forked from osmocom/wireshark
![Guy Harris](/assets/img/avatar_default.png)
add versions of CRC-16 and CRC-32 routines with seed arguments; add versions of those routines with an "offset in the tvbuff" argument; add Doxygen comments to the CRC-16 and CRC-32 headers. svn path=/trunk/; revision=11573
87 lines
3.6 KiB
C
87 lines
3.6 KiB
C
/* crc16.h
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* Declaration of CRC-16 routines and table
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*
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* 2004 Richard van der Hoff <richardv@mxtelecom.com>
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*
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* $Id$
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*
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* Ethereal - Network traffic analyzer
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* By Gerald Combs <gerald@xxxxxxxxxxxx>
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* Copyright 1998 Gerald Combs
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*
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* Copied from README.developer
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License
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* as published by the Free Software Foundation; either version 2
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* of the License, or (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
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*/
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/* Calculate the CCITT/ITU/CRC-16 16-bit CRC
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(parameters for this CRC are:
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Polynomial: x^16 + x^12 + x^5 + 1 (0x1021);
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Start value 0xFFFF;
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XOR result with 0xFFFF;
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First bit is LSB)
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*/
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/** Compute CRC16 CCITT checksum of a buffer of data.
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@param buf The buffer containing the data.
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@param len The number of bytes to include in the computation.
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@return The CRC16 CCITT checksum. */
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extern guint16 crc16_ccitt(const guint8 *buf, guint len);
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/** Compute CRC16 CCITT checksum of a buffer of data. If computing the
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* checksum over multiple buffers and you want to feed the partial CRC16
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* back in, remember to take the 1's complement of the partial CRC16 first.
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@param buf The buffer containing the data.
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@param len The number of bytes to include in the computation.
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@param seed The seed to use.
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@return The CRC16 CCITT checksum (using the given seed). */
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extern guint16 crc16_ccitt_seed(const guint8 *buf, guint len, guint16 seed);
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/** Compute CRC16 CCITT checksum of a tv buffer.
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@param tvb The tv buffer containing the data.
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@param len The number of bytes to include in the computation.
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@return The CRC16 CCITT checksum. */
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extern guint16 crc16_ccitt_tvb(tvbuff_t *tvb, guint len);
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/** Compute CRC16 CCITT checksum of a tv buffer.
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@param tvb The tv buffer containing the data.
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@param offset The offset into the tv buffer.
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@param len The number of bytes to include in the computation.
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@return The CRC16 CCITT checksum. */
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extern guint16 crc16_ccitt_tvb_offset(tvbuff_t *tvb, guint offset, guint len);
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/** Compute CRC16 CCITT checksum of a tv buffer. If computing the
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* checksum over multiple tv buffers and you want to feed the partial CRC16
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* back in, remember to take the 1's complement of the partial CRC16 first.
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@param tvb The tv buffer containing the data.
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@param len The number of bytes to include in the computation.
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@param seed The seed to use.
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@return The CRC16 CCITT checksum (using the given seed). */
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extern guint16 crc16_ccitt_tvb_seed(tvbuff_t *tvb, guint len, guint16 seed);
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/** Compute CRC16 CCITT checksum of a tv buffer. If computing the
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* checksum over multiple tv buffers and you want to feed the partial CRC16
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* back in, remember to take the 1's complement of the partial CRC16 first.
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@param tvb The tv buffer containing the data.
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@param offset The offset into the tv buffer.
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@param len The number of bytes to include in the computation.
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@param seed The seed to use.
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@return The CRC16 CCITT checksum (using the given seed). */
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extern guint16 crc16_ccitt_tvb_offset_seed(tvbuff_t *tvb, guint offset,
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guint len, guint16 seed);
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