wsutil/crc16-plain.c

   1 /*
   2  * crc16-plain.c
   3  * $Id$
   4  *
   5  * http://www.tty1.net/pycrc/faq_en.html#code-ownership
   6  *
   7  * Wireshark - Network traffic analyzer
   8  * By Gerald Combs <gerald@wireshark.org>
   9  * Copyright 1998 Gerald Combs
  10  *
  11  * This program is free software; you can redistribute it and/or
  12  * modify it under the terms of the GNU General Public License
  13  * as published by the Free Software Foundation; either version 2
  14  * of the License, or (at your option) any later version.
  15  *
  16  * This program is distributed in the hope that it will be useful,
  17  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  18  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  19  * GNU General Public License for more details.
  20  *
  21  * You should have received a copy of the GNU General Public License
  22  * along with this program; if not, write to the Free Software
  23  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
  24  */
  25
  26 /**
  27  * $Id$
  28  * \file crc16-plain.c
  29  * Functions and types for CRC checks.
  30  *
  31  * Generated on Wed Mar 18 14:12:09 2009,
  32  * by pycrc v0.7, http://www.tty1.net/pycrc/
  33  * using the configuration:
  34  *    Width        = 16
  35  *    Poly         = 0x8005
  36  *    XorIn        = 0x0000
  37  *    ReflectIn    = True
  38  *    XorOut       = 0x0000
  39  *    ReflectOut   = True
  40  *    Algorithm    = table-driven
  41  *    Direct       = True
  42  *
  43  * Modified 2009-03-16 not to include <stdint.h> as our Win32 environment
  44  * appears not to have it; we're using GLib types, instead.
  45  *****************************************************************************/
  46 #include <glib.h>
  47 #include "wsutil/crc16-plain.h"
  48 #include <stdlib.h>
  49
  50 /**
  51  * Static table used for the table_driven implementation.
  52  *****************************************************************************/
  53 static const crc16_plain_t crc_table_reflected[256] = {
  54     0x0000, 0xc0c1, 0xc181, 0x0140, 0xc301, 0x03c0, 0x0280, 0xc241,
  55     0xc601, 0x06c0, 0x0780, 0xc741, 0x0500, 0xc5c1, 0xc481, 0x0440,
  56     0xcc01, 0x0cc0, 0x0d80, 0xcd41, 0x0f00, 0xcfc1, 0xce81, 0x0e40,
  57     0x0a00, 0xcac1, 0xcb81, 0x0b40, 0xc901, 0x09c0, 0x0880, 0xc841,
  58     0xd801, 0x18c0, 0x1980, 0xd941, 0x1b00, 0xdbc1, 0xda81, 0x1a40,
  59     0x1e00, 0xdec1, 0xdf81, 0x1f40, 0xdd01, 0x1dc0, 0x1c80, 0xdc41,
  60     0x1400, 0xd4c1, 0xd581, 0x1540, 0xd701, 0x17c0, 0x1680, 0xd641,
  61     0xd201, 0x12c0, 0x1380, 0xd341, 0x1100, 0xd1c1, 0xd081, 0x1040,
  62     0xf001, 0x30c0, 0x3180, 0xf141, 0x3300, 0xf3c1, 0xf281, 0x3240,
  63     0x3600, 0xf6c1, 0xf781, 0x3740, 0xf501, 0x35c0, 0x3480, 0xf441,
  64     0x3c00, 0xfcc1, 0xfd81, 0x3d40, 0xff01, 0x3fc0, 0x3e80, 0xfe41,
  65     0xfa01, 0x3ac0, 0x3b80, 0xfb41, 0x3900, 0xf9c1, 0xf881, 0x3840,
  66     0x2800, 0xe8c1, 0xe981, 0x2940, 0xeb01, 0x2bc0, 0x2a80, 0xea41,
  67     0xee01, 0x2ec0, 0x2f80, 0xef41, 0x2d00, 0xedc1, 0xec81, 0x2c40,
  68     0xe401, 0x24c0, 0x2580, 0xe541, 0x2700, 0xe7c1, 0xe681, 0x2640,
  69     0x2200, 0xe2c1, 0xe381, 0x2340, 0xe101, 0x21c0, 0x2080, 0xe041,
  70     0xa001, 0x60c0, 0x6180, 0xa141, 0x6300, 0xa3c1, 0xa281, 0x6240,
  71     0x6600, 0xa6c1, 0xa781, 0x6740, 0xa501, 0x65c0, 0x6480, 0xa441,
  72     0x6c00, 0xacc1, 0xad81, 0x6d40, 0xaf01, 0x6fc0, 0x6e80, 0xae41,
  73     0xaa01, 0x6ac0, 0x6b80, 0xab41, 0x6900, 0xa9c1, 0xa881, 0x6840,
  74     0x7800, 0xb8c1, 0xb981, 0x7940, 0xbb01, 0x7bc0, 0x7a80, 0xba41,
  75     0xbe01, 0x7ec0, 0x7f80, 0xbf41, 0x7d00, 0xbdc1, 0xbc81, 0x7c40,
  76     0xb401, 0x74c0, 0x7580, 0xb541, 0x7700, 0xb7c1, 0xb681, 0x7640,
  77     0x7200, 0xb2c1, 0xb381, 0x7340, 0xb101, 0x71c0, 0x7080, 0xb041,
  78     0x5000, 0x90c1, 0x9181, 0x5140, 0x9301, 0x53c0, 0x5280, 0x9241,
  79     0x9601, 0x56c0, 0x5780, 0x9741, 0x5500, 0x95c1, 0x9481, 0x5440,
  80     0x9c01, 0x5cc0, 0x5d80, 0x9d41, 0x5f00, 0x9fc1, 0x9e81, 0x5e40,
  81     0x5a00, 0x9ac1, 0x9b81, 0x5b40, 0x9901, 0x59c0, 0x5880, 0x9841,
  82     0x8801, 0x48c0, 0x4980, 0x8941, 0x4b00, 0x8bc1, 0x8a81, 0x4a40,
  83     0x4e00, 0x8ec1, 0x8f81, 0x4f40, 0x8d01, 0x4dc0, 0x4c80, 0x8c41,
  84     0x4400, 0x84c1, 0x8581, 0x4540, 0x8701, 0x47c0, 0x4680, 0x8641,
  85     0x8201, 0x42c0, 0x4380, 0x8341, 0x4100, 0x81c1, 0x8081, 0x4040
  86 };
  87
  88 /**
  89  * Reflect all bits of a \a data word of \a data_len bytes.
  90  *
  91  * \param data         The data word to be reflected.
  92  * \param data_len     The width of \a data expressed in number of bits.
  93  * \return     The reflected data.
  94  *****************************************************************************/
  95 long crc16_plain_reflect(long data, size_t data_len)
  96 {
  97     unsigned int i;
  98     long ret;
  99
 100     ret = data & 0x01;
 101     for (i = 1; i < data_len; i++)
 102     {
 103         data >>= 1;
 104         ret = (ret << 1) | (data & 0x01);
 105     }
 106     return ret;
 107 }
 108
 109
 110 /**
 111  * Update the crc value with new data.
 112  *
 113  * \param crc      The current crc value.
 114  * \param data     Pointer to a buffer of \a data_len bytes.
 115  * \param data_len Number of bytes in the \a data buffer.
 116  * \return         The updated crc value.
 117  *****************************************************************************/
 118 crc16_plain_t crc16_plain_update(crc16_plain_t crc, const unsigned char *data, size_t data_len)
 119 {
 120     unsigned int tbl_idx;
 121
 122     while (data_len--) {
 123         tbl_idx = (crc ^ *data) & 0xff;
 124         crc = (crc_table_reflected[tbl_idx] ^ (crc >> 8)) & 0xffff;
 125
 126         data++;
 127     }
 128     return crc & 0xffff;
 129 }
 130
 131 /* Generated on Tue Jul 24 09:08:46 2012,
 132  * by pycrc v0.7.10, http://www.tty1.net/pycrc/
 133  * using the configuration:
 134  *    Width        = 16
 135  *    Poly         = 0x8005
 136  *    XorIn        = 0x0000
 137  *    ReflectIn    = False
 138  *    XorOut       = 0x0000
 139  *    ReflectOut   = False
 140  *    Algorithm    = table-driven
 141  *****************************************************************************/
 142 static const guint16 crc16_table_8005_noreflect_noxor[256] = {
 143     0x0000, 0x8005, 0x800f, 0x000a, 0x801b, 0x001e, 0x0014, 0x8011,
 144     0x8033, 0x0036, 0x003c, 0x8039, 0x0028, 0x802d, 0x8027, 0x0022,
 145     0x8063, 0x0066, 0x006c, 0x8069, 0x0078, 0x807d, 0x8077, 0x0072,
 146     0x0050, 0x8055, 0x805f, 0x005a, 0x804b, 0x004e, 0x0044, 0x8041,
 147     0x80c3, 0x00c6, 0x00cc, 0x80c9, 0x00d8, 0x80dd, 0x80d7, 0x00d2,
 148     0x00f0, 0x80f5, 0x80ff, 0x00fa, 0x80eb, 0x00ee, 0x00e4, 0x80e1,
 149     0x00a0, 0x80a5, 0x80af, 0x00aa, 0x80bb, 0x00be, 0x00b4, 0x80b1,
 150     0x8093, 0x0096, 0x009c, 0x8099, 0x0088, 0x808d, 0x8087, 0x0082,
 151     0x8183, 0x0186, 0x018c, 0x8189, 0x0198, 0x819d, 0x8197, 0x0192,
 152     0x01b0, 0x81b5, 0x81bf, 0x01ba, 0x81ab, 0x01ae, 0x01a4, 0x81a1,
 153     0x01e0, 0x81e5, 0x81ef, 0x01ea, 0x81fb, 0x01fe, 0x01f4, 0x81f1,
 154     0x81d3, 0x01d6, 0x01dc, 0x81d9, 0x01c8, 0x81cd, 0x81c7, 0x01c2,
 155     0x0140, 0x8145, 0x814f, 0x014a, 0x815b, 0x015e, 0x0154, 0x8151,
 156     0x8173, 0x0176, 0x017c, 0x8179, 0x0168, 0x816d, 0x8167, 0x0162,
 157     0x8123, 0x0126, 0x012c, 0x8129, 0x0138, 0x813d, 0x8137, 0x0132,
 158     0x0110, 0x8115, 0x811f, 0x011a, 0x810b, 0x010e, 0x0104, 0x8101,
 159     0x8303, 0x0306, 0x030c, 0x8309, 0x0318, 0x831d, 0x8317, 0x0312,
 160     0x0330, 0x8335, 0x833f, 0x033a, 0x832b, 0x032e, 0x0324, 0x8321,
 161     0x0360, 0x8365, 0x836f, 0x036a, 0x837b, 0x037e, 0x0374, 0x8371,
 162     0x8353, 0x0356, 0x035c, 0x8359, 0x0348, 0x834d, 0x8347, 0x0342,
 163     0x03c0, 0x83c5, 0x83cf, 0x03ca, 0x83db, 0x03de, 0x03d4, 0x83d1,
 164     0x83f3, 0x03f6, 0x03fc, 0x83f9, 0x03e8, 0x83ed, 0x83e7, 0x03e2,
 165     0x83a3, 0x03a6, 0x03ac, 0x83a9, 0x03b8, 0x83bd, 0x83b7, 0x03b2,
 166     0x0390, 0x8395, 0x839f, 0x039a, 0x838b, 0x038e, 0x0384, 0x8381,
 167     0x0280, 0x8285, 0x828f, 0x028a, 0x829b, 0x029e, 0x0294, 0x8291,
 168     0x82b3, 0x02b6, 0x02bc, 0x82b9, 0x02a8, 0x82ad, 0x82a7, 0x02a2,
 169     0x82e3, 0x02e6, 0x02ec, 0x82e9, 0x02f8, 0x82fd, 0x82f7, 0x02f2,
 170     0x02d0, 0x82d5, 0x82df, 0x02da, 0x82cb, 0x02ce, 0x02c4, 0x82c1,
 171     0x8243, 0x0246, 0x024c, 0x8249, 0x0258, 0x825d, 0x8257, 0x0252,
 172     0x0270, 0x8275, 0x827f, 0x027a, 0x826b, 0x026e, 0x0264, 0x8261,
 173     0x0220, 0x8225, 0x822f, 0x022a, 0x823b, 0x023e, 0x0234, 0x8231,
 174     0x8213, 0x0216, 0x021c, 0x8219, 0x0208, 0x820d, 0x8207, 0x0202
 175 };
 176
 177 /**
 178  * Calculate the crc-16 (x^16 + x^15 + x^2 + 1) value for data. Note that this
 179  * CRC is not equal to crc16_plain.
 180  *
 181  * \param data     Pointer to a buffer of \a data_len bytes.
 182  * \param data_len Number of bytes in the \a data buffer.
 183  * \return         The crc value.
 184  *****************************************************************************/
 185 guint16 crc16_8005_noreflect_noxor(const guint8 *data, guint64 data_len)
 186 {
 187     guint tbl_idx;
 188     guint16 crc = 0;
 189
 190     while (data_len--) {
 191         tbl_idx = ((crc >> 8) ^ *data) & 0xff;
 192         crc = (crc16_table_8005_noreflect_noxor[tbl_idx] ^ (crc << 8)) & 0xffff;
 193
 194         data++;
 195     }
 196     return crc & 0xffff;
 197 }
 198