@zxing/library
Version:
TypeScript port of ZXing multi-format 1D/2D barcode image processing library.
124 lines (123 loc) • 5.52 kB
JavaScript
;
var __values = (this && this.__values) || function(o) {
var s = typeof Symbol === "function" && Symbol.iterator, m = s && o[s], i = 0;
if (m) return m.call(o);
if (o && typeof o.length === "number") return {
next: function () {
if (o && i >= o.length) o = void 0;
return { value: o && o[i++], done: !o };
}
};
throw new TypeError(s ? "Object is not iterable." : "Symbol.iterator is not defined.");
};
Object.defineProperty(exports, "__esModule", { value: true });
var ChecksumException_1 = require("../../ChecksumException");
var GenericGF_1 = require("../../common/reedsolomon/GenericGF");
var ReedSolomonDecoder_1 = require("../../common/reedsolomon/ReedSolomonDecoder");
var BitMatrixParser_1 = require("./BitMatrixParser");
var DataBlock_1 = require("./DataBlock");
var DecodedBitStreamParser_1 = require("./DecodedBitStreamParser");
/*
* Copyright 2007 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.
*/
/**
* <p>The main class which implements Data Matrix Code decoding -- as opposed to locating and extracting
* the Data Matrix Code from an image.</p>
*
* @author bbrown@google.com (Brian Brown)
*/
var Decoder = /** @class */ (function () {
function Decoder() {
this.rsDecoder = new ReedSolomonDecoder_1.default(GenericGF_1.default.DATA_MATRIX_FIELD_256);
}
/**
* <p>Decodes a Data Matrix Code represented as a {@link BitMatrix}. A 1 or "true" is taken
* to mean a black module.</p>
*
* @param bits booleans representing white/black Data Matrix Code modules
* @return text and bytes encoded within the Data Matrix Code
* @throws FormatException if the Data Matrix Code cannot be decoded
* @throws ChecksumException if error correction fails
*/
Decoder.prototype.decode = function (bits) {
var e_1, _a;
// Construct a parser and read version, error-correction level
var parser = new BitMatrixParser_1.default(bits);
var version = parser.getVersion();
// Read codewords
var codewords = parser.readCodewords();
// Separate into data blocks
var dataBlocks = DataBlock_1.default.getDataBlocks(codewords, version);
// Count total number of data bytes
var totalBytes = 0;
try {
for (var dataBlocks_1 = __values(dataBlocks), dataBlocks_1_1 = dataBlocks_1.next(); !dataBlocks_1_1.done; dataBlocks_1_1 = dataBlocks_1.next()) {
var db = dataBlocks_1_1.value;
totalBytes += db.getNumDataCodewords();
}
}
catch (e_1_1) { e_1 = { error: e_1_1 }; }
finally {
try {
if (dataBlocks_1_1 && !dataBlocks_1_1.done && (_a = dataBlocks_1.return)) _a.call(dataBlocks_1);
}
finally { if (e_1) throw e_1.error; }
}
var resultBytes = new Uint8Array(totalBytes);
var dataBlocksCount = dataBlocks.length;
// Error-correct and copy data blocks together into a stream of bytes
for (var j = 0; j < dataBlocksCount; j++) {
var dataBlock = dataBlocks[j];
var codewordBytes = dataBlock.getCodewords();
var numDataCodewords = dataBlock.getNumDataCodewords();
this.correctErrors(codewordBytes, numDataCodewords);
for (var i = 0; i < numDataCodewords; i++) {
// De-interlace data blocks.
resultBytes[i * dataBlocksCount + j] = codewordBytes[i];
}
}
// Decode the contents of that stream of bytes
return DecodedBitStreamParser_1.default.decode(resultBytes);
};
/**
* <p>Given data and error-correction codewords received, possibly corrupted by errors, attempts to
* correct the errors in-place using Reed-Solomon error correction.</p>
*
* @param codewordBytes data and error correction codewords
* @param numDataCodewords number of codewords that are data bytes
* @throws ChecksumException if error correction fails
*/
Decoder.prototype.correctErrors = function (codewordBytes, numDataCodewords) {
// const numCodewords = codewordBytes.length;
// First read into an array of ints
var codewordsInts = new Int32Array(codewordBytes);
// for (let i = 0; i < numCodewords; i++) {
// codewordsInts[i] = codewordBytes[i] & 0xFF;
// }
try {
this.rsDecoder.decode(codewordsInts, codewordBytes.length - numDataCodewords);
}
catch (ignored /* ReedSolomonException */) {
throw new ChecksumException_1.default();
}
// Copy back into array of bytes -- only need to worry about the bytes that were data
// We don't care about errors in the error-correction codewords
for (var i = 0; i < numDataCodewords; i++) {
codewordBytes[i] = codewordsInts[i];
}
};
return Decoder;
}());
exports.default = Decoder;