libavutil/lzo.c
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00001 /*
00002  * LZO 1x decompression
00003  * Copyright (c) 2006 Reimar Doeffinger
00004  *
00005  * This file is part of Libav.
00006  *
00007  * Libav 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  * Libav 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 Libav; 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 < 0) {
00092         c->error |= AV_LZO_ERROR;
00093         return;
00094     }
00095     if (cnt > c->in_end - src) {
00096         cnt = FFMAX(c->in_end - src, 0);
00097         c->error |= AV_LZO_INPUT_DEPLETED;
00098     }
00099     if (cnt > c->out_end - dst) {
00100         cnt = FFMAX(c->out_end - dst, 0);
00101         c->error |= AV_LZO_OUTPUT_FULL;
00102     }
00103 #if defined(INBUF_PADDED) && defined(OUTBUF_PADDED)
00104     COPY4(dst, src);
00105     src += 4;
00106     dst += 4;
00107     cnt -= 4;
00108     if (cnt > 0)
00109 #endif
00110         memcpy(dst, src, cnt);
00111     c->in = src + cnt;
00112     c->out = dst + cnt;
00113 }
00114 
00115 static inline void memcpy_backptr(uint8_t *dst, int back, int cnt);
00116 
00125 static inline void copy_backptr(LZOContext *c, int back, int cnt) {
00126     register uint8_t *dst = c->out;
00127     if (cnt <= 0) {
00128         c->error |= AV_LZO_ERROR;
00129         return;
00130     }
00131     if (dst - c->out_start < back) {
00132         c->error |= AV_LZO_INVALID_BACKPTR;
00133         return;
00134     }
00135     if (cnt > c->out_end - dst) {
00136         cnt = FFMAX(c->out_end - dst, 0);
00137         c->error |= AV_LZO_OUTPUT_FULL;
00138     }
00139     memcpy_backptr(dst, back, cnt);
00140     c->out = dst + cnt;
00141 }
00142 
00143 static inline void memcpy_backptr(uint8_t *dst, int back, int cnt) {
00144     const uint8_t *src = &dst[-back];
00145     if (back == 1) {
00146         memset(dst, *src, cnt);
00147     } else {
00148 #ifdef OUTBUF_PADDED
00149         COPY2(dst, src);
00150         COPY2(dst + 2, src + 2);
00151         src += 4;
00152         dst += 4;
00153         cnt -= 4;
00154         if (cnt > 0) {
00155             COPY2(dst, src);
00156             COPY2(dst + 2, src + 2);
00157             COPY2(dst + 4, src + 4);
00158             COPY2(dst + 6, src + 6);
00159             src += 8;
00160             dst += 8;
00161             cnt -= 8;
00162         }
00163 #endif
00164         if (cnt > 0) {
00165             int blocklen = back;
00166             while (cnt > blocklen) {
00167                 memcpy(dst, src, blocklen);
00168                 dst += blocklen;
00169                 cnt -= blocklen;
00170                 blocklen <<= 1;
00171             }
00172             memcpy(dst, src, cnt);
00173         }
00174     }
00175 }
00176 
00177 void av_memcpy_backptr(uint8_t *dst, int back, int cnt) {
00178     memcpy_backptr(dst, back, cnt);
00179 }
00180 
00181 int av_lzo1x_decode(void *out, int *outlen, const void *in, int *inlen) {
00182     int state= 0;
00183     int x;
00184     LZOContext c;
00185     if (!*outlen || !*inlen) {
00186         int res = 0;
00187         if (!*outlen)
00188             res |= AV_LZO_OUTPUT_FULL;
00189         if (!*inlen)
00190             res |= AV_LZO_INPUT_DEPLETED;
00191         return res;
00192     }
00193     c.in = in;
00194     c.in_end = (const uint8_t *)in + *inlen;
00195     c.out = c.out_start = out;
00196     c.out_end = (uint8_t *)out + * outlen;
00197     c.error = 0;
00198     x = GETB(c);
00199     if (x > 17) {
00200         copy(&c, x - 17);
00201         x = GETB(c);
00202         if (x < 16) c.error |= AV_LZO_ERROR;
00203     }
00204     if (c.in > c.in_end)
00205         c.error |= AV_LZO_INPUT_DEPLETED;
00206     while (!c.error) {
00207         int cnt, back;
00208         if (x > 15) {
00209             if (x > 63) {
00210                 cnt = (x >> 5) - 1;
00211                 back = (GETB(c) << 3) + ((x >> 2) & 7) + 1;
00212             } else if (x > 31) {
00213                 cnt = get_len(&c, x, 31);
00214                 x = GETB(c);
00215                 back = (GETB(c) << 6) + (x >> 2) + 1;
00216             } else {
00217                 cnt = get_len(&c, x, 7);
00218                 back = (1 << 14) + ((x & 8) << 11);
00219                 x = GETB(c);
00220                 back += (GETB(c) << 6) + (x >> 2);
00221                 if (back == (1 << 14)) {
00222                     if (cnt != 1)
00223                         c.error |= AV_LZO_ERROR;
00224                     break;
00225                 }
00226             }
00227         } else if(!state){
00228                 cnt = get_len(&c, x, 15);
00229                 copy(&c, cnt + 3);
00230                 x = GETB(c);
00231                 if (x > 15)
00232                     continue;
00233                 cnt = 1;
00234                 back = (1 << 11) + (GETB(c) << 2) + (x >> 2) + 1;
00235         } else {
00236                 cnt = 0;
00237                 back = (GETB(c) << 2) + (x >> 2) + 1;
00238         }
00239         copy_backptr(&c, back, cnt + 2);
00240         state=
00241         cnt = x & 3;
00242         copy(&c, cnt);
00243         x = GETB(c);
00244     }
00245     *inlen = c.in_end - c.in;
00246     if (c.in > c.in_end)
00247         *inlen = 0;
00248     *outlen = c.out_end - c.out;
00249     return c.error;
00250 }
00251 
00252 #ifdef TEST
00253 #include <stdio.h>
00254 #include <lzo/lzo1x.h>
00255 #include "log.h"
00256 #define MAXSZ (10*1024*1024)
00257 
00258 /* Define one of these to 1 if you wish to benchmark liblzo
00259  * instead of our native implementation. */
00260 #define BENCHMARK_LIBLZO_SAFE   0
00261 #define BENCHMARK_LIBLZO_UNSAFE 0
00262 
00263 int main(int argc, char *argv[]) {
00264     FILE *in = fopen(argv[1], "rb");
00265     uint8_t *orig = av_malloc(MAXSZ + 16);
00266     uint8_t *comp = av_malloc(2*MAXSZ + 16);
00267     uint8_t *decomp = av_malloc(MAXSZ + 16);
00268     size_t s = fread(orig, 1, MAXSZ, in);
00269     lzo_uint clen = 0;
00270     long tmp[LZO1X_MEM_COMPRESS];
00271     int inlen, outlen;
00272     int i;
00273     av_log_set_level(AV_LOG_DEBUG);
00274     lzo1x_999_compress(orig, s, comp, &clen, tmp);
00275     for (i = 0; i < 300; i++) {
00276 START_TIMER
00277         inlen = clen; outlen = MAXSZ;
00278 #if BENCHMARK_LIBLZO_SAFE
00279         if (lzo1x_decompress_safe(comp, inlen, decomp, &outlen, NULL))
00280 #elif BENCHMARK_LIBLZO_UNSAFE
00281         if (lzo1x_decompress(comp, inlen, decomp, &outlen, NULL))
00282 #else
00283         if (av_lzo1x_decode(decomp, &outlen, comp, &inlen))
00284 #endif
00285             av_log(NULL, AV_LOG_ERROR, "decompression error\n");
00286 STOP_TIMER("lzod")
00287     }
00288     if (memcmp(orig, decomp, s))
00289         av_log(NULL, AV_LOG_ERROR, "decompression incorrect\n");
00290     else
00291         av_log(NULL, AV_LOG_ERROR, "decompression OK\n");
00292     return 0;
00293 }
00294 #endif