LCOV - code coverage report
Current view: top level - libavcodec - lzf.c (source / functions) Hit Total Coverage
Test: coverage.info Lines: 24 35 68.6 %
Date: 2017-12-15 11:05:35 Functions: 1 1 100.0 %

          Line data    Source code
       1             : /*
       2             :  * lzf decompression algorithm
       3             :  * Copyright (c) 2015 Luca Barbato
       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             : /**
      23             :  * @file
      24             :  * lzf decompression
      25             :  *
      26             :  * LZF is a fast compression/decompression algorithm that takes very little
      27             :  * code space and working memory, ideal for real-time and block compression.
      28             :  *
      29             :  * https://en.wikibooks.org/wiki/Data_Compression/Dictionary_compression#LZF
      30             :  */
      31             : 
      32             : #include "libavutil/mem.h"
      33             : 
      34             : #include "bytestream.h"
      35             : #include "lzf.h"
      36             : 
      37             : #define LZF_LITERAL_MAX (1 << 5)
      38             : #define LZF_LONG_BACKREF 7 + 2
      39             : 
      40           2 : int ff_lzf_uncompress(GetByteContext *gb, uint8_t **buf, int64_t *size)
      41             : {
      42           2 :     int ret     = 0;
      43           2 :     uint8_t *p  = *buf;
      44           2 :     int64_t len = 0;
      45             : 
      46       42582 :     while (bytestream2_get_bytes_left(gb) > 2) {
      47       42578 :         uint8_t s = bytestream2_get_byte(gb);
      48             : 
      49       42578 :         if (s < LZF_LITERAL_MAX) {
      50        9142 :             s++;
      51        9142 :             if (s > *size - len) {
      52           0 :                 *size += *size /2;
      53           0 :                 ret = av_reallocp(buf, *size);
      54           0 :                 if (ret < 0)
      55           0 :                     return ret;
      56           0 :                 p = *buf + len;
      57             :             }
      58             : 
      59        9142 :             bytestream2_get_buffer(gb, p, s);
      60        9142 :             p   += s;
      61        9142 :             len += s;
      62             :         } else {
      63       33436 :             int l   = 2 + (s >> 5);
      64       33436 :             int off = ((s & 0x1f) << 8) + 1;
      65             : 
      66       33436 :             if (l == LZF_LONG_BACKREF)
      67       19953 :                 l += bytestream2_get_byte(gb);
      68             : 
      69       33436 :             off += bytestream2_get_byte(gb);
      70             : 
      71       33436 :             if (off > len)
      72           0 :                 return AVERROR_INVALIDDATA;
      73             : 
      74       33436 :             if (l > *size - len) {
      75           0 :                 *size += *size / 2;
      76           0 :                 ret = av_reallocp(buf, *size);
      77           0 :                 if (ret < 0)
      78           0 :                     return ret;
      79           0 :                 p = *buf + len;
      80             :             }
      81             : 
      82       33436 :             av_memcpy_backptr(p, off, l);
      83             : 
      84       33436 :             p   += l;
      85       33436 :             len += l;
      86             :         }
      87             :     }
      88             : 
      89           2 :     *size = len;
      90             : 
      91           2 :     return 0;
      92             : }

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