45 lines
855 B
JavaScript
45 lines
855 B
JavaScript
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'use strict';
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var crcTable = [];
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(function() {
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for (var i = 0; i < 256; i++) {
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var currentCrc = i;
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for (var j = 0; j < 8; j++) {
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if (currentCrc & 1) {
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currentCrc = 0xedb88320 ^ (currentCrc >>> 1);
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}
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else {
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currentCrc = currentCrc >>> 1;
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}
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}
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crcTable[i] = currentCrc;
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}
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}());
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var CrcCalculator = module.exports = function() {
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this._crc = -1;
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};
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CrcCalculator.prototype.write = function(data) {
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for (var i = 0; i < data.length; i++) {
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this._crc = crcTable[(this._crc ^ data[i]) & 0xff] ^ (this._crc >>> 8);
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}
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return true;
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};
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CrcCalculator.prototype.crc32 = function() {
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return this._crc ^ -1;
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};
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CrcCalculator.crc32 = function(buf) {
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var crc = -1;
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for (var i = 0; i < buf.length; i++) {
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crc = crcTable[(crc ^ buf[i]) & 0xff] ^ (crc >>> 8);
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}
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return crc ^ -1;
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};
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