libavutil/lzo.c

   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 #include "common.h"
  22 //! avoid e.g. MPlayers fast_memcpy, it slows things down here
  23 #undef memcpy
  24 #include <string.h>
  25 #include "lzo.h"
  26
  27 //! define if we may write up to 12 bytes beyond the output buffer
  28 #define OUTBUF_PADDED 1
  29 //! define if we may read up to 8 bytes beyond the input buffer
  30 #define INBUF_PADDED 1
  31 typedef struct LZOContext {
  32     uint8_t *in, *in_end;
  33     uint8_t *out_start, *out, *out_end;
  34     int error;
  35 } LZOContext;
  36
  37 /**
  38  * \brief read one byte from input buffer, avoiding overrun
  39  * \return byte read
  40  */
  41 static inline int get_byte(LZOContext *c) {
  42     if (c->in < c->in_end)
  43         return *c->in++;
  44     c->error |= LZO_INPUT_DEPLETED;
  45     return 1;
  46 }
  47
  48 #ifdef INBUF_PADDED
  49 #define GETB(c) (*(c).in++)
  50 #else
  51 #define GETB(c) get_byte(&(c))
  52 #endif
  53
  54 /**
  55  * \brief decode a length value in the coding used by lzo
  56  * \param x previous byte value
  57  * \param mask bits used from x
  58  * \return decoded length value
  59  */
  60 static inline int get_len(LZOContext *c, int x, int mask) {
  61     int cnt = x & mask;
  62     if (!cnt) {
  63         while (!(x = get_byte(c))) cnt += 255;
  64         cnt += mask + x;
  65     }
  66     return cnt;
  67 }
  68
  69 //#define UNALIGNED_LOADSTORE
  70 #define BUILTIN_MEMCPY
  71 #ifdef UNALIGNED_LOADSTORE
  72 #define COPY2(d, s) *(uint16_t *)(d) = *(uint16_t *)(s);
  73 #define COPY4(d, s) *(uint32_t *)(d) = *(uint32_t *)(s);
  74 #elif defined(BUILTIN_MEMCPY)
  75 #define COPY2(d, s) memcpy(d, s, 2);
  76 #define COPY4(d, s) memcpy(d, s, 4);
  77 #else
  78 #define COPY2(d, s) (d)[0] = (s)[0]; (d)[1] = (s)[1];
  79 #define COPY4(d, s) (d)[0] = (s)[0]; (d)[1] = (s)[1]; (d)[2] = (s)[2]; (d)[3] = (s)[3];
  80 #endif
  81
  82 /**
  83  * \brief copy bytes from input to output buffer with checking
  84  * \param cnt number of bytes to copy, must be >= 0
  85  */
  86 static inline void copy(LZOContext *c, int cnt) {
  87     register uint8_t *src = c->in;
  88     register uint8_t *dst = c->out;
  89     if (cnt > c->in_end - src) {
  90         cnt = FFMAX(c->in_end - src, 0);
  91         c->error |= LZO_INPUT_DEPLETED;
  92     }
  93     if (cnt > c->out_end - dst) {
  94         cnt = FFMAX(c->out_end - dst, 0);
  95         c->error |= LZO_OUTPUT_FULL;
  96     }
  97 #if defined(INBUF_PADDED) && defined(OUTBUF_PADDED)
  98     COPY4(dst, src);
  99     src += 4;
 100     dst += 4;
 101     cnt -= 4;
 102     if (cnt > 0)
 103 #endif
 104         memcpy(dst, src, cnt);
 105     c->in = src + cnt;
 106     c->out = dst + cnt;
 107 }
 108
 109 /**
 110  * \brief copy previously decoded bytes to current position
 111  * \param back how many bytes back we start
 112  * \param cnt number of bytes to copy, must be >= 0
 113  *
 114  * cnt > back is valid, this will copy the bytes we just copied,
 115  * thus creating a repeating pattern with a period length of back.
 116  */
 117 static inline void copy_backptr(LZOContext *c, int back, int cnt) {
 118     register uint8_t *src = &c->out[-back];
 119     register uint8_t *dst = c->out;
 120     if (src < c->out_start || src > dst) {
 121         c->error |= LZO_INVALID_BACKPTR;
 122         return;
 123     }
 124     if (cnt > c->out_end - dst) {
 125         cnt = FFMAX(c->out_end - dst, 0);
 126         c->error |= LZO_OUTPUT_FULL;
 127     }
 128     if (back == 1) {
 129         memset(dst, *src, cnt);
 130         dst += cnt;
 131     } else {
 132 #ifdef OUTBUF_PADDED
 133         COPY2(dst, src);
 134         COPY2(dst + 2, src + 2);
 135         src += 4;
 136         dst += 4;
 137         cnt -= 4;
 138         if (cnt > 0) {
 139             COPY2(dst, src);
 140             COPY2(dst + 2, src + 2);
 141             COPY2(dst + 4, src + 4);
 142             COPY2(dst + 6, src + 6);
 143             src += 8;
 144             dst += 8;
 145             cnt -= 8;
 146         }
 147 #endif
 148         if (cnt > 0) {
 149             int blocklen = back;
 150             while (cnt > blocklen) {
 151                 memcpy(dst, src, blocklen);
 152                 dst += blocklen;
 153                 cnt -= blocklen;
 154                 blocklen <<= 1;
 155             }
 156             memcpy(dst, src, cnt);
 157         }
 158         dst += cnt;
 159     }
 160     c->out = dst;
 161 }
 162
 163 /**
 164  * \brief decode LZO 1x compressed data
 165  * \param out output buffer
 166  * \param outlen size of output buffer, number of bytes left are returned here
 167  * \param in input buffer
 168  * \param inlen size of input buffer, number of bytes left are returned here
 169  * \return 0 on success, otherwise error flags, see lzo.h
 170  *
 171  * make sure all buffers are appropriately padded, in must provide
 172  * LZO_INPUT_PADDING, out must provide LZO_OUTPUT_PADDING additional bytes
 173  */
 174 int lzo1x_decode(void *out, int *outlen, void *in, int *inlen) {
 175     int state= 0;
 176     int x;
 177     LZOContext c;
 178     c.in = in;
 179     c.in_end = (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 |= LZO_ERROR;
 188     }
 189     if (c.in > c.in_end)
 190         c.error |= 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 |= 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 int main(int argc, char *argv[]) {
 243     FILE *in = fopen(argv[1], "rb");
 244     uint8_t *orig = av_malloc(MAXSZ + 16);
 245     uint8_t *comp = av_malloc(2*MAXSZ + 16);
 246     uint8_t *decomp = av_malloc(MAXSZ + 16);
 247     size_t s = fread(orig, 1, MAXSZ, in);
 248     lzo_uint clen = 0;
 249     long tmp[LZO1X_MEM_COMPRESS];
 250     int inlen, outlen;
 251     int i;
 252     av_log_level = AV_LOG_DEBUG;
 253     lzo1x_999_compress(orig, s, comp, &clen, tmp);
 254     for (i = 0; i < 300; i++) {
 255 START_TIMER
 256         inlen = clen; outlen = MAXSZ;
 257 #ifdef LIBLZO
 258         if (lzo1x_decompress_safe(comp, inlen, decomp, &outlen, NULL))
 259 #elif defined(LIBLZO_UNSAFE)
 260         if (lzo1x_decompress(comp, inlen, decomp, &outlen, NULL))
 261 #else
 262         if (lzo1x_decode(decomp, &outlen, comp, &inlen))
 263 #endif
 264             av_log(NULL, AV_LOG_ERROR, "decompression error\n");
 265 STOP_TIMER("lzod")
 266     }
 267     if (memcmp(orig, decomp, s))
 268         av_log(NULL, AV_LOG_ERROR, "decompression incorrect\n");
 269     else
 270         av_log(NULL, AV_LOG_ERROR, "decompression ok\n");
 271     return 0;
 272 }
 273 #endif