/*
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* Copyright 2012 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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// package com.google.zxing.pdf417.decoder.ec;
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import IllegalArgumentException from '../../../IllegalArgumentException';
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import System from '../../../util/System';
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import StringBuilder from '../../../util/StringBuilder';
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/**
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* @author Sean Owen
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* @see com.google.zxing.common.reedsolomon.GenericGFPoly
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*/
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export default /*final*/ class ModulusPoly {
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constructor(field, coefficients) {
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if (coefficients.length === 0) {
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throw new IllegalArgumentException();
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}
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this.field = field;
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let coefficientsLength = /*int*/ coefficients.length;
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if (coefficientsLength > 1 && coefficients[0] === 0) {
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// Leading term must be non-zero for anything except the constant polynomial "0"
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let firstNonZero = /*int*/ 1;
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while (firstNonZero < coefficientsLength && coefficients[firstNonZero] === 0) {
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firstNonZero++;
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}
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if (firstNonZero === coefficientsLength) {
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this.coefficients = new Int32Array([0]);
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}
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else {
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this.coefficients = new Int32Array(coefficientsLength - firstNonZero);
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System.arraycopy(coefficients, firstNonZero, this.coefficients, 0, this.coefficients.length);
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}
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}
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else {
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this.coefficients = coefficients;
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}
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}
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getCoefficients() {
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return this.coefficients;
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}
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/**
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* @return degree of this polynomial
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*/
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getDegree() {
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return this.coefficients.length - 1;
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}
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/**
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* @return true iff this polynomial is the monomial "0"
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*/
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isZero() {
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return this.coefficients[0] === 0;
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}
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/**
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* @return coefficient of x^degree term in this polynomial
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*/
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getCoefficient(degree) {
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return this.coefficients[this.coefficients.length - 1 - degree];
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}
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/**
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* @return evaluation of this polynomial at a given point
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*/
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evaluateAt(a) {
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if (a === 0) {
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// Just return the x^0 coefficient
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return this.getCoefficient(0);
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}
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if (a === 1) {
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// Just the sum of the coefficients
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let sum = /*int*/ 0;
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for (let coefficient /*int*/ of this.coefficients) {
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sum = this.field.add(sum, coefficient);
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}
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return sum;
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}
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let result = /*int*/ this.coefficients[0];
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let size = /*int*/ this.coefficients.length;
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for (let i /*int*/ = 1; i < size; i++) {
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result = this.field.add(this.field.multiply(a, result), this.coefficients[i]);
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}
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return result;
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}
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add(other) {
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if (!this.field.equals(other.field)) {
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throw new IllegalArgumentException('ModulusPolys do not have same ModulusGF field');
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}
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if (this.isZero()) {
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return other;
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}
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if (other.isZero()) {
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return this;
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}
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let smallerCoefficients = this.coefficients;
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let largerCoefficients = other.coefficients;
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if (smallerCoefficients.length > largerCoefficients.length) {
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let temp = smallerCoefficients;
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smallerCoefficients = largerCoefficients;
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largerCoefficients = temp;
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}
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let sumDiff = new Int32Array(largerCoefficients.length);
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let lengthDiff = /*int*/ largerCoefficients.length - smallerCoefficients.length;
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// Copy high-order terms only found in higher-degree polynomial's coefficients
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System.arraycopy(largerCoefficients, 0, sumDiff, 0, lengthDiff);
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for (let i /*int*/ = lengthDiff; i < largerCoefficients.length; i++) {
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sumDiff[i] = this.field.add(smallerCoefficients[i - lengthDiff], largerCoefficients[i]);
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}
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return new ModulusPoly(this.field, sumDiff);
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}
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subtract(other) {
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if (!this.field.equals(other.field)) {
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throw new IllegalArgumentException('ModulusPolys do not have same ModulusGF field');
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}
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if (other.isZero()) {
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return this;
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}
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return this.add(other.negative());
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}
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multiply(other) {
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if (other instanceof ModulusPoly) {
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return this.multiplyOther(other);
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}
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return this.multiplyScalar(other);
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}
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multiplyOther(other) {
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if (!this.field.equals(other.field)) {
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throw new IllegalArgumentException('ModulusPolys do not have same ModulusGF field');
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}
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if (this.isZero() || other.isZero()) {
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// return this.field.getZero();
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return new ModulusPoly(this.field, new Int32Array([0]));
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}
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let aCoefficients = this.coefficients;
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let aLength = /*int*/ aCoefficients.length;
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let bCoefficients = other.coefficients;
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let bLength = /*int*/ bCoefficients.length;
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let product = new Int32Array(aLength + bLength - 1);
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for (let i /*int*/ = 0; i < aLength; i++) {
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let aCoeff = /*int*/ aCoefficients[i];
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for (let j /*int*/ = 0; j < bLength; j++) {
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product[i + j] = this.field.add(product[i + j], this.field.multiply(aCoeff, bCoefficients[j]));
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}
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}
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return new ModulusPoly(this.field, product);
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}
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negative() {
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let size = /*int*/ this.coefficients.length;
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let negativeCoefficients = new Int32Array(size);
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for (let i /*int*/ = 0; i < size; i++) {
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negativeCoefficients[i] = this.field.subtract(0, this.coefficients[i]);
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}
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return new ModulusPoly(this.field, negativeCoefficients);
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}
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multiplyScalar(scalar) {
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if (scalar === 0) {
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return new ModulusPoly(this.field, new Int32Array([0]));
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}
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if (scalar === 1) {
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return this;
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}
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let size = /*int*/ this.coefficients.length;
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let product = new Int32Array(size);
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for (let i /*int*/ = 0; i < size; i++) {
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product[i] = this.field.multiply(this.coefficients[i], scalar);
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}
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return new ModulusPoly(this.field, product);
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}
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multiplyByMonomial(degree, coefficient) {
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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 new ModulusPoly(this.field, new Int32Array([0]));
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}
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let size = /*int*/ this.coefficients.length;
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let product = new Int32Array(size + degree);
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for (let i /*int*/ = 0; i < size; i++) {
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product[i] = this.field.multiply(this.coefficients[i], coefficient);
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}
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return new ModulusPoly(this.field, product);
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}
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/*
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ModulusPoly[] divide(other: ModulusPoly) {
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if (!field.equals(other.field)) {
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throw new IllegalArgumentException("ModulusPolys do not have same ModulusGF field");
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}
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if (other.isZero()) {
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throw new IllegalArgumentException("Divide by 0");
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}
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let quotient: ModulusPoly = field.getZero();
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let remainder: ModulusPoly = this;
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let denominatorLeadingTerm: /*int/ number = other.getCoefficient(other.getDegree());
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let inverseDenominatorLeadingTerm: /*int/ number = field.inverse(denominatorLeadingTerm);
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while (remainder.getDegree() >= other.getDegree() && !remainder.isZero()) {
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let degreeDifference: /*int/ number = remainder.getDegree() - other.getDegree();
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let scale: /*int/ number = field.multiply(remainder.getCoefficient(remainder.getDegree()), inverseDenominatorLeadingTerm);
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let term: ModulusPoly = other.multiplyByMonomial(degreeDifference, scale);
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let iterationQuotient: ModulusPoly = field.buildMonomial(degreeDifference, scale);
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quotient = quotient.add(iterationQuotient);
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remainder = remainder.subtract(term);
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}
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return new ModulusPoly[] { quotient, remainder };
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}
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*/
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// @Override
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toString() {
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let result = new StringBuilder( /*8 * this.getDegree()*/); // dynamic string size in JS
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for (let degree /*int*/ = this.getDegree(); degree >= 0; degree--) {
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let coefficient = /*int*/ this.getCoefficient(degree);
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if (coefficient !== 0) {
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if (coefficient < 0) {
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result.append(' - ');
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coefficient = -coefficient;
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}
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else {
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if (result.length() > 0) {
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result.append(' + ');
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}
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}
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if (degree === 0 || coefficient !== 1) {
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result.append(coefficient);
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}
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if (degree !== 0) {
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if (degree === 1) {
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result.append('x');
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}
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else {
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result.append('x^');
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result.append(degree);
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}
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}
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}
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}
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return result.toString();
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}
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}
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