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/* Copyright (C) 2000 MySQL AB & MySQL Finland AB & TCX DataKonsult AB
This library is free software; you can redistribute it and/or
modify it under the terms of the GNU Library General Public
License as published by the Free Software Foundation; either
version 2 of the License, or (at your option) any later version.
This library 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
Library General Public License for more details.
You should have received a copy of the GNU Library General Public
License along with this library; 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>
#include <m_string.h>
#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)
{
if (*len < MIN_COMPRESS_LENGTH)
*complen=0;
else
{
byte *compbuf=my_compress_alloc(packet,len,complen);
if (!compbuf)
return *complen ? 0 : 1;
memcpy(packet,compbuf,*len);
my_free(compbuf,MYF(MY_WME)); }
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));
return 0;
}
swap(ulong,*len,*complen); /* *len is now packet length */
return compbuf;
}
my_bool my_uncompress (byte *packet, ulong *len, ulong *complen)
{
if (*complen) /* If compressed */
{
byte *compbuf = (byte *) my_malloc (*complen,MYF(MY_WME));
if (!compbuf)
return 1; /* Not enough memory */
if (uncompress((Bytef*) compbuf, complen, (Bytef*) packet, *len) != Z_OK)
{ /* Probably wrong packet */
my_free (compbuf,MYF(MY_WME));
return 1;
}
*len = *complen;
memcpy(packet,compbuf,*len);
my_free(compbuf,MYF(MY_WME));
}
return 0;
}
#endif /* HAVE_COMPRESS */
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