/* 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 */ #include #include #include #include /* This replaces the packet with a compressed packet SYNOPSIS my_compress() packet Data to compress. This is is replaced with the compressed data. len Length of data to compress at 'packet' complen out: 0 if packet was not compressed RETURN 1 error. 'len' is not changed' 0 ok. In this case 'len' contains the size of the compressed packet */ my_bool my_compress(uchar *packet, size_t *len, size_t *complen) { DBUG_ENTER("my_compress"); if (*len < MIN_COMPRESS_LENGTH) { *complen=0; DBUG_PRINT("note",("Packet too short: Not compressed")); } else { uchar *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); } uchar *my_compress_alloc(const uchar *packet, size_t *len, size_t *complen) { uchar *compbuf; uLongf tmp_complen; int res; *complen= *len * 120 / 100 + 12; if (!(compbuf= (uchar *) my_malloc(*complen, MYF(MY_WME)))) return 0; /* Not enough memory */ tmp_complen= *complen; res= compress((Bytef*) compbuf, &tmp_complen, (Bytef*) packet, (uLong) *len); *complen= tmp_complen; if (res != 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; } /* Store length of compressed packet in *len */ swap_variables(size_t, *len, *complen); return compbuf; } /* Uncompress packet SYNOPSIS my_uncompress() packet Compressed data. This is is replaced with the orignal data. len Length of compressed data complen Length of the packet buffer (must be enough for the original data) RETURN 1 error 0 ok. In this case 'complen' contains the updated size of the real data. */ my_bool my_uncompress(uchar *packet, size_t len, size_t *complen) { uLongf tmp_complen; DBUG_ENTER("my_uncompress"); if (*complen) /* If compressed */ { uchar *compbuf= (uchar *) my_malloc(*complen,MYF(MY_WME)); int error; if (!compbuf) DBUG_RETURN(1); /* Not enough memory */ tmp_complen= *complen; error= uncompress((Bytef*) compbuf, &tmp_complen, (Bytef*) packet, (uLong) len); *complen= tmp_complen; if (error != Z_OK) { /* Probably wrong packet */ DBUG_PRINT("error",("Can't uncompress packet, error: %d",error)); my_free(compbuf, MYF(MY_WME)); DBUG_RETURN(1); } memcpy(packet, compbuf, *complen); my_free(compbuf, MYF(MY_WME)); } else *complen= len; DBUG_RETURN(0); }