/*
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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.qrcode.decoder {*/
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import ChecksumException from '../../ChecksumException';
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import BitMatrix from '../../common/BitMatrix';
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import GenericGF from '../../common/reedsolomon/GenericGF';
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import ReedSolomonDecoder from '../../common/reedsolomon/ReedSolomonDecoder';
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import BitMatrixParser from './BitMatrixParser';
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import DataBlock from './DataBlock';
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import DecodedBitStreamParser from './DecodedBitStreamParser';
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import QRCodeDecoderMetaData from './QRCodeDecoderMetaData';
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/*import java.util.Map;*/
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/**
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* <p>The main class which implements QR Code decoding -- as opposed to locating and extracting
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* the QR Code from an image.</p>
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*
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* @author Sean Owen
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*/
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export default class Decoder {
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constructor() {
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this.rsDecoder = new ReedSolomonDecoder(GenericGF.QR_CODE_FIELD_256);
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}
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// public decode(image: boolean[][]): DecoderResult /*throws ChecksumException, FormatException*/ {
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// return decode(image, null)
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// }
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/**
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* <p>Convenience method that can decode a QR Code represented as a 2D array of booleans.
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* "true" is taken to mean a black module.</p>
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*
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* @param image booleans representing white/black QR Code modules
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* @param hints decoding hints that should be used to influence decoding
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* @return text and bytes encoded within the QR Code
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* @throws FormatException if the QR Code cannot be decoded
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* @throws ChecksumException if error correction fails
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*/
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decodeBooleanArray(image, hints) {
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return this.decodeBitMatrix(BitMatrix.parseFromBooleanArray(image), hints);
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}
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// public decodeBitMatrix(bits: BitMatrix): DecoderResult /*throws ChecksumException, FormatException*/ {
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// return decode(bits, null)
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// }
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/**
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* <p>Decodes a QR Code represented as a {@link BitMatrix}. A 1 or "true" is taken to mean a black module.</p>
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*
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* @param bits booleans representing white/black QR Code modules
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* @param hints decoding hints that should be used to influence decoding
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* @return text and bytes encoded within the QR Code
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* @throws FormatException if the QR Code cannot be decoded
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* @throws ChecksumException if error correction fails
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*/
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decodeBitMatrix(bits, hints) {
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// Construct a parser and read version, error-correction level
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const parser = new BitMatrixParser(bits);
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let ex = null;
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try {
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return this.decodeBitMatrixParser(parser, hints);
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}
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catch (e /*: FormatException, ChecksumException*/) {
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ex = e;
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}
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try {
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// Revert the bit matrix
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parser.remask();
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// Will be attempting a mirrored reading of the version and format info.
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parser.setMirror(true);
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// Preemptively read the version.
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parser.readVersion();
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// Preemptively read the format information.
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parser.readFormatInformation();
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/*
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* Since we're here, this means we have successfully detected some kind
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* of version and format information when mirrored. This is a good sign,
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* that the QR code may be mirrored, and we should try once more with a
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* mirrored content.
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*/
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// Prepare for a mirrored reading.
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parser.mirror();
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const result = this.decodeBitMatrixParser(parser, hints);
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// Success! Notify the caller that the code was mirrored.
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result.setOther(new QRCodeDecoderMetaData(true));
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return result;
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}
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catch (e /*FormatException | ChecksumException*/) {
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// Throw the exception from the original reading
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if (ex !== null) {
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throw ex;
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}
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throw e;
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}
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}
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decodeBitMatrixParser(parser, hints) {
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const version = parser.readVersion();
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const ecLevel = parser.readFormatInformation().getErrorCorrectionLevel();
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// Read codewords
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const codewords = parser.readCodewords();
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// Separate into data blocks
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const dataBlocks = DataBlock.getDataBlocks(codewords, version, ecLevel);
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// Count total number of data bytes
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let totalBytes = 0;
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for (const dataBlock of dataBlocks) {
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totalBytes += dataBlock.getNumDataCodewords();
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}
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const resultBytes = new Uint8Array(totalBytes);
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let resultOffset = 0;
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// Error-correct and copy data blocks together into a stream of bytes
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for (const dataBlock of dataBlocks) {
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const codewordBytes = dataBlock.getCodewords();
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const numDataCodewords = dataBlock.getNumDataCodewords();
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this.correctErrors(codewordBytes, numDataCodewords);
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for (let i = 0; i < numDataCodewords; i++) {
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resultBytes[resultOffset++] = codewordBytes[i];
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}
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}
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// Decode the contents of that stream of bytes
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return DecodedBitStreamParser.decode(resultBytes, version, ecLevel, hints);
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}
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/**
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* <p>Given data and error-correction codewords received, possibly corrupted by errors, attempts to
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* correct the errors in-place using Reed-Solomon error correction.</p>
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*
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* @param codewordBytes data and error correction codewords
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* @param numDataCodewords number of codewords that are data bytes
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* @throws ChecksumException if error correction fails
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*/
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correctErrors(codewordBytes, numDataCodewords /*int*/) {
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// const numCodewords = codewordBytes.length;
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// First read into an array of ints
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const codewordsInts = new Int32Array(codewordBytes);
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// TYPESCRIPTPORT: not realy necessary to transform to ints? could redesign everything to work with unsigned bytes?
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// const codewordsInts = new Int32Array(numCodewords)
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// for (let i = 0; i < numCodewords; i++) {
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// codewordsInts[i] = codewordBytes[i] & 0xFF
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// }
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try {
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this.rsDecoder.decode(codewordsInts, codewordBytes.length - numDataCodewords);
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}
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catch (ignored /*: ReedSolomonException*/) {
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throw new ChecksumException();
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}
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// Copy back into array of bytes -- only need to worry about the bytes that were data
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// We don't care about errors in the error-correction codewords
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for (let i = 0; i < numDataCodewords; i++) {
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codewordBytes[i] = /*(byte) */ codewordsInts[i];
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}
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}
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}
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