• Main Page
  • Related Pages
  • Modules
  • Data Structures
  • Files
  • File List
  • Globals

libavutil/lzo.c

Go to the documentation of this file.
00001 /*
00002  * LZO 1x decompression
00003  * Copyright (c) 2006 Reimar Doeffinger
00004  *
00005  * This file is part of FFmpeg.
00006  *
00007  * FFmpeg is free software; you can redistribute it and/or
00008  * modify it under the terms of the GNU Lesser General Public
00009  * License as published by the Free Software Foundation; either
00010  * version 2.1 of the License, or (at your option) any later version.
00011  *
00012  * FFmpeg is distributed in the hope that it will be useful,
00013  * but WITHOUT ANY WARRANTY; without even the implied warranty of
00014  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
00015  * Lesser General Public License for more details.
00016  *
00017  * You should have received a copy of the GNU Lesser General Public
00018  * License along with FFmpeg; if not, write to the Free Software
00019  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
00020  */
00021 
00022 #include "avutil.h"
00023 #include "common.h"
00025 #undef memcpy
00026 #include <string.h>
00027 #include "lzo.h"
00028 
00030 #define OUTBUF_PADDED 1
00031 
00032 #define INBUF_PADDED 1
00033 typedef struct LZOContext {
00034     const uint8_t *in, *in_end;
00035     uint8_t *out_start, *out, *out_end;
00036     int error;
00037 } LZOContext;
00038 
00043 static inline int get_byte(LZOContext *c) {
00044     if (c->in < c->in_end)
00045         return *c->in++;
00046     c->error |= AV_LZO_INPUT_DEPLETED;
00047     return 1;
00048 }
00049 
00050 #ifdef INBUF_PADDED
00051 #define GETB(c) (*(c).in++)
00052 #else
00053 #define GETB(c) get_byte(&(c))
00054 #endif
00055 
00062 static inline int get_len(LZOContext *c, int x, int mask) {
00063     int cnt = x & mask;
00064     if (!cnt) {
00065         while (!(x = get_byte(c))) cnt += 255;
00066         cnt += mask + x;
00067     }
00068     return cnt;
00069 }
00070 
00071 //#define UNALIGNED_LOADSTORE
00072 #define BUILTIN_MEMCPY
00073 #ifdef UNALIGNED_LOADSTORE
00074 #define COPY2(d, s) *(uint16_t *)(d) = *(uint16_t *)(s);
00075 #define COPY4(d, s) *(uint32_t *)(d) = *(uint32_t *)(s);
00076 #elif defined(BUILTIN_MEMCPY)
00077 #define COPY2(d, s) memcpy(d, s, 2);
00078 #define COPY4(d, s) memcpy(d, s, 4);
00079 #else
00080 #define COPY2(d, s) (d)[0] = (s)[0]; (d)[1] = (s)[1];
00081 #define COPY4(d, s) (d)[0] = (s)[0]; (d)[1] = (s)[1]; (d)[2] = (s)[2]; (d)[3] = (s)[3];
00082 #endif
00083 
00088 static inline void copy(LZOContext *c, int cnt) {
00089     register const uint8_t *src = c->in;
00090     register uint8_t *dst = c->out;
00091     if (cnt > c->in_end - src) {
00092         cnt = FFMAX(c->in_end - src, 0);
00093         c->error |= AV_LZO_INPUT_DEPLETED;
00094     }
00095     if (cnt > c->out_end - dst) {
00096         cnt = FFMAX(c->out_end - dst, 0);
00097         c->error |= AV_LZO_OUTPUT_FULL;
00098     }
00099 #if defined(INBUF_PADDED) && defined(OUTBUF_PADDED)
00100     COPY4(dst, src);
00101     src += 4;
00102     dst += 4;
00103     cnt -= 4;
00104     if (cnt > 0)
00105 #endif
00106         memcpy(dst, src, cnt);
00107     c->in = src + cnt;
00108     c->out = dst + cnt;
00109 }
00110 
00111 static inline void memcpy_backptr(uint8_t *dst, int back, int cnt);
00112 
00121 static inline void copy_backptr(LZOContext *c, int back, int cnt) {
00122     register const uint8_t *src = &c->out[-back];
00123     register uint8_t *dst = c->out;
00124     if (src < c->out_start || src > dst) {
00125         c->error |= AV_LZO_INVALID_BACKPTR;
00126         return;
00127     }
00128     if (cnt > c->out_end - dst) {
00129         cnt = FFMAX(c->out_end - dst, 0);
00130         c->error |= AV_LZO_OUTPUT_FULL;
00131     }
00132     memcpy_backptr(dst, back, cnt);
00133     c->out = dst + cnt;
00134 }
00135 
00136 static inline void memcpy_backptr(uint8_t *dst, int back, int cnt) {
00137     const uint8_t *src = &dst[-back];
00138     if (back == 1) {
00139         memset(dst, *src, cnt);
00140     } else {
00141 #ifdef OUTBUF_PADDED
00142         COPY2(dst, src);
00143         COPY2(dst + 2, src + 2);
00144         src += 4;
00145         dst += 4;
00146         cnt -= 4;
00147         if (cnt > 0) {
00148             COPY2(dst, src);
00149             COPY2(dst + 2, src + 2);
00150             COPY2(dst + 4, src + 4);
00151             COPY2(dst + 6, src + 6);
00152             src += 8;
00153             dst += 8;
00154             cnt -= 8;
00155         }
00156 #endif
00157         if (cnt > 0) {
00158             int blocklen = back;
00159             while (cnt > blocklen) {
00160                 memcpy(dst, src, blocklen);
00161                 dst += blocklen;
00162                 cnt -= blocklen;
00163                 blocklen <<= 1;
00164             }
00165             memcpy(dst, src, cnt);
00166         }
00167     }
00168 }
00169 
00170 void av_memcpy_backptr(uint8_t *dst, int back, int cnt) {
00171     memcpy_backptr(dst, back, cnt);
00172 }
00173 
00174 int av_lzo1x_decode(void *out, int *outlen, const void *in, int *inlen) {
00175     int state= 0;
00176     int x;
00177     LZOContext c;
00178     c.in = in;
00179     c.in_end = (const uint8_t *)in + *inlen;
00180     c.out = c.out_start = out;
00181     c.out_end = (uint8_t *)out + * outlen;
00182     c.error = 0;
00183     x = GETB(c);
00184     if (x > 17) {
00185         copy(&c, x - 17);
00186         x = GETB(c);
00187         if (x < 16) c.error |= AV_LZO_ERROR;
00188     }
00189     if (c.in > c.in_end)
00190         c.error |= AV_LZO_INPUT_DEPLETED;
00191     while (!c.error) {
00192         int cnt, back;
00193         if (x > 15) {
00194             if (x > 63) {
00195                 cnt = (x >> 5) - 1;
00196                 back = (GETB(c) << 3) + ((x >> 2) & 7) + 1;
00197             } else if (x > 31) {
00198                 cnt = get_len(&c, x, 31);
00199                 x = GETB(c);
00200                 back = (GETB(c) << 6) + (x >> 2) + 1;
00201             } else {
00202                 cnt = get_len(&c, x, 7);
00203                 back = (1 << 14) + ((x & 8) << 11);
00204                 x = GETB(c);
00205                 back += (GETB(c) << 6) + (x >> 2);
00206                 if (back == (1 << 14)) {
00207                     if (cnt != 1)
00208                         c.error |= AV_LZO_ERROR;
00209                     break;
00210                 }
00211             }
00212         } else if(!state){
00213                 cnt = get_len(&c, x, 15);
00214                 copy(&c, cnt + 3);
00215                 x = GETB(c);
00216                 if (x > 15)
00217                     continue;
00218                 cnt = 1;
00219                 back = (1 << 11) + (GETB(c) << 2) + (x >> 2) + 1;
00220         } else {
00221                 cnt = 0;
00222                 back = (GETB(c) << 2) + (x >> 2) + 1;
00223         }
00224         copy_backptr(&c, back, cnt + 2);
00225         state=
00226         cnt = x & 3;
00227         copy(&c, cnt);
00228         x = GETB(c);
00229     }
00230     *inlen = c.in_end - c.in;
00231     if (c.in > c.in_end)
00232         *inlen = 0;
00233     *outlen = c.out_end - c.out;
00234     return c.error;
00235 }
00236 
00237 #ifdef TEST
00238 #include <stdio.h>
00239 #include <lzo/lzo1x.h>
00240 #include "log.h"
00241 #define MAXSZ (10*1024*1024)
00242 
00243 /* Define one of these to 1 if you wish to benchmark liblzo
00244  * instead of our native implementation. */
00245 #define BENCHMARK_LIBLZO_SAFE   0
00246 #define BENCHMARK_LIBLZO_UNSAFE 0
00247 
00248 int main(int argc, char *argv[]) {
00249     FILE *in = fopen(argv[1], "rb");
00250     uint8_t *orig = av_malloc(MAXSZ + 16);
00251     uint8_t *comp = av_malloc(2*MAXSZ + 16);
00252     uint8_t *decomp = av_malloc(MAXSZ + 16);
00253     size_t s = fread(orig, 1, MAXSZ, in);
00254     lzo_uint clen = 0;
00255     long tmp[LZO1X_MEM_COMPRESS];
00256     int inlen, outlen;
00257     int i;
00258     av_log_set_level(AV_LOG_DEBUG);
00259     lzo1x_999_compress(orig, s, comp, &clen, tmp);
00260     for (i = 0; i < 300; i++) {
00261 START_TIMER
00262         inlen = clen; outlen = MAXSZ;
00263 #if BENCHMARK_LIBLZO_SAFE
00264         if (lzo1x_decompress_safe(comp, inlen, decomp, &outlen, NULL))
00265 #elif BENCHMARK_LIBLZO_UNSAFE
00266         if (lzo1x_decompress(comp, inlen, decomp, &outlen, NULL))
00267 #else
00268         if (av_lzo1x_decode(decomp, &outlen, comp, &inlen))
00269 #endif
00270             av_log(NULL, AV_LOG_ERROR, "decompression error\n");
00271 STOP_TIMER("lzod")
00272     }
00273     if (memcmp(orig, decomp, s))
00274         av_log(NULL, AV_LOG_ERROR, "decompression incorrect\n");
00275     else
00276         av_log(NULL, AV_LOG_ERROR, "decompression OK\n");
00277     return 0;
00278 }
00279 #endif

Generated on Fri Sep 16 2011 17:17:51 for FFmpeg by  doxygen 1.7.1