crc16.c 3.7 KB

1234567891011121314151617181920212223242526272829303132333435363738394041424344454647484950515253545556575859606162636465666768697071727374
  1. /*
  2. * Copyright 2001-2019 Georges Menie (www.menie.org)
  3. * All rights reserved.
  4. * Redistribution and use in source and binary forms, with or without
  5. * modification, are permitted provided that the following conditions are met:
  6. *
  7. * * Redistributions of source code must retain the above copyright
  8. * notice, this list of conditions and the following disclaimer.
  9. * * Redistributions in binary form must reproduce the above copyright
  10. * notice, this list of conditions and the following disclaimer in the
  11. * documentation and/or other materials provided with the distribution.
  12. * * Neither the name of the University of California, Berkeley nor the
  13. * names of its contributors may be used to endorse or promote products
  14. * derived from this software without specific prior written permission.
  15. *
  16. * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND ANY
  17. * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
  18. * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
  19. * DISCLAIMED. IN NO EVENT SHALL THE REGENTS AND CONTRIBUTORS BE LIABLE FOR ANY
  20. * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
  21. * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
  22. * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
  23. * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  24. * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
  25. * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  26. */
  27. #include "crc16.h"
  28. /* CRC16 implementation acording to CCITT standards */
  29. static const unsigned short crc16tab[256]= {
  30. 0x0000,0x1021,0x2042,0x3063,0x4084,0x50a5,0x60c6,0x70e7,
  31. 0x8108,0x9129,0xa14a,0xb16b,0xc18c,0xd1ad,0xe1ce,0xf1ef,
  32. 0x1231,0x0210,0x3273,0x2252,0x52b5,0x4294,0x72f7,0x62d6,
  33. 0x9339,0x8318,0xb37b,0xa35a,0xd3bd,0xc39c,0xf3ff,0xe3de,
  34. 0x2462,0x3443,0x0420,0x1401,0x64e6,0x74c7,0x44a4,0x5485,
  35. 0xa56a,0xb54b,0x8528,0x9509,0xe5ee,0xf5cf,0xc5ac,0xd58d,
  36. 0x3653,0x2672,0x1611,0x0630,0x76d7,0x66f6,0x5695,0x46b4,
  37. 0xb75b,0xa77a,0x9719,0x8738,0xf7df,0xe7fe,0xd79d,0xc7bc,
  38. 0x48c4,0x58e5,0x6886,0x78a7,0x0840,0x1861,0x2802,0x3823,
  39. 0xc9cc,0xd9ed,0xe98e,0xf9af,0x8948,0x9969,0xa90a,0xb92b,
  40. 0x5af5,0x4ad4,0x7ab7,0x6a96,0x1a71,0x0a50,0x3a33,0x2a12,
  41. 0xdbfd,0xcbdc,0xfbbf,0xeb9e,0x9b79,0x8b58,0xbb3b,0xab1a,
  42. 0x6ca6,0x7c87,0x4ce4,0x5cc5,0x2c22,0x3c03,0x0c60,0x1c41,
  43. 0xedae,0xfd8f,0xcdec,0xddcd,0xad2a,0xbd0b,0x8d68,0x9d49,
  44. 0x7e97,0x6eb6,0x5ed5,0x4ef4,0x3e13,0x2e32,0x1e51,0x0e70,
  45. 0xff9f,0xefbe,0xdfdd,0xcffc,0xbf1b,0xaf3a,0x9f59,0x8f78,
  46. 0x9188,0x81a9,0xb1ca,0xa1eb,0xd10c,0xc12d,0xf14e,0xe16f,
  47. 0x1080,0x00a1,0x30c2,0x20e3,0x5004,0x4025,0x7046,0x6067,
  48. 0x83b9,0x9398,0xa3fb,0xb3da,0xc33d,0xd31c,0xe37f,0xf35e,
  49. 0x02b1,0x1290,0x22f3,0x32d2,0x4235,0x5214,0x6277,0x7256,
  50. 0xb5ea,0xa5cb,0x95a8,0x8589,0xf56e,0xe54f,0xd52c,0xc50d,
  51. 0x34e2,0x24c3,0x14a0,0x0481,0x7466,0x6447,0x5424,0x4405,
  52. 0xa7db,0xb7fa,0x8799,0x97b8,0xe75f,0xf77e,0xc71d,0xd73c,
  53. 0x26d3,0x36f2,0x0691,0x16b0,0x6657,0x7676,0x4615,0x5634,
  54. 0xd94c,0xc96d,0xf90e,0xe92f,0x99c8,0x89e9,0xb98a,0xa9ab,
  55. 0x5844,0x4865,0x7806,0x6827,0x18c0,0x08e1,0x3882,0x28a3,
  56. 0xcb7d,0xdb5c,0xeb3f,0xfb1e,0x8bf9,0x9bd8,0xabbb,0xbb9a,
  57. 0x4a75,0x5a54,0x6a37,0x7a16,0x0af1,0x1ad0,0x2ab3,0x3a92,
  58. 0xfd2e,0xed0f,0xdd6c,0xcd4d,0xbdaa,0xad8b,0x9de8,0x8dc9,
  59. 0x7c26,0x6c07,0x5c64,0x4c45,0x3ca2,0x2c83,0x1ce0,0x0cc1,
  60. 0xef1f,0xff3e,0xcf5d,0xdf7c,0xaf9b,0xbfba,0x8fd9,0x9ff8,
  61. 0x6e17,0x7e36,0x4e55,0x5e74,0x2e93,0x3eb2,0x0ed1,0x1ef0
  62. };
  63. unsigned short crc16_ccitt(const void *buf, int len)
  64. {
  65. register int counter;
  66. register unsigned short crc = 0;
  67. for( counter = 0; counter < len; counter++)
  68. crc = (crc<<8) ^ crc16tab[((crc>>8) ^ *(char *)buf++)&0x00FF];
  69. return crc;
  70. }