/* * Copyright 2013 ZXing authors * * Licensed under the Apache License, Version 2.0 (the "License"); * you may not use this file except in compliance with the License. * You may obtain a copy of the License at * * http://www.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, software * distributed under the License is distributed on an "AS IS" BASIS, * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. * See the License for the specific language governing permissions and * limitations under the License. */ // package com.google.zxing.pdf417.decoder; // import com.google.zxing.common.detector.MathUtils; import MathUtils from '../../common/detector/MathUtils'; // import com.google.zxing.pdf417.PDF417Common; import PDF417Common from '../PDF417Common'; import Float from '../../util/Float'; /** * @author Guenther Grau * @author creatale GmbH (christoph.schulz@creatale.de) */ export default /*final*/ class PDF417CodewordDecoder { /* @note * this action have to be performed before first use of class * - static constructor * working with 32bit float (based from Java logic) */ static initialize() { // Pre-computes the symbol ratio table. for ( /*int*/let i = 0; i < PDF417Common.SYMBOL_TABLE.length; i++) { let currentSymbol = PDF417Common.SYMBOL_TABLE[i]; let currentBit = currentSymbol & 0x1; for ( /*int*/let j = 0; j < PDF417Common.BARS_IN_MODULE; j++) { let size = 0.0; while ((currentSymbol & 0x1) === currentBit) { size += 1.0; currentSymbol >>= 1; } currentBit = currentSymbol & 0x1; if (!PDF417CodewordDecoder.RATIOS_TABLE[i]) { PDF417CodewordDecoder.RATIOS_TABLE[i] = new Array(PDF417Common.BARS_IN_MODULE); } PDF417CodewordDecoder.RATIOS_TABLE[i][PDF417Common.BARS_IN_MODULE - j - 1] = Math.fround(size / PDF417Common.MODULES_IN_CODEWORD); } } this.bSymbolTableReady = true; } static getDecodedValue(moduleBitCount) { let decodedValue = PDF417CodewordDecoder.getDecodedCodewordValue(PDF417CodewordDecoder.sampleBitCounts(moduleBitCount)); if (decodedValue !== -1) { return decodedValue; } return PDF417CodewordDecoder.getClosestDecodedValue(moduleBitCount); } static sampleBitCounts(moduleBitCount) { let bitCountSum = MathUtils.sum(moduleBitCount); let result = new Int32Array(PDF417Common.BARS_IN_MODULE); let bitCountIndex = 0; let sumPreviousBits = 0; for ( /*int*/let i = 0; i < PDF417Common.MODULES_IN_CODEWORD; i++) { let sampleIndex = bitCountSum / (2 * PDF417Common.MODULES_IN_CODEWORD) + (i * bitCountSum) / PDF417Common.MODULES_IN_CODEWORD; if (sumPreviousBits + moduleBitCount[bitCountIndex] <= sampleIndex) { sumPreviousBits += moduleBitCount[bitCountIndex]; bitCountIndex++; } result[bitCountIndex]++; } return result; } static getDecodedCodewordValue(moduleBitCount) { let decodedValue = PDF417CodewordDecoder.getBitValue(moduleBitCount); return PDF417Common.getCodeword(decodedValue) === -1 ? -1 : decodedValue; } static getBitValue(moduleBitCount) { let result = /*long*/ 0; for (let /*int*/ i = 0; i < moduleBitCount.length; i++) { for ( /*int*/let bit = 0; bit < moduleBitCount[i]; bit++) { result = (result << 1) | (i % 2 === 0 ? 1 : 0); } } return Math.trunc(result); } // working with 32bit float (as in Java) static getClosestDecodedValue(moduleBitCount) { let bitCountSum = MathUtils.sum(moduleBitCount); let bitCountRatios = new Array(PDF417Common.BARS_IN_MODULE); if (bitCountSum > 1) { for (let /*int*/ i = 0; i < bitCountRatios.length; i++) { bitCountRatios[i] = Math.fround(moduleBitCount[i] / bitCountSum); } } let bestMatchError = Float.MAX_VALUE; let bestMatch = -1; if (!this.bSymbolTableReady) { PDF417CodewordDecoder.initialize(); } for ( /*int*/let j = 0; j < PDF417CodewordDecoder.RATIOS_TABLE.length; j++) { let error = 0.0; let ratioTableRow = PDF417CodewordDecoder.RATIOS_TABLE[j]; for ( /*int*/let k = 0; k < PDF417Common.BARS_IN_MODULE; k++) { let diff = Math.fround(ratioTableRow[k] - bitCountRatios[k]); error += Math.fround(diff * diff); if (error >= bestMatchError) { break; } } if (error < bestMatchError) { bestMatchError = error; bestMatch = PDF417Common.SYMBOL_TABLE[j]; } } return bestMatch; } } // flag that the table is ready for use PDF417CodewordDecoder.bSymbolTableReady = false; PDF417CodewordDecoder.RATIOS_TABLE = new Array(PDF417Common.SYMBOL_TABLE.length).map(x => x = new Array(PDF417Common.BARS_IN_MODULE));