79 lines
2.4 KiB
C
79 lines
2.4 KiB
C
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/**
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* \file
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* <!--
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* This file is part of BeRTOS.
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*
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* Bertos is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (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., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
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*
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* As a special exception, you may use this file as part of a free software
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* library without restriction. Specifically, if other files instantiate
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* templates or use macros or inline functions from this file, or you compile
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* this file and link it with other files to produce an executable, this
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* file does not by itself cause the resulting executable to be covered by
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* the GNU General Public License. This exception does not however
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* invalidate any other reasons why the executable file might be covered by
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* the GNU General Public License.
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*
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* Copyright 2009 Develer S.r.l. (http://www.develer.com/)
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*
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* -->
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*
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* \brief CCITT Cyclic Redundancy Check (CRC-CCITT).
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*
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* \note This algorithm is incompatible with the CRC16.
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*
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* \author Francesco Sacchi <batt@develer.com>
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*
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* $WIZ$ module_name = "crc-ccitt"
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*/
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#ifndef ALGO_CRC_CCITT_H
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#define ALGO_CRC_CCITT_H
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#include <cfg/compiler.h>
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#include <cpu/pgm.h>
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EXTERN_C_BEGIN
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/* CRC table */
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extern const uint16_t crc_ccitt_tab[256];
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/**
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* \brief Compute the updated CRC-CCITT value for one octet (inline version)
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*/
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INLINE uint16_t updcrc_ccitt(uint8_t c, uint16_t oldcrc)
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{
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return (oldcrc >> 8) ^ pgm_read16(&crc_ccitt_tab[(oldcrc ^ c) & 0xff]);
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}
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/** CRC-CCITT init value */
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#define CRC_CCITT_INIT_VAL ((uint16_t)0xFFFF)
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/**
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* This function implements the CRC-CCITT calculation on a buffer.
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*
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* \param crc Current CRC-CCITT value.
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* \param buf The buffer to perform CRC calculation on.
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* \param len The length of the Buffer.
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*
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* \return The updated CRC-CCITT value.
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*/
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extern uint16_t crc_ccitt(uint16_t crc, const void *buf, size_t len);
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EXTERN_C_END
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#endif /* ALGO_CRC_CCITT_H */
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