Created
March 7, 2013 22:05
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A quick and dirty copy of a C routine for generating a CRC16-CCITT with an intial value of 0xFFFF in Javascript
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// Modified from http://automationwiki.com/index.php?title=CRC-16-CCITT | |
var crcTable = [0x0000, 0x1021, 0x2042, 0x3063, 0x4084, 0x50a5, | |
0x60c6, 0x70e7, 0x8108, 0x9129, 0xa14a, 0xb16b, | |
0xc18c, 0xd1ad, 0xe1ce, 0xf1ef, 0x1231, 0x0210, | |
0x3273, 0x2252, 0x52b5, 0x4294, 0x72f7, 0x62d6, | |
0x9339, 0x8318, 0xb37b, 0xa35a, 0xd3bd, 0xc39c, | |
0xf3ff, 0xe3de, 0x2462, 0x3443, 0x0420, 0x1401, | |
0x64e6, 0x74c7, 0x44a4, 0x5485, 0xa56a, 0xb54b, | |
0x8528, 0x9509, 0xe5ee, 0xf5cf, 0xc5ac, 0xd58d, | |
0x3653, 0x2672, 0x1611, 0x0630, 0x76d7, 0x66f6, | |
0x5695, 0x46b4, 0xb75b, 0xa77a, 0x9719, 0x8738, | |
0xf7df, 0xe7fe, 0xd79d, 0xc7bc, 0x48c4, 0x58e5, | |
0x6886, 0x78a7, 0x0840, 0x1861, 0x2802, 0x3823, | |
0xc9cc, 0xd9ed, 0xe98e, 0xf9af, 0x8948, 0x9969, | |
0xa90a, 0xb92b, 0x5af5, 0x4ad4, 0x7ab7, 0x6a96, | |
0x1a71, 0x0a50, 0x3a33, 0x2a12, 0xdbfd, 0xcbdc, | |
0xfbbf, 0xeb9e, 0x9b79, 0x8b58, 0xbb3b, 0xab1a, | |
0x6ca6, 0x7c87, 0x4ce4, 0x5cc5, 0x2c22, 0x3c03, | |
0x0c60, 0x1c41, 0xedae, 0xfd8f, 0xcdec, 0xddcd, | |
0xad2a, 0xbd0b, 0x8d68, 0x9d49, 0x7e97, 0x6eb6, | |
0x5ed5, 0x4ef4, 0x3e13, 0x2e32, 0x1e51, 0x0e70, | |
0xff9f, 0xefbe, 0xdfdd, 0xcffc, 0xbf1b, 0xaf3a, | |
0x9f59, 0x8f78, 0x9188, 0x81a9, 0xb1ca, 0xa1eb, | |
0xd10c, 0xc12d, 0xf14e, 0xe16f, 0x1080, 0x00a1, | |
0x30c2, 0x20e3, 0x5004, 0x4025, 0x7046, 0x6067, | |
0x83b9, 0x9398, 0xa3fb, 0xb3da, 0xc33d, 0xd31c, | |
0xe37f, 0xf35e, 0x02b1, 0x1290, 0x22f3, 0x32d2, | |
0x4235, 0x5214, 0x6277, 0x7256, 0xb5ea, 0xa5cb, | |
0x95a8, 0x8589, 0xf56e, 0xe54f, 0xd52c, 0xc50d, | |
0x34e2, 0x24c3, 0x14a0, 0x0481, 0x7466, 0x6447, | |
0x5424, 0x4405, 0xa7db, 0xb7fa, 0x8799, 0x97b8, | |
0xe75f, 0xf77e, 0xc71d, 0xd73c, 0x26d3, 0x36f2, | |
0x0691, 0x16b0, 0x6657, 0x7676, 0x4615, 0x5634, | |
0xd94c, 0xc96d, 0xf90e, 0xe92f, 0x99c8, 0x89e9, | |
0xb98a, 0xa9ab, 0x5844, 0x4865, 0x7806, 0x6827, | |
0x18c0, 0x08e1, 0x3882, 0x28a3, 0xcb7d, 0xdb5c, | |
0xeb3f, 0xfb1e, 0x8bf9, 0x9bd8, 0xabbb, 0xbb9a, | |
0x4a75, 0x5a54, 0x6a37, 0x7a16, 0x0af1, 0x1ad0, | |
0x2ab3, 0x3a92, 0xfd2e, 0xed0f, 0xdd6c, 0xcd4d, | |
0xbdaa, 0xad8b, 0x9de8, 0x8dc9, 0x7c26, 0x6c07, | |
0x5c64, 0x4c45, 0x3ca2, 0x2c83, 0x1ce0, 0x0cc1, | |
0xef1f, 0xff3e, 0xcf5d, 0xdf7c, 0xaf9b, 0xbfba, | |
0x8fd9, 0x9ff8, 0x6e17, 0x7e36, 0x4e55, 0x5e74, | |
0x2e93, 0x3eb2, 0x0ed1, 0x1ef0]; | |
function crc16(s) { | |
var crc = 0xFFFF; | |
var j, i; | |
for (i = 0; i < s.length; i++) { | |
c = s.charCodeAt(i); | |
if (c > 255) { | |
throw new RangeError(); | |
} | |
j = (c ^ (crc >> 8)) & 0xFF; | |
crc = crcTable[j] ^ (crc << 8); | |
} | |
return ((crc ^ 0) & 0xFFFF); | |
} | |
document.write("CRC16 of test is 0x" + crc16('test').toString(16) + "<br>"); |
If you need to pass hex (as i do )
function crc16Hex(...s) {
var crc = 0x1D0F;
var j, i;
for (let c of s) {
if (c > 255) {
throw new RangeError();
}
j = (c ^ (crc >> 8)) & 0xFF;
crc = crcTable[j] ^ (crc << 8);
}
return ((crc ^ 0) & 0xFFFF).toString(16);
}
this works, too, with no lookup table, for buffers & strings:
export const crc16ccitt = (regInit, message) => {
if (typeof message === 'undefined') {
message = regInit
regInit = 0xFFFF
}
if (typeof message === 'string') {
message = message.split('').map(c => c.charCodeAt(0))
}
let crc = regInit + 0
const polynomial = 0x1021
for (const b of message) {
for (let i = 0; i < 8; i++) {
const bit = ((b >> (7 - i) & 1) === 1)
const c15 = ((crc >> 15 & 1) === 1)
crc <<= 1
if (c15 ^ bit) crc ^= polynomial
}
}
crc &= 0xffff
return crc
}
code run success and correct, thank you.
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Thanks, working well!
In case of CRC-16/AUG-CCITT initial value should be
var crc = 0x1d0f;
// CCITT-FALSE
// var crc = 0xFFFF;
// https://crates.io/crates/crc16