111 lines
3.7 KiB
C
111 lines
3.7 KiB
C
/* Copyright (c) 2002, 2003, 2004 Marek Michalkiewicz
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Copyright (c) 2005, 2007 Joerg Wunsch
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Copyright (c) 2013 Dave Hylands
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Copyright (c) 2013 Frederic Nadeau
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All rights reserved.
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Redistribution and use in source and binary forms, with or without
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modification, are permitted provided that the following conditions are met:
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* Redistributions of source code must retain the above copyright
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notice, this list of conditions and the following disclaimer.
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* Redistributions in binary form must reproduce the above copyright
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notice, this list of conditions and the following disclaimer in
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the documentation and/or other materials provided with the
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distribution.
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* Neither the name of the copyright holders nor the names of
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contributors may be used to endorse or promote products derived
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from this software without specific prior written permission.
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THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
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AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
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LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
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CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
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SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
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INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
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CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
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ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
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POSSIBILITY OF SUCH DAMAGE. */
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/* $Id: crc16.h 2398 2013-05-08 11:45:54Z joerg_wunsch $ */
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#ifndef _UTIL_CRC16_H_
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#define _UTIL_CRC16_H_
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/*
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This header file provides a optimized inline functions for calculating
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cyclic redundancy checks (CRC) using common polynomials.
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*/
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/*
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Optimized CRC-16 calculation.
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Polynomial: x^16 + x^15 + x^2 + 1 (0xa001)<br>
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Initial value: 0xffff
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This CRC is normally used in disk-drive controllers.
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*/
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uint16_t crc16_update(uint16_t crc, uint8_t a);
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/*
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Optimized CRC-XMODEM calculation.
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Polynomial: x^16 + x^12 + x^5 + 1 (0x1021)<br>
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Initial value: 0x0
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This is the CRC used by the Xmodem-CRC protocol.
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*/
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uint16_t crc_xmodem_update (uint16_t crc, uint8_t data);
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/*
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Optimized CRC-CCITT calculation.
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Polynomial: x^16 + x^12 + x^5 + 1 (0x8408)<br>
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Initial value: 0xffff
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This is the CRC used by PPP and IrDA.
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See RFC1171 (PPP protocol) and IrDA IrLAP 1.1
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\note Although the CCITT polynomial is the same as that used by the Xmodem
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protocol, they are quite different. The difference is in how the bits are
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shifted through the alorgithm. Xmodem shifts the MSB of the CRC and the
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input first, while CCITT shifts the LSB of the CRC and the input first.
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*/
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uint16_t crc_ccitt_update (uint16_t crc, uint8_t data);
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/*
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Optimized Dallas (now Maxim) iButton 8-bit CRC calculation.
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Polynomial: x^8 + x^5 + x^4 + 1 (0x8C)<br>
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Initial value: 0x0
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See http://www.maxim-ic.com/appnotes.cfm/appnote_number/27
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*/
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uint8_t _crc_ibutton_update(uint8_t crc, uint8_t data);
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/*
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Optimized CRC-8-CCITT calculation.
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Polynomial: x^8 + x^2 + x + 1 (0xE0)<br>
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For use with simple CRC-8<br>
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Initial value: 0x0
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For use with CRC-8-ROHC<br>
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Initial value: 0xff<br>
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Reference: http://tools.ietf.org/html/rfc3095#section-5.9.1
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For use with CRC-8-ATM/ITU<br>
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Initial value: 0xff<br>
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Final XOR value: 0x55<br>
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Reference: http://www.itu.int/rec/T-REC-I.432.1-199902-I/en
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*/
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uint8_t _crc8_ccitt_update (uint8_t inCrc, uint8_t inData);
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#endif /* _UTIL_CRC16_H_ */
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