2674525 [rkeene@sledge /home/rkeene/devel/dact]$ cat -n comp_mzlib.c
  1 /*
  2  * Copyright (C) 2001, 2002, and 2003  Roy Keene
  3  *
  4  * This program is free software; you can redistribute it and/or
  5  * modify it under the terms of the GNU General Public License
  6  * as published by the Free Software Foundation; either version 2
  7  * of the License, or (at your option) any later version.
  8  *
  9  * This program is distributed in the hope that it will be useful,
 10  * but WITHOUT ANY WARRANTY; without even the implied warranty of
 11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 12  * GNU General Public License for more details.
 13  *
 14  * You should have received a copy of the GNU General Public License
 15  * along with this program; if not, write to the Free Software
 16  * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
 17  *
 18  *      email: dact@rkeene.org
 19  */
 20 
 21 
 22 #include "dact.h"
 23 #include "comp_mzlib.h"
 24 
 25 #ifdef HAVE_LIBZ
 26 #include <stdio.h>
 27 #ifdef HAVE_UNISTD_H
 28 #include <unistd.h>
 29 #endif
 30 #ifdef HAVE_STDLIB_H
 31 #include <stdlib.h>
 32 #endif
 33 #ifdef HAVE_STRING_H
 34 #include <string.h>
 35 #endif
 36 #ifdef HAVE_ZLIB_H
 37 #include <zlib.h>
 38 #endif
 39 
 40 
 41 /*
 42     mode        - DACT_MODE_COMPR or DACT_MODE_DECMP
 43                 Determine whether to compress or decompress.
 44     prev_block  - Previous (uncompressed) block.
 45     curr_block  - The data to be compressed.
 46     out_block   - Where to put data after compression.
 47     blk_size    - Size of prev_block and curr_block.
 48 */
 49 
 50 #if defined(USE_MODULES) && defined(AS_MODULE)
 51 #include "module.h"
 52 uint32_t DC_NUM=5;
 53 uint32_t DC_TYPE=DACT_MOD_TYPE_COMP;
 54 void *DC_ALGO=comp_mzlib_algo;
 55 char *DC_NAME="Modifed Zlib Compression (MOD)";
 56 #endif
 57 
 58 int comp_mzlib_algo(int mode, unsigned char *prev_block, unsigned char *curr_block, char *out_block, int blk_size, int
	bufsize) {
 59     switch(mode) {
 60         case DACT_MODE_COMPR:
 61             return(comp_mzlib_compress(prev_block, curr_block, out_block, blk_size, bufsize));
 62             break; /* Heh */
 63         case DACT_MODE_DECMP:
 64             return(comp_mzlib_decompress(prev_block, curr_block, out_block, blk_size, bufsize));
 65             break;
 66         default:
 67             printf("Unsupported mode: %i\n", mode);
 68             return(-1);
 69     }
 70 }
 71 
 72 int comp_mzlib_compress(unsigned char *prev_block, unsigned char *curr_block, char *out_block, int blk_size, int
	bufsize) {
 73     unsigned long dest_size;
 74     char *tmp_block;
 75     int retval;
 76     int i;
 77 
 78     dest_size=(int) ((float) (blk_size*1.02)+15);
 79 
 80     if ((tmp_block=malloc(dest_size))==NULL) {
 81         return(-1);
 82     }
 83     memcpy(tmp_block,curr_block,blk_size);
 84 
 85     for (i=0;i<blk_size;i++) {
 86 /*
 87         tmp_block[i]=( \
 88             (  (tmp_block[i]&0x80) >> 7 ) + \
 89             (  (tmp_block[i]&0x20) >> 4 ) + \
 90             (  (tmp_block[i]&0x08) >> 1 ) + \
 91             (  (tmp_block[i]&0x02) << 2 ) + \
 92             (  (tmp_block[i]&0x40) >> 2 ) + \
 93             (  (tmp_block[i]&0x10) << 1 ) + \
 94             (  (tmp_block[i]&0x04) << 4 ) + \
 95             (  (tmp_block[i]&0x01) << 7 ) \
 96         );
 97 */
 98         tmp_block[i]=( ((tmp_block[i]&0xf0)>>4) + (  (tmp_block[i]&0x0f)  <<4) );
 99     }
100 #ifdef HAVE_COMPRESS2
101     retval=compress2(out_block, &dest_size, tmp_block, blk_size, Z_BEST_COMPRESSION);
102 #else
103     retval=compress(out_block, &dest_size, tmp_block, blk_size);
104 #endif
105     if (retval!=Z_OK) {
106         return(-1);
107     }
108     free(tmp_block);
109     return(dest_size);
110 }
111 
112 int comp_mzlib_decompress(unsigned char *prev_block, unsigned char *curr_block, char *out_block, int blk_size, int
	bufsize) {
113     unsigned long dest_size=(blk_size*2);
114     int retval;
115     int i;
116 
117     retval=uncompress(out_block,&dest_size,curr_block,blk_size);
118 
119     if (retval!=Z_OK) {
120         return(0);
121     }
122 
123     for (i=0;i<dest_size;i++) {
124         out_block[i]=( ( (out_block[i]&0xf0)>>4) + ((out_block[i]&0x0f)<<4) );
125     }
126 
127     return(dest_size);
128 }
129 #endif
2674526 [rkeene@sledge /home/rkeene/devel/dact]$

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last modified: 2004-04-04 01:01:50