/*-*- 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                              │
│                                                                              │
│ Permission to use, copy, modify, and/or distribute this software for         │
│ any purpose with or without fee is hereby granted, provided that the         │
│ above copyright notice and this permission notice appear in all copies.      │
│                                                                              │
│ THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL                │
│ WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED                │
│ WARRANTIES OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE             │
│ AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL         │
│ DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR        │
│ PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER               │
│ TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR             │
│ PERFORMANCE OF THIS SOFTWARE.                                                │
╚─────────────────────────────────────────────────────────────────────────────*/
#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;
  }
}