67 lines
1.3 KiB
JavaScript
67 lines
1.3 KiB
JavaScript
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var QRMath = require('./QRMath');
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function QRPolynomial(num, shift) {
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if (num.length === undefined) {
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throw new Error(num.length + "/" + shift);
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}
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var offset = 0;
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while (offset < num.length && num[offset] === 0) {
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offset++;
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}
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this.num = new Array(num.length - offset + shift);
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for (var i = 0; i < num.length - offset; i++) {
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this.num[i] = num[i + offset];
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}
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}
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QRPolynomial.prototype = {
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get : function(index) {
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return this.num[index];
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},
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getLength : function() {
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return this.num.length;
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},
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multiply : function(e) {
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var num = new Array(this.getLength() + e.getLength() - 1);
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for (var i = 0; i < this.getLength(); i++) {
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for (var j = 0; j < e.getLength(); j++) {
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num[i + j] ^= QRMath.gexp(QRMath.glog(this.get(i) ) + QRMath.glog(e.get(j) ) );
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}
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}
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return new QRPolynomial(num, 0);
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},
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mod : function(e) {
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if (this.getLength() - e.getLength() < 0) {
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return this;
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}
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var ratio = QRMath.glog(this.get(0) ) - QRMath.glog(e.get(0) );
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var num = new Array(this.getLength() );
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for (var i = 0; i < this.getLength(); i++) {
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num[i] = this.get(i);
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}
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for (var x = 0; x < e.getLength(); x++) {
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num[x] ^= QRMath.gexp(QRMath.glog(e.get(x) ) + ratio);
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}
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// recursive call
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return new QRPolynomial(num, 0).mod(e);
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}
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};
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module.exports = QRPolynomial;
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