buffer.h 1.89 KB
Newer Older
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37
#ifndef INCLUDES_MYSQL_INSTANCE_MANAGER_BUFFER_H
#define INCLUDES_MYSQL_INSTANCE_MANAGER_BUFFER_H
/* Copyright (C) 2004 MySQL AB

   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
   the Free Software Foundation; either version 2 of the License, or
   (at your option) any later version.

   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.

   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 */

#include <my_global.h>

#ifdef __GNUC__
#pragma interface
#endif

/*
  This class is a simple implementation of the buffer of varying size.
  It is used to store MySQL client-server protocol packets. This is why
  the maximum buffer size if 16Mb. (See internals manual section
  7. MySQL Client/Server Protocol)
*/

class Buffer
{
private:
  enum { BUFFER_INITIAL_SIZE= 4096 };
  /* maximum buffer size is 16Mb */
  enum { MAX_BUFFER_SIZE= 16777216 };
petr@mysql.com's avatar
petr@mysql.com committed
38
  size_t buffer_size;
39 40
  /* Error flag. Triggered if we get an error of some kind */
  int error;
41
public:
42 43
  Buffer(size_t buffer_size_arg= BUFFER_INITIAL_SIZE)
    :buffer_size(BUFFER_INITIAL_SIZE), error(0)
44
  {
45 46 47 48 49
    /*
      As append() will invokes realloc() anyway, it's ok if malloc returns 0
    */
    if (!(buffer= (char*) malloc(buffer_size)))
        buffer_size= 0;
50 51 52 53 54 55 56 57 58
  }

  ~Buffer()
  {
    free(buffer);
  }

public:
  char *buffer;
59 60
  int get_size();
  int is_error();
petr@mysql.com's avatar
petr@mysql.com committed
61
  int append(uint position, const char *string, uint len_arg);
petr@mysql.com's avatar
petr@mysql.com committed
62
  int reserve(uint position, uint len_arg);
63 64 65
};

#endif /* INCLUDES_MYSQL_INSTANCE_MANAGER_BUFFER_H */