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98 lines
2.7 KiB
C
98 lines
2.7 KiB
C
/* Copyright (C) 2000 MySQL AB
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This program is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; version 2 of the License.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program; if not, write to the Free Software
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Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA */
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/* Written by Sinisa Milivojevic <sinisa@mysql.com> */
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#include <my_global.h>
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#ifdef HAVE_COMPRESS
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#include <my_sys.h>
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#ifndef SCO
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#include <m_string.h>
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#endif
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#include <zlib.h>
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/*
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** This replaces the packet with a compressed packet
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** Returns 1 on error
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** *complen is 0 if the packet wasn't compressed
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*/
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my_bool my_compress(byte *packet, ulong *len, ulong *complen)
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{
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DBUG_ENTER("my_compress");
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if (*len < MIN_COMPRESS_LENGTH)
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{
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*complen=0;
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DBUG_PRINT("note",("Packet too short: Not compressed"));
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}
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else
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{
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byte *compbuf=my_compress_alloc(packet,len,complen);
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if (!compbuf)
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DBUG_RETURN(*complen ? 0 : 1);
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memcpy(packet,compbuf,*len);
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my_free(compbuf,MYF(MY_WME)); }
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DBUG_RETURN(0);
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}
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byte *my_compress_alloc(const byte *packet, ulong *len, ulong *complen)
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{
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byte *compbuf;
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*complen= *len * 120 / 100 + 12;
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if (!(compbuf= (byte *) my_malloc(*complen,MYF(MY_WME))))
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return 0; /* Not enough memory */
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if (compress((Bytef*) compbuf,(ulong *) complen, (Bytef*) packet,
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(uLong) *len ) != Z_OK)
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{
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my_free(compbuf,MYF(MY_WME));
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return 0;
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}
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if (*complen >= *len)
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{
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*complen= 0;
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my_free(compbuf, MYF(MY_WME));
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DBUG_PRINT("note",("Packet got longer on compression; Not compressed"));
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return 0;
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}
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swap_variables(ulong, *len, *complen); /* *len is now packet length */
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return compbuf;
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}
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my_bool my_uncompress (byte *packet, ulong *len, ulong *complen)
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{
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DBUG_ENTER("my_uncompress");
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if (*complen) /* If compressed */
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{
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byte *compbuf= (byte *) my_malloc(*complen,MYF(MY_WME));
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int error;
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if (!compbuf)
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DBUG_RETURN(1); /* Not enough memory */
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if ((error=uncompress((Bytef*) compbuf, complen, (Bytef*) packet, *len))
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!= Z_OK)
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{ /* Probably wrong packet */
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DBUG_PRINT("error",("Can't uncompress packet, error: %d",error));
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my_free(compbuf, MYF(MY_WME));
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DBUG_RETURN(1);
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}
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*len= *complen;
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memcpy(packet, compbuf, *len);
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my_free(compbuf, MYF(MY_WME));
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}
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DBUG_RETURN(0);
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}
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#endif /* HAVE_COMPRESS */
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