/*
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* Copyright 2007 ZXing authors
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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/*namespace com.google.zxing.common.reedsolomon {*/
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import GenericGFPoly from './GenericGFPoly';
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import AbstractGenericGF from './AbstractGenericGF';
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import Integer from '../../util/Integer';
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import IllegalArgumentException from '../../IllegalArgumentException';
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import ArithmeticException from '../../ArithmeticException';
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/**
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* <p>This class contains utility methods for performing mathematical operations over
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* the Galois Fields. Operations use a given primitive polynomial in calculations.</p>
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*
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* <p>Throughout this package, elements of the GF are represented as an {@code int}
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* for convenience and speed (but at the cost of memory).
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* </p>
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*
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* @author Sean Owen
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* @author David Olivier
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*/
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export default class GenericGF extends AbstractGenericGF {
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/**
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* Create a representation of GF(size) using the given primitive polynomial.
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*
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* @param primitive irreducible polynomial whose coefficients are represented by
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* the bits of an int, where the least-significant bit represents the constant
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* coefficient
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* @param size the size of the field
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* @param b the factor b in the generator polynomial can be 0- or 1-based
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* (g(x) = (x+a^b)(x+a^(b+1))...(x+a^(b+2t-1))).
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* In most cases it should be 1, but for QR code it is 0.
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*/
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constructor(primitive /*int*/, size /*int*/, generatorBase /*int*/) {
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super();
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this.primitive = primitive;
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this.size = size;
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this.generatorBase = generatorBase;
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const expTable = new Int32Array(size);
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let x = 1;
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for (let i = 0; i < size; i++) {
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expTable[i] = x;
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x *= 2; // we're assuming the generator alpha is 2
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if (x >= size) {
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x ^= primitive;
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x &= size - 1;
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}
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}
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this.expTable = expTable;
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const logTable = new Int32Array(size);
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for (let i = 0; i < size - 1; i++) {
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logTable[expTable[i]] = i;
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}
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this.logTable = logTable;
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// logTable[0] == 0 but this should never be used
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this.zero = new GenericGFPoly(this, Int32Array.from([0]));
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this.one = new GenericGFPoly(this, Int32Array.from([1]));
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}
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getZero() {
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return this.zero;
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}
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getOne() {
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return this.one;
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}
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/**
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* @return the monomial representing coefficient * x^degree
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*/
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buildMonomial(degree /*int*/, coefficient /*int*/) {
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if (degree < 0) {
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throw new IllegalArgumentException();
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}
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if (coefficient === 0) {
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return this.zero;
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}
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const coefficients = new Int32Array(degree + 1);
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coefficients[0] = coefficient;
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return new GenericGFPoly(this, coefficients);
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}
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/**
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* @return multiplicative inverse of a
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*/
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inverse(a /*int*/) {
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if (a === 0) {
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throw new ArithmeticException();
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}
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return this.expTable[this.size - this.logTable[a] - 1];
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}
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/**
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* @return product of a and b in GF(size)
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*/
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multiply(a /*int*/, b /*int*/) {
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if (a === 0 || b === 0) {
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return 0;
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}
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return this.expTable[(this.logTable[a] + this.logTable[b]) % (this.size - 1)];
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}
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getSize() {
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return this.size;
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}
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getGeneratorBase() {
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return this.generatorBase;
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}
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/*@Override*/
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toString() {
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return ('GF(0x' + Integer.toHexString(this.primitive) + ',' + this.size + ')');
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}
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equals(o) {
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return o === this;
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}
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}
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GenericGF.AZTEC_DATA_12 = new GenericGF(0x1069, 4096, 1); // x^12 + x^6 + x^5 + x^3 + 1
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GenericGF.AZTEC_DATA_10 = new GenericGF(0x409, 1024, 1); // x^10 + x^3 + 1
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GenericGF.AZTEC_DATA_6 = new GenericGF(0x43, 64, 1); // x^6 + x + 1
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GenericGF.AZTEC_PARAM = new GenericGF(0x13, 16, 1); // x^4 + x + 1
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GenericGF.QR_CODE_FIELD_256 = new GenericGF(0x011d, 256, 0); // x^8 + x^4 + x^3 + x^2 + 1
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GenericGF.DATA_MATRIX_FIELD_256 = new GenericGF(0x012d, 256, 1); // x^8 + x^5 + x^3 + x^2 + 1
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GenericGF.AZTEC_DATA_8 = GenericGF.DATA_MATRIX_FIELD_256;
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GenericGF.MAXICODE_FIELD_64 = GenericGF.AZTEC_DATA_6;
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