bd75219ba0
Add the simplest possible CRC 16 function that computes the CRC value without the help of lookup tables. Change-Id: I9163389adaa4a70c4e8ce8ce6d5f0661f40c7871 Signed-off-by: Patrik Flykt <patrik.flykt@intel.com>
67 lines
1.6 KiB
C
67 lines
1.6 KiB
C
/*
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* Copyright (c) 2017 Intel Corporation.
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*
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* SPDX-License-Identifier: Apache-2.0
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*/
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/** @file
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* @brief CRC 16 computation function
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*/
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#ifndef __CRC16_H
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#define __CRC16_H
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#include <stdint.h>
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#include <stddef.h>
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/**
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* @brief Generic function for computing CRC 16
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*
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* Compute CRC 16 by passing in the address of the input, the input length
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* and polynomial used in addition to the initial value.
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*
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* @param src Input bytes for the computation
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* @param len Length of the input in bytes
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* @param polynomial The polynomial to use omitting the leading x^16
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* coefficient
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* @param initial_value Initial value for the CRC computation
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*
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* @return The computed CRC16 value
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*/
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uint16_t crc16(const uint8_t *src, size_t len, uint16_t polynomial,
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uint16_t initial_value);
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/**
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* @brief Compute CCITT variant of CRC 16
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*
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* CCITT variant of CRC 16 is using 0x1021 as its polynomial with the initial
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* value set to 0xffff.
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*
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* @param src Input bytes for the computation
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* @param len Length of the input in bytes
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*
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* @return The computed CRC16 value
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*/
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static inline uint16_t crc16_ccitt(const uint8_t *src, size_t len)
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{
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return crc16(src, len, 0x1021, 0xffff);
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}
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/**
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* @brief Compute ANSI variant of CRC 16
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*
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* ANSI variant of CRC 16 is using 0x8005 as its polynomial with the initial
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* value set to 0xffff.
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*
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* @param src Input bytes for the computation
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* @param len Length of the input in bytes
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*
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* @return The computed CRC16 value
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*/
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static inline uint16_t crc16_ansi(const uint8_t *src, size_t len)
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{
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return crc16(src, len, 0x8005, 0xffff);
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}
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#endif
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