@zxing/library/es2015/core/datamatrix/decoder/DataBlock.js

TypeScript port of ZXing multi-format 1D/2D barcode image processing library.

import IllegalArgumentException from '../../IllegalArgumentException';
/*
 * Copyright 2008 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>Encapsulates a block of data within a Data Matrix Code. Data Matrix Codes may split their data into
 * multiple blocks, each of which is a unit of data and error-correction codewords. Each
 * is represented by an instance of this class.</p>
 *
 * @author bbrown@google.com (Brian Brown)
 */
export default class DataBlock {
    constructor(numDataCodewords, codewords) {
        this.numDataCodewords = numDataCodewords;
        this.codewords = codewords;
    }
    /**
     * <p>When Data Matrix Codes use multiple data blocks, they actually interleave the bytes of each of them.
     * That is, the first byte of data block 1 to n is written, then the second bytes, and so on. This
     * method will separate the data into original blocks.</p>
     *
     * @param rawCodewords bytes as read directly from the Data Matrix Code
     * @param version version of the Data Matrix Code
     * @return DataBlocks containing original bytes, "de-interleaved" from representation in the
     *         Data Matrix Code
     */
    static getDataBlocks(rawCodewords, version) {
        // Figure out the number and size of data blocks used by this version
        const ecBlocks = version.getECBlocks();
        // First count the total number of data blocks
        let totalBlocks = 0;
        const ecBlockArray = ecBlocks.getECBlocks();
        for (let ecBlock of ecBlockArray) {
            totalBlocks += ecBlock.getCount();
        }
        // Now establish DataBlocks of the appropriate size and number of data codewords
        const result = new Array(totalBlocks);
        let numResultBlocks = 0;
        for (let ecBlock of ecBlockArray) {
            for (let i = 0; i < ecBlock.getCount(); i++) {
                const numDataCodewords = ecBlock.getDataCodewords();
                const numBlockCodewords = ecBlocks.getECCodewords() + numDataCodewords;
                result[numResultBlocks++] = new DataBlock(numDataCodewords, new Uint8Array(numBlockCodewords));
            }
        }
        // All blocks have the same amount of data, except that the last n
        // (where n may be 0) have 1 less byte. Figure out where these start.
        // TODO(bbrown): There is only one case where there is a difference for Data Matrix for size 144
        const longerBlocksTotalCodewords = result[0].codewords.length;
        // int shorterBlocksTotalCodewords = longerBlocksTotalCodewords - 1;
        const longerBlocksNumDataCodewords = longerBlocksTotalCodewords - ecBlocks.getECCodewords();
        const shorterBlocksNumDataCodewords = longerBlocksNumDataCodewords - 1;
        // The last elements of result may be 1 element shorter for 144 matrix
        // first fill out as many elements as all of them have minus 1
        let rawCodewordsOffset = 0;
        for (let i = 0; i < shorterBlocksNumDataCodewords; i++) {
            for (let j = 0; j < numResultBlocks; j++) {
                result[j].codewords[i] = rawCodewords[rawCodewordsOffset++];
            }
        }
        // Fill out the last data block in the longer ones
        const specialVersion = version.getVersionNumber() === 24;
        const numLongerBlocks = specialVersion ? 8 : numResultBlocks;
        for (let j = 0; j < numLongerBlocks; j++) {
            result[j].codewords[longerBlocksNumDataCodewords - 1] = rawCodewords[rawCodewordsOffset++];
        }
        // Now add in error correction blocks
        const max = result[0].codewords.length;
        for (let i = longerBlocksNumDataCodewords; i < max; i++) {
            for (let j = 0; j < numResultBlocks; j++) {
                const jOffset = specialVersion ? (j + 8) % numResultBlocks : j;
                const iOffset = specialVersion && jOffset > 7 ? i - 1 : i;
                result[jOffset].codewords[iOffset] = rawCodewords[rawCodewordsOffset++];
            }
        }
        if (rawCodewordsOffset !== rawCodewords.length) {
            throw new IllegalArgumentException();
        }
        return result;
    }
    getNumDataCodewords() {
        return this.numDataCodewords;
    }
    getCodewords() {
        return this.codewords;
    }
}