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 |