#include <stdio.h>

#include <stddef.h>

#include <stdint.h>

#include <string.h>

#include <assert.h>

#include <stdlib.h>

#include <inttypes.h>

#include "zlib.h"

int LLVMFuzzerTestOneInput(const uint8_t *data, size_t dataLen) {

  uint32_t crc0 = crc32(0L, NULL, 0);

  uint32_t crc1 = crc0;

  uint32_t crc2 = crc0;

  uint32_t adler0 = adler32(0L, NULL, 0);

  uint32_t adler1 = adler0;

  uint32_t adler2 = adler0;

  /* Checksum with a buffer of size equal to the first byte in the input. */

  uint32_t buffSize = data[0];

  uint32_t offset = 0;

  uint32_t op;

  /* Discard inputs larger than 1Mb. */

  static size_t kMaxSize = 1024 * 1024;

  if (dataLen < 1 || dataLen > kMaxSize)

    return 0;

  /* Make sure the buffer has at least a byte. */

  if (buffSize == 0)

    ++buffSize;

  /* CRC32 */

  op = crc32_combine_gen(buffSize);

  for (offset = 0; offset + buffSize <= dataLen; offset += buffSize) {

    uint32_t crc3 = crc32_z(crc0, data + offset, buffSize);

    uint32_t crc4 = crc32_combine_op(crc1, crc3, op);

    crc1 = crc32_z(crc1, data + offset, buffSize);

    assert(crc1 == crc4);

  }

  crc1 = crc32_z(crc1, data + offset, dataLen % buffSize);

  crc2 = crc32(crc2, data, (uint32_t) dataLen);

  assert(crc1 == crc2);

  assert(crc32_combine(crc1, crc2, dataLen) ==

         crc32_combine(crc1, crc1, dataLen));

  /* Fast CRC32 combine. */

  op = crc32_combine_gen(dataLen);

  assert(crc32_combine_op(crc1, crc2, op) ==

         crc32_combine_op(crc2, crc1, op));

  assert(crc32_combine(crc1, crc2, dataLen) ==

         crc32_combine_op(crc2, crc1, op));

  /* Adler32 */

  for (offset = 0; offset + buffSize <= dataLen; offset += buffSize)

    adler1 = adler32_z(adler1, data + offset, buffSize);

  adler1 = adler32_z(adler1, data + offset, dataLen % buffSize);

  adler2 = adler32(adler2, data, (uint32_t) dataLen);

  assert(adler1 == adler2);

  assert(adler32_combine(adler1, adler2, dataLen) ==

         adler32_combine(adler1, adler1, dataLen));

  /* This function must return 0. */

  return 0;

}