flac_private_crc.h 2.6 KB

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  1. /* libFLAC - Free Lossless Audio Codec library
  2. * Copyright (C) 2000,2001,2002,2003,2004,2005,2006,2007 Josh Coalson
  3. *
  4. * Redistribution and use in source and binary forms, with or without
  5. * modification, are permitted provided that the following conditions
  6. * are met:
  7. *
  8. * - Redistributions of source code must retain the above copyright
  9. * notice, this list of conditions and the following disclaimer.
  10. *
  11. * - Redistributions in binary form must reproduce the above copyright
  12. * notice, this list of conditions and the following disclaimer in the
  13. * documentation and/or other materials provided with the distribution.
  14. *
  15. * - Neither the name of the Xiph.org Foundation nor the names of its
  16. * contributors may be used to endorse or promote products derived from
  17. * this software without specific prior written permission.
  18. *
  19. * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
  20. * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
  21. * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
  22. * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR
  23. * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
  24. * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
  25. * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
  26. * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
  27. * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
  28. * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
  29. * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  30. */
  31. #ifndef FLAC__PRIVATE__CRC_H
  32. #define FLAC__PRIVATE__CRC_H
  33. #include "flac_FLAC_ordinals.h"
  34. /* 8 bit CRC generator, MSB shifted first
  35. ** polynomial = x^8 + x^2 + x^1 + x^0
  36. ** init = 0
  37. */
  38. extern FLAC__byte const FLAC__crc8_table[256];
  39. #define FLAC__CRC8_UPDATE(data, crc) (crc) = FLAC__crc8_table[(crc) ^ (data)];
  40. void FLAC__crc8_update(const FLAC__byte data, FLAC__uint8 *crc);
  41. void FLAC__crc8_update_block(const FLAC__byte *data, unsigned len, FLAC__uint8 *crc);
  42. FLAC__uint8 FLAC__crc8(const FLAC__byte *data, unsigned len);
  43. /* 16 bit CRC generator, MSB shifted first
  44. ** polynomial = x^16 + x^15 + x^2 + x^0
  45. ** init = 0
  46. */
  47. extern unsigned FLAC__crc16_table[256];
  48. #define FLAC__CRC16_UPDATE(data, crc) (((((crc)<<8) & 0xffff) ^ FLAC__crc16_table[((crc)>>8) ^ (data)]))
  49. /* this alternate may be faster on some systems/compilers */
  50. #if 0
  51. #define FLAC__CRC16_UPDATE(data, crc) ((((crc)<<8) ^ FLAC__crc16_table[((crc)>>8) ^ (data)]) & 0xffff)
  52. #endif
  53. unsigned FLAC__crc16(const FLAC__byte *data, unsigned len);
  54. #endif