mirror of
https://github.com/xenia-project/FFmpeg.git
synced 2024-11-24 20:19:55 +00:00
1964aeae42
* commit '0c7707610f46a28b65eff935500c78c9781f8f4f': lavc: Add a lzf decompressor Merged-by: Hendrik Leppkes <h.leppkes@gmail.com>
91 lines
2.4 KiB
C
91 lines
2.4 KiB
C
/*
|
|
* lzf decompression algorithm
|
|
* Copyright (c) 2015 Luca Barbato
|
|
*
|
|
* This file is part of FFmpeg.
|
|
*
|
|
* FFmpeg is free software; you can redistribute it and/or
|
|
* modify it under the terms of the GNU Lesser General Public
|
|
* License as published by the Free Software Foundation; either
|
|
* version 2.1 of the License, or (at your option) any later version.
|
|
*
|
|
* FFmpeg is distributed in the hope that it will be useful,
|
|
* but WITHOUT ANY WARRANTY; without even the implied warranty of
|
|
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
|
|
* Lesser General Public License for more details.
|
|
*
|
|
* You should have received a copy of the GNU Lesser General Public
|
|
* License along with FFmpeg; if not, write to the Free Software
|
|
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
|
|
*/
|
|
|
|
/**
|
|
* @file
|
|
* lzf decompression
|
|
*
|
|
* LZF is a fast compression/decompression algorithm that takes very little
|
|
* code space and working memory, ideal for real-time and block compression.
|
|
*
|
|
* https://en.wikibooks.org/wiki/Data_Compression/Dictionary_compression#LZF
|
|
*/
|
|
|
|
#include "libavutil/mem.h"
|
|
|
|
#include "bytestream.h"
|
|
#include "lzf.h"
|
|
|
|
#define LZF_LITERAL_MAX (1 << 5)
|
|
#define LZF_LONG_BACKREF 7 + 2
|
|
|
|
int ff_lzf_uncompress(GetByteContext *gb, uint8_t **buf, int64_t *size)
|
|
{
|
|
int ret = 0;
|
|
uint8_t *p = *buf;
|
|
int64_t len = 0;
|
|
|
|
while (bytestream2_get_bytes_left(gb) > 2) {
|
|
uint8_t s = bytestream2_get_byte(gb);
|
|
|
|
if (s < LZF_LITERAL_MAX) {
|
|
s++;
|
|
if (s > *size - len) {
|
|
*size += *size /2;
|
|
ret = av_reallocp(buf, *size);
|
|
if (ret < 0)
|
|
return ret;
|
|
}
|
|
|
|
bytestream2_get_buffer(gb, p, s);
|
|
p += s;
|
|
len += s;
|
|
} else {
|
|
int l = 2 + (s >> 5);
|
|
int off = ((s & 0x1f) << 8) + 1;
|
|
|
|
if (l == LZF_LONG_BACKREF)
|
|
l += bytestream2_get_byte(gb);
|
|
|
|
off += bytestream2_get_byte(gb);
|
|
|
|
if (off > len)
|
|
return AVERROR_INVALIDDATA;
|
|
|
|
if (l > *size - len) {
|
|
*size += *size / 2;
|
|
ret = av_reallocp(buf, *size);
|
|
if (ret < 0)
|
|
return ret;
|
|
}
|
|
|
|
av_memcpy_backptr(p, off, l);
|
|
|
|
p += l;
|
|
len += l;
|
|
}
|
|
}
|
|
|
|
*size = len;
|
|
|
|
return 0;
|
|
}
|