1 /* testmini.c -- very simple test program for the miniLZO library 2 3 This file is part of the LZO real-time data compression library. 4 5 Copyright (C) 1996-2017 Markus Franz Xaver Johannes Oberhumer 6 All Rights Reserved. 7 8 The LZO library is free software; you can redistribute it and/or 9 modify it under the terms of the GNU General Public License as 10 published by the Free Software Foundation; either version 2 of 11 the License, or (at your option) any later version. 12 13 The LZO library is distributed in the hope that it will be useful, 14 but WITHOUT ANY WARRANTY; without even the implied warranty of 15 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 16 GNU General Public License for more details. 17 18 You should have received a copy of the GNU General Public License 19 along with the LZO library; see the file COPYING. 20 If not, write to the Free Software Foundation, Inc., 21 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA. 22 23 Markus F.X.J. Oberhumer 24 <markus@oberhumer.com> 25 http://www.oberhumer.com/opensource/lzo/ 26 */ 27 28 29 #include <stdio.h> 30 #include <stdlib.h> 31 32 33 /************************************************************************* 34 // This program shows the basic usage of the LZO library. 35 // We will compress a block of data and decompress again. 36 // 37 // For more information, documentation, example programs and other support 38 // files (like Makefiles and build scripts) please download the full LZO 39 // package from 40 // http://www.oberhumer.com/opensource/lzo/ 41 **************************************************************************/ 42 43 /* First let's include "minizo.h". */ 44 45 #include "minilzo.h" 46 47 48 /* We want to compress the data block at 'in' with length 'IN_LEN' to 49 * the block at 'out'. Because the input block may be incompressible, 50 * we must provide a little more output space in case that compression 51 * is not possible. 52 */ 53 54 #define IN_LEN (128*1024ul) 55 #define OUT_LEN (IN_LEN + IN_LEN / 16 + 64 + 3) 56 57 static unsigned char __LZO_MMODEL in [ IN_LEN ]; 58 static unsigned char __LZO_MMODEL out [ OUT_LEN ]; 59 60 61 /* Work-memory needed for compression. Allocate memory in units 62 * of 'lzo_align_t' (instead of 'char') to make sure it is properly aligned. 63 */ 64 65 #define HEAP_ALLOC(var,size) 66 lzo_align_t __LZO_MMODEL var [ ((size) + (sizeof(lzo_align_t) - 1)) / sizeof(lzo_align_t) ] 67 68 static HEAP_ALLOC(wrkmem, LZO1X_1_MEM_COMPRESS); 69 70 71 /************************************************************************* 72 // 73 **************************************************************************/ 74 75 int main(int argc, char *argv[]) 76 { 77 int r; 78 lzo_uint in_len; 79 lzo_uint out_len; 80 lzo_uint new_len; 81 82 if (argc < 0 && argv == NULL) /* avoid warning about unused args */ 83 return 0; 84 85 printf(" LZO real-time data compression library (v%s, %s). ", 86 lzo_version_string(), lzo_version_date()); 87 printf("Copyright (C) 1996-2017 Markus Franz Xaver Johannes Oberhumer All Rights Reserved. "); 88 89 90 /* 91 * Step 1: initialize the LZO library 92 */ 93 if (lzo_init() != LZO_E_OK) 94 { 95 printf("internal error - lzo_init() failed !!! "); 96 printf("(this usually indicates a compiler bug - try recompiling without optimizations, and enable '-DLZO_DEBUG' for diagnostics) "); 97 return 3; 98 } 99 100 /* 101 * Step 2: prepare the input block that will get compressed. 102 * We just fill it with zeros in this example program, 103 * but you would use your real-world data here. 104 */ 105 in_len = IN_LEN; 106 lzo_memset(in,0,in_len); 107 108 /* 109 * Step 3: compress from 'in' to 'out' with LZO1X-1 110 */ 111 r = lzo1x_1_compress(in,in_len,out,&out_len,wrkmem); 112 if (r == LZO_E_OK) 113 printf("compressed %lu bytes into %lu bytes ", 114 (unsigned long) in_len, (unsigned long) out_len); 115 else 116 { 117 /* this should NEVER happen */ 118 printf("internal error - compression failed: %d ", r); 119 return 2; 120 } 121 /* check for an incompressible block */ 122 if (out_len >= in_len) 123 { 124 printf("This block contains incompressible data. "); 125 return 0; 126 } 127 128 /* 129 * Step 4: decompress again, now going from 'out' to 'in' 130 */ 131 new_len = in_len; 132 r = lzo1x_decompress(out,out_len,in,&new_len,NULL); 133 if (r == LZO_E_OK && new_len == in_len) 134 printf("decompressed %lu bytes back into %lu bytes ", 135 (unsigned long) out_len, (unsigned long) in_len); 136 else 137 { 138 /* this should NEVER happen */ 139 printf("internal error - decompression failed: %d ", r); 140 return 1; 141 } 142 143 printf(" miniLZO simple compression test passed. "); 144 return 0; 145 } 146 147 148 /* vim:set ts=4 sw=4 et: */
首先需要准备好数组，然后知道长度。
第一步：初始化LZO库
if (lzo_init() != LZO_E_OK) { ... }
第二步：清空数组，准备存放的缓存
in_len = IN_LEN; lzo_memset(in,0,in_len);
第三步：压缩后数据放入缓存中
r = lzo1x_1_compress(in,in_len,out,&out_len,wrkmem); if (r == LZO_E_OK) printf("compressed %lu bytes into %lu bytes ", (unsigned long) in_len, (unsigned long) out_len); else { /* this should NEVER happen */ printf("internal error - compression failed: %d ", r); return 2; } /* check for an incompressible block */ if (out_len >= in_len) { printf("This block contains incompressible data. "); return 0; }