->db_name= db_name;
5398
}
5399 5400


5401 5402
void Item_ref_null_helper::print(String *str)
{
5403
  str->append(STRING_WITH_LEN("<ref_null_helper>("));
5404
  if (ref)
5405 5406 5407 5408 5409 5410 5411
    (*ref)->print(str);
  else
    str->append('?');
  str->append(')');
}


5412 5413 5414 5415 5416 5417 5418 5419 5420 5421 5422 5423 5424 5425 5426 5427 5428 5429 5430 5431 5432 5433 5434 5435 5436 5437 5438 5439 5440 5441 5442 5443 5444 5445 5446 5447 5448 5449 5450 5451 5452 5453
double Item_direct_ref::val_real()
{
  double tmp=(*ref)->val_real();
  null_value=(*ref)->null_value;
  return tmp;
}


longlong Item_direct_ref::val_int()
{
  longlong tmp=(*ref)->val_int();
  null_value=(*ref)->null_value;
  return tmp;
}


String *Item_direct_ref::val_str(String* tmp)
{
  tmp=(*ref)->val_str(tmp);
  null_value=(*ref)->null_value;
  return tmp;
}


my_decimal *Item_direct_ref::val_decimal(my_decimal *decimal_value)
{
  my_decimal *tmp= (*ref)->val_decimal(decimal_value);
  null_value=(*ref)->null_value;
  return tmp;
}


bool Item_direct_ref::val_bool()
{
  bool tmp= (*ref)->val_bool();
  null_value=(*ref)->null_value;
  return tmp;
}


bool Item_direct_ref::is_null()
{
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5454
  return (*ref)->is_null();
5455 5456 5457 5458 5459 5460 5461 5462 5463
}


bool Item_direct_ref::get_date(TIME *ltime,uint fuzzydate)
{
  return (null_value=(*ref)->get_date(ltime,fuzzydate));
}


5464 5465 5466 5467 5468 5469 5470 5471 5472 5473 5474 5475 5476 5477 5478 5479 5480 5481 5482 5483 5484 5485 5486 5487
/*
  Prepare referenced view viewld then call usual Item_direct_ref::fix_fields

  SYNOPSIS
    Item_direct_view_ref::fix_fields()
    thd         thread handler
    reference   reference on reference where this item stored

  RETURN
    FALSE   OK
    TRUE    Error
*/

bool Item_direct_view_ref::fix_fields(THD *thd, Item **reference)
{
  /* view fild reference must be defined */
  DBUG_ASSERT(*ref);
  /* (*ref)->check_cols() will be made in Item_direct_ref::fix_fields */
  if (!(*ref)->fixed &&
      ((*ref)->fix_fields(thd, ref)))
    return TRUE;
  return Item_direct_ref::fix_fields(thd, reference);
}

5488
/*
5489
  Compare two view column references for equality.
5490 5491 5492 5493 5494 5495 5496

  SYNOPSIS
    Item_direct_view_ref::eq()
    item        item to compare with
    binary_cmp  make binary comparison

  DESCRIPTION
5497 5498
    A view column reference is considered equal to another column
    reference if the second one is a view column and if both column
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5499 5500
    references resolve to the same item. It is assumed that both
    items are of the same type.
5501 5502 5503 5504 5505 5506 5507 5508 5509

  RETURN
    TRUE    Referenced item is equal to given item
    FALSE   otherwise
*/


bool Item_direct_view_ref::eq(const Item *item, bool binary_cmp) const
{
5510 5511 5512 5513 5514 5515
  if (item->type() == REF_ITEM)
  {
    Item_ref *item_ref= (Item_ref*) item;
    if (item_ref->ref_type() == VIEW_REF)
    {
      Item *item_ref_ref= *(item_ref->ref);
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5516 5517
      DBUG_ASSERT((*ref)->real_item()->type() == 
                  item_ref_ref->real_item()->type());
5518
      return ((*ref)->real_item() == item_ref_ref->real_item());
5519 5520 5521
    }
  }
  return FALSE;
5522
}
5523

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5524 5525
bool Item_default_value::eq(const Item *item, bool binary_cmp) const
{
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5526
  return item->type() == DEFAULT_VALUE_ITEM && 
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5527 5528 5529
    ((Item_default_value *)item)->arg->eq(arg, binary_cmp);
}

5530

5531
bool Item_default_value::fix_fields(THD *thd, Item **items)
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5532
{
5533
  Item *real_arg;
5534 5535
  Item_field *field_arg;
  Field *def_field;
5536
  DBUG_ASSERT(fixed == 0);
5537

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5538
  if (!arg)
5539 5540
  {
    fixed= 1;
5541
    return FALSE;
5542
  }
5543 5544 5545
  if (!arg->fixed && arg->fix_fields(thd, &arg))
    goto error;

5546

5547 5548
  real_arg= arg->real_item();
  if (real_arg->type() != FIELD_ITEM)
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5549
  {
5550
    my_error(ER_NO_DEFAULT_FOR_FIELD, MYF(0), arg->name);
5551
    goto error;
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5552
  }
5553

5554
  field_arg= (Item_field *)real_arg;
5555 5556
  if (field_arg->field->flags & NO_DEFAULT_VALUE_FLAG)
  {
5557
    my_error(ER_NO_DEFAULT_FOR_FIELD, MYF(0), field_arg->field->field_name);
5558
    goto error;
5559 5560
  }
  if (!(def_field= (Field*) sql_alloc(field_arg->field->size_of())))
5561
    goto error;
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5562
  memcpy(def_field, field_arg->field, field_arg->field->size_of());
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  def_field->move_field_offset((my_ptrdiff_t)
                               (def_field->table->s->default_values -
                                def_field->table->record[0]));
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5566
  set_field(def_field);
5567
  return FALSE;
5568 5569 5570 5571

error:
  context->process_error(thd);
  return TRUE;
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}

5574

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5575 5576
void Item_default_value::print(String *str)
{
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5577 5578
  if (!arg)
  {
5579
    str->append(STRING_WITH_LEN("default"));
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5580
    return;
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5581
  }
5582
  str->append(STRING_WITH_LEN("default("));
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5583 5584 5585
  arg->print(str);
  str->append(')');
}
5586

5587 5588 5589 5590 5591 5592 5593

int Item_default_value::save_in_field(Field *field_arg, bool no_conversions)
{
  if (!arg)
  {
    if (field_arg->flags & NO_DEFAULT_VALUE_FLAG)
    {
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      if (field_arg->reset())
      {
        my_message(ER_CANT_CREATE_GEOMETRY_OBJECT,
                   ER(ER_CANT_CREATE_GEOMETRY_OBJECT), MYF(0));
        return -1;
      }

5601 5602
      if (context->error_processor == &view_error_processor)
      {
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5603
        TABLE_LIST *view= cached_table->top_table();
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        push_warning_printf(field_arg->table->in_use,
                            MYSQL_ERROR::WARN_LEVEL_WARN,
                            ER_NO_DEFAULT_FOR_VIEW_FIELD,
                            ER(ER_NO_DEFAULT_FOR_VIEW_FIELD),
                            view->view_db.str,
                            view->view_name.str);
      }
      else
      {
        push_warning_printf(field_arg->table->in_use,
                            MYSQL_ERROR::WARN_LEVEL_WARN,
                            ER_NO_DEFAULT_FOR_FIELD,
                            ER(ER_NO_DEFAULT_FOR_FIELD),
                            field_arg->field_name);
      }
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      return 1;
    }
    field_arg->set_default();
    return 0;
  }
  return Item_field::save_in_field(field_arg, no_conversions);
}


5628
/* 
5629 5630
  This method like the walk method traverses the item tree, but at the
  same time it can replace some nodes in the tree
5631
*/ 
5632

5633 5634 5635 5636 5637 5638 5639 5640 5641 5642 5643 5644 5645 5646 5647 5648 5649 5650 5651 5652
Item *Item_default_value::transform(Item_transformer transformer, byte *args)
{
  DBUG_ASSERT(!current_thd->is_stmt_prepare());

  Item *new_item= arg->transform(transformer, args);
  if (!new_item)
    return 0;

  /*
    THD::change_item_tree() should be called only if the tree was
    really transformed, i.e. when a new item has been created.
    Otherwise we'll be allocating a lot of unnecessary memory for
    change records at each execution.
  */
  if (arg != new_item)
    current_thd->change_item_tree(&arg, new_item);
  return (this->*transformer)(args);
}


5653 5654 5655 5656 5657 5658 5659
bool Item_insert_value::eq(const Item *item, bool binary_cmp) const
{
  return item->type() == INSERT_VALUE_ITEM &&
    ((Item_default_value *)item)->arg->eq(arg, binary_cmp);
}


5660
bool Item_insert_value::fix_fields(THD *thd, Item **items)
5661
{
5662
  DBUG_ASSERT(fixed == 0);
5663
  /* We should only check that arg is in first table */
5664
  if (!arg->fixed)
5665
  {
5666 5667 5668 5669
    bool res;
    st_table_list *orig_next_table= context->last_name_resolution_table;
    context->last_name_resolution_table= context->first_name_resolution_table;
    res= arg->fix_fields(thd, &arg);
5670
    context->last_name_resolution_table= orig_next_table;
5671 5672
    if (res)
      return TRUE;
5673
  }
5674

5675 5676 5677 5678 5679
  if (arg->type() == REF_ITEM)
  {
    Item_ref *ref= (Item_ref *)arg;
    if (ref->ref[0]->type() != FIELD_ITEM)
    {
5680
      my_error(ER_BAD_FIELD_ERROR, MYF(0), "", "VALUES() function");
5681
      return TRUE;
5682 5683 5684
    }
    arg= ref->ref[0];
  }
5685 5686 5687 5688 5689 5690
  /*
    According to our SQL grammar, VALUES() function can reference
    only to a column.
  */
  DBUG_ASSERT(arg->type() == FIELD_ITEM);

5691
  Item_field *field_arg= (Item_field *)arg;
5692

5693 5694 5695 5696
  if (field_arg->field->table->insert_values)
  {
    Field *def_field= (Field*) sql_alloc(field_arg->field->size_of());
    if (!def_field)
5697
      return TRUE;
5698
    memcpy(def_field, field_arg->field, field_arg->field->size_of());
5699 5700 5701
    def_field->move_field_offset((my_ptrdiff_t)
                                 (def_field->table->insert_values -
                                  def_field->table->record[0]));
5702 5703 5704 5705
    set_field(def_field);
  }
  else
  {
5706
    Field *tmp_field= field_arg->field;
5707
    /* charset doesn't matter here, it's to avoid sigsegv only */
5708 5709 5710 5711 5712 5713 5714
    tmp_field= new Field_null(0, 0, Field::NONE, field_arg->field->field_name,
                          &my_charset_bin);
    if (tmp_field)
    {
      tmp_field->init(field_arg->field->table);
      set_field(tmp_field);
    }
5715
  }
5716
  return FALSE;
5717 5718 5719 5720
}

void Item_insert_value::print(String *str)
{
5721
  str->append(STRING_WITH_LEN("values("));
5722 5723 5724 5725
  arg->print(str);
  str->append(')');
}

5726 5727

/*
5728 5729
  Find index of Field object which will be appropriate for item
  representing field of row being changed in trigger.
5730 5731 5732 5733 5734

  SYNOPSIS
    setup_field()
      thd   - current thread context
      table - table of trigger (and where we looking for fields)
5735
      table_grant_info - GRANT_INFO of the subject table
5736 5737 5738

  NOTE
    This function does almost the same as fix_fields() for Item_field
5739 5740 5741 5742 5743 5744 5745 5746
    but is invoked right after trigger definition parsing. Since at
    this stage we can't say exactly what Field object (corresponding
    to TABLE::record[0] or TABLE::record[1]) should be bound to this
    Item, we only find out index of the Field and then select concrete
    Field object in fix_fields() (by that time Table_trigger_list::old_field/
    new_field should point to proper array of Fields).
    It also binds Item_trigger_field to Table_triggers_list object for
    table of trigger which uses this item.
5747
*/
5748

5749 5750
void Item_trigger_field::setup_field(THD *thd, TABLE *table,
                                     GRANT_INFO *table_grant_info)
5751
{
5752
  /*
5753 5754 5755 5756 5757
    It is too early to mark fields used here, because before execution
    of statement that will invoke trigger other statements may use same
    TABLE object, so all such mark-up will be wiped out.
    So instead we do it in Table_triggers_list::mark_fields_used()
    method which is called during execution of these statements.
5758
  */
5759 5760
  enum_mark_columns save_mark_used_columns= thd->mark_used_columns;
  thd->mark_used_columns= MARK_COLUMNS_NONE;
5761 5762 5763 5764
  /*
    Try to find field by its name and if it will be found
    set field_idx properly.
  */
5765
  (void)find_field_in_table(thd, table, field_name, (uint) strlen(field_name),
5766
                            0, &field_idx);
5767
  thd->mark_used_columns= save_mark_used_columns;
5768
  triggers= table->triggers;
5769
  table_grants= table_grant_info;
5770 5771 5772 5773 5774 5775 5776 5777 5778 5779 5780 5781
}


bool Item_trigger_field::eq(const Item *item, bool binary_cmp) const
{
  return item->type() == TRIGGER_FIELD_ITEM &&
         row_version == ((Item_trigger_field *)item)->row_version &&
         !my_strcasecmp(system_charset_info, field_name,
                        ((Item_trigger_field *)item)->field_name);
}


5782
void Item_trigger_field::set_required_privilege(bool rw)
5783 5784 5785 5786 5787 5788 5789 5790 5791
{
  /*
    Require SELECT and UPDATE privilege if this field will be read and
    set, and only UPDATE privilege for setting the field.
  */
  want_privilege= (rw ? SELECT_ACL | UPDATE_ACL : UPDATE_ACL);
}


5792
bool Item_trigger_field::set_value(THD *thd, sp_rcontext * /*ctx*/, Item **it)
5793
{
5794
  Item *item= sp_prepare_func_item(thd, it);
5795 5796 5797 5798 5799 5800

  return (!item || (!fixed && fix_fields(thd, 0)) ||
          (item->save_in_field(field, 0) < 0));
}


5801
bool Item_trigger_field::fix_fields(THD *thd, Item **items)
5802 5803 5804 5805 5806 5807
{
  /*
    Since trigger is object tightly associated with TABLE object most
    of its set up can be performed during trigger loading i.e. trigger
    parsing! So we have little to do in fix_fields. :)
  */
5808

5809
  DBUG_ASSERT(fixed == 0);
5810

5811 5812
  /* Set field. */

5813
  if (field_idx != (uint)-1)
5814
  {
5815 5816 5817 5818 5819 5820 5821 5822
#ifndef NO_EMBEDDED_ACCESS_CHECKS
    /*
      Check access privileges for the subject table. We check privileges only
      in runtime.
    */

    if (table_grants)
    {
5823
      table_grants->want_privilege= want_privilege;
5824

5825 5826
      if (check_grant_column(thd, table_grants, triggers->trigger_table->s->db.str,
                             triggers->trigger_table->s->table_name.str, field_name,
5827 5828 5829 5830 5831
                             strlen(field_name), thd->security_ctx))
        return TRUE;
    }
#endif // NO_EMBEDDED_ACCESS_CHECKS

5832 5833
    field= (row_version == OLD_ROW) ? triggers->old_field[field_idx] :
                                      triggers->new_field[field_idx];
5834 5835
    set_field(field);
    fixed= 1;
5836
    return FALSE;
5837 5838 5839 5840
  }

  my_error(ER_BAD_FIELD_ERROR, MYF(0), field_name,
           (row_version == NEW_ROW) ? "NEW" : "OLD");
5841
  return TRUE;
5842 5843 5844 5845 5846 5847 5848 5849 5850 5851 5852 5853 5854
}


void Item_trigger_field::print(String *str)
{
  str->append((row_version == NEW_ROW) ? "NEW" : "OLD", 3);
  str->append('.');
  str->append(field_name);
}


void Item_trigger_field::cleanup()
{
5855
  want_privilege= original_privilege;
5856 5857 5858 5859 5860 5861 5862 5863
  /*
    Since special nature of Item_trigger_field we should not do most of
    things from Item_field::cleanup() or Item_ident::cleanup() here.
  */
  Item::cleanup();
}


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5864 5865 5866 5867
Item_result item_cmp_type(Item_result a,Item_result b)
{
  if (a == STRING_RESULT && b == STRING_RESULT)
    return STRING_RESULT;
5868
  if (a == INT_RESULT && b == INT_RESULT)
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5869
    return INT_RESULT;
5870 5871
  else if (a == ROW_RESULT || b == ROW_RESULT)
    return ROW_RESULT;
5872 5873 5874
  if ((a == INT_RESULT || a == DECIMAL_RESULT) &&
      (b == INT_RESULT || b == DECIMAL_RESULT))
    return DECIMAL_RESULT;
5875
  return REAL_RESULT;
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5876 5877 5878
}


5879
void resolve_const_item(THD *thd, Item **ref, Item *comp_item)
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5880
{
5881
  Item *item= *ref;
5882
  Item *new_item= NULL;
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5883
  if (item->basic_const_item())
5884
    return;                                     // Can't be better
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5885 5886 5887 5888
  Item_result res_type=item_cmp_type(comp_item->result_type(),
				     item->result_type());
  char *name=item->name;			// Alloced by sql_alloc

5889
  switch (res_type) {
5890
  case STRING_RESULT:
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5891 5892
  {
    char buff[MAX_FIELD_WIDTH];
5893
    String tmp(buff,sizeof(buff),&my_charset_bin),*result;
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5894 5895
    result=item->val_str(&tmp);
    if (item->null_value)
5896 5897 5898 5899 5900 5901 5902
      new_item= new Item_null(name);
    else
    {
      uint length= result->length();
      char *tmp_str= sql_strmake(result->ptr(), length);
      new_item= new Item_string(name, tmp_str, length, result->charset());
    }
5903
    break;
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5904
  }
5905
  case INT_RESULT:
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5906 5907 5908 5909
  {
    longlong result=item->val_int();
    uint length=item->max_length;
    bool null_value=item->null_value;
5910 5911
    new_item= (null_value ? (Item*) new Item_null(name) :
               (Item*) new Item_int(name, result, length));
5912
    break;
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5913
  }
5914
  case ROW_RESULT:
5915
  if (item->type() == Item::ROW_ITEM && comp_item->type() == Item::ROW_ITEM)
5916
  {
5917 5918 5919 5920 5921 5922 5923 5924
    /*
      Substitute constants only in Item_rows. Don't affect other Items
      with ROW_RESULT (eg Item_singlerow_subselect).

      For such Items more optimal is to detect if it is constant and replace
      it with Item_row. This would optimize queries like this:
      SELECT * FROM t1 WHERE (a,b) = (SELECT a,b FROM t2 LIMIT 1);
    */
5925 5926 5927
    Item_row *item_row= (Item_row*) item;
    Item_row *comp_item_row= (Item_row*) comp_item;
    uint col;
5928 5929 5930
    new_item= 0;
    /*
      If item and comp_item are both Item_rows and have same number of cols
5931 5932 5933
      then process items in Item_row one by one.
      We can't ignore NULL values here as this item may be used with <=>, in
      which case NULL's are significant.
5934
    */
5935 5936 5937 5938
    DBUG_ASSERT(item->result_type() == comp_item->result_type());
    DBUG_ASSERT(item_row->cols() == comp_item_row->cols());
    col= item_row->cols();
    while (col-- > 0)
5939 5940
      resolve_const_item(thd, item_row->addr(col),
                         comp_item_row->element_index(col));
5941
    break;
5942
  }
5943
  /* Fallthrough */
5944
  case REAL_RESULT:
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5945
  {						// It must REAL_RESULT
5946
    double result= item->val_real();
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5947 5948
    uint length=item->max_length,decimals=item->decimals;
    bool null_value=item->null_value;
5949
    new_item= (null_value ? (Item*) new Item_null(name) : (Item*)
5950 5951 5952 5953 5954 5955 5956 5957 5958 5959 5960 5961 5962 5963 5964 5965
               new Item_float(name, result, decimals, length));
    break;
  }
  case DECIMAL_RESULT:
  {
    my_decimal decimal_value;
    my_decimal *result= item->val_decimal(&decimal_value);
    uint length= item->max_length, decimals= item->decimals;
    bool null_value= item->null_value;
    new_item= (null_value ?
               (Item*) new Item_null(name) :
               (Item*) new Item_decimal(name, result, length, decimals));
    break;
  }
  default:
    DBUG_ASSERT(0);
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5966
  }
5967 5968
  if (new_item)
    thd->change_item_tree(ref, new_item);
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}

/*
  Return true if the value stored in the field is equal to the const item
  We need to use this on the range optimizer because in some cases
  we can't store the value in the field without some precision/character loss.
*/

bool field_is_equal_to_item(Field *field,Item *item)
{

  Item_result res_type=item_cmp_type(field->result_type(),
				     item->result_type());
  if (res_type == STRING_RESULT)
  {
    char item_buff[MAX_FIELD_WIDTH];
    char field_buff[MAX_FIELD_WIDTH];
5986 5987
    String item_tmp(item_buff,sizeof(item_buff),&my_charset_bin),*item_result;
    String field_tmp(field_buff,sizeof(field_buff),&my_charset_bin);
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    item_result=item->val_str(&item_tmp);
    if (item->null_value)
      return 1;					// This must be true
5991
    field->val_str(&field_tmp);
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5992
    return !stringcmp(&field_tmp,item_result);
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  }
  if (res_type == INT_RESULT)
    return 1;					// Both where of type int
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  if (res_type == DECIMAL_RESULT)
  {
    my_decimal item_buf, *item_val,
               field_buf, *field_val;
    item_val= item->val_decimal(&item_buf);
    if (item->null_value)
      return 1;					// This must be true
    field_val= field->val_decimal(&field_buf);
    return !my_decimal_cmp(item_val, field_val);
  }
6006
  double result= item->val_real();
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6007 6008 6009 6010 6011
  if (item->null_value)
    return 1;
  return result == field->val_real();
}

6012 6013
Item_cache* Item_cache::get_cache(Item_result type)
{
6014
  switch (type) {
6015 6016 6017 6018
  case INT_RESULT:
    return new Item_cache_int();
  case REAL_RESULT:
    return new Item_cache_real();
6019 6020
  case DECIMAL_RESULT:
    return new Item_cache_decimal();
6021 6022
  case STRING_RESULT:
    return new Item_cache_str();
6023 6024
  case ROW_RESULT:
    return new Item_cache_row();
6025 6026 6027 6028 6029 6030 6031
  default:
    // should never be in real life
    DBUG_ASSERT(0);
    return 0;
  }
}

6032 6033 6034

void Item_cache::print(String *str)
{
6035
  str->append(STRING_WITH_LEN("<cache>("));
6036 6037 6038 6039 6040 6041 6042 6043 6044 6045 6046 6047
  if (example)
    example->print(str);
  else
    Item::print(str);
  str->append(')');
}


void Item_cache_int::store(Item *item)
{
  value= item->val_int_result();
  null_value= item->null_value;
6048 6049 6050 6051 6052 6053 6054 6055 6056 6057 6058 6059 6060 6061 6062 6063 6064
  unsigned_flag= item->unsigned_flag;
}


String *Item_cache_int::val_str(String *str)
{
  DBUG_ASSERT(fixed == 1);
  str->set(value, default_charset());
  return str;
}


my_decimal *Item_cache_int::val_decimal(my_decimal *decimal_val)
{
  DBUG_ASSERT(fixed == 1);
  int2my_decimal(E_DEC_FATAL_ERROR, value, unsigned_flag, decimal_val);
  return decimal_val;
6065 6066 6067 6068 6069 6070 6071 6072 6073 6074
}


void Item_cache_real::store(Item *item)
{
  value= item->val_result();
  null_value= item->null_value;
}


6075 6076 6077
longlong Item_cache_real::val_int()
{
  DBUG_ASSERT(fixed == 1);
6078
  return (longlong) rint(value);
6079 6080 6081 6082 6083 6084
}


String* Item_cache_real::val_str(String *str)
{
  DBUG_ASSERT(fixed == 1);
6085
  str->set_real(value, decimals, default_charset());
6086 6087 6088 6089 6090 6091 6092 6093 6094 6095 6096 6097 6098 6099 6100
  return str;
}


my_decimal *Item_cache_real::val_decimal(my_decimal *decimal_val)
{
  DBUG_ASSERT(fixed == 1);
  double2my_decimal(E_DEC_FATAL_ERROR, value, decimal_val);
  return decimal_val;
}


void Item_cache_decimal::store(Item *item)
{
  my_decimal *val= item->val_decimal_result(&decimal_value);
6101
  if (!(null_value= item->null_value) && val != &decimal_value)
6102 6103 6104 6105 6106 6107 6108 6109 6110 6111 6112 6113 6114 6115 6116 6117 6118 6119 6120 6121 6122 6123 6124 6125 6126 6127 6128 6129 6130 6131 6132 6133 6134 6135 6136
    my_decimal2decimal(val, &decimal_value);
}

double Item_cache_decimal::val_real()
{
  DBUG_ASSERT(fixed);
  double res;
  my_decimal2double(E_DEC_FATAL_ERROR, &decimal_value, &res);
  return res;
}

longlong Item_cache_decimal::val_int()
{
  DBUG_ASSERT(fixed);
  longlong res;
  my_decimal2int(E_DEC_FATAL_ERROR, &decimal_value, unsigned_flag, &res);
  return res;
}

String* Item_cache_decimal::val_str(String *str)
{
  DBUG_ASSERT(fixed);
  my_decimal_round(E_DEC_FATAL_ERROR, &decimal_value, decimals, FALSE,
                   &decimal_value);
  my_decimal2string(E_DEC_FATAL_ERROR, &decimal_value, 0, 0, 0, str);
  return str;
}

my_decimal *Item_cache_decimal::val_decimal(my_decimal *val)
{
  DBUG_ASSERT(fixed);
  return &decimal_value;
}


6137 6138
void Item_cache_str::store(Item *item)
{
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6139
  value_buff.set(buffer, sizeof(buffer), item->collation.collation);
6140
  value= item->str_result(&value_buff);
6141 6142
  if ((null_value= item->null_value))
    value= 0;
6143
  else if (value != &value_buff)
6144 6145 6146 6147 6148 6149 6150 6151 6152
  {
    /*
      We copy string value to avoid changing value if 'item' is table field
      in queries like following (where t1.c is varchar):
      select a, 
             (select a,b,c from t1 where t1.a=t2.a) = ROW(a,2,'a'),
             (select c from t1 where a=t2.a)
        from t2;
    */
6153 6154
    value_buff.copy(*value);
    value= &value_buff;
6155 6156
  }
}
6157

6158
double Item_cache_str::val_real()
6159 6160
{
  DBUG_ASSERT(fixed == 1);
6161 6162
  int err_not_used;
  char *end_not_used;
6163
  if (value)
6164
    return my_strntod(value->charset(), (char*) value->ptr(),
6165 6166
		      value->length(), &end_not_used, &err_not_used);
  return (double) 0;
6167
}
6168 6169


6170 6171
longlong Item_cache_str::val_int()
{
6172
  DBUG_ASSERT(fixed == 1);
6173
  int err;
6174 6175
  if (value)
    return my_strntoll(value->charset(), value->ptr(),
6176
		       value->length(), 10, (char**) 0, &err);
6177 6178 6179
  else
    return (longlong)0;
}
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6180

6181 6182 6183 6184 6185 6186 6187 6188 6189 6190
my_decimal *Item_cache_str::val_decimal(my_decimal *decimal_val)
{
  DBUG_ASSERT(fixed == 1);
  if (value)
    string2my_decimal(E_DEC_FATAL_ERROR, value, decimal_val);
  else
    decimal_val= 0;
  return decimal_val;
}

6191

6192 6193
bool Item_cache_row::allocate(uint num)
{
6194
  item_count= num;
6195
  THD *thd= current_thd;
6196 6197
  return (!(values= 
	    (Item_cache **) thd->calloc(sizeof(Item_cache *)*item_count)));
6198 6199
}

6200

6201 6202
bool Item_cache_row::setup(Item * item)
{
6203
  example= item;
6204 6205
  if (!values && allocate(item->cols()))
    return 1;
6206
  for (uint i= 0; i < item_count; i++)
6207
  {
6208
    Item *el= item->element_index(i);
6209 6210
    Item_cache *tmp;
    if (!(tmp= values[i]= Item_cache::get_cache(el->result_type())))
6211
      return 1;
6212
    tmp->setup(el);
6213 6214 6215 6216
  }
  return 0;
}

6217

6218 6219 6220 6221
void Item_cache_row::store(Item * item)
{
  null_value= 0;
  item->bring_value();
6222
  for (uint i= 0; i < item_count; i++)
6223
  {
6224
    values[i]->store(item->element_index(i));
6225 6226 6227 6228
    null_value|= values[i]->null_value;
  }
}

6229

6230 6231 6232 6233 6234
void Item_cache_row::illegal_method_call(const char *method)
{
  DBUG_ENTER("Item_cache_row::illegal_method_call");
  DBUG_PRINT("error", ("!!! %s method was called for row item", method));
  DBUG_ASSERT(0);
6235
  my_error(ER_OPERAND_COLUMNS, MYF(0), 1);
6236 6237 6238
  DBUG_VOID_RETURN;
}

6239

6240 6241
bool Item_cache_row::check_cols(uint c)
{
6242
  if (c != item_count)
6243
  {
6244
    my_error(ER_OPERAND_COLUMNS, MYF(0), c);
6245 6246 6247 6248 6249
    return 1;
  }
  return 0;
}

6250

6251 6252
bool Item_cache_row::null_inside()
{
6253
  for (uint i= 0; i < item_count; i++)
6254 6255 6256 6257 6258 6259 6260 6261
  {
    if (values[i]->cols() > 1)
    {
      if (values[i]->null_inside())
	return 1;
    }
    else
    {
6262
      values[i]->update_null_value();
6263 6264 6265 6266 6267 6268 6269
      if (values[i]->null_value)
	return 1;
    }
  }
  return 0;
}

6270

6271 6272
void Item_cache_row::bring_value()
{
6273
  for (uint i= 0; i < item_count; i++)
6274 6275 6276
    values[i]->bring_value();
  return;
}
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6277

6278

6279 6280
Item_type_holder::Item_type_holder(THD *thd, Item *item)
  :Item(thd, item), enum_set_typelib(0), fld_type(get_real_type(item))
6281 6282
{
  DBUG_ASSERT(item->fixed);
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6283

6284
  max_length= display_length(item);
6285
  maybe_null= item->maybe_null;
6286
  collation.set(item->collation);
6287
  get_full_info(item);
6288 6289 6290
  /* fix variable decimals which always is NOT_FIXED_DEC */
  if (Field::result_merge_type(fld_type) == INT_RESULT)
    decimals= 0;
6291
  prev_decimal_int_part= item->decimal_int_part();
6292 6293 6294
}


6295
/*
6296
  Return expression type of Item_type_holder
6297 6298

  SYNOPSIS
6299
    Item_type_holder::result_type()
6300 6301

  RETURN
6302
     Item_result (type of internal MySQL expression result)
6303 6304
*/

6305
Item_result Item_type_holder::result_type() const
6306
{
6307
  return Field::result_merge_type(fld_type);
6308
}
6309

6310

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6311
/*
6312
  Find real field type of item
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6313 6314

  SYNOPSIS
6315
    Item_type_holder::get_real_type()
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6316 6317

  RETURN
6318
    type of field which should be created to store item value
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6319 6320
*/

6321
enum_field_types Item_type_holder::get_real_type(Item *item)
6322
{
6323
  switch(item->type())
6324
  {
6325
  case FIELD_ITEM:
6326
  {
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6327
    /*
6328 6329
      Item_fields::field_type ask Field_type() but sometimes field return
      a different type, like for enum/set, so we need to ask real type.
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    */
6331 6332 6333 6334 6335 6336
    Field *field= ((Item_field *) item)->field;
    enum_field_types type= field->real_type();
    /* work around about varchar type field detection */
    if (type == MYSQL_TYPE_STRING && field->type() == MYSQL_TYPE_VAR_STRING)
      return MYSQL_TYPE_VAR_STRING;
    return type;
6337
  }
6338
  case SUM_FUNC_ITEM:
6339
  {
6340 6341 6342 6343
    /*
      Argument of aggregate function sometimes should be asked about field
      type
    */
6344 6345
    Item_sum *item_sum= (Item_sum *) item;
    if (item_sum->keep_field_type())
6346 6347 6348 6349
      return get_real_type(item_sum->args[0]);
    break;
  }
  case FUNC_ITEM:
6350
    if (((Item_func *) item)->functype() == Item_func::GUSERVAR_FUNC)
6351
    {
6352
      /*
6353 6354 6355 6356
        There are work around of problem with changing variable type on the
        fly and variable always report "string" as field type to get
        acceptable information for client in send_field, so we make field
        type from expression type.
6357
      */
6358
      switch (item->result_type()) {
6359 6360 6361 6362 6363 6364
      case STRING_RESULT:
        return MYSQL_TYPE_VAR_STRING;
      case INT_RESULT:
        return MYSQL_TYPE_LONGLONG;
      case REAL_RESULT:
        return MYSQL_TYPE_DOUBLE;
6365 6366
      case DECIMAL_RESULT:
        return MYSQL_TYPE_NEWDECIMAL;
6367 6368 6369 6370 6371
      case ROW_RESULT:
      default:
        DBUG_ASSERT(0);
        return MYSQL_TYPE_VAR_STRING;
      }
6372
    }
6373 6374 6375
    break;
  default:
    break;
6376
  }
6377
  return item->field_type();
6378 6379
}

6380
/*
6381 6382
  Find field type which can carry current Item_type_holder type and
  type of given Item.
6383 6384

  SYNOPSIS
6385 6386 6387
    Item_type_holder::join_types()
    thd     thread handler
    item    given item to join its parameters with this item ones
6388 6389

  RETURN
6390 6391
    TRUE   error - types are incompatible
    FALSE  OK
6392 6393
*/

6394
bool Item_type_holder::join_types(THD *thd, Item *item)
6395
{
6396 6397
  uint max_length_orig= max_length;
  uint decimals_orig= decimals;
6398 6399 6400 6401 6402 6403 6404
  DBUG_ENTER("Item_type_holder::join_types");
  DBUG_PRINT("info:", ("was type %d len %d, dec %d name %s",
                       fld_type, max_length, decimals,
                       (name ? name : "<NULL>")));
  DBUG_PRINT("info:", ("in type %d len %d, dec %d",
                       get_real_type(item),
                       item->max_length, item->decimals));
6405
  fld_type= Field::field_type_merge(fld_type, get_real_type(item));
6406
  {
6407 6408 6409 6410 6411
    int item_decimals= item->decimals;
    /* fix variable decimals which always is NOT_FIXED_DEC */
    if (Field::result_merge_type(fld_type) == INT_RESULT)
      item_decimals= 0;
    decimals= max(decimals, item_decimals);
6412
  }
6413
  if (Field::result_merge_type(fld_type) == DECIMAL_RESULT)
6414
  {
6415 6416 6417 6418 6419 6420
    decimals= min(max(decimals, item->decimals), DECIMAL_MAX_SCALE);
    int precision= min(max(prev_decimal_int_part, item->decimal_int_part())
                       + decimals, DECIMAL_MAX_PRECISION);
    unsigned_flag&= item->unsigned_flag;
    max_length= my_decimal_precision_to_length(precision, decimals,
                                               unsigned_flag);
6421
  }
6422

6423 6424 6425
  switch (Field::result_merge_type(fld_type))
  {
  case STRING_RESULT:
6426
  {
6427
    const char *old_cs, *old_derivation;
6428
    uint32 old_max_chars= max_length / collation.collation->mbmaxlen;
6429 6430
    old_cs= collation.collation->name;
    old_derivation= collation.derivation_name();
6431
    if (collation.aggregate(item->collation, MY_COLL_ALLOW_CONV))
6432
    {
6433
      my_error(ER_CANT_AGGREGATE_2COLLATIONS, MYF(0),
6434 6435 6436 6437
	       old_cs, old_derivation,
	       item->collation.collation->name,
	       item->collation.derivation_name(),
	       "UNION");
6438
      DBUG_RETURN(TRUE);
6439
    }
6440 6441 6442 6443 6444 6445 6446 6447
    /*
      To figure out max_length, we have to take into account possible
      expansion of the size of the values because of character set
      conversions.
     */
    max_length= max(old_max_chars * collation.collation->mbmaxlen,
                    display_length(item) / item->collation.collation->mbmaxlen *
                    collation.collation->mbmaxlen);
6448
    break;
6449
  }
6450 6451 6452 6453 6454 6455
  case REAL_RESULT:
  {
    if (decimals != NOT_FIXED_DEC)
    {
      int delta1= max_length_orig - decimals_orig;
      int delta2= item->max_length - item->decimals;
6456 6457 6458 6459 6460
      if (fld_type == MYSQL_TYPE_DECIMAL)
        max_length= max(delta1, delta2) + decimals;
      else
        max_length= min(max(delta1, delta2) + decimals,
                        (fld_type == MYSQL_TYPE_FLOAT) ? FLT_DIG+6 : DBL_DIG+7);
6461 6462 6463 6464
    }
    else
      max_length= (fld_type == MYSQL_TYPE_FLOAT) ? FLT_DIG+6 : DBL_DIG+7;
    break;
6465
  }
6466 6467
  default:
    max_length= max(max_length, display_length(item));
6468
  };
6469 6470
  maybe_null|= item->maybe_null;
  get_full_info(item);
6471 6472 6473

  /* Remember decimal integer part to be used in DECIMAL_RESULT handleng */
  prev_decimal_int_part= decimal_int_part();
6474 6475
  DBUG_PRINT("info", ("become type: %d  len: %u  dec: %u",
                      (int) fld_type, max_length, (uint) decimals));
6476
  DBUG_RETURN(FALSE);
6477 6478
}

6479 6480
/*
  Calculate lenth for merging result for given Item type
6481

6482 6483 6484
  SYNOPSIS
    Item_type_holder::real_length()
    item  Item for lrngth detection
6485

6486 6487 6488
  RETURN
    length
*/
6489

6490
uint32 Item_type_holder::display_length(Item *item)
6491 6492
{
  if (item->type() == Item::FIELD_ITEM)
6493
    return ((Item_field *)item)->max_disp_length();
6494

6495
  switch (item->field_type())
6496
  {
6497 6498 6499 6500 6501 6502 6503
  case MYSQL_TYPE_DECIMAL:
  case MYSQL_TYPE_TIMESTAMP:
  case MYSQL_TYPE_DATE:
  case MYSQL_TYPE_TIME:
  case MYSQL_TYPE_DATETIME:
  case MYSQL_TYPE_YEAR:
  case MYSQL_TYPE_NEWDATE:
6504 6505 6506
  case MYSQL_TYPE_VARCHAR:
  case MYSQL_TYPE_BIT:
  case MYSQL_TYPE_NEWDECIMAL:
6507 6508 6509 6510 6511 6512 6513 6514 6515
  case MYSQL_TYPE_ENUM:
  case MYSQL_TYPE_SET:
  case MYSQL_TYPE_TINY_BLOB:
  case MYSQL_TYPE_MEDIUM_BLOB:
  case MYSQL_TYPE_LONG_BLOB:
  case MYSQL_TYPE_BLOB:
  case MYSQL_TYPE_VAR_STRING:
  case MYSQL_TYPE_STRING:
  case MYSQL_TYPE_GEOMETRY:
6516
    return item->max_length;
6517 6518 6519 6520 6521 6522 6523 6524 6525
  case MYSQL_TYPE_TINY:
    return 4;
  case MYSQL_TYPE_SHORT:
    return 6;
  case MYSQL_TYPE_LONG:
    return 11;
  case MYSQL_TYPE_FLOAT:
    return 25;
  case MYSQL_TYPE_DOUBLE:
6526
    return 53;
6527
  case MYSQL_TYPE_NULL:
6528
    return 0;
6529
  case MYSQL_TYPE_LONGLONG:
6530
    return 20;
6531 6532
  case MYSQL_TYPE_INT24:
    return 8;
6533 6534 6535 6536 6537
  default:
    DBUG_ASSERT(0); // we should never go there
    return 0;
  }
}
6538

6539 6540 6541 6542 6543 6544 6545 6546 6547 6548 6549 6550 6551 6552 6553

/*
  Make temporary table field according collected information about type
  of UNION result

  SYNOPSIS
    Item_type_holder::make_field_by_type()
    table  temporary table for which we create fields

  RETURN
    created field
*/

Field *Item_type_holder::make_field_by_type(TABLE *table)
{
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6554 6555 6556 6557
  /*
    The field functions defines a field to be not null if null_ptr is not 0
  */
  uchar *null_ptr= maybe_null ? (uchar*) "" : 0;
6558 6559 6560
  Field *field;

  switch (fld_type) {
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6561
  case MYSQL_TYPE_ENUM:
6562
    DBUG_ASSERT(enum_set_typelib);
6563
    field= new Field_enum((char *) 0, max_length, null_ptr, 0,
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6564
                          Field::NONE, name,
6565
                          get_enum_pack_length(enum_set_typelib->count),
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6566
                          enum_set_typelib, collation.collation);
6567 6568 6569
    if (field)
      field->init(table);
    return field;
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6570 6571
  case MYSQL_TYPE_SET:
    DBUG_ASSERT(enum_set_typelib);
6572
    field= new Field_set((char *) 0, max_length, null_ptr, 0,
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6573
                         Field::NONE, name,
6574
                         get_set_pack_length(enum_set_typelib->count),
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6575
                         enum_set_typelib, collation.collation);
6576 6577 6578
    if (field)
      field->init(table);
    return field;
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6579 6580
  default:
    break;
6581
  }
6582
  return tmp_table_field_from_field_type(table, 0);
6583 6584 6585 6586 6587 6588 6589 6590 6591 6592 6593 6594 6595 6596 6597 6598
}


/*
  Get full information from Item about enum/set fields to be able to create
  them later

  SYNOPSIS
    Item_type_holder::get_full_info
    item    Item for information collection
*/
void Item_type_holder::get_full_info(Item *item)
{
  if (fld_type == MYSQL_TYPE_ENUM ||
      fld_type == MYSQL_TYPE_SET)
  {
6599 6600 6601 6602
    if (item->type() == Item::SUM_FUNC_ITEM &&
        (((Item_sum*)item)->sum_func() == Item_sum::MAX_FUNC ||
         ((Item_sum*)item)->sum_func() == Item_sum::MIN_FUNC))
      item = ((Item_sum*)item)->args[0];
6603
    /*
6604 6605
      We can have enum/set type after merging only if we have one enum|set
      field (or MIN|MAX(enum|set field)) and number of NULL fields
6606 6607 6608 6609 6610 6611 6612 6613 6614 6615 6616 6617 6618 6619 6620 6621
    */
    DBUG_ASSERT((enum_set_typelib &&
                 get_real_type(item) == MYSQL_TYPE_NULL) ||
                (!enum_set_typelib &&
                 item->type() == Item::FIELD_ITEM &&
                 (get_real_type(item) == MYSQL_TYPE_ENUM ||
                  get_real_type(item) == MYSQL_TYPE_SET) &&
                 ((Field_enum*)((Item_field *) item)->field)->typelib));
    if (!enum_set_typelib)
    {
      enum_set_typelib= ((Field_enum*)((Item_field *) item)->field)->typelib;
    }
  }
}


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double Item_type_holder::val_real()
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{
  DBUG_ASSERT(0); // should never be called
  return 0.0;
}


longlong Item_type_holder::val_int()
{
  DBUG_ASSERT(0); // should never be called
  return 0;
}

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my_decimal *Item_type_holder::val_decimal(my_decimal *)
{
  DBUG_ASSERT(0); // should never be called
  return 0;
}
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String *Item_type_holder::val_str(String*)
{
  DBUG_ASSERT(0); // should never be called
  return 0;
}

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void Item_result_field::cleanup()
{
  DBUG_ENTER("Item_result_field::cleanup()");
  Item::cleanup();
  result_field= 0;
  DBUG_VOID_RETURN;
}

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/*
  Dummy error processor used by default by Name_resolution_context

  SYNOPSIS
    dummy_error_processor()

  NOTE
    do nothing
*/

void dummy_error_processor(THD *thd, void *data)
{}

/*
  Wrapper of hide_view_error call for Name_resolution_context error processor

  SYNOPSIS
    view_error_processor()

  NOTE
    hide view underlying tables details in error messages
*/

void view_error_processor(THD *thd, void *data)
{
  ((TABLE_LIST *)data)->hide_view_error(thd);
}

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/*****************************************************************************
** Instantiate templates
*****************************************************************************/

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#ifdef HAVE_EXPLICIT_TEMPLATE_INSTANTIATION
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template class List<Item>;
template class List_iterator<Item>;
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template class List_iterator_fast<Item>;
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template class List_iterator_fast<Item_field>;
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template class List<List_item>;
#endif