~mysql/mysql-server/mysql-5.1

/* 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; version 2 of the License.

   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 */

#if defined(__GNUC__) && defined(USE_PRAGMA_IMPLEMENTATION)

#pragma implementation

#endif

#include "buffer.h"

#include <m_string.h>

const uint Buffer::BUFFER_INITIAL_SIZE= 4096;

const uint Buffer::MAX_BUFFER_SIZE= 16777216;

/*

  Puts the given string to the buffer.

  SYNOPSIS

    append()

    position          start position in the buffer

    string            string to be put in the buffer

    len_arg           the length of the string. This way we can avoid some

                      strlens.

  DESCRIPTION

    The method puts a string into the buffer, starting from position .

    In the case when the buffer is too small it reallocs the buffer. The

    total size of the buffer is restricted with 16.

  RETURN

    0 - ok

    1 - got an error in reserve()

*/

int Buffer::append(size_t position, const char *string, size_t len_arg)

{

  if (reserve(position, len_arg))

    return 1;

  strnmov((char*) buffer + position, string, len_arg);

  return 0;

}

/*

  Checks whether the current buffer size is ok to put a string of the length

  "len_arg" starting from "position" and reallocs it if no.

  SYNOPSIS

    reserve()

    position          the number starting byte on the buffer to store a buffer

    len_arg           the length of the string.

  DESCRIPTION

    The method checks whether it is possible to put a string of the "len_arg"

    length into the buffer, starting from "position" byte. In the case when the

    buffer is too small it reallocs the buffer. The total size of the buffer is

    restricted with 16 Mb.

  RETURN

    0 - ok

    1 - realloc error or we have come to the 16Mb barrier

*/

int Buffer::reserve(size_t position, size_t len_arg)

{

  if (position + len_arg >= MAX_BUFFER_SIZE)

    goto err;

  if (position + len_arg >= buffer_size)

  {

    buffer= (uchar*) my_realloc(buffer,

                                min(MAX_BUFFER_SIZE,

                                    max((uint) (buffer_size*1.5),

                                        position + len_arg)), MYF(0));

    if (!(buffer))

      goto err;

    buffer_size= (size_t) (buffer_size*1.5);

  }

  return 0;

err:

  error= 1;

  return 1;

}

int Buffer::get_size()

{

  return buffer_size;

}

int Buffer::is_error()

{

  return error;

}