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node_modules/qrcode/lib/core/polynomial.js

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+const GF = require('./galois-field')
+
+/**
+ * Multiplies two polynomials inside Galois Field
+ *
+ * @param  {Uint8Array} p1 Polynomial
+ * @param  {Uint8Array} p2 Polynomial
+ * @return {Uint8Array}    Product of p1 and p2
+ */
+exports.mul = function mul (p1, p2) {
+  const coeff = new Uint8Array(p1.length + p2.length - 1)
+
+  for (let i = 0; i < p1.length; i++) {
+    for (let j = 0; j < p2.length; j++) {
+      coeff[i + j] ^= GF.mul(p1[i], p2[j])
+    }
+  }
+
+  return coeff
+}
+
+/**
+ * Calculate the remainder of polynomials division
+ *
+ * @param  {Uint8Array} divident Polynomial
+ * @param  {Uint8Array} divisor  Polynomial
+ * @return {Uint8Array}          Remainder
+ */
+exports.mod = function mod (divident, divisor) {
+  let result = new Uint8Array(divident)
+
+  while ((result.length - divisor.length) >= 0) {
+    const coeff = result[0]
+
+    for (let i = 0; i < divisor.length; i++) {
+      result[i] ^= GF.mul(divisor[i], coeff)
+    }
+
+    // remove all zeros from buffer head
+    let offset = 0
+    while (offset < result.length && result[offset] === 0) offset++
+    result = result.slice(offset)
+  }
+
+  return result
+}
+
+/**
+ * Generate an irreducible generator polynomial of specified degree
+ * (used by Reed-Solomon encoder)
+ *
+ * @param  {Number} degree Degree of the generator polynomial
+ * @return {Uint8Array}    Buffer containing polynomial coefficients
+ */
+exports.generateECPolynomial = function generateECPolynomial (degree) {
+  let poly = new Uint8Array([1])
+  for (let i = 0; i < degree; i++) {
+    poly = exports.mul(poly, new Uint8Array([1, GF.exp(i)]))
+  }
+
+  return poly
+}