forked from mohr/ArduinoIO
141 lines
4.4 KiB
C++
141 lines
4.4 KiB
C++
#include "crc_ccitt.h"
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#include <math.h>
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static const uint16_t crc_table[256] = {
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0x0000, 0x1021, 0x2042, 0x3063, 0x4084, 0x50a5, 0x60c6, 0x70e7,
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0x8108, 0x9129, 0xa14a, 0xb16b, 0xc18c, 0xd1ad, 0xe1ce, 0xf1ef,
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0x1231, 0x0210, 0x3273, 0x2252, 0x52b5, 0x4294, 0x72f7, 0x62d6,
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0x9339, 0x8318, 0xb37b, 0xa35a, 0xd3bd, 0xc39c, 0xf3ff, 0xe3de,
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0x2462, 0x3443, 0x0420, 0x1401, 0x64e6, 0x74c7, 0x44a4, 0x5485,
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0xa56a, 0xb54b, 0x8528, 0x9509, 0xe5ee, 0xf5cf, 0xc5ac, 0xd58d,
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0x3653, 0x2672, 0x1611, 0x0630, 0x76d7, 0x66f6, 0x5695, 0x46b4,
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0xb75b, 0xa77a, 0x9719, 0x8738, 0xf7df, 0xe7fe, 0xd79d, 0xc7bc,
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0x48c4, 0x58e5, 0x6886, 0x78a7, 0x0840, 0x1861, 0x2802, 0x3823,
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0xc9cc, 0xd9ed, 0xe98e, 0xf9af, 0x8948, 0x9969, 0xa90a, 0xb92b,
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0x5af5, 0x4ad4, 0x7ab7, 0x6a96, 0x1a71, 0x0a50, 0x3a33, 0x2a12,
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0xdbfd, 0xcbdc, 0xfbbf, 0xeb9e, 0x9b79, 0x8b58, 0xbb3b, 0xab1a,
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0x6ca6, 0x7c87, 0x4ce4, 0x5cc5, 0x2c22, 0x3c03, 0x0c60, 0x1c41,
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0xedae, 0xfd8f, 0xcdec, 0xddcd, 0xad2a, 0xbd0b, 0x8d68, 0x9d49,
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0x7e97, 0x6eb6, 0x5ed5, 0x4ef4, 0x3e13, 0x2e32, 0x1e51, 0x0e70,
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0xff9f, 0xefbe, 0xdfdd, 0xcffc, 0xbf1b, 0xaf3a, 0x9f59, 0x8f78,
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0x9188, 0x81a9, 0xb1ca, 0xa1eb, 0xd10c, 0xc12d, 0xf14e, 0xe16f,
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0x1080, 0x00a1, 0x30c2, 0x20e3, 0x5004, 0x4025, 0x7046, 0x6067,
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0x83b9, 0x9398, 0xa3fb, 0xb3da, 0xc33d, 0xd31c, 0xe37f, 0xf35e,
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0x02b1, 0x1290, 0x22f3, 0x32d2, 0x4235, 0x5214, 0x6277, 0x7256,
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0xb5ea, 0xa5cb, 0x95a8, 0x8589, 0xf56e, 0xe54f, 0xd52c, 0xc50d,
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0x34e2, 0x24c3, 0x14a0, 0x0481, 0x7466, 0x6447, 0x5424, 0x4405,
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0xa7db, 0xb7fa, 0x8799, 0x97b8, 0xe75f, 0xf77e, 0xc71d, 0xd73c,
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0x26d3, 0x36f2, 0x0691, 0x16b0, 0x6657, 0x7676, 0x4615, 0x5634,
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0xd94c, 0xc96d, 0xf90e, 0xe92f, 0x99c8, 0x89e9, 0xb98a, 0xa9ab,
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0x5844, 0x4865, 0x7806, 0x6827, 0x18c0, 0x08e1, 0x3882, 0x28a3,
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0xcb7d, 0xdb5c, 0xeb3f, 0xfb1e, 0x8bf9, 0x9bd8, 0xabbb, 0xbb9a,
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0x4a75, 0x5a54, 0x6a37, 0x7a16, 0x0af1, 0x1ad0, 0x2ab3, 0x3a92,
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0xfd2e, 0xed0f, 0xdd6c, 0xcd4d, 0xbdaa, 0xad8b, 0x9de8, 0x8dc9,
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0x7c26, 0x6c07, 0x5c64, 0x4c45, 0x3ca2, 0x2c83, 0x1ce0, 0x0cc1,
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0xef1f, 0xff3e, 0xcf5d, 0xdf7c, 0xaf9b, 0xbfba, 0x8fd9, 0x9ff8,
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0x6e17, 0x7e36, 0x4e55, 0x5e74, 0x2e93, 0x3eb2, 0x0ed1, 0x1ef0
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};
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// CRC implementation
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uint16_t Calculate_CRC(uint8_t const input[], uint32_t length)
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{
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uint16_t crc = 0xFFFF;
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uint8_t *data = (uint8_t *)input;
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unsigned int tbl_idx;
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while (length--) {
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tbl_idx = ((crc >> 8) ^ *data) & 0xff;
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crc = (crc_table[tbl_idx] ^ (crc << 8)) & 0xffff;
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data++;
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}
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return crc & 0xffff;
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//The part below is not used!
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// bool temr[16];
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// bool xor_out[16];
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// bool r[16];
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// bool d[8];
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// uint16_t crc_value = 0;
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//
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//
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// for (int i=0; i<16 ;i++) {
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// temr[i] = false;
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// xor_out[i] = false;
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// }
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//
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//
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// for (int i=0; i<16 ;i++)
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// r[i] = true; // initialize with 0xFFFF
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//
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//
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//
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// for (int j=0; j<length ;j++)
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// {
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//
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// for (int i=0; i<8 ;i++)
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// if ((input[j] & 1<<i) == 1<<i)
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// d[7-i]=true; // reverse input data
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// else
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// d[7-i]=false; // reverse input data
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//
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//
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//
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// temr[0] = d[4] ^ d[0];
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// temr[1] = d[5] ^ d[1];
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// temr[2] = d[6] ^ d[2];
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// temr[3] = d[7] ^ d[3];
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// temr[4] = r[12] ^ r[8];
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// temr[5] = r[13] ^ r[9];
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// temr[6] = r[14] ^ r[10];
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// temr[7] = r[15] ^ r[11];
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// temr[8] = d[4] ^ r[12];
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// temr[9] = d[5] ^ r[13];
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// temr[10] = d[6] ^ r[14];
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// temr[11] = d[7] ^ r[15];
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// temr[12] = temr[0] ^ temr[4];
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// temr[13] = temr[1] ^ temr[5];
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// temr[14] = temr[2] ^ temr[6];
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// temr[15] = temr[3] ^ temr[7];
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//
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//
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// xor_out[0] = temr[12];
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// xor_out[1] = temr[13];
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// xor_out[2] = temr[14];
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// xor_out[3] = temr[15];
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// xor_out[4] = temr[8];
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// xor_out[5] = temr[9] ^ temr[12];
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// xor_out[6] = temr[10] ^ temr[13];
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// xor_out[7] = temr[11] ^ temr[14];
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// xor_out[8] = temr[15] ^ r[0];
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// xor_out[9] = temr[8] ^ r[1];
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// xor_out[10] = temr[9] ^ r[2];
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// xor_out[11] = temr[10] ^ r[3];
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// xor_out[12] = temr[11] ^ temr[12] ^ r[4];
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// xor_out[13] = temr[13] ^ r[5];
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// xor_out[14] = temr[14] ^ r[6];
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// xor_out[15] = temr[15] ^ r[7];
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//
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// for (int i=0; i<16 ;i++)
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// {
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// r[i]= xor_out[i] ;
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// }
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//
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// }
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//
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//
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//
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// for (int i=0; i<16 ;i++)
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// {
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// if (xor_out[i] == true)
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// crc_value = crc_value + pow(2,(15 -i)); // reverse CrC result before Final XOR
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// }
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//
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// crc_value = 0;// for debug mode
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// return (crc_value);
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} /* Calculate_CRC() */
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