ebml-stream/lib/EbmlStreamEncoder.js

Ebml parser and encoder

"use strict";
Object.defineProperty(exports, "__esModule", { value: true });
const stream_1 = require("stream");
const EbmlTagPosition_1 = require("./models/enums/EbmlTagPosition");
const EbmlTagId_1 = require("./models/enums/EbmlTagId");
class EbmlStreamEncoder extends stream_1.Transform {
    constructor(options = {}) {
        super(Object.assign({}, options, { writableObjectMode: true }));
        this.dataBuffer = Buffer.alloc(0);
        this.mCorked = false;
        this.openTags = [];
    }
    _transform(chunk, enc, done) {
        if (chunk) {
            if (!chunk.id) {
                throw new Error(`No id found for ${JSON.stringify(chunk)}`);
            }
            switch (chunk.position) {
                case EbmlTagPosition_1.EbmlTagPosition.Start:
                    this.startTag(chunk);
                    break;
                case EbmlTagPosition_1.EbmlTagPosition.Content:
                    this.writeTag(chunk);
                    break;
                case EbmlTagPosition_1.EbmlTagPosition.End:
                    this.endTag(chunk);
                    break;
                default:
                    break;
            }
        }
        done();
    }
    bufferAndFlush(buffer) {
        this.dataBuffer = Buffer.concat([this.dataBuffer, buffer]);
        this._flush(() => { });
    }
    _flush(callback) {
        let chunk = null;
        if (this.dataBuffer.length > 0 && !this.mCorked) {
            chunk = Buffer.from(this.dataBuffer);
            this.dataBuffer = Buffer.alloc(0);
            this.push(chunk);
        }
        callback();
    }
    _bufferAndFlush(buffer) {
        this.bufferAndFlush(buffer);
    }
    flush() {
        this._flush(() => { });
    }
    get buffer() {
        return this.dataBuffer;
    }
    set buffer(val) {
        this.dataBuffer = val;
    }
    get stack() {
        return this.openTags;
    }
    cork() {
        this.mCorked = true;
    }
    uncork() {
        this.mCorked = false;
        this._flush(() => { });
    }
    writeTag(tag) {
        if (this.openTags.length > 0) {
            this.openTags[this.openTags.length - 1].Children.push(tag);
        }
        else {
            this.bufferAndFlush(tag.encode());
        }
    }
    startTag(tag) {
        if (this.openTags.length > 0) {
            this.openTags[this.openTags.length - 1].Children.push(tag);
        }
        this.openTags.push(tag);
    }
    endTag(tag) {
        const inMemoryTag = this.openTags.pop();
        if (tag.id !== inMemoryTag.id) {
            throw `Logic error - closing tag "${EbmlTagId_1.EbmlTagId[tag.id]}" is not expected tag "${EbmlTagId_1.EbmlTagId[inMemoryTag.id]}"`;
        }
        if (this.openTags.length < 1) {
            this.bufferAndFlush(inMemoryTag.encode());
        }
    }
}
exports.EbmlStreamEncoder = EbmlStreamEncoder;