mi_packrec.c 50.2 KB
Newer Older
1
/* Copyright (C) 2000-2006 MySQL AB
monty@hundin.mysql.fi's avatar
monty@hundin.mysql.fi committed
2

bk@work.mysql.com's avatar
bk@work.mysql.com committed
3 4
   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
5
   the Free Software Foundation; version 2 of the License.
monty@hundin.mysql.fi's avatar
monty@hundin.mysql.fi committed
6

bk@work.mysql.com's avatar
bk@work.mysql.com committed
7 8 9 10
   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.
monty@hundin.mysql.fi's avatar
monty@hundin.mysql.fi committed
11

bk@work.mysql.com's avatar
bk@work.mysql.com committed
12 13 14 15 16 17
   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 */

	/* Functions to compressed records */

18
#include "fulltext.h"
bk@work.mysql.com's avatar
bk@work.mysql.com committed
19 20 21

#define IS_CHAR ((uint) 32768)		/* Bit if char (not offset) in tree */

22 23 24 25
/* Some definitions to keep in sync with myisampack.c */
#define HEAD_LENGTH	32              /* Length of fixed header */

#if INT_MAX > 32767
bk@work.mysql.com's avatar
bk@work.mysql.com committed
26 27 28 29 30 31 32 33 34 35 36
#define BITS_SAVED 32
#define MAX_QUICK_TABLE_BITS 9		/* Because we may shift in 24 bits */
#else
#define BITS_SAVED 16
#define MAX_QUICK_TABLE_BITS 6
#endif

#define get_bit(BU) ((BU)->bits ? \
		     (BU)->current_byte & ((mi_bit_type) 1 << --(BU)->bits) :\
		     (fill_buffer(BU), (BU)->bits= BITS_SAVED-1,\
		      (BU)->current_byte & ((mi_bit_type) 1 << (BITS_SAVED-1))))
37
#define skip_to_next_byte(BU) ((BU)->bits&=~7)
bk@work.mysql.com's avatar
bk@work.mysql.com committed
38 39 40 41 42 43 44 45 46
#define get_bits(BU,count) (((BU)->bits >= count) ? (((BU)->current_byte >> ((BU)->bits-=count)) & mask[count]) : fill_and_get_bits(BU,count))

#define decode_bytes_test_bit(bit) \
  if (low_byte & (1 << (7-bit))) \
    pos++; \
  if (*pos & IS_CHAR) \
  { bits-=(bit+1); break; } \
  pos+= *pos

47
/* Size in uint16 of a Huffman tree for byte compression of 256 byte values. */
serg@serg.mylan's avatar
serg@serg.mylan committed
48
#define OFFSET_TABLE_SIZE 512
bk@work.mysql.com's avatar
bk@work.mysql.com committed
49

50
static uint read_huff_table(MI_BIT_BUFF *bit_buff,MI_DECODE_TREE *decode_tree,
51
			    uint16 **decode_table,uchar **intervall_buff,
bk@work.mysql.com's avatar
bk@work.mysql.com committed
52 53 54 55 56 57 58 59
			    uint16 *tmp_buff);
static void make_quick_table(uint16 *to_table,uint16 *decode_table,
			     uint *next_free,uint value,uint bits,
			     uint max_bits);
static void fill_quick_table(uint16 *table,uint bits, uint max_bits,
			     uint value);
static uint copy_decode_table(uint16 *to_pos,uint offset,
			      uint16 *decode_table);
serg@serg.mylan's avatar
serg@serg.mylan committed
60
static uint find_longest_bitstream(uint16 *table, uint16 *end);
bk@work.mysql.com's avatar
bk@work.mysql.com committed
61 62 63 64
static void (*get_unpack_function(MI_COLUMNDEF *rec))(MI_COLUMNDEF *field,
						    MI_BIT_BUFF *buff,
						    uchar *to,
						    uchar *end);
65
static void uf_zerofill_skip_zero(MI_COLUMNDEF *rec,MI_BIT_BUFF *bit_buff,
bk@work.mysql.com's avatar
bk@work.mysql.com committed
66
				   uchar *to,uchar *end);
67
static void uf_skip_zero(MI_COLUMNDEF *rec,MI_BIT_BUFF *bit_buff,
bk@work.mysql.com's avatar
bk@work.mysql.com committed
68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96
			  uchar *to,uchar *end);
static void uf_space_normal(MI_COLUMNDEF *rec,MI_BIT_BUFF *bit_buff,
			    uchar *to,uchar *end);
static void uf_space_endspace_selected(MI_COLUMNDEF *rec,MI_BIT_BUFF *bit_buff,
				       uchar *to, uchar *end);
static void uf_endspace_selected(MI_COLUMNDEF *rec,MI_BIT_BUFF *bit_buff,
				 uchar *to,uchar *end);
static void uf_space_endspace(MI_COLUMNDEF *rec,MI_BIT_BUFF *bit_buff,
			      uchar *to,uchar *end);
static void uf_endspace(MI_COLUMNDEF *rec,MI_BIT_BUFF *bit_buff,
			uchar *to,uchar *end);
static void uf_space_prespace_selected(MI_COLUMNDEF *rec,MI_BIT_BUFF *bit_buff,
				       uchar *to, uchar *end);
static void uf_prespace_selected(MI_COLUMNDEF *rec,MI_BIT_BUFF *bit_buff,
				 uchar *to,uchar *end);
static void uf_space_prespace(MI_COLUMNDEF *rec,MI_BIT_BUFF *bit_buff,
			      uchar *to,uchar *end);
static void uf_prespace(MI_COLUMNDEF *rec,MI_BIT_BUFF *bit_buff,
			uchar *to,uchar *end);
static void uf_zerofill_normal(MI_COLUMNDEF *rec,MI_BIT_BUFF *bit_buff,
			       uchar *to,uchar *end);
static void uf_constant(MI_COLUMNDEF *rec,MI_BIT_BUFF *bit_buff,
			uchar *to,uchar *end);
static void uf_intervall(MI_COLUMNDEF *rec,MI_BIT_BUFF *bit_buff,
			 uchar *to,uchar *end);
static void uf_zero(MI_COLUMNDEF *rec,MI_BIT_BUFF *bit_buff,
		    uchar *to,uchar *end);
static void uf_blob(MI_COLUMNDEF *rec, MI_BIT_BUFF *bit_buff,
		    uchar *to, uchar *end);
97 98 99 100
static void uf_varchar1(MI_COLUMNDEF *rec, MI_BIT_BUFF *bit_buff,
                        uchar *to, uchar *end);
static void uf_varchar2(MI_COLUMNDEF *rec, MI_BIT_BUFF *bit_buff,
                        uchar *to, uchar *end);
bk@work.mysql.com's avatar
bk@work.mysql.com committed
101 102 103 104 105 106 107 108
static void decode_bytes(MI_COLUMNDEF *rec,MI_BIT_BUFF *bit_buff,
			 uchar *to,uchar *end);
static uint decode_pos(MI_BIT_BUFF *bit_buff,MI_DECODE_TREE *decode_tree);
static void init_bit_buffer(MI_BIT_BUFF *bit_buff,uchar *buffer,uint length);
static uint fill_and_get_bits(MI_BIT_BUFF *bit_buff,uint count);
static void fill_buffer(MI_BIT_BUFF *bit_buff);
static uint max_bit(uint value);
#ifdef HAVE_MMAP
109
static uchar *_mi_mempack_get_block_info(MI_INFO *myisam, MI_BIT_BUFF *bit_buff,
110
                                         MI_BLOCK_INFO *info, uchar **rec_buff_p,
bk@work.mysql.com's avatar
bk@work.mysql.com committed
111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138
					 uchar *header);
#endif

static mi_bit_type mask[]=
{
   0x00000000,
   0x00000001, 0x00000003, 0x00000007, 0x0000000f,
   0x0000001f, 0x0000003f, 0x0000007f, 0x000000ff,
   0x000001ff, 0x000003ff, 0x000007ff, 0x00000fff,
   0x00001fff, 0x00003fff, 0x00007fff, 0x0000ffff,
#if BITS_SAVED > 16
   0x0001ffff, 0x0003ffff, 0x0007ffff, 0x000fffff,
   0x001fffff, 0x003fffff, 0x007fffff, 0x00ffffff,
   0x01ffffff, 0x03ffffff, 0x07ffffff, 0x0fffffff,
   0x1fffffff, 0x3fffffff, 0x7fffffff, 0xffffffff,
#endif
 };


	/* Read all packed info, allocate memory and fix field structs */

my_bool _mi_read_pack_info(MI_INFO *info, pbool fix_keys)
{
  File file;
  int diff_length;
  uint i,trees,huff_tree_bits,rec_reflength,length;
  uint16 *decode_table,*tmp_buff;
  ulong elements,intervall_length;
139
  uchar *disk_cache;
140
  uchar *intervall_buff;
141
  uchar header[HEAD_LENGTH];
bk@work.mysql.com's avatar
bk@work.mysql.com committed
142 143 144 145 146 147 148 149 150 151 152
  MYISAM_SHARE *share=info->s;
  MI_BIT_BUFF bit_buff;
  DBUG_ENTER("_mi_read_pack_info");

  if (myisam_quick_table_bits < 4)
    myisam_quick_table_bits=4;
  else if (myisam_quick_table_bits > MAX_QUICK_TABLE_BITS)
    myisam_quick_table_bits=MAX_QUICK_TABLE_BITS;

  file=info->dfile;
  my_errno=0;
153
  if (my_read(file,(uchar*) header,sizeof(header),MYF(MY_NABP)))
bk@work.mysql.com's avatar
bk@work.mysql.com committed
154 155 156
  {
    if (!my_errno)
      my_errno=HA_ERR_END_OF_FILE;
157
    goto err0;
bk@work.mysql.com's avatar
bk@work.mysql.com committed
158
  }
159
  /* Only the first three bytes of magic number are independent of version. */
160
  if (memcmp((uchar*) header, (uchar*) myisam_pack_file_magic, 3))
bk@work.mysql.com's avatar
bk@work.mysql.com committed
161 162
  {
    my_errno=HA_ERR_WRONG_IN_RECORD;
163
    goto err0;
bk@work.mysql.com's avatar
bk@work.mysql.com committed
164
  }
165
  share->pack.version= header[3]; /* fourth byte of magic number */
bk@work.mysql.com's avatar
bk@work.mysql.com committed
166 167 168 169 170 171 172 173 174 175 176
  share->pack.header_length=	uint4korr(header+4);
  share->min_pack_length=(uint) uint4korr(header+8);
  share->max_pack_length=(uint) uint4korr(header+12);
  elements=uint4korr(header+16);
  intervall_length=uint4korr(header+20);
  trees=uint2korr(header+24);
  share->pack.ref_length=header[26];
  rec_reflength=header[27];
  diff_length=(int) rec_reflength - (int) share->base.rec_reflength;
  if (fix_keys)
    share->rec_reflength=rec_reflength;
177 178 179
  share->base.min_block_length=share->min_pack_length+1;
  if (share->min_pack_length > 254)
    share->base.min_block_length+=2;
180
  DBUG_PRINT("info", ("fixed header length:   %u", HEAD_LENGTH));
181
  DBUG_PRINT("info", ("total header length:   %lu", share->pack.header_length));
182
  DBUG_PRINT("info", ("pack file version:     %u", share->pack.version));
183 184 185 186
  DBUG_PRINT("info", ("min pack length:       %lu", share->min_pack_length));
  DBUG_PRINT("info", ("max pack length:       %lu", share->max_pack_length));
  DBUG_PRINT("info", ("elements of all trees: %lu", elements));
  DBUG_PRINT("info", ("distinct values bytes: %lu", intervall_length));
187 188 189 190 191 192 193 194 195
  DBUG_PRINT("info", ("number of code trees:  %u", trees));
  DBUG_PRINT("info", ("bytes for record lgt:  %u", share->pack.ref_length));
  DBUG_PRINT("info", ("record pointer length: %u", rec_reflength));

  /*
    Memory segment #1:
    - Decode tree heads
    - Distinct column values
  */
bk@work.mysql.com's avatar
bk@work.mysql.com committed
196 197
  if (!(share->decode_trees=(MI_DECODE_TREE*)
	my_malloc((uint) (trees*sizeof(MI_DECODE_TREE)+
198
			  intervall_length*sizeof(uchar)),
bk@work.mysql.com's avatar
bk@work.mysql.com committed
199
		  MYF(MY_WME))))
200
    goto err0;
201
  intervall_buff=(uchar*) (share->decode_trees+trees);
bk@work.mysql.com's avatar
bk@work.mysql.com committed
202

203 204 205 206 207 208 209 210
  /*
    Memory segment #2:
    - Decode tables
    - Quick decode tables
    - Temporary decode table
    - Compressed data file header cache
    This segment will be reallocated after construction of the tables.
  */
bk@work.mysql.com's avatar
bk@work.mysql.com committed
211
  length=(uint) (elements*2+trees*(1 << myisam_quick_table_bits));
212 213 214 215 216 217 218
  /*
    To keep some algorithms simpler, we accept that they access
    bytes beyond the end of the input data. This can affect up to
    one byte less than the "word size" size used in this file,
    which is BITS_SAVED / 8. To avoid accessing non-allocated
    data, we add (BITS_SAVED / 8) - 1 bytes to the buffer size.
  */
bk@work.mysql.com's avatar
bk@work.mysql.com committed
219
  if (!(share->decode_tables=(uint16*)
220
        my_malloc((length + OFFSET_TABLE_SIZE) * sizeof(uint16) +
221 222
                  (uint) (share->pack.header_length - sizeof(header) +
                  (BITS_SAVED / 8) - 1), MYF(MY_WME | MY_ZEROFILL))))
223
    goto err1;
bk@work.mysql.com's avatar
bk@work.mysql.com committed
224
  tmp_buff=share->decode_tables+length;
225
  disk_cache= (uchar*) (tmp_buff+OFFSET_TABLE_SIZE);
bk@work.mysql.com's avatar
bk@work.mysql.com committed
226 227 228 229

  if (my_read(file,disk_cache,
	      (uint) (share->pack.header_length-sizeof(header)),
	      MYF(MY_NABP)))
230
    goto err2;
bk@work.mysql.com's avatar
bk@work.mysql.com committed
231 232

  huff_tree_bits=max_bit(trees ? trees-1 : 0);
233
  init_bit_buffer(&bit_buff, disk_cache,
bk@work.mysql.com's avatar
bk@work.mysql.com committed
234
		  (uint) (share->pack.header_length-sizeof(header)));
235
  /* Read new info for each field */
bk@work.mysql.com's avatar
bk@work.mysql.com committed
236 237 238 239 240 241 242 243
  for (i=0 ; i < share->base.fields ; i++)
  {
    share->rec[i].base_type=(enum en_fieldtype) get_bits(&bit_buff,5);
    share->rec[i].pack_type=(uint) get_bits(&bit_buff,6);
    share->rec[i].space_length_bits=get_bits(&bit_buff,5);
    share->rec[i].huff_tree=share->decode_trees+(uint) get_bits(&bit_buff,
								huff_tree_bits);
    share->rec[i].unpack=get_unpack_function(share->rec+i);
244 245 246
    DBUG_PRINT("info", ("col: %2u  type: %2u  pack: %u  slbits: %2u",
                        i, share->rec[i].base_type, share->rec[i].pack_type,
                        share->rec[i].space_length_bits));
bk@work.mysql.com's avatar
bk@work.mysql.com committed
247
  }
248
  skip_to_next_byte(&bit_buff);
249 250 251 252
  /*
    Construct the decoding tables from the file header. Keep track of
    the used memory.
  */
bk@work.mysql.com's avatar
bk@work.mysql.com committed
253 254
  decode_table=share->decode_tables;
  for (i=0 ; i < trees ; i++)
255 256 257
    if (read_huff_table(&bit_buff,share->decode_trees+i,&decode_table,
                        &intervall_buff,tmp_buff))
      goto err3;
258
  /* Reallocate the decoding tables to the used size. */
bk@work.mysql.com's avatar
bk@work.mysql.com committed
259
  decode_table=(uint16*)
260 261
    my_realloc((uchar*) share->decode_tables,
	       (uint) ((uchar*) decode_table - (uchar*) share->decode_tables),
bk@work.mysql.com's avatar
bk@work.mysql.com committed
262
	       MYF(MY_HOLD_ON_ERROR));
263
  /* Fix the table addresses in the tree heads. */
bk@work.mysql.com's avatar
bk@work.mysql.com committed
264
  {
265
    my_ptrdiff_t diff=PTR_BYTE_DIFF(decode_table,share->decode_tables);
bk@work.mysql.com's avatar
bk@work.mysql.com committed
266 267 268
    share->decode_tables=decode_table;
    for (i=0 ; i < trees ; i++)
      share->decode_trees[i].table=ADD_TO_PTR(share->decode_trees[i].table,
269
                                              diff, uint16*);
bk@work.mysql.com's avatar
bk@work.mysql.com committed
270 271
  }

272
  /* Fix record-ref-length for keys */
bk@work.mysql.com's avatar
bk@work.mysql.com committed
273 274 275 276
  if (fix_keys)
  {
    for (i=0 ; i < share->base.keys ; i++)
    {
277 278 279 280 281 282 283 284 285 286 287 288 289
      MI_KEYDEF *keyinfo= &share->keyinfo[i];
      keyinfo->keylength+= (uint16) diff_length;
      keyinfo->minlength+= (uint16) diff_length;
      keyinfo->maxlength+= (uint16) diff_length;
      keyinfo->seg[keyinfo->flag & HA_FULLTEXT ?
                   FT_SEGS : keyinfo->keysegs].length= (uint16) rec_reflength;
    }
    if (share->ft2_keyinfo.seg)
    {
      MI_KEYDEF *ft2_keyinfo= &share->ft2_keyinfo;
      ft2_keyinfo->keylength+= (uint16) diff_length;
      ft2_keyinfo->minlength+= (uint16) diff_length;
      ft2_keyinfo->maxlength+= (uint16) diff_length;
bk@work.mysql.com's avatar
bk@work.mysql.com committed
290 291 292 293
    }
  }

  if (bit_buff.error || bit_buff.pos < bit_buff.end)
294 295
    goto err3;

bk@work.mysql.com's avatar
bk@work.mysql.com committed
296
  DBUG_RETURN(0);
297 298 299 300

err3:
  my_errno=HA_ERR_WRONG_IN_RECORD;
err2:
301
  my_free((uchar*) share->decode_tables,MYF(0));
302
err1:
303
  my_free((uchar*) share->decode_trees,MYF(0));
304 305
err0:
  DBUG_RETURN(1);
bk@work.mysql.com's avatar
bk@work.mysql.com committed
306 307 308
}


309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325
/*
  Read a huff-code-table from datafile.

  SYNOPSIS
    read_huff_table()
      bit_buff                  Bit buffer pointing at start of the
                                decoding table in the file header cache.
      decode_tree               Pointer to the decode tree head.
      decode_table      IN/OUT  Address of a pointer to the next free space.
      intervall_buff    IN/OUT  Address of a pointer to the next unused values.
      tmp_buff                  Buffer for temporary extraction of a full
                                decoding table as read from bit_buff.

  RETURN
    0           OK.
    1           Error.
*/
bk@work.mysql.com's avatar
bk@work.mysql.com committed
326

327
static uint read_huff_table(MI_BIT_BUFF *bit_buff, MI_DECODE_TREE *decode_tree,
328
			    uint16 **decode_table, uchar **intervall_buff,
bk@work.mysql.com's avatar
bk@work.mysql.com committed
329 330 331 332 333
			    uint16 *tmp_buff)
{
  uint min_chr,elements,char_bits,offset_bits,size,intervall_length,table_bits,
  next_free_offset;
  uint16 *ptr,*end;
334
  DBUG_ENTER("read_huff_table");
bk@work.mysql.com's avatar
bk@work.mysql.com committed
335 336 337

  if (!get_bits(bit_buff,1))
  {
338
    /* Byte value compression. */
bk@work.mysql.com's avatar
bk@work.mysql.com committed
339 340 341 342 343 344
    min_chr=get_bits(bit_buff,8);
    elements=get_bits(bit_buff,9);
    char_bits=get_bits(bit_buff,5);
    offset_bits=get_bits(bit_buff,5);
    intervall_length=0;
    ptr=tmp_buff;
345 346 347 348 349 350 351 352 353 354 355
    DBUG_PRINT("info", ("byte value compression"));
    DBUG_PRINT("info", ("minimum byte value:    %u", min_chr));
    DBUG_PRINT("info", ("number of tree nodes:  %u", elements));
    DBUG_PRINT("info", ("bits for values:       %u", char_bits));
    DBUG_PRINT("info", ("bits for tree offsets: %u", offset_bits));
    if (elements > 256)
    {
      DBUG_PRINT("error", ("ERROR: illegal number of tree elements: %u",
                           elements));
      DBUG_RETURN(1);
    }
bk@work.mysql.com's avatar
bk@work.mysql.com committed
356 357 358
  }
  else
  {
359
    /* Distinct column value compression. */
bk@work.mysql.com's avatar
bk@work.mysql.com committed
360 361 362 363 364 365 366
    min_chr=0;
    elements=get_bits(bit_buff,15);
    intervall_length=get_bits(bit_buff,16);
    char_bits=get_bits(bit_buff,5);
    offset_bits=get_bits(bit_buff,5);
    decode_tree->quick_table_bits=0;
    ptr= *decode_table;
367 368 369 370 371
    DBUG_PRINT("info", ("distinct column value compression"));
    DBUG_PRINT("info", ("number of tree nodes:  %u", elements));
    DBUG_PRINT("info", ("value buffer length:   %u", intervall_length));
    DBUG_PRINT("info", ("bits for value index:  %u", char_bits));
    DBUG_PRINT("info", ("bits for tree offsets: %u", offset_bits));
bk@work.mysql.com's avatar
bk@work.mysql.com committed
372 373
  }
  size=elements*2-2;
374
  DBUG_PRINT("info", ("tree size in uint16:   %u", size));
375 376
  DBUG_PRINT("info", ("tree size in bytes:    %u",
                      size * (uint) sizeof(uint16)));
bk@work.mysql.com's avatar
bk@work.mysql.com committed
377 378 379 380

  for (end=ptr+size ; ptr < end ; ptr++)
  {
    if (get_bit(bit_buff))
381
    {
bk@work.mysql.com's avatar
bk@work.mysql.com committed
382
      *ptr= (uint16) get_bits(bit_buff,offset_bits);
383 384 385 386 387 388
      if ((ptr + *ptr >= end) || !*ptr)
      {
        DBUG_PRINT("error", ("ERROR: illegal pointer in decode tree"));
        DBUG_RETURN(1);
      }
    }
bk@work.mysql.com's avatar
bk@work.mysql.com committed
389 390 391
    else
      *ptr= (uint16) (IS_CHAR + (get_bits(bit_buff,char_bits) + min_chr));
  }
392
  skip_to_next_byte(bit_buff);
bk@work.mysql.com's avatar
bk@work.mysql.com committed
393 394 395 396 397

  decode_tree->table= *decode_table;
  decode_tree->intervalls= *intervall_buff;
  if (! intervall_length)
  {
398 399 400 401 402
    /* Byte value compression. ptr started from tmp_buff. */
    /* Find longest Huffman code from begin to end of tree in bits. */
    table_bits= find_longest_bitstream(tmp_buff, ptr);
    if (table_bits >= OFFSET_TABLE_SIZE)
      DBUG_RETURN(1);
bk@work.mysql.com's avatar
bk@work.mysql.com committed
403 404
    if (table_bits > myisam_quick_table_bits)
      table_bits=myisam_quick_table_bits;
405 406
    DBUG_PRINT("info", ("table bits:            %u", table_bits));

bk@work.mysql.com's avatar
bk@work.mysql.com committed
407 408 409 410 411 412 413 414
    next_free_offset= (1 << table_bits);
    make_quick_table(*decode_table,tmp_buff,&next_free_offset,0,table_bits,
		     table_bits);
    (*decode_table)+= next_free_offset;
    decode_tree->quick_table_bits=table_bits;
  }
  else
  {
415
    /* Distinct column value compression. ptr started from *decode_table */
bk@work.mysql.com's avatar
bk@work.mysql.com committed
416
    (*decode_table)=end;
417 418 419 420
    /*
      get_bits() moves some bytes to a cache buffer in advance. May need
      to step back.
    */
bk@work.mysql.com's avatar
bk@work.mysql.com committed
421
    bit_buff->pos-= bit_buff->bits/8;
422
    /* Copy the distinct column values from the buffer. */
bk@work.mysql.com's avatar
bk@work.mysql.com committed
423 424 425 426 427
    memcpy(*intervall_buff,bit_buff->pos,(size_t) intervall_length);
    (*intervall_buff)+=intervall_length;
    bit_buff->pos+=intervall_length;
    bit_buff->bits=0;
  }
428
  DBUG_RETURN(0);
bk@work.mysql.com's avatar
bk@work.mysql.com committed
429 430 431
}


432 433 434 435 436 437 438 439 440 441 442 443 444 445 446 447 448 449 450 451 452 453 454 455 456 457 458 459 460 461 462 463 464 465 466 467 468 469 470
/*
  Make a quick_table for faster decoding.

  SYNOPSIS
    make_quick_table()
      to_table                  Target quick_table and remaining decode table.
      decode_table              Source Huffman (sub-)tree within tmp_buff.
      next_free_offset   IN/OUT Next free offset from to_table.
                                Starts behind quick_table on the top-level.
      value                     Huffman bits found so far.
      bits                      Remaining bits to be collected.
      max_bits                  Total number of bits to collect (table_bits).

  DESCRIPTION

    The quick table is an array of 16-bit values. There exists one value
    for each possible code representable by max_bits (table_bits) bits.
    In most cases table_bits is 9. So there are 512 16-bit values.

    If the high-order bit (16) is set (IS_CHAR) then the array slot for
    this value is a valid Huffman code for a resulting byte value.

    The low-order 8 bits (1..8) are the resulting byte value.

    Bits 9..14 are the length of the Huffman code for this byte value.
    This means so many bits from the input stream were needed to
    represent this byte value. The remaining bits belong to later
    Huffman codes. This also means that for every Huffman code shorter
    than table_bits there are multiple entires in the array, which
    differ just in the unused bits.

    If the high-order bit (16) is clear (0) then the remaining bits are
    the position of the remaining Huffman decode tree segment behind the
    quick table.

  RETURN
    void
*/

bk@work.mysql.com's avatar
bk@work.mysql.com committed
471 472 473 474
static void make_quick_table(uint16 *to_table, uint16 *decode_table,
			     uint *next_free_offset, uint value, uint bits,
			     uint max_bits)
{
475 476 477 478 479 480
  DBUG_ENTER("make_quick_table");

  /*
    When down the table to the requested maximum, copy the rest of the
    Huffman table.
  */
bk@work.mysql.com's avatar
bk@work.mysql.com committed
481 482
  if (!bits--)
  {
483 484 485 486
    /*
      Remaining left  Huffman tree segment starts behind quick table.
      Remaining right Huffman tree segment starts behind left segment.
    */
bk@work.mysql.com's avatar
bk@work.mysql.com committed
487
    to_table[value]= (uint16) *next_free_offset;
488 489 490 491 492 493 494
    /*
      Re-construct the remaining Huffman tree segment at
      next_free_offset in to_table.
    */
    *next_free_offset= copy_decode_table(to_table, *next_free_offset,
                                         decode_table);
    DBUG_VOID_RETURN;
bk@work.mysql.com's avatar
bk@work.mysql.com committed
495
  }
496 497

  /* Descent on the left side. Left side bits are clear (0). */
bk@work.mysql.com's avatar
bk@work.mysql.com committed
498 499
  if (!(*decode_table & IS_CHAR))
  {
500 501 502
    /* Not a leaf. Follow the pointer. */
    make_quick_table(to_table, decode_table + *decode_table,
                     next_free_offset, value, bits, max_bits);
bk@work.mysql.com's avatar
bk@work.mysql.com committed
503 504
  }
  else
505 506 507 508 509 510 511 512 513 514
  {
    /*
      A leaf. A Huffman code is complete. Fill the quick_table
      array for all possible bit strings starting with this Huffman
      code.
    */
    fill_quick_table(to_table + value, bits, max_bits, (uint) *decode_table);
  }

  /* Descent on the right side. Right side bits are set (1). */
bk@work.mysql.com's avatar
bk@work.mysql.com committed
515 516 517 518
  decode_table++;
  value|= (1 << bits);
  if (!(*decode_table & IS_CHAR))
  {
519 520 521
    /* Not a leaf. Follow the pointer. */
    make_quick_table(to_table, decode_table + *decode_table,
                     next_free_offset, value, bits, max_bits);
bk@work.mysql.com's avatar
bk@work.mysql.com committed
522 523
  }
  else
524 525 526 527 528 529 530 531 532 533
  {
    /*
      A leaf. A Huffman code is complete. Fill the quick_table
      array for all possible bit strings starting with this Huffman
      code.
    */
    fill_quick_table(to_table + value, bits, max_bits, (uint) *decode_table);
  }

  DBUG_VOID_RETURN;
bk@work.mysql.com's avatar
bk@work.mysql.com committed
534 535 536
}


537 538 539 540 541 542 543 544 545 546 547 548 549 550 551 552 553 554 555 556 557 558 559 560
/*
  Fill quick_table for all possible values starting with this Huffman code.

  SYNOPSIS
    fill_quick_table()
      table                     Target quick_table position.
      bits                      Unused bits from max_bits.
      max_bits                  Total number of bits to collect (table_bits).
      value                     The byte encoded by the found Huffman code.

  DESCRIPTION

    Fill the segment (all slots) of the quick_table array with the
    resulting value for the found Huffman code. There are as many slots
    as there are combinations representable by the unused bits.

    In most cases we use 9 table bits. Assume a 3-bit Huffman code. Then
    there are 6 unused bits. Hence we fill 2**6 = 64 slots with the
    value.

  RETURN
    void
*/

bk@work.mysql.com's avatar
bk@work.mysql.com committed
561 562 563 564
static void fill_quick_table(uint16 *table, uint bits, uint max_bits,
			     uint value)
{
  uint16 *end;
565 566 567 568 569 570 571 572 573
  DBUG_ENTER("fill_quick_table");

  /*
    Bits 1..8 of value represent the decoded byte value.
    Bits 9..14 become the length of the Huffman code for this byte value.
    Bit 16 flags a valid code (IS_CHAR).
  */
  value|= (max_bits - bits) << 8 | IS_CHAR;

574
  for (end= table + ((my_ptrdiff_t) 1 << bits); table < end; table++)
575 576 577 578
  {
    *table= (uint16) value;
  }
  DBUG_VOID_RETURN;
bk@work.mysql.com's avatar
bk@work.mysql.com committed
579 580 581
}


582 583 584 585 586 587 588 589 590 591 592 593 594 595 596 597
/*
  Reconstruct a decode subtree at the target position.

  SYNOPSIS
    copy_decode_table()
      to_pos                    Target quick_table and remaining decode table.
      offset                    Next free offset from to_pos.
      decode_table              Source Huffman subtree within tmp_buff.

  NOTE
    Pointers in the decode tree are relative to the pointers position.

  RETURN
    next free offset from to_pos.
*/

bk@work.mysql.com's avatar
bk@work.mysql.com committed
598 599 600
static uint copy_decode_table(uint16 *to_pos, uint offset,
			      uint16 *decode_table)
{
601
  uint prev_offset= offset;
602
  DBUG_ENTER("copy_decode_table");
bk@work.mysql.com's avatar
bk@work.mysql.com committed
603

604
  /* Descent on the left side. */
bk@work.mysql.com's avatar
bk@work.mysql.com committed
605 606
  if (!(*decode_table & IS_CHAR))
  {
607
    /* Set a pointer to the next target node. */
bk@work.mysql.com's avatar
bk@work.mysql.com committed
608
    to_pos[offset]=2;
609
    /* Copy the left hand subtree there. */
bk@work.mysql.com's avatar
bk@work.mysql.com committed
610 611 612 613
    offset=copy_decode_table(to_pos,offset+2,decode_table+ *decode_table);
  }
  else
  {
614
    /* Copy the byte value. */
bk@work.mysql.com's avatar
bk@work.mysql.com committed
615
    to_pos[offset]= *decode_table;
616
    /* Step behind this node. */
bk@work.mysql.com's avatar
bk@work.mysql.com committed
617 618 619
    offset+=2;
  }

620 621
  /* Descent on the right side. */
  decode_table++;
bk@work.mysql.com's avatar
bk@work.mysql.com committed
622 623
  if (!(*decode_table & IS_CHAR))
  {
624
    /* Set a pointer to the next free target node. */
bk@work.mysql.com's avatar
bk@work.mysql.com committed
625
    to_pos[prev_offset+1]=(uint16) (offset-prev_offset-1);
626
    /* Copy the right hand subtree to the entry of that node. */
bk@work.mysql.com's avatar
bk@work.mysql.com committed
627 628 629
    offset=copy_decode_table(to_pos,offset,decode_table+ *decode_table);
  }
  else
630 631
  {
    /* Copy the byte value. */
bk@work.mysql.com's avatar
bk@work.mysql.com committed
632
    to_pos[prev_offset+1]= *decode_table;
633 634
  }
  DBUG_RETURN(offset);
bk@work.mysql.com's avatar
bk@work.mysql.com committed
635 636 637
}


638 639 640 641 642 643 644 645 646 647 648 649 650 651 652 653 654 655 656 657 658 659 660 661
/*
  Find the length of the longest Huffman code in this table in bits.

  SYNOPSIS
    find_longest_bitstream()
      table                     Code (sub-)table start.
      end                       End of code table.

  IMPLEMENTATION

    Recursively follow the branch(es) of the code pair on every level of
    the tree until two byte values (and no branch) are found. Add one to
    each level when returning back from each recursion stage.

    'end' is used for error checking only. A clean tree terminates
    before reaching 'end'. Hence the exact value of 'end' is not too
    important. However having it higher than necessary could lead to
    misbehaviour should 'next' jump into the dirty area.

  RETURN
    length                  Length of longest Huffman code in bits.
    >= OFFSET_TABLE_SIZE    Error, broken tree. It does not end before 'end'.
*/

serg@serg.mylan's avatar
serg@serg.mylan committed
662
static uint find_longest_bitstream(uint16 *table, uint16 *end)
bk@work.mysql.com's avatar
bk@work.mysql.com committed
663
{
664 665 666
  uint length= 1;
  uint length2;

bk@work.mysql.com's avatar
bk@work.mysql.com committed
667
  if (!(*table & IS_CHAR))
serg@serg.mylan's avatar
serg@serg.mylan committed
668 669 670
  {
    uint16 *next= table + *table;
    if (next > end || next == table)
671 672 673 674 675
    {
      DBUG_PRINT("error", ("ERROR: illegal pointer in decode tree"));
      return OFFSET_TABLE_SIZE;
    }
    length= find_longest_bitstream(next, end) + 1;
serg@serg.mylan's avatar
serg@serg.mylan committed
676
  }
bk@work.mysql.com's avatar
bk@work.mysql.com committed
677 678 679
  table++;
  if (!(*table & IS_CHAR))
  {
serg@serg.mylan's avatar
serg@serg.mylan committed
680 681
    uint16 *next= table + *table;
    if (next > end || next == table)
682 683 684 685 686
    {
      DBUG_PRINT("error", ("ERROR: illegal pointer in decode tree"));
      return OFFSET_TABLE_SIZE;
    }
    length2= find_longest_bitstream(next, end) + 1;
bk@work.mysql.com's avatar
bk@work.mysql.com committed
687 688 689 690 691 692
    length=max(length,length2);
  }
  return length;
}


693 694 695 696 697 698 699 700 701 702 703 704 705
/*
  Read record from datafile.

  SYNOPSIS
    _mi_read_pack_record()
    info                        A pointer to MI_INFO.
    filepos                     File offset of the record.
    buf                 RETURN  The buffer to receive the record.

  RETURN
    0                                   on success
    HA_ERR_WRONG_IN_RECORD or -1        on error
*/
bk@work.mysql.com's avatar
bk@work.mysql.com committed
706

707
int _mi_read_pack_record(MI_INFO *info, my_off_t filepos, uchar *buf)
bk@work.mysql.com's avatar
bk@work.mysql.com committed
708 709 710 711 712 713 714 715 716
{
  MI_BLOCK_INFO block_info;
  File file;
  DBUG_ENTER("mi_read_pack_record");

  if (filepos == HA_OFFSET_ERROR)
    DBUG_RETURN(-1);			/* _search() didn't find record */

  file=info->dfile;
717 718
  if (_mi_pack_get_block_info(info, &info->bit_buff, &block_info,
                              &info->rec_buff, file, filepos))
bk@work.mysql.com's avatar
bk@work.mysql.com committed
719
    goto err;
720
  if (my_read(file,(uchar*) info->rec_buff + block_info.offset ,
bk@work.mysql.com's avatar
bk@work.mysql.com committed
721 722 723
	      block_info.rec_len - block_info.offset, MYF(MY_NABP)))
    goto panic;
  info->update|= HA_STATE_AKTIV;
724 725
  DBUG_RETURN(_mi_pack_rec_unpack(info, &info->bit_buff, buf,
                                  info->rec_buff, block_info.rec_len));
bk@work.mysql.com's avatar
bk@work.mysql.com committed
726 727 728 729 730 731 732 733
panic:
  my_errno=HA_ERR_WRONG_IN_RECORD;
err:
  DBUG_RETURN(-1);
}



734
int _mi_pack_rec_unpack(register MI_INFO *info, MI_BIT_BUFF *bit_buff,
735
                        register uchar *to, uchar *from, ulong reclength)
bk@work.mysql.com's avatar
bk@work.mysql.com committed
736
{
737
  uchar *end_field;
bk@work.mysql.com's avatar
bk@work.mysql.com committed
738 739 740 741 742
  reg3 MI_COLUMNDEF *end;
  MI_COLUMNDEF *current_field;
  MYISAM_SHARE *share=info->s;
  DBUG_ENTER("_mi_pack_rec_unpack");

743
  init_bit_buffer(bit_buff, (uchar*) from, reclength);
bk@work.mysql.com's avatar
bk@work.mysql.com committed
744 745 746 747 748 749

  for (current_field=share->rec, end=current_field+share->base.fields ;
       current_field < end ;
       current_field++,to=end_field)
  {
    end_field=to+current_field->length;
750
    (*current_field->unpack)(current_field, bit_buff, (uchar*) to,
bk@work.mysql.com's avatar
bk@work.mysql.com committed
751 752
			     (uchar*) end_field);
  }
753 754
  if (!bit_buff->error &&
      bit_buff->pos - bit_buff->bits / 8 == bit_buff->end)
bk@work.mysql.com's avatar
bk@work.mysql.com committed
755 756 757 758 759 760 761 762 763 764 765 766
    DBUG_RETURN(0);
  info->update&= ~HA_STATE_AKTIV;
  DBUG_RETURN(my_errno=HA_ERR_WRONG_IN_RECORD);
} /* _mi_pack_rec_unpack */


	/* Return function to unpack field */

static void (*get_unpack_function(MI_COLUMNDEF *rec))
(MI_COLUMNDEF *, MI_BIT_BUFF *, uchar *, uchar *)
{
  switch (rec->base_type) {
monty@hundin.mysql.fi's avatar
monty@hundin.mysql.fi committed
767
  case FIELD_SKIP_ZERO:
bk@work.mysql.com's avatar
bk@work.mysql.com committed
768
    if (rec->pack_type & PACK_TYPE_ZERO_FILL)
769 770
      return &uf_zerofill_skip_zero;
    return &uf_skip_zero;
bk@work.mysql.com's avatar
bk@work.mysql.com committed
771 772 773 774 775 776
  case FIELD_NORMAL:
    if (rec->pack_type & PACK_TYPE_SPACE_FIELDS)
      return &uf_space_normal;
    if (rec->pack_type & PACK_TYPE_ZERO_FILL)
      return &uf_zerofill_normal;
    return &decode_bytes;
monty@hundin.mysql.fi's avatar
monty@hundin.mysql.fi committed
777
  case FIELD_SKIP_ENDSPACE:
bk@work.mysql.com's avatar
bk@work.mysql.com committed
778 779 780 781 782 783 784 785 786
    if (rec->pack_type & PACK_TYPE_SPACE_FIELDS)
    {
      if (rec->pack_type & PACK_TYPE_SELECTED)
	return &uf_space_endspace_selected;
      return &uf_space_endspace;
    }
    if (rec->pack_type & PACK_TYPE_SELECTED)
      return &uf_endspace_selected;
    return &uf_endspace;
monty@hundin.mysql.fi's avatar
monty@hundin.mysql.fi committed
787
  case FIELD_SKIP_PRESPACE:
bk@work.mysql.com's avatar
bk@work.mysql.com committed
788 789 790 791 792 793 794 795 796 797 798 799 800 801 802 803 804 805 806
    if (rec->pack_type & PACK_TYPE_SPACE_FIELDS)
    {
      if (rec->pack_type & PACK_TYPE_SELECTED)
	return &uf_space_prespace_selected;
      return &uf_space_prespace;
    }
    if (rec->pack_type & PACK_TYPE_SELECTED)
      return &uf_prespace_selected;
    return &uf_prespace;
  case FIELD_CONSTANT:
    return &uf_constant;
  case FIELD_INTERVALL:
    return &uf_intervall;
  case FIELD_ZERO:
  case FIELD_CHECK:
    return &uf_zero;
  case FIELD_BLOB:
    return &uf_blob;
  case FIELD_VARCHAR:
807 808 809
    if (rec->length <= 256)                      /* 255 + 1 byte length */
      return &uf_varchar1;
    return &uf_varchar2;
bk@work.mysql.com's avatar
bk@work.mysql.com committed
810 811 812 813 814 815
  case FIELD_LAST:
  default:
    return 0;			/* This should never happend */
  }
}

816
	/* The different functions to unpack a field */
bk@work.mysql.com's avatar
bk@work.mysql.com committed
817

818
static void uf_zerofill_skip_zero(MI_COLUMNDEF *rec, MI_BIT_BUFF *bit_buff,
bk@work.mysql.com's avatar
bk@work.mysql.com committed
819 820 821 822 823 824 825 826 827 828 829 830
				   uchar *to, uchar *end)
{
  if (get_bit(bit_buff))
    bzero((char*) to,(uint) (end-to));
  else
  {
    end-=rec->space_length_bits;
    decode_bytes(rec,bit_buff,to,end);
    bzero((char*) end,rec->space_length_bits);
  }
}

831
static void uf_skip_zero(MI_COLUMNDEF *rec, MI_BIT_BUFF *bit_buff, uchar *to,
bk@work.mysql.com's avatar
bk@work.mysql.com committed
832 833 834 835 836 837 838 839 840 841 842 843
			  uchar *end)
{
  if (get_bit(bit_buff))
    bzero((char*) to,(uint) (end-to));
  else
    decode_bytes(rec,bit_buff,to,end);
}

static void uf_space_normal(MI_COLUMNDEF *rec, MI_BIT_BUFF *bit_buff, uchar *to,
			    uchar *end)
{
  if (get_bit(bit_buff))
844
    bfill((uchar*) to,(end-to),' ');
bk@work.mysql.com's avatar
bk@work.mysql.com committed
845 846 847 848 849 850 851 852 853
  else
    decode_bytes(rec,bit_buff,to,end);
}

static void uf_space_endspace_selected(MI_COLUMNDEF *rec, MI_BIT_BUFF *bit_buff,
				       uchar *to, uchar *end)
{
  uint spaces;
  if (get_bit(bit_buff))
854
    bfill((uchar*) to,(end-to),' ');
bk@work.mysql.com's avatar
bk@work.mysql.com committed
855 856 857 858 859 860 861 862 863 864 865
  else
  {
    if (get_bit(bit_buff))
    {
      if ((spaces=get_bits(bit_buff,rec->space_length_bits))+to > end)
      {
	bit_buff->error=1;
	return;
      }
      if (to+spaces != end)
	decode_bytes(rec,bit_buff,to,end-spaces);
866
      bfill((uchar*) end-spaces,spaces,' ');
bk@work.mysql.com's avatar
bk@work.mysql.com committed
867 868 869 870 871 872 873 874 875 876 877 878 879 880 881 882 883 884 885
    }
    else
      decode_bytes(rec,bit_buff,to,end);
  }
}

static void uf_endspace_selected(MI_COLUMNDEF *rec, MI_BIT_BUFF *bit_buff,
				 uchar *to, uchar *end)
{
  uint spaces;
  if (get_bit(bit_buff))
  {
    if ((spaces=get_bits(bit_buff,rec->space_length_bits))+to > end)
    {
      bit_buff->error=1;
      return;
    }
    if (to+spaces != end)
      decode_bytes(rec,bit_buff,to,end-spaces);
886
    bfill((uchar*) end-spaces,spaces,' ');
bk@work.mysql.com's avatar
bk@work.mysql.com committed
887 888 889 890 891 892 893 894 895 896
  }
  else
    decode_bytes(rec,bit_buff,to,end);
}

static void uf_space_endspace(MI_COLUMNDEF *rec, MI_BIT_BUFF *bit_buff, uchar *to,
			      uchar *end)
{
  uint spaces;
  if (get_bit(bit_buff))
897
    bfill((uchar*) to,(end-to),' ');
bk@work.mysql.com's avatar
bk@work.mysql.com committed
898 899 900 901 902 903 904 905 906
  else
  {
    if ((spaces=get_bits(bit_buff,rec->space_length_bits))+to > end)
    {
      bit_buff->error=1;
      return;
    }
    if (to+spaces != end)
      decode_bytes(rec,bit_buff,to,end-spaces);
907
    bfill((uchar*) end-spaces,spaces,' ');
bk@work.mysql.com's avatar
bk@work.mysql.com committed
908 909 910 911 912 913 914 915 916 917 918 919 920 921
  }
}

static void uf_endspace(MI_COLUMNDEF *rec, MI_BIT_BUFF *bit_buff, uchar *to,
			uchar *end)
{
  uint spaces;
  if ((spaces=get_bits(bit_buff,rec->space_length_bits))+to > end)
  {
    bit_buff->error=1;
    return;
  }
  if (to+spaces != end)
    decode_bytes(rec,bit_buff,to,end-spaces);
922
  bfill((uchar*) end-spaces,spaces,' ');
bk@work.mysql.com's avatar
bk@work.mysql.com committed
923 924 925 926 927 928 929
}

static void uf_space_prespace_selected(MI_COLUMNDEF *rec, MI_BIT_BUFF *bit_buff,
				       uchar *to, uchar *end)
{
  uint spaces;
  if (get_bit(bit_buff))
930
    bfill((uchar*) to,(end-to),' ');
bk@work.mysql.com's avatar
bk@work.mysql.com committed
931 932 933 934 935 936 937 938 939
  else
  {
    if (get_bit(bit_buff))
    {
      if ((spaces=get_bits(bit_buff,rec->space_length_bits))+to > end)
      {
	bit_buff->error=1;
	return;
      }
940
      bfill((uchar*) to,spaces,' ');
bk@work.mysql.com's avatar
bk@work.mysql.com committed
941 942 943 944 945 946 947 948 949 950 951 952 953 954 955 956 957 958 959 960
      if (to+spaces != end)
	decode_bytes(rec,bit_buff,to+spaces,end);
    }
    else
      decode_bytes(rec,bit_buff,to,end);
  }
}


static void uf_prespace_selected(MI_COLUMNDEF *rec, MI_BIT_BUFF *bit_buff,
				 uchar *to, uchar *end)
{
  uint spaces;
  if (get_bit(bit_buff))
  {
    if ((spaces=get_bits(bit_buff,rec->space_length_bits))+to > end)
    {
      bit_buff->error=1;
      return;
    }
961
    bfill((uchar*) to,spaces,' ');
bk@work.mysql.com's avatar
bk@work.mysql.com committed
962 963 964 965 966 967 968 969 970 971 972 973 974
    if (to+spaces != end)
      decode_bytes(rec,bit_buff,to+spaces,end);
  }
  else
    decode_bytes(rec,bit_buff,to,end);
}


static void uf_space_prespace(MI_COLUMNDEF *rec, MI_BIT_BUFF *bit_buff, uchar *to,
			      uchar *end)
{
  uint spaces;
  if (get_bit(bit_buff))
975
    bfill((uchar*) to,(end-to),' ');
bk@work.mysql.com's avatar
bk@work.mysql.com committed
976 977 978 979 980 981 982
  else
  {
    if ((spaces=get_bits(bit_buff,rec->space_length_bits))+to > end)
    {
      bit_buff->error=1;
      return;
    }
983
    bfill((uchar*) to,spaces,' ');
bk@work.mysql.com's avatar
bk@work.mysql.com committed
984 985 986 987 988 989 990 991 992 993 994 995 996 997
    if (to+spaces != end)
      decode_bytes(rec,bit_buff,to+spaces,end);
  }
}

static void uf_prespace(MI_COLUMNDEF *rec, MI_BIT_BUFF *bit_buff, uchar *to,
			uchar *end)
{
  uint spaces;
  if ((spaces=get_bits(bit_buff,rec->space_length_bits))+to > end)
  {
    bit_buff->error=1;
    return;
  }
998
  bfill((uchar*) to,spaces,' ');
bk@work.mysql.com's avatar
bk@work.mysql.com committed
999 1000 1001 1002 1003 1004 1005 1006 1007 1008 1009 1010 1011 1012 1013 1014 1015 1016 1017 1018 1019 1020 1021 1022 1023 1024 1025 1026 1027 1028 1029 1030 1031 1032 1033 1034 1035 1036 1037 1038 1039 1040
  if (to+spaces != end)
    decode_bytes(rec,bit_buff,to+spaces,end);
}

static void uf_zerofill_normal(MI_COLUMNDEF *rec, MI_BIT_BUFF *bit_buff, uchar *to,
			       uchar *end)
{
  end-=rec->space_length_bits;
  decode_bytes(rec,bit_buff,(uchar*) to,end);
  bzero((char*) end,rec->space_length_bits);
}

static void uf_constant(MI_COLUMNDEF *rec,
			MI_BIT_BUFF *bit_buff __attribute__((unused)),
			uchar *to,
			uchar *end)
{
  memcpy(to,rec->huff_tree->intervalls,(size_t) (end-to));
}

static void uf_intervall(MI_COLUMNDEF *rec, MI_BIT_BUFF *bit_buff, uchar *to,
			 uchar *end)
{
  reg1 uint field_length=(uint) (end-to);
  memcpy(to,rec->huff_tree->intervalls+field_length*decode_pos(bit_buff,
							       rec->huff_tree),
	 (size_t) field_length);
}


/*ARGSUSED*/
static void uf_zero(MI_COLUMNDEF *rec __attribute__((unused)),
		    MI_BIT_BUFF *bit_buff __attribute__((unused)),
		    uchar *to, uchar *end)
{
  bzero((char*) to,(uint) (end-to));
}

static void uf_blob(MI_COLUMNDEF *rec, MI_BIT_BUFF *bit_buff,
		    uchar *to, uchar *end)
{
  if (get_bit(bit_buff))
1041
    bzero((uchar*) to,(end-to));
bk@work.mysql.com's avatar
bk@work.mysql.com committed
1042 1043 1044
  else
  {
    ulong length=get_bits(bit_buff,rec->space_length_bits);
1045
    uint pack_length=(uint) (end-to)-portable_sizeof_char_ptr;
1046
    if (bit_buff->blob_pos+length > bit_buff->blob_end)
1047 1048
    {
      bit_buff->error=1;
1049
      bzero((uchar*) to,(end-to));
1050 1051
      return;
    }
bk@work.mysql.com's avatar
bk@work.mysql.com committed
1052
    decode_bytes(rec,bit_buff,bit_buff->blob_pos,bit_buff->blob_pos+length);
1053
    _my_store_blob_length((uchar*) to,pack_length,length);
bk@work.mysql.com's avatar
bk@work.mysql.com committed
1054 1055 1056 1057 1058 1059
    memcpy_fixed((char*) to+pack_length,(char*) &bit_buff->blob_pos,
		 sizeof(char*));
    bit_buff->blob_pos+=length;
  }
}

1060 1061 1062 1063 1064 1065 1066 1067 1068 1069 1070 1071 1072 1073 1074 1075

static void uf_varchar1(MI_COLUMNDEF *rec, MI_BIT_BUFF *bit_buff,
		       uchar *to, uchar *end __attribute__((unused)))
{
  if (get_bit(bit_buff))
    to[0]= 0;				/* Zero lengths */
  else
  {
    ulong length=get_bits(bit_buff,rec->space_length_bits);
    *to= (uchar) length;
    decode_bytes(rec,bit_buff,to+1,to+1+length);
  }
}


static void uf_varchar2(MI_COLUMNDEF *rec, MI_BIT_BUFF *bit_buff,
bk@work.mysql.com's avatar
bk@work.mysql.com committed
1076 1077 1078 1079 1080 1081 1082 1083 1084 1085 1086 1087 1088 1089 1090 1091 1092 1093 1094 1095 1096 1097 1098 1099 1100 1101 1102 1103 1104 1105 1106 1107 1108 1109
		       uchar *to, uchar *end __attribute__((unused)))
{
  if (get_bit(bit_buff))
    to[0]=to[1]=0;				/* Zero lengths */
  else
  {
    ulong length=get_bits(bit_buff,rec->space_length_bits);
    int2store(to,length);
    decode_bytes(rec,bit_buff,to+2,to+2+length);
  }
}

	/* Functions to decode of buffer of bits */

#if BITS_SAVED == 64

static void decode_bytes(MI_COLUMNDEF *rec,MI_BIT_BUFF *bit_buff,uchar *to,
			 uchar *end)
{
  reg1 uint bits,low_byte;
  reg3 uint16 *pos;
  reg4 uint table_bits,table_and;
  MI_DECODE_TREE *decode_tree;

  decode_tree=rec->decode_tree;
  bits=bit_buff->bits;			/* Save in reg for quicker access */
  table_bits=decode_tree->quick_table_bits;
  table_and= (1 << table_bits)-1;

  do
  {
    if (bits <= 32)
    {
      if (bit_buff->pos > bit_buff->end+4)
1110 1111
      {
	bit_buff->error=1;
bk@work.mysql.com's avatar
bk@work.mysql.com committed
1112
	return;				/* Can't be right */
1113
      }
bk@work.mysql.com's avatar
bk@work.mysql.com committed
1114 1115 1116 1117 1118 1119 1120 1121
      bit_buff->current_byte= (bit_buff->current_byte << 32) +
	((((uint) bit_buff->pos[3])) +
	 (((uint) bit_buff->pos[2]) << 8) +
	 (((uint) bit_buff->pos[1]) << 16) +
	 (((uint) bit_buff->pos[0]) << 24));
      bit_buff->pos+=4;
      bits+=32;
    }
1122 1123 1124 1125 1126 1127 1128 1129 1130 1131 1132 1133 1134 1135 1136 1137 1138 1139 1140 1141 1142 1143 1144
    /*
      First use info in quick_table.

      The quick table is an array of 16-bit values. There exists one
      value for each possible code representable by table_bits bits.
      In most cases table_bits is 9. So there are 512 16-bit values.

      If the high-order bit (16) is set (IS_CHAR) then the array slot
      for this value is a valid Huffman code for a resulting byte value.

      The low-order 8 bits (1..8) are the resulting byte value.

      Bits 9..14 are the length of the Huffman code for this byte value.
      This means so many bits from the input stream were needed to
      represent this byte value. The remaining bits belong to later
      Huffman codes. This also means that for every Huffman code shorter
      than table_bits there are multiple entires in the array, which
      differ just in the unused bits.

      If the high-order bit (16) is clear (0) then the remaining bits are
      the position of the remaining Huffman decode tree segment behind the
      quick table.
    */
bk@work.mysql.com's avatar
bk@work.mysql.com committed
1145 1146 1147 1148
    low_byte=(uint) (bit_buff->current_byte >> (bits - table_bits)) & table_and;
    low_byte=decode_tree->table[low_byte];
    if (low_byte & IS_CHAR)
    {
1149 1150 1151 1152
      /*
        All Huffman codes of less or equal table_bits length are in the
        quick table. This is one of them.
      */
bk@work.mysql.com's avatar
bk@work.mysql.com committed
1153 1154 1155 1156 1157
      *to++ = (low_byte & 255);		/* Found char in quick table */
      bits-=  ((low_byte >> 8) & 31);	/* Remove bits used */
    }
    else
    {					/* Map through rest of decode-table */
1158
      /* This means that the Huffman code must be longer than table_bits. */
bk@work.mysql.com's avatar
bk@work.mysql.com committed
1159 1160
      pos=decode_tree->table+low_byte;
      bits-=table_bits;
1161
      /* NOTE: decode_bytes_test_bit() is a macro wich contains a break !!! */
bk@work.mysql.com's avatar
bk@work.mysql.com committed
1162 1163 1164 1165 1166 1167 1168 1169 1170 1171 1172 1173 1174 1175 1176 1177 1178 1179 1180 1181 1182 1183 1184
      for (;;)
      {
	low_byte=(uint) (bit_buff->current_byte >> (bits-8));
	decode_bytes_test_bit(0);
	decode_bytes_test_bit(1);
	decode_bytes_test_bit(2);
	decode_bytes_test_bit(3);
	decode_bytes_test_bit(4);
	decode_bytes_test_bit(5);
	decode_bytes_test_bit(6);
	decode_bytes_test_bit(7);
	bits-=8;
      }
      *to++ = *pos;
    }
  } while (to != end);

  bit_buff->bits=bits;
  return;
}

#else

1185 1186
static void decode_bytes(MI_COLUMNDEF *rec, MI_BIT_BUFF *bit_buff, uchar *to,
			 uchar *end)
bk@work.mysql.com's avatar
bk@work.mysql.com committed
1187 1188 1189 1190 1191 1192 1193 1194 1195 1196 1197 1198 1199 1200 1201 1202
{
  reg1 uint bits,low_byte;
  reg3 uint16 *pos;
  reg4 uint table_bits,table_and;
  MI_DECODE_TREE *decode_tree;

  decode_tree=rec->huff_tree;
  bits=bit_buff->bits;			/* Save in reg for quicker access */
  table_bits=decode_tree->quick_table_bits;
  table_and= (1 << table_bits)-1;

  do
  {
    if (bits < table_bits)
    {
      if (bit_buff->pos > bit_buff->end+1)
1203 1204
      {
	bit_buff->error=1;
bk@work.mysql.com's avatar
bk@work.mysql.com committed
1205
	return;				/* Can't be right */
1206
      }
bk@work.mysql.com's avatar
bk@work.mysql.com committed
1207 1208 1209 1210 1211 1212 1213 1214 1215 1216 1217 1218 1219 1220 1221 1222 1223 1224 1225 1226 1227 1228 1229 1230 1231 1232 1233 1234 1235 1236 1237 1238 1239 1240 1241 1242 1243 1244 1245 1246 1247 1248 1249 1250 1251 1252 1253 1254 1255 1256 1257 1258 1259 1260 1261 1262 1263 1264 1265 1266 1267 1268 1269 1270 1271 1272 1273 1274 1275 1276 1277 1278 1279 1280 1281 1282 1283 1284 1285 1286 1287 1288 1289 1290 1291 1292 1293 1294 1295
#if BITS_SAVED == 32
      bit_buff->current_byte= (bit_buff->current_byte << 24) +
	(((uint) ((uchar) bit_buff->pos[2]))) +
	  (((uint) ((uchar) bit_buff->pos[1])) << 8) +
	    (((uint) ((uchar) bit_buff->pos[0])) << 16);
      bit_buff->pos+=3;
      bits+=24;
#else
      if (bits)				/* We must have at leasts 9 bits */
      {
	bit_buff->current_byte=  (bit_buff->current_byte << 8) +
	  (uint) ((uchar) bit_buff->pos[0]);
	bit_buff->pos++;
	bits+=8;
      }
      else
      {
	bit_buff->current_byte= ((uint) ((uchar) bit_buff->pos[0]) << 8) +
	  ((uint) ((uchar) bit_buff->pos[1]));
	bit_buff->pos+=2;
	bits+=16;
      }
#endif
    }
	/* First use info in quick_table */
    low_byte=(bit_buff->current_byte >> (bits - table_bits)) & table_and;
    low_byte=decode_tree->table[low_byte];
    if (low_byte & IS_CHAR)
    {
      *to++ = (low_byte & 255);		/* Found char in quick table */
      bits-=  ((low_byte >> 8) & 31);	/* Remove bits used */
    }
    else
    {					/* Map through rest of decode-table */
      pos=decode_tree->table+low_byte;
      bits-=table_bits;
      for (;;)
      {
	if (bits < 8)
	{				/* We don't need to check end */
#if BITS_SAVED == 32
	  bit_buff->current_byte= (bit_buff->current_byte << 24) +
	    (((uint) ((uchar) bit_buff->pos[2]))) +
	      (((uint) ((uchar) bit_buff->pos[1])) << 8) +
		(((uint) ((uchar) bit_buff->pos[0])) << 16);
	  bit_buff->pos+=3;
	  bits+=24;
#else
	  bit_buff->current_byte=  (bit_buff->current_byte << 8) +
	    (uint) ((uchar) bit_buff->pos[0]);
	  bit_buff->pos+=1;
	  bits+=8;
#endif
	}
	low_byte=(uint) (bit_buff->current_byte >> (bits-8));
	decode_bytes_test_bit(0);
	decode_bytes_test_bit(1);
	decode_bytes_test_bit(2);
	decode_bytes_test_bit(3);
	decode_bytes_test_bit(4);
	decode_bytes_test_bit(5);
	decode_bytes_test_bit(6);
	decode_bytes_test_bit(7);
	bits-=8;
      }
      *to++ = (uchar) *pos;
    }
  } while (to != end);

  bit_buff->bits=bits;
  return;
}
#endif /* BIT_SAVED == 64 */


static uint decode_pos(MI_BIT_BUFF *bit_buff, MI_DECODE_TREE *decode_tree)
{
  uint16 *pos=decode_tree->table;
  for (;;)
  {
    if (get_bit(bit_buff))
      pos++;
    if (*pos & IS_CHAR)
      return (uint) (*pos & ~IS_CHAR);
    pos+= *pos;
  }
}


1296
int _mi_read_rnd_pack_record(MI_INFO *info, uchar *buf,
bk@work.mysql.com's avatar
bk@work.mysql.com committed
1297 1298 1299 1300 1301 1302 1303 1304 1305 1306 1307 1308 1309 1310 1311 1312
			     register my_off_t filepos,
			     my_bool skip_deleted_blocks)
{
  uint b_type;
  MI_BLOCK_INFO block_info;
  MYISAM_SHARE *share=info->s;
  DBUG_ENTER("_mi_read_rnd_pack_record");

  if (filepos >= info->state->data_file_length)
  {
    my_errno= HA_ERR_END_OF_FILE;
    goto err;
  }

  if (info->opt_flag & READ_CACHE_USED)
  {
1313
    if (_mi_read_cache(&info->rec_cache, (uchar*) block_info.header,
1314 1315
                       filepos, share->pack.ref_length,
                       skip_deleted_blocks ? READING_NEXT : 0))
bk@work.mysql.com's avatar
bk@work.mysql.com committed
1316
      goto err;
1317 1318
    b_type=_mi_pack_get_block_info(info, &info->bit_buff, &block_info,
                                   &info->rec_buff, -1, filepos);
bk@work.mysql.com's avatar
bk@work.mysql.com committed
1319 1320
  }
  else
1321 1322
    b_type=_mi_pack_get_block_info(info, &info->bit_buff, &block_info,
                                   &info->rec_buff, info->dfile, filepos);
bk@work.mysql.com's avatar
bk@work.mysql.com committed
1323
  if (b_type)
monty@hundin.mysql.fi's avatar
monty@hundin.mysql.fi committed
1324
    goto err;					/* Error code is already set */
bk@work.mysql.com's avatar
bk@work.mysql.com committed
1325 1326 1327 1328 1329 1330 1331 1332 1333 1334
#ifndef DBUG_OFF
  if (block_info.rec_len > share->max_pack_length)
  {
    my_errno=HA_ERR_WRONG_IN_RECORD;
    goto err;
  }
#endif

  if (info->opt_flag & READ_CACHE_USED)
  {
1335
    if (_mi_read_cache(&info->rec_cache, (uchar*) info->rec_buff,
1336 1337
                       block_info.filepos, block_info.rec_len,
                       skip_deleted_blocks ? READING_NEXT : 0))
bk@work.mysql.com's avatar
bk@work.mysql.com committed
1338 1339 1340 1341
      goto err;
  }
  else
  {
1342
    if (my_read(info->dfile,(uchar*) info->rec_buff + block_info.offset,
bk@work.mysql.com's avatar
bk@work.mysql.com committed
1343 1344 1345 1346 1347 1348 1349 1350 1351
		block_info.rec_len-block_info.offset,
		MYF(MY_NABP)))
      goto err;
  }
  info->packed_length=block_info.rec_len;
  info->lastpos=filepos;
  info->nextpos=block_info.filepos+block_info.rec_len;
  info->update|= HA_STATE_AKTIV | HA_STATE_KEY_CHANGED;

1352 1353
  DBUG_RETURN (_mi_pack_rec_unpack(info, &info->bit_buff, buf,
                                   info->rec_buff, block_info.rec_len));
bk@work.mysql.com's avatar
bk@work.mysql.com committed
1354 1355 1356 1357 1358 1359 1360
 err:
  DBUG_RETURN(my_errno);
}


	/* Read and process header from a huff-record-file */

1361
uint _mi_pack_get_block_info(MI_INFO *myisam, MI_BIT_BUFF *bit_buff,
1362
                             MI_BLOCK_INFO *info, uchar **rec_buff_p,
1363
                             File file, my_off_t filepos)
bk@work.mysql.com's avatar
bk@work.mysql.com committed
1364 1365
{
  uchar *header=info->header;
1366
  uint head_length, UNINIT_VAR(ref_length);
bk@work.mysql.com's avatar
bk@work.mysql.com committed
1367 1368 1369 1370 1371 1372
  LINT_INIT(ref_length);

  if (file >= 0)
  {
    ref_length=myisam->s->pack.ref_length;
    /*
1373
      We can't use my_pread() here because mi_read_rnd_pack_record assumes
bk@work.mysql.com's avatar
bk@work.mysql.com committed
1374 1375 1376
      position is ok
    */
    VOID(my_seek(file,filepos,MY_SEEK_SET,MYF(0)));
1377
    if (my_read(file, header,ref_length,MYF(MY_NABP)))
bk@work.mysql.com's avatar
bk@work.mysql.com committed
1378
      return BLOCK_FATAL_ERROR;
1379
    DBUG_DUMP("header",(uchar*) header,ref_length);
bk@work.mysql.com's avatar
bk@work.mysql.com committed
1380
  }
1381 1382
  head_length= read_pack_length((uint) myisam->s->pack.version, header,
                                &info->rec_len);
bk@work.mysql.com's avatar
bk@work.mysql.com committed
1383 1384
  if (myisam->s->base.blobs)
  {
1385 1386
    head_length+= read_pack_length((uint) myisam->s->pack.version,
                                   header + head_length, &info->blob_len);
1387 1388 1389 1390 1391
    /*
      Ensure that the record buffer is big enough for the compressed
      record plus all expanded blobs. [We do not have an extra buffer
      for the resulting blobs. Sigh.]
    */
1392
    if (!(mi_alloc_rec_buff(myisam,info->rec_len + info->blob_len,
1393
			    rec_buff_p)))
bk@work.mysql.com's avatar
bk@work.mysql.com committed
1394
      return BLOCK_FATAL_ERROR;			/* not enough memory */
1395 1396
    bit_buff->blob_pos= (uchar*) *rec_buff_p + info->rec_len;
    bit_buff->blob_end= bit_buff->blob_pos + info->blob_len;
bk@work.mysql.com's avatar
bk@work.mysql.com committed
1397 1398 1399 1400 1401 1402
    myisam->blob_length=info->blob_len;
  }
  info->filepos=filepos+head_length;
  if (file > 0)
  {
    info->offset=min(info->rec_len, ref_length - head_length);
1403
    memcpy(*rec_buff_p, header + head_length, info->offset);
bk@work.mysql.com's avatar
bk@work.mysql.com committed
1404 1405 1406 1407 1408 1409 1410 1411 1412 1413 1414 1415 1416 1417 1418 1419 1420 1421 1422 1423 1424 1425 1426 1427 1428 1429 1430 1431 1432 1433 1434 1435 1436 1437 1438 1439 1440
  }
  return 0;
}


	/* rutines for bit buffer */
	/* Note buffer must be 6 byte bigger than longest row */

static void init_bit_buffer(MI_BIT_BUFF *bit_buff, uchar *buffer, uint length)
{
  bit_buff->pos=buffer;
  bit_buff->end=buffer+length;
  bit_buff->bits=bit_buff->error=0;
  bit_buff->current_byte=0;			/* Avoid purify errors */
}

static uint fill_and_get_bits(MI_BIT_BUFF *bit_buff, uint count)
{
  uint tmp;
  count-=bit_buff->bits;
  tmp=(bit_buff->current_byte & mask[bit_buff->bits]) << count;
  fill_buffer(bit_buff);
  bit_buff->bits=BITS_SAVED - count;
  return tmp+(bit_buff->current_byte >> (BITS_SAVED - count));
}

	/* Fill in empty bit_buff->current_byte from buffer */
	/* Sets bit_buff->error if buffer is exhausted */

static void fill_buffer(MI_BIT_BUFF *bit_buff)
{
  if (bit_buff->pos >= bit_buff->end)
  {
    bit_buff->error= 1;
    bit_buff->current_byte=0;
    return;
  }
1441

bk@work.mysql.com's avatar
bk@work.mysql.com committed
1442 1443 1444 1445 1446 1447 1448 1449 1450 1451 1452 1453 1454 1455 1456 1457 1458 1459 1460 1461 1462 1463 1464 1465 1466 1467 1468 1469 1470 1471 1472 1473 1474 1475 1476 1477 1478 1479 1480 1481 1482
#if BITS_SAVED == 64
  bit_buff->current_byte=  ((((uint) ((uchar) bit_buff->pos[7]))) +
			     (((uint) ((uchar) bit_buff->pos[6])) << 8) +
			     (((uint) ((uchar) bit_buff->pos[5])) << 16) +
			     (((uint) ((uchar) bit_buff->pos[4])) << 24) +
			     ((ulonglong)
			      ((((uint) ((uchar) bit_buff->pos[3]))) +
			       (((uint) ((uchar) bit_buff->pos[2])) << 8) +
			       (((uint) ((uchar) bit_buff->pos[1])) << 16) +
			       (((uint) ((uchar) bit_buff->pos[0])) << 24)) << 32));
  bit_buff->pos+=8;
#else
#if BITS_SAVED == 32
  bit_buff->current_byte=  (((uint) ((uchar) bit_buff->pos[3])) +
			     (((uint) ((uchar) bit_buff->pos[2])) << 8) +
			     (((uint) ((uchar) bit_buff->pos[1])) << 16) +
			     (((uint) ((uchar) bit_buff->pos[0])) << 24));
  bit_buff->pos+=4;
#else
  bit_buff->current_byte=  (uint) (((uint) ((uchar) bit_buff->pos[1]))+
				    (((uint) ((uchar) bit_buff->pos[0])) << 8));
  bit_buff->pos+=2;
#endif
#endif
}

	/* Get number of bits neaded to represent value */

static uint max_bit(register uint value)
{
  reg2 uint power=1;

  while ((value>>=1))
    power++;
  return (power);
}


/*****************************************************************************
	Some redefined functions to handle files when we are using memmap
*****************************************************************************/
1483 1484 1485
#ifdef HAVE_SYS_MMAN_H
#include <sys/mman.h>
#endif
bk@work.mysql.com's avatar
bk@work.mysql.com committed
1486 1487 1488

#ifdef HAVE_MMAP

1489 1490
static int _mi_read_mempack_record(MI_INFO *info,my_off_t filepos,uchar *buf);
static int _mi_read_rnd_mempack_record(MI_INFO*, uchar *,my_off_t, my_bool);
bk@work.mysql.com's avatar
bk@work.mysql.com committed
1491 1492 1493 1494

my_bool _mi_memmap_file(MI_INFO *info)
{
  MYISAM_SHARE *share=info->s;
1495 1496
  my_bool eom;

bk@work.mysql.com's avatar
bk@work.mysql.com committed
1497 1498 1499 1500
  DBUG_ENTER("mi_memmap_file");

  if (!info->s->file_map)
  {
1501
    my_off_t data_file_length= share->state.state.data_file_length;
1502 1503 1504 1505 1506 1507 1508 1509 1510 1511 1512 1513 1514

    if (myisam_mmap_size != SIZE_T_MAX)
    {
      pthread_mutex_lock(&THR_LOCK_myisam_mmap);
      eom= data_file_length > myisam_mmap_size - myisam_mmap_used - MEMMAP_EXTRA_MARGIN;
      if (!eom)
        myisam_mmap_used+= data_file_length + MEMMAP_EXTRA_MARGIN;
      pthread_mutex_unlock(&THR_LOCK_myisam_mmap);
    }
    else
      eom= data_file_length > myisam_mmap_size - MEMMAP_EXTRA_MARGIN;

    if (eom)
1515 1516 1517 1518
    {
      DBUG_PRINT("warning", ("File is too large for mmap"));
      DBUG_RETURN(0);
    }
bk@work.mysql.com's avatar
bk@work.mysql.com committed
1519
    if (my_seek(info->dfile,0L,MY_SEEK_END,MYF(0)) <
vtkachenko@quadxeon.mysql.com's avatar
vtkachenko@quadxeon.mysql.com committed
1520
        share->state.state.data_file_length+MEMMAP_EXTRA_MARGIN)
bk@work.mysql.com's avatar
bk@work.mysql.com committed
1521 1522
    {
      DBUG_PRINT("warning",("File isn't extended for memmap"));
1523 1524 1525 1526 1527 1528
      if (myisam_mmap_size != SIZE_T_MAX)
      {
        pthread_mutex_lock(&THR_LOCK_myisam_mmap);
        myisam_mmap_used-= data_file_length + MEMMAP_EXTRA_MARGIN;
        pthread_mutex_unlock(&THR_LOCK_myisam_mmap);
      }
bk@work.mysql.com's avatar
bk@work.mysql.com committed
1529 1530
      DBUG_RETURN(0);
    }
1531 1532 1533
    if (mi_dynmap_file(info,
                       share->state.state.data_file_length + 
                         MEMMAP_EXTRA_MARGIN))
bk@work.mysql.com's avatar
bk@work.mysql.com committed
1534
    {
1535 1536 1537 1538 1539 1540
      if (myisam_mmap_size != SIZE_T_MAX)
      {
        pthread_mutex_lock(&THR_LOCK_myisam_mmap);
        myisam_mmap_used-= data_file_length + MEMMAP_EXTRA_MARGIN;
        pthread_mutex_unlock(&THR_LOCK_myisam_mmap);
      }
bk@work.mysql.com's avatar
bk@work.mysql.com committed
1541 1542 1543 1544
      DBUG_RETURN(0);
    }
  }
  info->opt_flag|= MEMMAP_USED;
vtkachenko@quadxeon.mysql.com's avatar
vtkachenko@quadxeon.mysql.com committed
1545 1546
  info->read_record= share->read_record= _mi_read_mempack_record;
  share->read_rnd= _mi_read_rnd_mempack_record;
bk@work.mysql.com's avatar
bk@work.mysql.com committed
1547 1548 1549 1550 1551 1552
  DBUG_RETURN(1);
}


void _mi_unmap_file(MI_INFO *info)
{
1553
  VOID(my_munmap((char*) info->s->file_map, 
vtkachenko@quadxeon.mysql.com's avatar
vtkachenko@quadxeon.mysql.com committed
1554
                 (size_t) info->s->mmaped_length + MEMMAP_EXTRA_MARGIN));
1555 1556 1557 1558

  if (myisam_mmap_size != SIZE_T_MAX)
  {
    pthread_mutex_lock(&THR_LOCK_myisam_mmap);
1559
    myisam_mmap_used-= info->s->mmaped_length + MEMMAP_EXTRA_MARGIN;
1560 1561
    pthread_mutex_unlock(&THR_LOCK_myisam_mmap);
  }
bk@work.mysql.com's avatar
bk@work.mysql.com committed
1562 1563 1564
}


1565
static uchar *_mi_mempack_get_block_info(MI_INFO *myisam, MI_BIT_BUFF *bit_buff,
1566
                                         MI_BLOCK_INFO *info, uchar **rec_buff_p,
bk@work.mysql.com's avatar
bk@work.mysql.com committed
1567 1568
					 uchar *header)
{
1569 1570
  header+= read_pack_length((uint) myisam->s->pack.version, header,
                            &info->rec_len);
bk@work.mysql.com's avatar
bk@work.mysql.com committed
1571 1572
  if (myisam->s->base.blobs)
  {
1573 1574
    header+= read_pack_length((uint) myisam->s->pack.version, header,
                              &info->blob_len);
1575 1576
    /* mi_alloc_rec_buff sets my_errno on error */
    if (!(mi_alloc_rec_buff(myisam, info->blob_len,
1577
			    rec_buff_p)))
bk@work.mysql.com's avatar
bk@work.mysql.com committed
1578
      return 0;				/* not enough memory */
1579 1580
    bit_buff->blob_pos= (uchar*) *rec_buff_p;
    bit_buff->blob_end= (uchar*) *rec_buff_p + info->blob_len;
bk@work.mysql.com's avatar
bk@work.mysql.com committed
1581 1582 1583 1584 1585
  }
  return header;
}


1586
static int _mi_read_mempack_record(MI_INFO *info, my_off_t filepos, uchar *buf)
bk@work.mysql.com's avatar
bk@work.mysql.com committed
1587 1588 1589
{
  MI_BLOCK_INFO block_info;
  MYISAM_SHARE *share=info->s;
1590
  uchar *pos;
bk@work.mysql.com's avatar
bk@work.mysql.com committed
1591 1592 1593 1594 1595
  DBUG_ENTER("mi_read_mempack_record");

  if (filepos == HA_OFFSET_ERROR)
    DBUG_RETURN(-1);			/* _search() didn't find record */

1596
  if (!(pos= (uchar*) _mi_mempack_get_block_info(info, &info->bit_buff,
1597
                                                &block_info, &info->rec_buff,
bk@work.mysql.com's avatar
bk@work.mysql.com committed
1598 1599 1600
						(uchar*) share->file_map+
						filepos)))
    DBUG_RETURN(-1);
1601 1602
  DBUG_RETURN(_mi_pack_rec_unpack(info, &info->bit_buff, buf,
                                  pos, block_info.rec_len));
bk@work.mysql.com's avatar
bk@work.mysql.com committed
1603 1604 1605 1606
}


/*ARGSUSED*/
1607
static int _mi_read_rnd_mempack_record(MI_INFO *info, uchar *buf,
bk@work.mysql.com's avatar
bk@work.mysql.com committed
1608 1609 1610 1611 1612 1613
				       register my_off_t filepos,
				       my_bool skip_deleted_blocks
				       __attribute__((unused)))
{
  MI_BLOCK_INFO block_info;
  MYISAM_SHARE *share=info->s;
1614
  uchar *pos,*start;
bk@work.mysql.com's avatar
bk@work.mysql.com committed
1615 1616 1617 1618 1619 1620 1621
  DBUG_ENTER("_mi_read_rnd_mempack_record");

  if (filepos >= share->state.state.data_file_length)
  {
    my_errno=HA_ERR_END_OF_FILE;
    goto err;
  }
1622
  if (!(pos= (uchar*) _mi_mempack_get_block_info(info, &info->bit_buff,
1623
                                                &block_info, &info->rec_buff,
bk@work.mysql.com's avatar
bk@work.mysql.com committed
1624 1625 1626 1627 1628 1629 1630 1631 1632 1633 1634 1635 1636 1637 1638 1639
						(uchar*)
						(start=share->file_map+
						 filepos))))
    goto err;
#ifndef DBUG_OFF
  if (block_info.rec_len > info->s->max_pack_length)
  {
    my_errno=HA_ERR_WRONG_IN_RECORD;
    goto err;
  }
#endif
  info->packed_length=block_info.rec_len;
  info->lastpos=filepos;
  info->nextpos=filepos+(uint) (pos-start)+block_info.rec_len;
  info->update|= HA_STATE_AKTIV | HA_STATE_KEY_CHANGED;

1640 1641
  DBUG_RETURN (_mi_pack_rec_unpack(info, &info->bit_buff, buf,
                                   pos, block_info.rec_len));
bk@work.mysql.com's avatar
bk@work.mysql.com committed
1642 1643 1644 1645 1646 1647 1648 1649
 err:
  DBUG_RETURN(my_errno);
}

#endif /* HAVE_MMAP */

	/* Save length of row */

1650
uint save_pack_length(uint version, uchar *block_buff, ulong length)
bk@work.mysql.com's avatar
bk@work.mysql.com committed
1651 1652 1653 1654 1655 1656 1657 1658 1659 1660 1661 1662 1663
{
  if (length < 254)
  {
    *(uchar*) block_buff= (uchar) length;
    return 1;
  }
  if (length <= 65535)
  {
    *(uchar*) block_buff=254;
    int2store(block_buff+1,(uint) length);
    return 3;
  }
  *(uchar*) block_buff=255;
1664 1665 1666 1667 1668 1669 1670 1671 1672 1673 1674 1675 1676 1677 1678 1679 1680 1681 1682 1683 1684 1685 1686 1687 1688 1689 1690 1691 1692 1693 1694 1695 1696 1697 1698 1699 1700 1701 1702 1703 1704 1705
  if (version == 1) /* old format */
  {
    DBUG_ASSERT(length <= 0xFFFFFF);
    int3store(block_buff + 1, (ulong) length);
    return 4;
  }
  else
  {
    int4store(block_buff + 1, (ulong) length);
    return 5;
  }
}


uint read_pack_length(uint version, const uchar *buf, ulong *length)
{
  if (buf[0] < 254)
  {
    *length= buf[0];
    return 1;
  }
  else if (buf[0] == 254)
  {
    *length= uint2korr(buf + 1);
    return 3;
  }
  if (version == 1) /* old format */
  {
    *length= uint3korr(buf + 1);
    return 4;
  }
  else
  {
    *length= uint4korr(buf + 1);
    return 5;
  }
}


uint calc_pack_length(uint version, ulong length)
{
  return (length < 254) ? 1 : (length < 65536) ? 3 : (version == 1) ? 4 : 5;
bk@work.mysql.com's avatar
bk@work.mysql.com committed
1706
}