| Line | Branch | Exec | Source |
|---|---|---|---|
| 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 | 4 | int ff_lzf_uncompress(GetByteContext *gb, uint8_t **buf, int64_t *size) | |
| 41 | { | ||
| 42 | 4 | int ret = 0; | |
| 43 | 4 | uint8_t *p = *buf; | |
| 44 | 4 | int64_t len = 0; | |
| 45 | |||
| 46 |
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85160 | while (bytestream2_get_bytes_left(gb) > 2) { |
| 47 | 85156 | uint8_t s = bytestream2_get_byte(gb); | |
| 48 | |||
| 49 |
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85156 | if (s < LZF_LITERAL_MAX) { |
| 50 | 18284 | s++; | |
| 51 |
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18284 | if (s > *size - len) { |
| 52 | 2 | *size += s + *size /2; | |
| 53 | 2 | ret = av_reallocp(buf, *size); | |
| 54 |
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2 | if (ret < 0) |
| 55 | ✗ | return ret; | |
| 56 | 2 | p = *buf + len; | |
| 57 | } | ||
| 58 | |||
| 59 | 18284 | bytestream2_get_buffer(gb, p, s); | |
| 60 | 18284 | p += s; | |
| 61 | 18284 | len += s; | |
| 62 | } else { | ||
| 63 | 66872 | int l = 2 + (s >> 5); | |
| 64 | 66872 | int off = ((s & 0x1f) << 8) + 1; | |
| 65 | |||
| 66 |
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66872 | if (l == LZF_LONG_BACKREF) |
| 67 | 39906 | l += bytestream2_get_byte(gb); | |
| 68 | |||
| 69 | 66872 | off += bytestream2_get_byte(gb); | |
| 70 | |||
| 71 |
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66872 | if (off > len) |
| 72 | ✗ | return AVERROR_INVALIDDATA; | |
| 73 | |||
| 74 |
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66872 | if (l > *size - len) { |
| 75 | 2 | *size += l + *size / 2; | |
| 76 | 2 | ret = av_reallocp(buf, *size); | |
| 77 |
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2 | if (ret < 0) |
| 78 | ✗ | return ret; | |
| 79 | 2 | p = *buf + len; | |
| 80 | } | ||
| 81 | |||
| 82 | 66872 | av_memcpy_backptr(p, off, l); | |
| 83 | |||
| 84 | 66872 | p += l; | |
| 85 | 66872 | len += l; | |
| 86 | } | ||
| 87 | } | ||
| 88 | |||
| 89 | 4 | *size = len; | |
| 90 | |||
| 91 | 4 | return 0; | |
| 92 | } | ||
| 93 |