#include "crc.h"
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uint16_t ComputeCrc( uint16_t crc, uint8_t dataByte, uint16_t polynomial )
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{
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uint8_t i;
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for( i = 0; i < 8; i++ )
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{
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if( ( ( ( crc & 0x8000 ) >> 8 ) ^ ( dataByte & 0x80 ) ) != 0 )
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{
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crc <<= 1; // shift left once
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crc ^= polynomial; // XOR with polynomial
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}
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else
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{
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crc <<= 1; // shift left once
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}
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dataByte <<= 1; // Next data bit
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}
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return crc;
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}
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uint16_t RadioComputeCRC( uint8_t *buffer, uint8_t length, uint8_t crcType )
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{
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uint8_t i = 0;
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uint16_t crc = 0;
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uint16_t polynomial = 0;
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polynomial = ( crcType == CRC_TYPE_IBM ) ? POLYNOMIAL_IBM : POLYNOMIAL_CCITT;
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crc = ( crcType == CRC_TYPE_IBM ) ? CRC_IBM_SEED : CRC_CCITT_SEED;
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for( i = 0; i < length; i++ )
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{
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crc = ComputeCrc( crc, buffer[i], polynomial );
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}
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if( crcType == CRC_TYPE_IBM )
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{
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return crc;
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}
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else
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{
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return( ( uint16_t ) ( ~crc ));
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}
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}
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