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 Uses zlib. 26 */ 27 28 29 #include "dact.h" 30 #include "comp_zlib.h" 31 32 #ifdef HAVE_LIBZ 33 #include <stdio.h> 34 #ifdef HAVE_UNISTD_H 35 #include <unistd.h> 36 #endif 37 #ifdef HAVE_STDLIB_H 38 #include <stdlib.h> 39 #endif 40 #ifdef HAVE_STRING_H 41 #include <string.h> 42 #endif 43 #ifdef HAVE_ZLIB_H 44 #include <zlib.h> 45 #endif 46 47 48 /* 49 mode - DACT_MODE_COMPR or DACT_MODE_DECMP 50 Determine whether to compress or decompress. 51 prev_block - Previous (uncompressed) block. 52 curr_block - The data to be compressed. 53 out_block - Where to put data after compression. 54 blk_size - Size of prev_block and curr_block. 55 */ 56 57 #if defined(USE_MODULES) && defined(AS_MODULE) 58 #include "module.h" 59 uint32_t DC_NUM=4; 60 uint32_t DC_TYPE=DACT_MOD_TYPE_COMP; 61 void *DC_ALGO=comp_zlib_algo; 62 char *DC_NAME="Zlib Compression (MOD)"; 63 #endif 64 65 int comp_zlib_algo(int mode, unsigned char *prev_block, unsigned char *curr_block, char *out_block, int blk_size, int bufsize) { 66 switch(mode) { 67 case DACT_MODE_COMPR: 68 return(comp_zlib_compress(prev_block, curr_block, out_block, blk_size, bufsize)); 69 break; /* Heh */ 70 case DACT_MODE_DECMP: 71 return(comp_zlib_decompress(prev_block, curr_block, out_block, blk_size, bufsize)); 72 break; 73 default: 74 printf("Unsupported mode: %i\n", mode); 75 return(-1); 76 } 77 } 78 79 int comp_zlib_compress(unsigned char *prev_block, unsigned char *curr_block, unsigned char *out_block, int blk_size, int bufsize) { 80 unsigned long dest_size; 81 int retval; 82 dest_size=(int) ((float) (blk_size*1.01)+13); 83 84 #ifdef HAVE_COMPRESS2 85 retval=compress2(out_block, &dest_size, curr_block, blk_size, Z_BEST_COMPRESSION); 86 #else 87 retval=compress(out_block, &dest_size, curr_block, blk_size); 88 #endif 89 if (retval!=Z_OK) return(-1); 90 /* Remove the 120,218 header */ 91 dest_size-=2; 92 memmove(out_block, out_block+2, dest_size); 93 94 return(dest_size); 95 } 96 97 int comp_zlib_decompress(unsigned char *prev_block, unsigned char *curr_block, char *out_block, int blk_size, int bufsize) { 98 unsigned long dest_size; 99 unsigned char *tmpbuf; 100 int retval; 101 102 /* Replant the header. */ 103 tmpbuf=malloc(blk_size+2); 104 tmpbuf[0]=120; 105 tmpbuf[1]=218; 106 memcpy(tmpbuf+2, curr_block, blk_size); 107 108 dest_size=bufsize; 109 retval=uncompress(out_block,&dest_size,tmpbuf,blk_size+2); 110 111 free(tmpbuf); 112 113 if (retval!=Z_OK) return(0); 114 115 return(dest_size); 116 } 117 #endif |