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/* Copyright (C) 2000 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 */
/* Written by Sinisa Milivojevic <sinisa@mysql.com> */
#include <my_global.h>
#ifdef HAVE_COMPRESS
#include <my_sys.h>
#ifndef SCO
#include <m_string.h>
#endif
#include <zlib.h>
/*
** This replaces the packet with a compressed packet
** Returns 1 on error
** *complen is 0 if the packet wasn't compressed
*/
my_bool my_compress(byte *packet, ulong *len, ulong *complen)
{
DBUG_ENTER("my_compress");
if (*len < MIN_COMPRESS_LENGTH)
{
*complen=0;
DBUG_PRINT("note",("Packet too short: Not compressed"));
}
else
{
byte *compbuf=my_compress_alloc(packet,len,complen);
if (!compbuf)
DBUG_RETURN(*complen ? 0 : 1);
memcpy(packet,compbuf,*len);
my_free(compbuf,MYF(MY_WME)); }
DBUG_RETURN(0);
}
byte *my_compress_alloc(const byte *packet, ulong *len, ulong *complen)
{
byte *compbuf;
*complen= *len * 120 / 100 + 12;
if (!(compbuf= (byte *) my_malloc(*complen,MYF(MY_WME))))
return 0; /* Not enough memory */
if (compress((Bytef*) compbuf,(ulong *) complen, (Bytef*) packet,
(uLong) *len ) != Z_OK)
{
my_free(compbuf,MYF(MY_WME));
return 0;
}
if (*complen >= *len)
{
*complen= 0;
my_free(compbuf, MYF(MY_WME));
DBUG_PRINT("note",("Packet got longer on compression; Not compressed"));
return 0;
}
swap_variables(ulong, *len, *complen); /* *len is now packet length */
return compbuf;
}
my_bool my_uncompress (byte *packet, ulong *len, ulong *complen)
{
DBUG_ENTER("my_uncompress");
if (*complen) /* If compressed */
{
byte *compbuf= (byte *) my_malloc(*complen,MYF(MY_WME));
int error;
if (!compbuf)
DBUG_RETURN(1); /* Not enough memory */
if ((error=uncompress((Bytef*) compbuf, complen, (Bytef*) packet, *len))
!= Z_OK)
{ /* Probably wrong packet */
DBUG_PRINT("error",("Can't uncompress packet, error: %d",error));
my_free(compbuf, MYF(MY_WME));
DBUG_RETURN(1);
}
*len= *complen;
memcpy(packet, compbuf, *len);
my_free(compbuf, MYF(MY_WME));
}
DBUG_RETURN(0);
}
#endif /* HAVE_COMPRESS */
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