@awayjs/core/lib/utils/Byte32Array.ts

AwayJS core classes

export class Byte32Array {
	private _maxLength: number = -1;
	private _arrayBuffer: ArrayBuffer;

	private _float32Array: Float32Array;
	private _int32Array: Int32Array;
	private _uint32Array: Uint32Array;

	public bytePosition: number = 0;

	public byteLength: number = -1;

	public get arrayBuffer(): ArrayBuffer {
		return this._arrayBuffer;
	}

	public set arrayBuffer(value: ArrayBuffer) {
		//reset position
		this.bytePosition = 0;

		//clear length
		this.byteLength = -1;
		this._maxLength = -1;

		//calc new length
		this._ensureSpace(value.byteLength);

		//write new buffer
		this._int32Array.set(new Int32Array(value));
	}

	constructor(byteLength: number = 0) {
		this._ensureSpace(byteLength);
	}

	public readByte32Array(byte32Array: Byte32Array, byteLength: number = -1): void {
		if (byteLength == -1)
			byteLength = byte32Array.byteLength - byte32Array.bytePosition;

		byte32Array.writeInt32Array(
			this._int32Array.subarray(this.bytePosition / 4, (this.bytePosition + byteLength) / 4)
		);

		this.bytePosition += byteLength;
	}

	public writeByte32Array(byte32Array: Byte32Array): void {
		byte32Array.bytePosition = 0;

		byte32Array.readByte32Array(this, byte32Array.byteLength);
	}

	public writeFloat32Array(float32Array: Float32Array): void {
		this._ensureSpace(this.bytePosition + float32Array.length * 4);

		this._float32Array.set(float32Array, this.bytePosition / 4);

		this.bytePosition += float32Array.length * 4;
	}

	public writeInt32Array(int32Array: Int32Array): void {
		this._ensureSpace(this.bytePosition + int32Array.length * 4);

		this._uint32Array.set(int32Array, this.bytePosition / 4);

		this.bytePosition += int32Array.length * 4;
	}

	public writeUint32Array(uint32Array: Uint32Array): void {
		this._ensureSpace(this.bytePosition + uint32Array.length * 4);

		this._uint32Array.set(uint32Array, this.bytePosition / 4);

		this.bytePosition += uint32Array.length * 4;
	}

	public readFloat32Array(float32Array: Float32Array): void {
		float32Array.set(
			this._float32Array.subarray(this.bytePosition / 4, this.bytePosition / 4 + float32Array.length)
		);
	}

	public readInt32Array(int32Array: Int32Array): void {
		int32Array.set(
			this._int32Array.subarray(this.bytePosition / 4, this.bytePosition / 4 + int32Array.length)
		);
	}

	public readUint32Array(uint32Array: Uint32Array): void {
		uint32Array.set(
			this._uint32Array.subarray(this.bytePosition / 4, this.bytePosition / 4 + uint32Array.length)
		);
	}

	public getBytesAvailable(): number {
		return this.byteLength - this.bytePosition;
	}

	public readUTFBytes(len: number): string {
		let value: string = '';
		const max: number = this.bytePosition + len;
		const data: DataView = new DataView(this._arrayBuffer);
		// utf8-encode
		while (this.bytePosition < max) {

			const c: number = data.getUint8(this.bytePosition++);

			if (c < 0x80) {

				if (c == 0) break;
				value += String.fromCharCode(c);

			} else if (c < 0xE0) {

				value += String.fromCharCode(((c & 0x3F) << 6)
											| (data.getUint8(this.bytePosition++) & 0x7F));

			} else if (c < 0xF0) {

				const c2 = data.getUint8(this.bytePosition++);
				value += String.fromCharCode(((c & 0x1F) << 12)
											| ((c2 & 0x7F) << 6)
											| (data.getUint8(this.bytePosition++) & 0x7F));

			} else {

				const c2 = data.getUint8(this.bytePosition++);
				const c3 = data.getUint8(this.bytePosition++);

				value += String.fromCharCode(((c & 0x0F) << 18)
											| ((c2 & 0x7F) << 12)
											| ((c3 << 6) & 0x7F)
											| (data.getUint8(this.bytePosition++) & 0x7F));

			}

		}

		return value;
	}

	public writeUTFBytes(s: string) {
		const escstr: string = encodeURIComponent(s);
		let binstr: string = escstr.replace(/%([0-9A-F]{2})/g, function(match, p1) {
			return String.fromCharCode(parseInt('0x' + p1));
		});

		if (binstr.length % 4) {
			const padding: number = 4 - (binstr.length % 4);
			for (let i = 0; i < padding; i++)
				binstr += ' ';
		}

		this._ensureSpace(this.bytePosition + 4 + binstr.length);

		this.writeInt(binstr.length);

		for (let i = 0; i < binstr.length; i += 4)
			this.writeUnsignedInt((binstr.charCodeAt(i + 3) << 24)
								| (binstr.charCodeAt(i + 2) << 16)
								| (binstr.charCodeAt(i + 1) << 8)
								| binstr.charCodeAt(i));

		return binstr.length;
	}

	public readInt(): number {
		if (this.bytePosition > this.byteLength + 4)
			throw 'ByteArray out of bounds read. Position=' + this.bytePosition + ', Length=' + this.byteLength;

		const pa: number = this.bytePosition >> 2;
		this.bytePosition += 4;
		return this._int32Array[ pa ];
	}

	public writeUnsignedInt(b: number): void {
		this._ensureSpace(this.bytePosition + 4);

		this._uint32Array[ this.bytePosition >> 2 ] = (~~b) & 0xffffffff; // ~~ is cast to int in js...

		this.bytePosition += 4;
	}

	public writeInt(b: number): void {
		this._ensureSpace(this.bytePosition + 4);

		this._int32Array[ this.bytePosition >> 2 ] = (~~b); // ~~ is cast to int in js...

		this.bytePosition += 4;
	}

	public readUnsignedInt(): number {
		if (this.bytePosition > this.byteLength + 4)
			throw 'ByteArray out of bounds read. Position=' + this.bytePosition + ', Length=' + this.byteLength;

		const pa: number = this.bytePosition >> 2;
		this.bytePosition += 4;
		return this._uint32Array[ pa ];
	}

	public writeFloat(b: number): void {
		this._ensureSpace(this.bytePosition + 4);

		this._float32Array[this.bytePosition >> 2] = b;

		this.bytePosition += 4;
	}

	public readFloat(): number {
		if (this.bytePosition > this.byteLength + 4)
			throw 'ByteArray out of bounds read. Positon=' + this.bytePosition + ', Length=' + this.byteLength;

		const pa: number = this.bytePosition >> 2;
		this.bytePosition += 4;
		return this._float32Array[pa];
	}

	public _ensureSpace(length: number): void {
		if (this.byteLength < length) {
			this.byteLength = length;

			if (this._maxLength < length) { //add additional length in minimum 255-byte increments
				this._maxLength = Math.max((length + 255) & (~255), 4);

				const newArrayBuffer: ArrayBuffer = new ArrayBuffer(this._maxLength);
				const newInt32Array: Int32Array = new Int32Array(newArrayBuffer);

				if (this._int32Array)
					newInt32Array.set(this._int32Array); // memcpy

				this._uint32Array = new Uint32Array(newArrayBuffer);
				this._float32Array = new Float32Array(newArrayBuffer);
				this._int32Array = newInt32Array;

				this._arrayBuffer = newArrayBuffer;
			}
		}
	}
}