Method constructor

modules/data/wavreader/wavreader.js:22–58

(buffer)

class WavReader {
	constructor(buffer) {
		this.wav = new DataView(buffer);
		this.position = 0;
		this.waveSize = buffer.byteLength;

		if ("RIFF" !== this.readFourCC())
			throw new Error("expected RIFF");
		this.seekBy(4);		// file size
		if ("WAVE" !== this.readFourCC())
			throw new Error("expected WAVE");

		if ("JUNK" === this.readFourCC())
			this.seekBy(this.readUint32())
		else
			this.seekBy(-4);

		if ("fmt " !== this.readFourCC())
			throw new Error("expected fmt");
		let next = this.readUint32();
		next += this.position;

		this.audioFormat = this.readUint16();
		this.numChannels = this.readUint16();
		this.sampleRate = this.readUint32();
		this.seekBy(4 + 2);
		this.bitsPerSample = this.readUint16();

		this.seekTo(next);

		while ("data" !== this.readFourCC())
			this.seekBy(this.readUint32());

		let bytes = this.readUint32();
		if (bytes > (this.waveSize - this.position))
			bytes = this.waveSize - this.position;
		this.samples = Math.floor(bytes / ((this.numChannels * this.bitsPerSample) >> 3));
	}

	getSamples(buffer, count) {		// always returns signed 16-bit sample values
		this.samples -= count;