51 lines
3.0 KiB
C
51 lines
3.0 KiB
C
|
/*-*- mode:c;indent-tabs-mode:nil;c-basic-offset:2;tab-width:8;coding:utf-8 -*-│
|
||
|
|
│vi: set net ft=c ts=2 sts=2 sw=2 fenc=utf-8 :vi│
|
||
|
|
╞══════════════════════════════════════════════════════════════════════════════╡
|
||
|
|
│ Copyright 2020 Justine Alexandra Roberts Tunney │
|
||
|
|
│ │
|
||
|
|
│ This program is free software; you can redistribute it and/or modify │
|
||
|
|
│ it under the terms of the GNU General Public License as published by │
|
||
|
|
│ the Free Software Foundation; version 2 of the License. │
|
||
|
|
│ │
|
||
|
|
│ This program 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 │
|
||
|
|
│ General Public License for more details. │
|
||
|
|
│ │
|
||
|
|
│ You should have received a copy of the GNU General Public License │
|
||
|
|
│ along with this program; if not, write to the Free Software │
|
||
|
|
│ Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA │
|
||
|
|
│ 02110-1301 USA │
|
||
|
|
╚─────────────────────────────────────────────────────────────────────────────*/
|
||
|
|
#include "libc/nexgen32e/kompressor.h"
|
||
|
|
#include "libc/nexgen32e/lz4.h"
|
||
|
|
#include "libc/str/str.h"
|
||
|
|
|
||
|
|
/**
|
||
|
|
* Decompresses LZ4 file.
|
||
|
|
*
|
||
|
|
* We assume (1) the file is mmap()'d or was copied into into memory
|
||
|
|
* beforehand; and (2) folks handling untrustworthy data shall place
|
||
|
|
* 64kb of guard pages on the ends of each buffer, see mapanon(). We
|
||
|
|
* don't intend to support XXHASH; we recommend folks needing checks
|
||
|
|
* against data corruption consider crc32c(), or gzip since it's the
|
||
|
|
* best at file recovery. Dictionaries are supported; by convention,
|
||
|
|
* they are passed in the ≤64kb bytes preceding src.
|
||
|
|
*
|
||
|
|
* @return pointer to end of decoded data, similar to mempcpy()
|
||
|
|
* @see mapanon(), lz4check()
|
||
|
|
*/
|
||
|
|
void *lz4decode(void *dest, const void *src) {
|
||
|
|
const unsigned char *frame, *block;
|
||
|
|
frame = (const unsigned char *)src;
|
||
|
|
for (block = frame + LZ4_FRAME_HEADERSIZE(frame); !LZ4_BLOCK_ISEOF(block);
|
||
|
|
block += LZ4_BLOCK_SIZE(frame, block)) {
|
||
|
|
if (LZ4_BLOCK_ISCOMPRESSED(block)) {
|
||
|
|
dest = lz4cpy(dest, LZ4_BLOCK_DATA(block), LZ4_BLOCK_DATASIZE(block));
|
||
|
|
} else {
|
||
|
|
dest = mempcpy(dest, LZ4_BLOCK_DATA(block), LZ4_BLOCK_DATASIZE(block));
|
||
|
|
}
|
||
|
|
}
|
||
|
|
return dest;
|
||
|
|
}
|