epan/crc16-tvb.h

   1 /* crc16-tvb.h
   2  * Declaration of CRC-16 tvbuff routines
   3  *
   4  * 2004 Richard van der Hoff <richardv@mxtelecom.com>
   5  *
   6  * $Id$
   7  *
   8  * Wireshark - Network traffic analyzer
   9  * By Gerald Combs <gerald@wireshark.org>
  10  * Copyright 1998 Gerald Combs
  11  *
  12  * This program is free software; you can redistribute it and/or
  13  * modify it under the terms of the GNU General Public License
  14  * as published by the Free Software Foundation; either version 2
  15  * of the License, or (at your option) any later version.
  16  *
  17  * This program is distributed in the hope that it will be useful,
  18  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  19  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  20  * GNU General Public License for more details.
  21  *
  22  * You should have received a copy of the GNU General Public License
  23  * along with this program; if not, write to the Free Software
  24  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
  25 */
  26
  27 #ifndef __CRC16_TVB_H__
  28 #define __CRC16_TVB_H__
  29
  30 #include "ws_symbol_export.h"
  31
  32 #ifdef __cplusplus
  33 extern "C" {
  34 #endif /* __cplusplus */
  35
  36 /** Compute CRC16 CCITT checksum of a tv buffer.
  37  @param tvb The tv buffer containing the data.
  38  @param len The number of bytes to include in the computation.
  39  @return The CRC16 CCITT checksum. */
  40 WS_DLL_PUBLIC guint16 crc16_ccitt_tvb(tvbuff_t *tvb, guint len);
  41
  42 /** Compute CRC16 X.25 CCITT checksum of a tv buffer.
  43  @param tvb The tv buffer containing the data.
  44  @param len The number of bytes to include in the computation.
  45  @return The CRC16 X.25 CCITT checksum. */
  46 WS_DLL_PUBLIC guint16 crc16_x25_ccitt_tvb(tvbuff_t *tvb, guint len);
  47
  48 /** Compute CRC16 CCITT checksum of a tv buffer.
  49  @param tvb The tv buffer containing the data.
  50  @param offset The offset into the tv buffer.
  51  @param len The number of bytes to include in the computation.
  52  @return The CRC16 CCITT checksum. */
  53 WS_DLL_PUBLIC guint16 crc16_ccitt_tvb_offset(tvbuff_t *tvb, guint offset, guint len);
  54
  55 /** Compute CRC16 CCITT checksum of a tv buffer.  If computing the
  56  *  checksum over multiple tv buffers and you want to feed the partial CRC16
  57  *  back in, remember to take the 1's complement of the partial CRC16 first.
  58  @param tvb The tv buffer containing the data.
  59  @param len The number of bytes to include in the computation.
  60  @param seed The seed to use.
  61  @return The CRC16 CCITT checksum (using the given seed). */
  62 WS_DLL_PUBLIC guint16 crc16_ccitt_tvb_seed(tvbuff_t *tvb, guint len, guint16 seed);
  63
  64 /** Compute CRC16 CCITT checksum of a tv buffer.  If computing the
  65  *  checksum over multiple tv buffers and you want to feed the partial CRC16
  66  *  back in, remember to take the 1's complement of the partial CRC16 first.
  67  @param tvb The tv buffer containing the data.
  68  @param offset The offset into the tv buffer.
  69  @param len The number of bytes to include in the computation.
  70  @param seed The seed to use.
  71  @return The CRC16 CCITT checksum (using the given seed). */
  72 WS_DLL_PUBLIC guint16 crc16_ccitt_tvb_offset_seed(tvbuff_t *tvb, guint offset,
  73                                            guint len, guint16 seed);
  74
  75 /** Compute the "plain" CRC16 checksum of a tv buffer using the following
  76  * parameters:
  77  *    Width        = 16
  78  *    Poly         = 0x8005
  79  *    XorIn        = 0x0000
  80  *    ReflectIn    = True
  81  *    XorOut       = 0x0000
  82  *    ReflectOut   = True
  83  *    Algorithm    = table-driven
  84  *    Direct       = True
  85  @param tvb The tv buffer containing the data.
  86  @param offset The offset into the tv buffer.
  87  @param len The number of bytes to include in the computation.
  88  @return The CRC16 checksum. */
  89 WS_DLL_PUBLIC guint16 crc16_plain_tvb_offset(tvbuff_t *tvb, guint offset, guint len);
  90
  91 /** Compute the "plain" CRC16 checksum of a tv buffer using the following
  92  * parameters:
  93  *    Width        = 16
  94  *    Poly         = 0x8005
  95  *    XorIn        = 0x0000
  96  *    ReflectIn    = True
  97  *    XorOut       = 0x0000
  98  *    ReflectOut   = True
  99  *    Algorithm    = table-driven
 100  *    Direct       = True
 101  @param tvb The tv buffer containing the data.
 102  @param offset The offset into the tv buffer.
 103  @param len The number of bytes to include in the computation.
 104  @param crc Starting CRC value
 105  @return The CRC16 checksum. */
 106 WS_DLL_PUBLIC guint16 crc16_plain_tvb_offset_seed(tvbuff_t *tvb, guint offset, guint len, guint16 crc);
 107
 108 /** Compute CRC16 checksum of a tv buffer using the parameters
 109  *    Width        = 16 bits
 110  *    Poly         = 0x9949
 111  *    Reflection   = true
 112  *    Algorithm    = table-driven
 113  @param tvb The tv buffer containing the data.
 114  @param offset The offset into the tv buffer.
 115  @param len The number of bytes to include in the computation.
 116  @param seed The seed to use.
 117  @return The CRC16 checksum. */
 118 WS_DLL_PUBLIC guint16 crc16_0x9949_tvb_offset_seed(tvbuff_t *tvb, guint offset, guint len, guint16 seed);
 119
 120 #ifdef __cplusplus
 121 }
 122 #endif /* __cplusplus */
 123
 124 #endif /* crc16-tvb.h */