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673 B

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