/*
   Copyright (c) 2014 Anton Titov.

   Copyright (c) 2014 pCloud Ltd.  All rights reserved.

   Redistribution and use in source and binary forms, with or without
   modification, are permitted provided that the following conditions
   are met: Redistributions of source code must retain the above
   copyright notice, this list of conditions and the following
   disclaimer.  Redistributions in binary form must reproduce the
   above copyright notice, this list of conditions and the following
   disclaimer in the documentation and/or other materials provided
   with the distribution.  Neither the name of pCloud Ltd nor the
   names of its contributors may be used to endorse or promote
   products derived from this software without specific prior written
   permission.

   THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
   "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
   LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
   FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL pCloud
   Ltd BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
   EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
   PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
   PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
   OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
   (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE
   USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH
   DAMAGE.
*/

#ifndef _PSYNC_CRC32_H
#define _PSYNC_CRC32_H

#include <stddef.h>
#include <stdint.h>

#define PSYNC_CRC_INITIAL 0

#define PSYNC_FAST_HASH256_LEN 32
#define PSYNC_FAST_HASH256_HEXLEN 64

#define PSYNC_FAST_HASH256_BLOCK_LEN 64

typedef struct {
  uint64_t state[6];
  uint64_t length;
  union {
    uint64_t buff64[PSYNC_FAST_HASH256_BLOCK_LEN / sizeof(uint64_t)];
    unsigned char buff[PSYNC_FAST_HASH256_BLOCK_LEN];
  };
} psync_fast_hash256_ctx;

uint32_t pcrc32c_compute(uint32_t crc, const void *ptr, size_t len);

/* psync_fast_hash256 is supposed to be fast, non-cryptographic strength,
 * non-collision resistant hash function with large output. Think of it as CRC32
 * but faster, with 256bit output and for cases that you can't live with the
 * chances of CRC32 _random_ collision. It is intended for large inputs,
 * finalization is relatively expensive.
 */
void pcrc32c_fast_hash256_init(psync_fast_hash256_ctx *ctx);
void pcrc32c_fast_hash256_seed(psync_fast_hash256_ctx *ctx, const void *seed, size_t seedlen);
void pcrc32c_fast_hash256_update(psync_fast_hash256_ctx *ctx, const void *data, size_t len);
void pcrc32c_fast_hash256_final(void *hash, psync_fast_hash256_ctx *ctx);

#endif