wsutil/crc16.c

   1 /* crc16.c
   2  * CRC-16 routine
   3  *
   4  * 2004 Richard van der Hoff <richardv@mxtelecom.com>
   5  *
   6  * Wireshark - Network traffic analyzer
   7  * By Gerald Combs <gerald@wireshark.org>
   8  * Copyright 1998 Gerald Combs
   9  *
  10  * SPDX-License-Identifier: GPL-2.0-or-later
  11  *
  12  * References:
  13  *  "A Painless Guide to CRC Error Detection Algorithms", Ross Williams
  14  *      http://www.repairfaq.org/filipg/LINK/F_crc_v3.html
  15  *
  16  *  ITU-T Recommendation V.42 (2002), "Error-Correcting Procedures for
  17  *      DCEs using asynchronous-to-synchronous conversion", Para. 8.1.1.6.1
  18  */
  19
  20 #include "config.h"
  21
  22 #include <glib.h>
  23 #include <wsutil/crc16.h>
  24
  25
  26 /*****************************************************************/
  27
  28 /*
  29  * Table for the CCITT/ITU/CRC-16 16-bit CRC
  30  *
  31  * Polynomial is
  32  *
  33  *     x^16 + x^12 + x^5 + 1
  34  */
  35
  36 /*                                                               */
  37 /* CRC LOOKUP TABLE                                              */
  38 /* ================                                              */
  39 /* The following CRC lookup table was generated automagically    */
  40 /* by the Rocksoft^tm Model CRC Algorithm Table Generation       */
  41 /* Program V1.0 using the following model parameters:            */
  42 /*                                                               */
  43 /*    Width   : 2 bytes.                                         */
  44 /*    Poly    : 0x1021                                           */
  45 /*    Reverse : TRUE.                                           */
  46 /*                                                               */
  47 /* For more information on the Rocksoft^tm Model CRC Algorithm,  */
  48 /* see the document titled "A Painless Guide to CRC Error        */
  49 /* Detection Algorithms" by Ross Williams.  See                  */
  50 /*                                                               */
  51 /*    http://www.ross.net/crc/crcpaper.html                      */
  52 /*                                                               */
  53 /* which links to a text version and an HTML-but-not-all-on-one- */
  54 /* page version, or various HTML-all-on-one-page versions such   */
  55 /* as the one at                                                 */
  56 /*                                                               */
  57 /*    http://www.geocities.com/SiliconValley/Pines/8659/crc.htm  */
  58 /*                                                               */
  59 /* (search for the title to find others).                        */
  60 /*                                                               */
  61 /*****************************************************************/
  62
  63 static const guint crc16_ccitt_table_reverse[256] =
  64 {
  65     0x0000, 0x1189, 0x2312, 0x329B, 0x4624, 0x57AD, 0x6536, 0x74BF,
  66     0x8C48, 0x9DC1, 0xAF5A, 0xBED3, 0xCA6C, 0xDBE5, 0xE97E, 0xF8F7,
  67     0x1081, 0x0108, 0x3393, 0x221A, 0x56A5, 0x472C, 0x75B7, 0x643E,
  68     0x9CC9, 0x8D40, 0xBFDB, 0xAE52, 0xDAED, 0xCB64, 0xF9FF, 0xE876,
  69     0x2102, 0x308B, 0x0210, 0x1399, 0x6726, 0x76AF, 0x4434, 0x55BD,
  70     0xAD4A, 0xBCC3, 0x8E58, 0x9FD1, 0xEB6E, 0xFAE7, 0xC87C, 0xD9F5,
  71     0x3183, 0x200A, 0x1291, 0x0318, 0x77A7, 0x662E, 0x54B5, 0x453C,
  72     0xBDCB, 0xAC42, 0x9ED9, 0x8F50, 0xFBEF, 0xEA66, 0xD8FD, 0xC974,
  73     0x4204, 0x538D, 0x6116, 0x709F, 0x0420, 0x15A9, 0x2732, 0x36BB,
  74     0xCE4C, 0xDFC5, 0xED5E, 0xFCD7, 0x8868, 0x99E1, 0xAB7A, 0xBAF3,
  75     0x5285, 0x430C, 0x7197, 0x601E, 0x14A1, 0x0528, 0x37B3, 0x263A,
  76     0xDECD, 0xCF44, 0xFDDF, 0xEC56, 0x98E9, 0x8960, 0xBBFB, 0xAA72,
  77     0x6306, 0x728F, 0x4014, 0x519D, 0x2522, 0x34AB, 0x0630, 0x17B9,
  78     0xEF4E, 0xFEC7, 0xCC5C, 0xDDD5, 0xA96A, 0xB8E3, 0x8A78, 0x9BF1,
  79     0x7387, 0x620E, 0x5095, 0x411C, 0x35A3, 0x242A, 0x16B1, 0x0738,
  80     0xFFCF, 0xEE46, 0xDCDD, 0xCD54, 0xB9EB, 0xA862, 0x9AF9, 0x8B70,
  81     0x8408, 0x9581, 0xA71A, 0xB693, 0xC22C, 0xD3A5, 0xE13E, 0xF0B7,
  82     0x0840, 0x19C9, 0x2B52, 0x3ADB, 0x4E64, 0x5FED, 0x6D76, 0x7CFF,
  83     0x9489, 0x8500, 0xB79B, 0xA612, 0xD2AD, 0xC324, 0xF1BF, 0xE036,
  84     0x18C1, 0x0948, 0x3BD3, 0x2A5A, 0x5EE5, 0x4F6C, 0x7DF7, 0x6C7E,
  85     0xA50A, 0xB483, 0x8618, 0x9791, 0xE32E, 0xF2A7, 0xC03C, 0xD1B5,
  86     0x2942, 0x38CB, 0x0A50, 0x1BD9, 0x6F66, 0x7EEF, 0x4C74, 0x5DFD,
  87     0xB58B, 0xA402, 0x9699, 0x8710, 0xF3AF, 0xE226, 0xD0BD, 0xC134,
  88     0x39C3, 0x284A, 0x1AD1, 0x0B58, 0x7FE7, 0x6E6E, 0x5CF5, 0x4D7C,
  89     0xC60C, 0xD785, 0xE51E, 0xF497, 0x8028, 0x91A1, 0xA33A, 0xB2B3,
  90     0x4A44, 0x5BCD, 0x6956, 0x78DF, 0x0C60, 0x1DE9, 0x2F72, 0x3EFB,
  91     0xD68D, 0xC704, 0xF59F, 0xE416, 0x90A9, 0x8120, 0xB3BB, 0xA232,
  92     0x5AC5, 0x4B4C, 0x79D7, 0x685E, 0x1CE1, 0x0D68, 0x3FF3, 0x2E7A,
  93     0xE70E, 0xF687, 0xC41C, 0xD595, 0xA12A, 0xB0A3, 0x8238, 0x93B1,
  94     0x6B46, 0x7ACF, 0x4854, 0x59DD, 0x2D62, 0x3CEB, 0x0E70, 0x1FF9,
  95     0xF78F, 0xE606, 0xD49D, 0xC514, 0xB1AB, 0xA022, 0x92B9, 0x8330,
  96     0x7BC7, 0x6A4E, 0x58D5, 0x495C, 0x3DE3, 0x2C6A, 0x1EF1, 0x0F78
  97 };
  98
  99 /* Same as above, only without reverse (Reverse=FALSE) */
 100 static const guint crc16_ccitt_table[256] =
 101 {
 102     0x0000, 0x1021, 0x2042, 0x3063, 0x4084, 0x50A5, 0x60C6, 0x70E7,
 103     0x8108, 0x9129, 0xA14A, 0xB16B, 0xC18C, 0xD1AD, 0xE1CE, 0xF1EF,
 104     0x1231, 0x0210, 0x3273, 0x2252, 0x52B5, 0x4294, 0x72F7, 0x62D6,
 105     0x9339, 0x8318, 0xB37B, 0xA35A, 0xD3BD, 0xC39C, 0xF3FF, 0xE3DE,
 106     0x2462, 0x3443, 0x0420, 0x1401, 0x64E6, 0x74C7, 0x44A4, 0x5485,
 107     0xA56A, 0xB54B, 0x8528, 0x9509, 0xE5EE, 0xF5CF, 0xC5AC, 0xD58D,
 108     0x3653, 0x2672, 0x1611, 0x0630, 0x76D7, 0x66F6, 0x5695, 0x46B4,
 109     0xB75B, 0xA77A, 0x9719, 0x8738, 0xF7DF, 0xE7FE, 0xD79D, 0xC7BC,
 110     0x48C4, 0x58E5, 0x6886, 0x78A7, 0x0840, 0x1861, 0x2802, 0x3823,
 111     0xC9CC, 0xD9ED, 0xE98E, 0xF9AF, 0x8948, 0x9969, 0xA90A, 0xB92B,
 112     0x5AF5, 0x4AD4, 0x7AB7, 0x6A96, 0x1A71, 0x0A50, 0x3A33, 0x2A12,
 113     0xDBFD, 0xCBDC, 0xFBBF, 0xEB9E, 0x9B79, 0x8B58, 0xBB3B, 0xAB1A,
 114     0x6CA6, 0x7C87, 0x4CE4, 0x5CC5, 0x2C22, 0x3C03, 0x0C60, 0x1C41,
 115     0xEDAE, 0xFD8F, 0xCDEC, 0xDDCD, 0xAD2A, 0xBD0B, 0x8D68, 0x9D49,
 116     0x7E97, 0x6EB6, 0x5ED5, 0x4EF4, 0x3E13, 0x2E32, 0x1E51, 0x0E70,
 117     0xFF9F, 0xEFBE, 0xDFDD, 0xCFFC, 0xBF1B, 0xAF3A, 0x9F59, 0x8F78,
 118     0x9188, 0x81A9, 0xB1CA, 0xA1EB, 0xD10C, 0xC12D, 0xF14E, 0xE16F,
 119     0x1080, 0x00A1, 0x30C2, 0x20E3, 0x5004, 0x4025, 0x7046, 0x6067,
 120     0x83B9, 0x9398, 0xA3FB, 0xB3DA, 0xC33D, 0xD31C, 0xE37F, 0xF35E,
 121     0x02B1, 0x1290, 0x22F3, 0x32D2, 0x4235, 0x5214, 0x6277, 0x7256,
 122     0xB5EA, 0xA5CB, 0x95A8, 0x8589, 0xF56E, 0xE54F, 0xD52C, 0xC50D,
 123     0x34E2, 0x24C3, 0x14A0, 0x0481, 0x7466, 0x6447, 0x5424, 0x4405,
 124     0xA7DB, 0xB7FA, 0x8799, 0x97B8, 0xE75F, 0xF77E, 0xC71D, 0xD73C,
 125     0x26D3, 0x36F2, 0x0691, 0x16B0, 0x6657, 0x7676, 0x4615, 0x5634,
 126     0xD94C, 0xC96D, 0xF90E, 0xE92F, 0x99C8, 0x89E9, 0xB98A, 0xA9AB,
 127     0x5844, 0x4865, 0x7806, 0x6827, 0x18C0, 0x08E1, 0x3882, 0x28A3,
 128     0xCB7D, 0xDB5C, 0xEB3F, 0xFB1E, 0x8BF9, 0x9BD8, 0xABBB, 0xBB9A,
 129     0x4A75, 0x5A54, 0x6A37, 0x7A16, 0x0AF1, 0x1AD0, 0x2AB3, 0x3A92,
 130     0xFD2E, 0xED0F, 0xDD6C, 0xCD4D, 0xBDAA, 0xAD8B, 0x9DE8, 0x8DC9,
 131     0x7C26, 0x6C07, 0x5C64, 0x4C45, 0x3CA2, 0x2C83, 0x1CE0, 0x0CC1,
 132     0xEF1F, 0xFF3E, 0xCF5D, 0xDF7C, 0xAF9B, 0xBFBA, 0x8FD9, 0x9FF8,
 133     0x6E17, 0x7E36, 0x4E55, 0x5E74, 0x2E93, 0x3EB2, 0x0ED1, 0x1EF0
 134 };
 135
 136 /* This table was compiled using the polynom 0x5935 */
 137 static const guint crc16_precompiled_5935[256] =
 138 {
 139     0x0000, 0x5935, 0xB26A, 0xEB5F, 0x3DE1, 0x64D4, 0x8F8B, 0xD6BE,
 140     0x7BC2, 0x22F7, 0xC9A8, 0x909D, 0x4623, 0x1F16, 0xF449, 0xAD7C,
 141     0xF784, 0xAEB1, 0x45EE, 0x1CDB, 0xCA65, 0x9350, 0x780F, 0x213A,
 142     0x8C46, 0xD573, 0x3E2C, 0x6719, 0xB1A7, 0xE892, 0x03CD, 0x5AF8,
 143     0xB63D, 0xEF08, 0x0457, 0x5D62, 0x8BDC, 0xD2E9, 0x39B6, 0x6083,
 144     0xCDFF, 0x94CA, 0x7F95, 0x26A0, 0xF01E, 0xA92B, 0x4274, 0x1B41,
 145     0x41B9, 0x188C, 0xF3D3, 0xAAE6, 0x7C58, 0x256D, 0xCE32, 0x9707,
 146     0x3A7B, 0x634E, 0x8811, 0xD124, 0x079A, 0x5EAF, 0xB5F0, 0xECC5,
 147     0x354F, 0x6C7A, 0x8725, 0xDE10, 0x08AE, 0x519B, 0xBAC4, 0xE3F1,
 148     0x4E8D, 0x17B8, 0xFCE7, 0xA5D2, 0x736C, 0x2A59, 0xC106, 0x9833,
 149     0xC2CB, 0x9BFE, 0x70A1, 0x2994, 0xFF2A, 0xA61F, 0x4D40, 0x1475,
 150     0xB909, 0xE03C, 0x0B63, 0x5256, 0x84E8, 0xDDDD, 0x3682, 0x6FB7,
 151     0x8372, 0xDA47, 0x3118, 0x682D, 0xBE93, 0xE7A6, 0x0CF9, 0x55CC,
 152     0xF8B0, 0xA185, 0x4ADA, 0x13EF, 0xC551, 0x9C64, 0x773B, 0x2E0E,
 153     0x74F6, 0x2DC3, 0xC69C, 0x9FA9, 0x4917, 0x1022, 0xFB7D, 0xA248,
 154     0x0F34, 0x5601, 0xBD5E, 0xE46B, 0x32D5, 0x6BE0, 0x80BF, 0xD98A,
 155     0x6A9E, 0x33AB, 0xD8F4, 0x81C1, 0x577F, 0x0E4A, 0xE515, 0xBC20,
 156     0x115C, 0x4869, 0xA336, 0xFA03, 0x2CBD, 0x7588, 0x9ED7, 0xC7E2,
 157     0x9D1A, 0xC42F, 0x2F70, 0x7645, 0xA0FB, 0xF9CE, 0x1291, 0x4BA4,
 158     0xE6D8, 0xBFED, 0x54B2, 0x0D87, 0xDB39, 0x820C, 0x6953, 0x3066,
 159     0xDCA3, 0x8596, 0x6EC9, 0x37FC, 0xE142, 0xB877, 0x5328, 0x0A1D,
 160     0xA761, 0xFE54, 0x150B, 0x4C3E, 0x9A80, 0xC3B5, 0x28EA, 0x71DF,
 161     0x2B27, 0x7212, 0x994D, 0xC078, 0x16C6, 0x4FF3, 0xA4AC, 0xFD99,
 162     0x50E5, 0x09D0, 0xE28F, 0xBBBA, 0x6D04, 0x3431, 0xDF6E, 0x865B,
 163     0x5FD1, 0x06E4, 0xEDBB, 0xB48E, 0x6230, 0x3B05, 0xD05A, 0x896F,
 164     0x2413, 0x7D26, 0x9679, 0xCF4C, 0x19F2, 0x40C7, 0xAB98, 0xF2AD,
 165     0xA855, 0xF160, 0x1A3F, 0x430A, 0x95B4, 0xCC81, 0x27DE, 0x7EEB,
 166     0xD397, 0x8AA2, 0x61FD, 0x38C8, 0xEE76, 0xB743, 0x5C1C, 0x0529,
 167     0xE9EC, 0xB0D9, 0x5B86, 0x02B3, 0xD40D, 0x8D38, 0x6667, 0x3F52,
 168     0x922E, 0xCB1B, 0x2044, 0x7971, 0xAFCF, 0xF6FA, 0x1DA5, 0x4490,
 169     0x1E68, 0x475D, 0xAC02, 0xF537, 0x2389, 0x7ABC, 0x91E3, 0xC8D6,
 170     0x65AA, 0x3C9F, 0xD7C0, 0x8EF5, 0x584B, 0x017E, 0xEA21, 0xB314
 171 };
 172
 173 /* This table was compiled using the polynom 0x755B */
 174 static const guint crc16_precompiled_755B[] =
 175 {
 176     0x0000, 0x755b, 0xeab6, 0x9fed, 0xa037, 0xd56c, 0x4a81, 0x3fda,     /* 0x00 */
 177     0x3535, 0x406e, 0xdf83, 0xaad8, 0x9502, 0xe059, 0x7fb4, 0x0aef,     /* 0x08 */
 178     0x6a6a, 0x1f31, 0x80dc, 0xf587, 0xca5d, 0xbf06, 0x20eb, 0x55b0,     /* 0x10 */
 179     0x5f5f, 0x2a04, 0xb5e9, 0xc0b2, 0xff68, 0x8a33, 0x15de, 0x6085,     /* 0x18 */
 180     0xd4d4, 0xa18f, 0x3e62, 0x4b39, 0x74e3, 0x01b8, 0x9e55, 0xeb0e,     /* 0x20 */
 181     0xe1e1, 0x94ba, 0x0b57, 0x7e0c, 0x41d6, 0x348d, 0xab60, 0xde3b,     /* 0x28 */
 182     0xbebe, 0xcbe5, 0x5408, 0x2153, 0x1e89, 0x6bd2, 0xf43f, 0x8164,     /* 0x30 */
 183     0x8b8b, 0xfed0, 0x613d, 0x1466, 0x2bbc, 0x5ee7, 0xc10a, 0xb451,     /* 0x38 */
 184     0xdcf3, 0xa9a8, 0x3645, 0x431e, 0x7cc4, 0x099f, 0x9672, 0xe329,     /* 0x40 */
 185     0xe9c6, 0x9c9d, 0x0370, 0x762b, 0x49f1, 0x3caa, 0xa347, 0xd61c,     /* 0x48 */
 186     0xb699, 0xc3c2, 0x5c2f, 0x2974, 0x16ae, 0x63f5, 0xfc18, 0x8943,     /* 0x50 */
 187     0x83ac, 0xf6f7, 0x691a, 0x1c41, 0x239b, 0x56c0, 0xc92d, 0xbc76,     /* 0x58 */
 188     0x0827, 0x7d7c, 0xe291, 0x97ca, 0xa810, 0xdd4b, 0x42a6, 0x37fd,     /* 0x60 */
 189     0x3d12, 0x4849, 0xd7a4, 0xa2ff, 0x9d25, 0xe87e, 0x7793, 0x02c8,     /* 0x68 */
 190     0x624d, 0x1716, 0x88fb, 0xfda0, 0xc27a, 0xb721, 0x28cc, 0x5d97,     /* 0x70 */
 191     0x5778, 0x2223, 0xbdce, 0xc895, 0xf74f, 0x8214, 0x1df9, 0x68a2,     /* 0x78 */
 192     0xccbd, 0xb9e6, 0x260b, 0x5350, 0x6c8a, 0x19d1, 0x863c, 0xf367,     /* 0x80 */
 193     0xf988, 0x8cd3, 0x133e, 0x6665, 0x59bf, 0x2ce4, 0xb309, 0xc652,     /* 0x88 */
 194     0xa6d7, 0xd38c, 0x4c61, 0x393a, 0x06e0, 0x73bb, 0xec56, 0x990d,     /* 0x90 */
 195     0x93e2, 0xe6b9, 0x7954, 0x0c0f, 0x33d5, 0x468e, 0xd963, 0xac38,     /* 0x98 */
 196     0x1869, 0x6d32, 0xf2df, 0x8784, 0xb85e, 0xcd05, 0x52e8, 0x27b3,     /* 0xA0 */
 197     0x2d5c, 0x5807, 0xc7ea, 0xb2b1, 0x8d6b, 0xf830, 0x67dd, 0x1286,     /* 0xA8 */
 198     0x7203, 0x0758, 0x98b5, 0xedee, 0xd234, 0xa76f, 0x3882, 0x4dd9,     /* 0xB0 */
 199     0x4736, 0x326d, 0xad80, 0xd8db, 0xe701, 0x925a, 0x0db7, 0x78ec,     /* 0xB8 */
 200     0x104e, 0x6515, 0xfaf8, 0x8fa3, 0xb079, 0xc522, 0x5acf, 0x2f94,     /* 0xC0 */
 201     0x257b, 0x5020, 0xcfcd, 0xba96, 0x854c, 0xf017, 0x6ffa, 0x1aa1,     /* 0xC8 */
 202     0x7a24, 0x0f7f, 0x9092, 0xe5c9, 0xda13, 0xaf48, 0x30a5, 0x45fe,     /* 0xD0 */
 203     0x4f11, 0x3a4a, 0xa5a7, 0xd0fc, 0xef26, 0x9a7d, 0x0590, 0x70cb,     /* 0xD8 */
 204     0xc49a, 0xb1c1, 0x2e2c, 0x5b77, 0x64ad, 0x11f6, 0x8e1b, 0xfb40,     /* 0xE0 */
 205     0xf1af, 0x84f4, 0x1b19, 0x6e42, 0x5198, 0x24c3, 0xbb2e, 0xce75,     /* 0xE8 */
 206     0xaef0, 0xdbab, 0x4446, 0x311d, 0x0ec7, 0x7b9c, 0xe471, 0x912a,     /* 0xF0 */
 207     0x9bc5, 0xee9e, 0x7173, 0x0428, 0x3bf2, 0x4ea9, 0xd144, 0xa41f      /* 0xF8 */
 208 };
 209
 210 /* This table was compiled using the polynom: 0x9949 */
 211 static const guint crc16_precompiled_9949_reverse[] =
 212 {
 213     0x0000, 0x0ED2, 0x1DA4, 0x1376, 0x3B48, 0x359A, 0x26EC, 0x283E,
 214     0x7690, 0x7842, 0x6B34, 0x65E6, 0x4DD8, 0x430A, 0x507C, 0x5EAE,
 215     0xED20, 0xE3F2, 0xF084, 0xFE56, 0xD668, 0xD8BA, 0xCBCC, 0xC51E,
 216     0x9BB0, 0x9562, 0x8614, 0x88C6, 0xA0F8, 0xAE2A, 0xBD5C, 0xB38E,
 217     0xFF73, 0xF1A1, 0xE2D7, 0xEC05, 0xC43B, 0xCAE9, 0xD99F, 0xD74D,
 218     0x89E3, 0x8731, 0x9447, 0x9A95, 0xB2AB, 0xBC79, 0xAF0F, 0xA1DD,
 219     0x1253, 0x1C81, 0x0FF7, 0x0125, 0x291B, 0x27C9, 0x34BF, 0x3A6D,
 220     0x64C3, 0x6A11, 0x7967, 0x77B5, 0x5F8B, 0x5159, 0x422F, 0x4CFD,
 221     0xDBD5, 0xD507, 0xC671, 0xC8A3, 0xE09D, 0xEE4F, 0xFD39, 0xF3EB,
 222     0xAD45, 0xA397, 0xB0E1, 0xBE33, 0x960D, 0x98DF, 0x8BA9, 0x857B,
 223     0x36F5, 0x3827, 0x2B51, 0x2583, 0x0DBD, 0x036F, 0x1019, 0x1ECB,
 224     0x4065, 0x4EB7, 0x5DC1, 0x5313, 0x7B2D, 0x75FF, 0x6689, 0x685B,
 225     0x24A6, 0x2A74, 0x3902, 0x37D0, 0x1FEE, 0x113C, 0x024A, 0x0C98,
 226     0x5236, 0x5CE4, 0x4F92, 0x4140, 0x697E, 0x67AC, 0x74DA, 0x7A08,
 227     0xC986, 0xC754, 0xD422, 0xDAF0, 0xF2CE, 0xFC1C, 0xEF6A, 0xE1B8,
 228     0xBF16, 0xB1C4, 0xA2B2, 0xAC60, 0x845E, 0x8A8C, 0x99FA, 0x9728,
 229     0x9299, 0x9C4B, 0x8F3D, 0x81EF, 0xA9D1, 0xA703, 0xB475, 0xBAA7,
 230     0xE409, 0xEADB, 0xF9AD, 0xF77F, 0xDF41, 0xD193, 0xC2E5, 0xCC37,
 231     0x7FB9, 0x716B, 0x621D, 0x6CCF, 0x44F1, 0x4A23, 0x5955, 0x5787,
 232     0x0929, 0x07FB, 0x148D, 0x1A5F, 0x3261, 0x3CB3, 0x2FC5, 0x2117,
 233     0x6DEA, 0x6338, 0x704E, 0x7E9C, 0x56A2, 0x5870, 0x4B06, 0x45D4,
 234     0x1B7A, 0x15A8, 0x06DE, 0x080C, 0x2032, 0x2EE0, 0x3D96, 0x3344,
 235     0x80CA, 0x8E18, 0x9D6E, 0x93BC, 0xBB82, 0xB550, 0xA626, 0xA8F4,
 236     0xF65A, 0xF888, 0xEBFE, 0xE52C, 0xCD12, 0xC3C0, 0xD0B6, 0xDE64,
 237     0x494C, 0x479E, 0x54E8, 0x5A3A, 0x7204, 0x7CD6, 0x6FA0, 0x6172,
 238     0x3FDC, 0x310E, 0x2278, 0x2CAA, 0x0494, 0x0A46, 0x1930, 0x17E2,
 239     0xA46C, 0xAABE, 0xB9C8, 0xB71A, 0x9F24, 0x91F6, 0x8280, 0x8C52,
 240     0xD2FC, 0xDC2E, 0xCF58, 0xC18A, 0xE9B4, 0xE766, 0xF410, 0xFAC2,
 241     0xB63F, 0xB8ED, 0xAB9B, 0xA549, 0x8D77, 0x83A5, 0x90D3, 0x9E01,
 242     0xC0AF, 0xCE7D, 0xDD0B, 0xD3D9, 0xFBE7, 0xF535, 0xE643, 0xE891,
 243     0x5B1F, 0x55CD, 0x46BB, 0x4869, 0x6057, 0x6E85, 0x7DF3, 0x7321,
 244     0x2D8F, 0x235D, 0x302B, 0x3EF9, 0x16C7, 0x1815, 0x0B63, 0x05B1
 245 };
 246
 247 /* This table was compiled using the polynom: 0x3D65 */
 248 static const guint crc16_precompiled_3D65_reverse[] =
 249 {
 250     0x0000, 0x365E, 0x6CBC, 0x5AE2, 0xD978, 0xEF26, 0xB5C4, 0x839A,
 251     0xFF89, 0xC9D7, 0x9335, 0xA56B, 0x26F1, 0x10AF, 0x4A4D, 0x7C13,
 252     0xB26B, 0x8435, 0xDED7, 0xE889, 0x6B13, 0x5D4D, 0x07AF, 0x31F1,
 253     0x4DE2, 0x7BBC, 0x215E, 0x1700, 0x949A, 0xA2C4, 0xF826, 0xCE78,
 254     0x29AF, 0x1FF1, 0x4513, 0x734D, 0xF0D7, 0xC689, 0x9C6B, 0xAA35,
 255     0xD626, 0xE078, 0xBA9A, 0x8CC4, 0x0F5E, 0x3900, 0x63E2, 0x55BC,
 256     0x9BC4, 0xAD9A, 0xF778, 0xC126, 0x42BC, 0x74E2, 0x2E00, 0x185E,
 257     0x644D, 0x5213, 0x08F1, 0x3EAF, 0xBD35, 0x8B6B, 0xD189, 0xE7D7,
 258     0x535E, 0x6500, 0x3FE2, 0x09BC, 0x8A26, 0xBC78, 0xE69A, 0xD0C4,
 259     0xACD7, 0x9A89, 0xC06B, 0xF635, 0x75AF, 0x43F1, 0x1913, 0x2F4D,
 260     0xE135, 0xD76B, 0x8D89, 0xBBD7, 0x384D, 0x0E13, 0x54F1, 0x62AF,
 261     0x1EBC, 0x28E2, 0x7200, 0x445E, 0xC7C4, 0xF19A, 0xAB78, 0x9D26,
 262     0x7AF1, 0x4CAF, 0x164D, 0x2013, 0xA389, 0x95D7, 0xCF35, 0xF96B,
 263     0x8578, 0xB326, 0xE9C4, 0xDF9A, 0x5C00, 0x6A5E, 0x30BC, 0x06E2,
 264     0xC89A, 0xFEC4, 0xA426, 0x9278, 0x11E2, 0x27BC, 0x7D5E, 0x4B00,
 265     0x3713, 0x014D, 0x5BAF, 0x6DF1, 0xEE6B, 0xD835, 0x82D7, 0xB489,
 266     0xA6BC, 0x90E2, 0xCA00, 0xFC5E, 0x7FC4, 0x499A, 0x1378, 0x2526,
 267     0x5935, 0x6F6B, 0x3589, 0x03D7, 0x804D, 0xB613, 0xECF1, 0xDAAF,
 268     0x14D7, 0x2289, 0x786B, 0x4E35, 0xCDAF, 0xFBF1, 0xA113, 0x974D,
 269     0xEB5E, 0xDD00, 0x87E2, 0xB1BC, 0x3226, 0x0478, 0x5E9A, 0x68C4,
 270     0x8F13, 0xB94D, 0xE3AF, 0xD5F1, 0x566B, 0x6035, 0x3AD7, 0x0C89,
 271     0x709A, 0x46C4, 0x1C26, 0x2A78, 0xA9E2, 0x9FBC, 0xC55E, 0xF300,
 272     0x3D78, 0x0B26, 0x51C4, 0x679A, 0xE400, 0xD25E, 0x88BC, 0xBEE2,
 273     0xC2F1, 0xF4AF, 0xAE4D, 0x9813, 0x1B89, 0x2DD7, 0x7735, 0x416B,
 274     0xF5E2, 0xC3BC, 0x995E, 0xAF00, 0x2C9A, 0x1AC4, 0x4026, 0x7678,
 275     0x0A6B, 0x3C35, 0x66D7, 0x5089, 0xD313, 0xE54D, 0xBFAF, 0x89F1,
 276     0x4789, 0x71D7, 0x2B35, 0x1D6B, 0x9EF1, 0xA8AF, 0xF24D, 0xC413,
 277     0xB800, 0x8E5E, 0xD4BC, 0xE2E2, 0x6178, 0x5726, 0x0DC4, 0x3B9A,
 278     0xDC4D, 0xEA13, 0xB0F1, 0x86AF, 0x0535, 0x336B, 0x6989, 0x5FD7,
 279     0x23C4, 0x159A, 0x4F78, 0x7926, 0xFABC, 0xCCE2, 0x9600, 0xA05E,
 280     0x6E26, 0x5878, 0x029A, 0x34C4, 0xB75E, 0x8100, 0xDBE2, 0xEDBC,
 281     0x91AF, 0xA7F1, 0xFD13, 0xCB4D, 0x48D7, 0x7E89, 0x246B, 0x1235
 282 };
 283
 284 /* This table was compiled using the polynom: 0x080F */
 285 static const guint crc16_precompiled_080F[] =
 286 {
 287     0x0000, 0x080F, 0x101E, 0x1811, 0x203C, 0x2833, 0x3022, 0x382D,
 288     0x4078, 0x4877, 0x5066, 0x5869, 0x6044, 0x684B, 0x705A, 0x7855,
 289     0x80F0, 0x88FF, 0x90EE, 0x98E1, 0xA0CC, 0xA8C3, 0xB0D2, 0xB8DD,
 290     0xC088, 0xC887, 0xD096, 0xD899, 0xE0B4, 0xE8BB, 0xF0AA, 0xF8A5,
 291     0x09EF, 0x01E0, 0x19F1, 0x11FE, 0x29D3, 0x21DC, 0x39CD, 0x31C2,
 292     0x4997, 0x4198, 0x5989, 0x5186, 0x69AB, 0x61A4, 0x79B5, 0x71BA,
 293     0x891F, 0x8110, 0x9901, 0x910E, 0xA923, 0xA12C, 0xB93D, 0xB132,
 294     0xC967, 0xC168, 0xD979, 0xD176, 0xE95B, 0xE154, 0xF945, 0xF14A,
 295     0x13DE, 0x1BD1, 0x03C0, 0x0BCF, 0x33E2, 0x3BED, 0x23FC, 0x2BF3,
 296     0x53A6, 0x5BA9, 0x43B8, 0x4BB7, 0x739A, 0x7B95, 0x6384, 0x6B8B,
 297     0x932E, 0x9B21, 0x8330, 0x8B3F, 0xB312, 0xBB1D, 0xA30C, 0xAB03,
 298     0xD356, 0xDB59, 0xC348, 0xCB47, 0xF36A, 0xFB65, 0xE374, 0xEB7B,
 299     0x1A31, 0x123E, 0x0A2F, 0x0220, 0x3A0D, 0x3202, 0x2A13, 0x221C,
 300     0x5A49, 0x5246, 0x4A57, 0x4258, 0x7A75, 0x727A, 0x6A6B, 0x6264,
 301     0x9AC1, 0x92CE, 0x8ADF, 0x82D0, 0xBAFD, 0xB2F2, 0xAAE3, 0xA2EC,
 302     0xDAB9, 0xD2B6, 0xCAA7, 0xC2A8, 0xFA85, 0xF28A, 0xEA9B, 0xE294,
 303     0x27BC, 0x2FB3, 0x37A2, 0x3FAD, 0x0780, 0x0F8F, 0x179E, 0x1F91,
 304     0x67C4, 0x6FCB, 0x77DA, 0x7FD5, 0x47F8, 0x4FF7, 0x57E6, 0x5FE9,
 305     0xA74C, 0xAF43, 0xB752, 0xBF5D, 0x8770, 0x8F7F, 0x976E, 0x9F61,
 306     0xE734, 0xEF3B, 0xF72A, 0xFF25, 0xC708, 0xCF07, 0xD716, 0xDF19,
 307     0x2E53, 0x265C, 0x3E4D, 0x3642, 0x0E6F, 0x0660, 0x1E71, 0x167E,
 308     0x6E2B, 0x6624, 0x7E35, 0x763A, 0x4E17, 0x4618, 0x5E09, 0x5606,
 309     0xAEA3, 0xA6AC, 0xBEBD, 0xB6B2, 0x8E9F, 0x8690, 0x9E81, 0x968E,
 310     0xEEDB, 0xE6D4, 0xFEC5, 0xF6CA, 0xCEE7, 0xC6E8, 0xDEF9, 0xD6F6,
 311     0x3462, 0x3C6D, 0x247C, 0x2C73, 0x145E, 0x1C51, 0x0440, 0x0C4F,
 312     0x741A, 0x7C15, 0x6404, 0x6C0B, 0x5426, 0x5C29, 0x4438, 0x4C37,
 313     0xB492, 0xBC9D, 0xA48C, 0xAC83, 0x94AE, 0x9CA1, 0x84B0, 0x8CBF,
 314     0xF4EA, 0xFCE5, 0xE4F4, 0xECFB, 0xD4D6, 0xDCD9, 0xC4C8, 0xCCC7,
 315     0x3D8D, 0x3582, 0x2D93, 0x259C, 0x1DB1, 0x15BE, 0x0DAF, 0x05A0,
 316     0x7DF5, 0x75FA, 0x6DEB, 0x65E4, 0x5DC9, 0x55C6, 0x4DD7, 0x45D8,
 317     0xBD7D, 0xB572, 0xAD63, 0xA56C, 0x9D41, 0x954E, 0x8D5F, 0x8550,
 318     0xFD05, 0xF50A, 0xED1B, 0xE514, 0xDD39, 0xD536, 0xCD27, 0xC528
 319 };
 320
 321 static const guint16 crc16_ccitt_start = 0xFFFF;
 322 static const guint16 crc16_ccitt_xorout = 0xFFFF;
 323
 324 /* two types of crcs are possible: unreflected (bits shift left) and
 325  * reflected (bits shift right).
 326  */
 327 static guint16 crc16_unreflected(const guint8 *buf, guint len,
 328                                  guint16 crc_in, const guint table[])
 329 {
 330     /* we use guints, rather than guint16s, as they are likely to be
 331        faster. We just ignore the top 16 bits and let them do what they want.
 332     */
 333     guint crc16 = (guint)crc_in;
 334
 335     while( len-- != 0 )
 336         crc16 = table[((crc16 >> 8) ^ *buf++) & 0xff] ^ (crc16 << 8);
 337
 338     return (guint16)crc16;
 339 }
 340
 341 static guint16 crc16_reflected(const guint8 *buf, guint len,
 342                                 guint16 crc_in, const guint table[])
 343 {
 344     /* we use guints, rather than guint16s, as they are likely to be
 345        faster. We just ignore the top 16 bits and let them do what they want.
 346        XXX - does any time saved not zero-extending guint16's to 32 bits
 347        into a register outweigh any increased cache footprint from the
 348        larger CRC table? */
 349     guint crc16 = (guint)crc_in;
 350
 351     while( len-- != 0 )
 352        crc16 = table[(crc16 ^ *buf++) & 0xff] ^ (crc16 >> 8);
 353
 354     return (guint16)crc16;
 355 }
 356
 357 guint16 crc16_ccitt(const guint8 *buf, guint len)
 358 {
 359     return crc16_reflected(buf,len,crc16_ccitt_start,crc16_ccitt_table_reverse)
 360        ^ crc16_ccitt_xorout;
 361 }
 362
 363 guint16 crc16_x25_ccitt_seed(const guint8 *buf, guint len, guint16 seed)
 364 {
 365     return crc16_unreflected(buf,len,seed,crc16_ccitt_table);
 366 }
 367
 368 guint16 crc16_ccitt_seed(const guint8 *buf, guint len, guint16 seed)
 369 {
 370     return crc16_reflected(buf,len,seed,crc16_ccitt_table_reverse)
 371        ^ crc16_ccitt_xorout;
 372 }
 373
 374 /* ISO14443-3, section 6.2.4: For ISO14443-A, the polynomial 0x1021 is
 375    used, the initial register value shall be 0x6363, the final register
 376    value is not XORed with anything. */
 377 guint16 crc16_iso14443a(const guint8 *buf, guint len)
 378 {
 379     return crc16_reflected(buf,len, 0x6363 ,crc16_ccitt_table_reverse);
 380 }
 381
 382 guint16 crc16_0x5935(const guint8 *buf, guint32 len, guint16 seed)
 383 {
 384     return crc16_unreflected(buf, len, seed, crc16_precompiled_5935);
 385 }
 386
 387 guint16 crc16_0x755B(const guint8 *buf, guint32 len, guint16 seed)
 388 {
 389     return crc16_unreflected(buf, len, seed, crc16_precompiled_755B);
 390 }
 391
 392 guint16 crc16_0x9949_seed(const guint8 *buf, guint len, guint16 seed)
 393 {
 394     return crc16_reflected(buf, len, seed, crc16_precompiled_9949_reverse);
 395 }
 396
 397 guint16 crc16_0x3D65_seed(const guint8 *buf, guint len, guint16 seed)
 398 {
 399     return crc16_reflected(buf, len, seed, crc16_precompiled_3D65_reverse);
 400 }
 401
 402 guint16 crc16_0x080F_seed(const guint8 *buf, guint len, guint16 seed)
 403 {
 404     guint16 crc = seed;
 405
 406     if (len > 0)
 407     {
 408         while (len-- > 0)
 409         {
 410             guint8 data = *buf++;
 411             crc = crc16_precompiled_080F[((crc >> 8) ^ data)] ^ (crc << 8);
 412         }
 413     }
 414
 415     return crc;
 416 }
 417
 418 /*
 419  * Editor modelines  -  http://www.wireshark.org/tools/modelines.html
 420  *
 421  * Local variables:
 422  * c-basic-offset: 4
 423  * tab-width: 8
 424  * indent-tabs-mode: nil
 425  * End:
 426  *
 427  * vi: set shiftwidth=4 tabstop=8 expandtab:
 428  * :indentSize=4:tabSize=8:noTabs=true:
 429  */