/*
  * copyright (c) 2006 Michael Niedermayer <michaelni@gmx.at>
  *

  * This file is part of FFmpeg.
  *
  * FFmpeg is free software; you can redistribute it and/or

  * modify it under the terms of the GNU Lesser General Public
  * License as published by the Free Software Foundation; either

  * version 2.1 of the License, or (at your option) any later version.

  *

  * FFmpeg 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
  * Lesser General Public License for more details.
  *
  * You should have received a copy of the GNU Lesser General Public

  * License along with FFmpeg; if not, write to the Free Software

  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  */
 

 /**
  * @file
  * @ingroup lavu_crc32
  * Public header for CRC hash function implementation.
  */
 

 #ifndef AVUTIL_CRC_H
 #define AVUTIL_CRC_H

 #include <stdint.h>

 #include <stddef.h>

 #include "attributes.h"

 #include "version.h"

 /**

  * @defgroup lavu_crc32 CRC
  * @ingroup lavu_hash
  * CRC (Cyclic Redundancy Check) hash function implementation.
  *

  * This module supports numerous CRC polynomials, in addition to the most
  * widely used CRC-32-IEEE. See @ref AVCRCId for a list of available
  * polynomials.
  *

  * @{
  */
 

 typedef uint32_t AVCRC;
 

 typedef enum {
     AV_CRC_8_ATM,
     AV_CRC_16_ANSI,
     AV_CRC_16_CCITT,
     AV_CRC_32_IEEE,
     AV_CRC_32_IEEE_LE,  /*< reversed bitorder version of AV_CRC_32_IEEE */

     AV_CRC_16_ANSI_LE,  /*< reversed bitorder version of AV_CRC_16_ANSI */

 #if FF_API_CRC_BIG_TABLE

     AV_CRC_24_IEEE = 12,

 #else
     AV_CRC_24_IEEE,
 #endif /* FF_API_CRC_BIG_TABLE */

     AV_CRC_MAX,         /*< Not part of public API! Do not use outside libavutil. */

 }AVCRCId;

 /**
  * Initialize a CRC table.
  * @param ctx must be an array of size sizeof(AVCRC)*257 or sizeof(AVCRC)*1024
  * @param le If 1, the lowest bit represents the coefficient for the highest
  *           exponent of the corresponding polynomial (both for poly and
  *           actual CRC).
  *           If 0, you must swap the CRC parameter and the result of av_crc
  *           if you need the standard representation (can be simplified in
  *           most cases to e.g. bswap16):
  *           av_bswap32(crc << (32-bits))
  * @param bits number of bits for the CRC
  * @param poly generator polynomial without the x**bits coefficient, in the
  *             representation as specified by le
  * @param ctx_size size of ctx in bytes
  * @return <0 on failure
  */

 int av_crc_init(AVCRC *ctx, int le, int bits, uint32_t poly, int ctx_size);

 
 /**
  * Get an initialized standard CRC table.
  * @param crc_id ID of a standard CRC
  * @return a pointer to the CRC table or NULL on failure
  */

 const AVCRC *av_crc_get_table(AVCRCId crc_id);

 
 /**
  * Calculate the CRC of a block.
  * @param crc CRC of previous blocks if any or initial value for CRC
  * @return CRC updated with the data from the given block
  *
  * @see av_crc_init() "le" parameter
  */

 uint32_t av_crc(const AVCRC *ctx, uint32_t crc,
                 const uint8_t *buffer, size_t length) av_pure;

 /**
  * @}
  */
 

 #endif /* AVUTIL_CRC_H */