89 lines
2.2 KiB
C
89 lines
2.2 KiB
C
/**
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* Calculation of CRC 16 CCITT polynomial.
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*
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* @file crc16-ccitt.h
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* @ingroup CO_crc16_ccitt
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* @author Lammert Bies
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* @author Janez Paternoster
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* @copyright 2012 - 2020 Janez Paternoster
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*
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* This file is part of CANopenNode, an opensource CANopen Stack.
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* Project home page is <https://github.com/CANopenNode/CANopenNode>.
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* For more information on CANopen see <http://www.can-cia.org/>.
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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#ifndef CRC16_CCITT_H
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#define CRC16_CCITT_H
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#ifdef __cplusplus
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extern "C" {
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#endif
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/**
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* @defgroup CO_crc16_ccitt CRC 16 CCITT
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* @ingroup CO_CANopen_301
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* @{
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*
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* Calculation of CRC 16 CCITT polynomial.
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*
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* Equation:
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*
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* `x^16 + x^12 + x^5 + 1`
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*/
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/**
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* Update crc16_ccitt variable with one data byte
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*
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* This function updates crc variable for one data byte using crc16 ccitt
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* algorithm.
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*
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* @param [in,out] crc Externally defined variable for CRC checksum. Before
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* start of new CRC calculation, variable must be initialized (zero for xmodem).
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* @param chr One byte of data
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*/
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#ifdef CO_USE_OWN_CRC16
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extern
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#endif
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void crc16_ccitt_single(unsigned short *crc, const unsigned char chr);
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/**
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* Calculate CRC sum on block of data.
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*
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* @param block Pointer to block of data.
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* @param blockLength Length of data in bytes;
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* @param crc Initial value (zero for xmodem). If block is split into
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* multiple segments, previous CRC is used as initial.
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*
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* @return Calculated CRC.
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*/
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#ifdef CO_USE_OWN_CRC16
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extern
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#endif
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unsigned short crc16_ccitt(
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const unsigned char block[],
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unsigned int blockLength,
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unsigned short crc);
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/** @} */
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#ifdef __cplusplus
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}
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#endif /*__cplusplus*/
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#endif
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