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 /*
23 Example block compression routine for interfacing with DACT.
24
25 This does no compression.
26
27 (This is used as the minimum case, so block can be atmost blk_size
28 +3 bytes in size)
29 */
30
31
32 #include "dact.h"
33 #include "comp_plain.h"
34 #include <stdio.h>
35 #ifdef HAVE_UNISTD_H
36 #include <unistd.h>
37 #endif
38 #ifdef HAVE_STDLIB_H
39 #include <stdlib.h>
40 #endif
41 #ifdef HAVE_STRING_H
42 #include <string.h>
43 #endif
44
45
46 /*
47 mode - DACT_MODE_COMPR or DACT_MODE_DECMP
48 Determine whether to compress or decompress.
49 prev_block - Previous (uncompressed) block.
50 curr_block - The data to be compressed.
51 out_block - Where to put data after compression.
52 blk_size - Size of prev_block and curr_block.
53 */
comp_plain_algo(int mode,unsigned char * prev_block,unsigned char * curr_block,char * out_block,int blk_size,int bufsize)54 int comp_plain_algo(int mode, unsigned char *prev_block, unsigned char *curr_block, char *out_block, int blk_size, int bufsize) {
55 switch(mode) {
56 case DACT_MODE_COMPR:
57 return(comp_plain_compress(prev_block, curr_block, out_block, blk_size, bufsize));
58 break; /* Heh */
59 case DACT_MODE_DECMP:
60 return(comp_plain_decompress(prev_block, curr_block, out_block, blk_size, bufsize));
61 break;
62 default:
63 printf("Unsupported mode: %i\n", mode);
64 return(-1);
65 }
66 }
67
comp_plain_compress(unsigned char * prev_block,unsigned char * curr_block,char * out_block,int blk_size,int bufsize)68 int comp_plain_compress(unsigned char *prev_block, unsigned char *curr_block, char *out_block, int blk_size, int bufsize) {
69 memcpy(out_block,curr_block,blk_size);
70 return(blk_size);
71 }
72
comp_plain_decompress(unsigned char * prev_block,unsigned char * curr_block,char * out_block,int blk_size,int bufsize)73 int comp_plain_decompress(unsigned char *prev_block, unsigned char *curr_block, char *out_block, int blk_size, int bufsize) {
74 memcpy(out_block,curr_block,blk_size);
75 return(blk_size);
76 }
77