cosmopolitan/libc/str/lz4check.c

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2020-06-15 14:18:57 +00:00
/*-*- 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"
const unsigned char *lz4check(const void *data) {
const unsigned char *frame = data;
if (LZ4_MAGIC(frame) == LZ4_MAGICNUMBER && LZ4_FRAME_VERSION(frame) == 1 &&
LZ4_FRAME_BLOCKINDEPENDENCE(frame) == true &&
LZ4_FRAME_BLOCKCONTENTSIZEFLAG(frame) == true &&
LZ4_FRAME_RESERVED1(frame) == 0 && LZ4_FRAME_RESERVED2(frame) == 0 &&
LZ4_FRAME_RESERVED3(frame) == 0) {
return frame;
} else {
return NULL;
}
}