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45 lines
673 B
45 lines
673 B
2 years ago
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var QRMath = {
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glog : function(n) {
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if (n < 1) {
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throw new Error("glog(" + n + ")");
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}
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return QRMath.LOG_TABLE[n];
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},
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gexp : function(n) {
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while (n < 0) {
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n += 255;
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}
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while (n >= 256) {
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n -= 255;
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}
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return QRMath.EXP_TABLE[n];
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},
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EXP_TABLE : new Array(256),
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LOG_TABLE : new Array(256)
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};
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for (var i = 0; i < 8; i++) {
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QRMath.EXP_TABLE[i] = 1 << i;
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}
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for (var i = 8; i < 256; i++) {
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QRMath.EXP_TABLE[i] = QRMath.EXP_TABLE[i - 4]
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^ QRMath.EXP_TABLE[i - 5]
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^ QRMath.EXP_TABLE[i - 6]
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^ QRMath.EXP_TABLE[i - 8];
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}
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for (var i = 0; i < 255; i++) {
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QRMath.LOG_TABLE[QRMath.EXP_TABLE[i] ] = i;
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}
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module.exports = QRMath;
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