@l5i/dashjs/src/streaming/utils/BoxParser.js

A reference client implementation for the playback of MPEG DASH via Javascript and compliant browsers.

/**
 * The copyright in this software is being made available under the BSD License,
 * included below. This software may be subject to other third party and contributor
 * rights, including patent rights, and no such rights are granted under this license.
 *
 * Copyright (c) 2013, Dash Industry Forum.
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without modification,
 * are permitted provided that the following conditions are met:
 *  * Redistributions of source code must retain the above copyright notice, this
 *  list of conditions and the following disclaimer.
 *  * Redistributions in binary form must reproduce the above copyright notice,
 *  this list of conditions and the following disclaimer in the documentation and/or
 *  other materials provided with the distribution.
 *  * Neither the name of Dash Industry Forum nor the names of its
 *  contributors may be used to endorse or promote products derived from this software
 *  without specific prior written permission.
 *
 *  THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS AS IS AND ANY
 *  EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
 *  WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
 *  IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT,
 *  INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
 *  NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
 *  PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
 *  WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 *  ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 *  POSSIBILITY OF SUCH DAMAGE.
 */

import IsoFile from './IsoFile';
import FactoryMaker from '../../core/FactoryMaker';
import ISOBoxer from 'codem-isoboxer';

import IsoBoxSearchInfo from '../vo/IsoBoxSearchInfo';

function BoxParser(/*config*/) {

    let instance;
    let context = this.context;

    /**
     * @param {ArrayBuffer} data
     * @returns {IsoFile|null}
     * @memberof BoxParser#
     */
    function parse(data) {
        if (!data) return null;

        if (data.fileStart === undefined) {
            data.fileStart = 0;
        }

        let parsedFile = ISOBoxer.parseBuffer(data);
        let dashIsoFile = IsoFile(context).create();

        dashIsoFile.setData(parsedFile);

        return dashIsoFile;
    }

    /**
     * From the list of type boxes to look for, returns the latest one that is fully completed (header + payload). This
     * method only looks into the list of top boxes and doesn't analyze nested boxes.
     * @param {string[]} types
     * @param {ArrayBuffer|uint8Array} buffer
     * @param {number} offset
     * @returns {IsoBoxSearchInfo}
     * @memberof BoxParser#
     */
    function findLastTopIsoBoxCompleted(types, buffer, offset) {
        if (offset === undefined) {
            offset = 0;
        }

        // 8 = size (uint32) + type (4 characters)
        if (!buffer || offset + 8 >= buffer.byteLength) {
            return new IsoBoxSearchInfo(0, false);
        }

        const data = (buffer instanceof ArrayBuffer) ? new Uint8Array(buffer) : buffer;
        let boxInfo;
        let lastCompletedOffset = 0;
        while (offset < data.byteLength) {
            const boxSize = parseUint32(data, offset);
            const boxType = parseIsoBoxType(data, offset + 4);

            if (boxSize === 0) {
                break;
            }

            if (offset + boxSize <= data.byteLength) {
                if (types.indexOf(boxType) >= 0) {
                    boxInfo = new IsoBoxSearchInfo(offset, true, boxSize);
                } else {
                    lastCompletedOffset = offset + boxSize;
                }
            }

            offset += boxSize;
        }

        if (!boxInfo) {
            return new IsoBoxSearchInfo(lastCompletedOffset, false);
        }

        return boxInfo;
    }

    function parseUint32(data, offset) {
        return data[offset + 3] >>> 0 |
            (data[offset + 2] << 8) >>> 0 |
            (data[offset + 1] << 16) >>> 0 |
            (data[offset] << 24) >>> 0;
    }

    function parseIsoBoxType(data, offset) {
        return String.fromCharCode(data[offset++]) +
            String.fromCharCode(data[offset++]) +
            String.fromCharCode(data[offset++]) +
            String.fromCharCode(data[offset]);
    }

    instance = {
        parse: parse,
        findLastTopIsoBoxCompleted: findLastTopIsoBoxCompleted
    };

    return instance;
}
BoxParser.__dashjs_factory_name = 'BoxParser';
export default FactoryMaker.getSingletonFactory(BoxParser);