1/* 2 * LZO 1x decompression 3 * Copyright (c) 2006 Reimar Doeffinger 4 * 5 * This file is part of FFmpeg. 6 * 7 * FFmpeg is free software; you can redistribute it and/or 8 * modify it under the terms of the GNU Lesser General Public 9 * License as published by the Free Software Foundation; either 10 * version 2.1 of the License, or (at your option) any later version. 11 * 12 * FFmpeg is distributed in the hope that it will be useful, 13 * but WITHOUT ANY WARRANTY; without even the implied warranty of 14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 15 * Lesser General Public License for more details. 16 * 17 * You should have received a copy of the GNU Lesser General Public 18 * License along with FFmpeg; if not, write to the Free Software 19 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA 20 */ 21 22#include "avutil.h" 23#include "common.h" 24//! Avoid e.g. MPlayers fast_memcpy, it slows things down here. 25#undef memcpy 26#include <string.h> 27#include "lzo.h" 28 29//! Define if we may write up to 12 bytes beyond the output buffer. 30#define OUTBUF_PADDED 1 31//! Define if we may read up to 8 bytes beyond the input buffer. 32#define INBUF_PADDED 1 33typedef struct LZOContext { 34 const uint8_t *in, *in_end; 35 uint8_t *out_start, *out, *out_end; 36 int error; 37} LZOContext; 38 39/** 40 * \brief Reads one byte from the input buffer, avoiding an overrun. 41 * \return byte read 42 */ 43static inline int get_byte(LZOContext *c) { 44 if (c->in < c->in_end) 45 return *c->in++; 46 c->error |= AV_LZO_INPUT_DEPLETED; 47 return 1; 48} 49 50#ifdef INBUF_PADDED 51#define GETB(c) (*(c).in++) 52#else 53#define GETB(c) get_byte(&(c)) 54#endif 55 56/** 57 * \brief Decodes a length value in the coding used by lzo. 58 * \param x previous byte value 59 * \param mask bits used from x 60 * \return decoded length value 61 */ 62static inline int get_len(LZOContext *c, int x, int mask) { 63 int cnt = x & mask; 64 if (!cnt) { 65 while (!(x = get_byte(c))) cnt += 255; 66 cnt += mask + x; 67 } 68 return cnt; 69} 70 71//#define UNALIGNED_LOADSTORE 72#define BUILTIN_MEMCPY 73#ifdef UNALIGNED_LOADSTORE 74#define COPY2(d, s) *(uint16_t *)(d) = *(uint16_t *)(s); 75#define COPY4(d, s) *(uint32_t *)(d) = *(uint32_t *)(s); 76#elif defined(BUILTIN_MEMCPY) 77#define COPY2(d, s) memcpy(d, s, 2); 78#define COPY4(d, s) memcpy(d, s, 4); 79#else 80#define COPY2(d, s) (d)[0] = (s)[0]; (d)[1] = (s)[1]; 81#define COPY4(d, s) (d)[0] = (s)[0]; (d)[1] = (s)[1]; (d)[2] = (s)[2]; (d)[3] = (s)[3]; 82#endif 83 84/** 85 * \brief Copies bytes from input to output buffer with checking. 86 * \param cnt number of bytes to copy, must be >= 0 87 */ 88static inline void copy(LZOContext *c, int cnt) { 89 register const uint8_t *src = c->in; 90 register uint8_t *dst = c->out; 91 if (cnt > c->in_end - src) { 92 cnt = FFMAX(c->in_end - src, 0); 93 c->error |= AV_LZO_INPUT_DEPLETED; 94 } 95 if (cnt > c->out_end - dst) { 96 cnt = FFMAX(c->out_end - dst, 0); 97 c->error |= AV_LZO_OUTPUT_FULL; 98 } 99#if defined(INBUF_PADDED) && defined(OUTBUF_PADDED) 100 COPY4(dst, src); 101 src += 4; 102 dst += 4; 103 cnt -= 4; 104 if (cnt > 0) 105#endif 106 memcpy(dst, src, cnt); 107 c->in = src + cnt; 108 c->out = dst + cnt; 109} 110 111static inline void memcpy_backptr(uint8_t *dst, int back, int cnt); 112 113/** 114 * \brief Copies previously decoded bytes to current position. 115 * \param back how many bytes back we start 116 * \param cnt number of bytes to copy, must be >= 0 117 * 118 * cnt > back is valid, this will copy the bytes we just copied, 119 * thus creating a repeating pattern with a period length of back. 120 */ 121static inline void copy_backptr(LZOContext *c, int back, int cnt) { 122 register const uint8_t *src = &c->out[-back]; 123 register uint8_t *dst = c->out; 124 if (src < c->out_start || src > dst) { 125 c->error |= AV_LZO_INVALID_BACKPTR; 126 return; 127 } 128 if (cnt > c->out_end - dst) { 129 cnt = FFMAX(c->out_end - dst, 0); 130 c->error |= AV_LZO_OUTPUT_FULL; 131 } 132 memcpy_backptr(dst, back, cnt); 133 c->out = dst + cnt; 134} 135 136static inline void memcpy_backptr(uint8_t *dst, int back, int cnt) { 137 const uint8_t *src = &dst[-back]; 138 if (back == 1) { 139 memset(dst, *src, cnt); 140 } else { 141#ifdef OUTBUF_PADDED 142 COPY2(dst, src); 143 COPY2(dst + 2, src + 2); 144 src += 4; 145 dst += 4; 146 cnt -= 4; 147 if (cnt > 0) { 148 COPY2(dst, src); 149 COPY2(dst + 2, src + 2); 150 COPY2(dst + 4, src + 4); 151 COPY2(dst + 6, src + 6); 152 src += 8; 153 dst += 8; 154 cnt -= 8; 155 } 156#endif 157 if (cnt > 0) { 158 int blocklen = back; 159 while (cnt > blocklen) { 160 memcpy(dst, src, blocklen); 161 dst += blocklen; 162 cnt -= blocklen; 163 blocklen <<= 1; 164 } 165 memcpy(dst, src, cnt); 166 } 167 } 168} 169 170void av_memcpy_backptr(uint8_t *dst, int back, int cnt) { 171 memcpy_backptr(dst, back, cnt); 172} 173 174int av_lzo1x_decode(void *out, int *outlen, const void *in, int *inlen) { 175 int state= 0; 176 int x; 177 LZOContext c; 178 c.in = in; 179 c.in_end = (const uint8_t *)in + *inlen; 180 c.out = c.out_start = out; 181 c.out_end = (uint8_t *)out + * outlen; 182 c.error = 0; 183 x = GETB(c); 184 if (x > 17) { 185 copy(&c, x - 17); 186 x = GETB(c); 187 if (x < 16) c.error |= AV_LZO_ERROR; 188 } 189 if (c.in > c.in_end) 190 c.error |= AV_LZO_INPUT_DEPLETED; 191 while (!c.error) { 192 int cnt, back; 193 if (x > 15) { 194 if (x > 63) { 195 cnt = (x >> 5) - 1; 196 back = (GETB(c) << 3) + ((x >> 2) & 7) + 1; 197 } else if (x > 31) { 198 cnt = get_len(&c, x, 31); 199 x = GETB(c); 200 back = (GETB(c) << 6) + (x >> 2) + 1; 201 } else { 202 cnt = get_len(&c, x, 7); 203 back = (1 << 14) + ((x & 8) << 11); 204 x = GETB(c); 205 back += (GETB(c) << 6) + (x >> 2); 206 if (back == (1 << 14)) { 207 if (cnt != 1) 208 c.error |= AV_LZO_ERROR; 209 break; 210 } 211 } 212 } else if(!state){ 213 cnt = get_len(&c, x, 15); 214 copy(&c, cnt + 3); 215 x = GETB(c); 216 if (x > 15) 217 continue; 218 cnt = 1; 219 back = (1 << 11) + (GETB(c) << 2) + (x >> 2) + 1; 220 } else { 221 cnt = 0; 222 back = (GETB(c) << 2) + (x >> 2) + 1; 223 } 224 copy_backptr(&c, back, cnt + 2); 225 state= 226 cnt = x & 3; 227 copy(&c, cnt); 228 x = GETB(c); 229 } 230 *inlen = c.in_end - c.in; 231 if (c.in > c.in_end) 232 *inlen = 0; 233 *outlen = c.out_end - c.out; 234 return c.error; 235} 236 237#ifdef TEST 238#include <stdio.h> 239#include <lzo/lzo1x.h> 240#include "log.h" 241#define MAXSZ (10*1024*1024) 242 243/* Define one of these to 1 if you wish to benchmark liblzo 244 * instead of our native implementation. */ 245#define BENCHMARK_LIBLZO_SAFE 0 246#define BENCHMARK_LIBLZO_UNSAFE 0 247 248int main(int argc, char *argv[]) { 249 FILE *in = fopen(argv[1], "rb"); 250 uint8_t *orig = av_malloc(MAXSZ + 16); 251 uint8_t *comp = av_malloc(2*MAXSZ + 16); 252 uint8_t *decomp = av_malloc(MAXSZ + 16); 253 size_t s = fread(orig, 1, MAXSZ, in); 254 lzo_uint clen = 0; 255 long tmp[LZO1X_MEM_COMPRESS]; 256 int inlen, outlen; 257 int i; 258 av_log_set_level(AV_LOG_DEBUG); 259 lzo1x_999_compress(orig, s, comp, &clen, tmp); 260 for (i = 0; i < 300; i++) { 261START_TIMER 262 inlen = clen; outlen = MAXSZ; 263#if BENCHMARK_LIBLZO_SAFE 264 if (lzo1x_decompress_safe(comp, inlen, decomp, &outlen, NULL)) 265#elif BENCHMARK_LIBLZO_UNSAFE 266 if (lzo1x_decompress(comp, inlen, decomp, &outlen, NULL)) 267#else 268 if (av_lzo1x_decode(decomp, &outlen, comp, &inlen)) 269#endif 270 av_log(NULL, AV_LOG_ERROR, "decompression error\n"); 271STOP_TIMER("lzod") 272 } 273 if (memcmp(orig, decomp, s)) 274 av_log(NULL, AV_LOG_ERROR, "decompression incorrect\n"); 275 else 276 av_log(NULL, AV_LOG_ERROR, "decompression OK\n"); 277 return 0; 278} 279#endif 280