@zxing/library
Version:
TypeScript port of ZXing multi-format 1D/2D barcode image processing library.
129 lines (128 loc) • 5.91 kB
JavaScript
;
/*
* 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.
*/
Object.defineProperty(exports, "__esModule", { value: true });
// package com.google.zxing.pdf417.decoder;
// import com.google.zxing.common.detector.MathUtils;
var MathUtils_1 = require("../../common/detector/MathUtils");
// import com.google.zxing.pdf417.PDF417Common;
var PDF417Common_1 = require("../PDF417Common");
var Float_1 = require("../../util/Float");
/**
* @author Guenther Grau
* @author creatale GmbH (christoph.schulz@creatale.de)
*/
var PDF417CodewordDecoder = /** @class */ (function () {
function PDF417CodewordDecoder() {
}
/* @note
* this action have to be performed before first use of class
* - static constructor
* working with 32bit float (based from Java logic)
*/
PDF417CodewordDecoder.initialize = function () {
// Pre-computes the symbol ratio table.
for ( /*int*/var i = 0; i < PDF417Common_1.default.SYMBOL_TABLE.length; i++) {
var currentSymbol = PDF417Common_1.default.SYMBOL_TABLE[i];
var currentBit = currentSymbol & 0x1;
for ( /*int*/var j = 0; j < PDF417Common_1.default.BARS_IN_MODULE; j++) {
var 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_1.default.BARS_IN_MODULE);
}
PDF417CodewordDecoder.RATIOS_TABLE[i][PDF417Common_1.default.BARS_IN_MODULE - j - 1] = Math.fround(size / PDF417Common_1.default.MODULES_IN_CODEWORD);
}
}
this.bSymbolTableReady = true;
};
PDF417CodewordDecoder.getDecodedValue = function (moduleBitCount) {
var decodedValue = PDF417CodewordDecoder.getDecodedCodewordValue(PDF417CodewordDecoder.sampleBitCounts(moduleBitCount));
if (decodedValue !== -1) {
return decodedValue;
}
return PDF417CodewordDecoder.getClosestDecodedValue(moduleBitCount);
};
PDF417CodewordDecoder.sampleBitCounts = function (moduleBitCount) {
var bitCountSum = MathUtils_1.default.sum(moduleBitCount);
var result = new Int32Array(PDF417Common_1.default.BARS_IN_MODULE);
var bitCountIndex = 0;
var sumPreviousBits = 0;
for ( /*int*/var i = 0; i < PDF417Common_1.default.MODULES_IN_CODEWORD; i++) {
var sampleIndex = bitCountSum / (2 * PDF417Common_1.default.MODULES_IN_CODEWORD) +
(i * bitCountSum) / PDF417Common_1.default.MODULES_IN_CODEWORD;
if (sumPreviousBits + moduleBitCount[bitCountIndex] <= sampleIndex) {
sumPreviousBits += moduleBitCount[bitCountIndex];
bitCountIndex++;
}
result[bitCountIndex]++;
}
return result;
};
PDF417CodewordDecoder.getDecodedCodewordValue = function (moduleBitCount) {
var decodedValue = PDF417CodewordDecoder.getBitValue(moduleBitCount);
return PDF417Common_1.default.getCodeword(decodedValue) === -1 ? -1 : decodedValue;
};
PDF417CodewordDecoder.getBitValue = function (moduleBitCount) {
var result = /*long*/ 0;
for (var /*int*/ i = 0; i < moduleBitCount.length; i++) {
for ( /*int*/var 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)
PDF417CodewordDecoder.getClosestDecodedValue = function (moduleBitCount) {
var bitCountSum = MathUtils_1.default.sum(moduleBitCount);
var bitCountRatios = new Array(PDF417Common_1.default.BARS_IN_MODULE);
if (bitCountSum > 1) {
for (var /*int*/ i = 0; i < bitCountRatios.length; i++) {
bitCountRatios[i] = Math.fround(moduleBitCount[i] / bitCountSum);
}
}
var bestMatchError = Float_1.default.MAX_VALUE;
var bestMatch = -1;
if (!this.bSymbolTableReady) {
PDF417CodewordDecoder.initialize();
}
for ( /*int*/var j = 0; j < PDF417CodewordDecoder.RATIOS_TABLE.length; j++) {
var error = 0.0;
var ratioTableRow = PDF417CodewordDecoder.RATIOS_TABLE[j];
for ( /*int*/var k = 0; k < PDF417Common_1.default.BARS_IN_MODULE; k++) {
var diff = Math.fround(ratioTableRow[k] - bitCountRatios[k]);
error += Math.fround(diff * diff);
if (error >= bestMatchError) {
break;
}
}
if (error < bestMatchError) {
bestMatchError = error;
bestMatch = PDF417Common_1.default.SYMBOL_TABLE[j];
}
}
return bestMatch;
};
// flag that the table is ready for use
PDF417CodewordDecoder.bSymbolTableReady = false;
PDF417CodewordDecoder.RATIOS_TABLE = new Array(PDF417Common_1.default.SYMBOL_TABLE.length).map(function (x) { return x = new Array(PDF417Common_1.default.BARS_IN_MODULE); });
return PDF417CodewordDecoder;
}());
exports.default = PDF417CodewordDecoder;