js/util.js

Object.prototype.inherit = function() {
	for (var v in this) {
		this[v] = this[v];
	}
};

function hex(number, leading, usePrefix) {
	if (typeof(usePrefix) === 'undefined') {
		usePrefix = true;
	}
	if (typeof(leading) === 'undefined') {
		leading = 8;
	}
	var string = (number >>> 0).toString(16).toUpperCase();
	leading -= string.length;
	if (leading < 0)
		return string;
	return (usePrefix ? '0x' : '') + new Array(leading + 1).join('0') + string;
}

Serializer = {
	TAG_INT: 1,
	TAG_STRING: 2,
	TAG_STRUCT: 3,
	TAG_BLOB: 4,
	TAG_BOOLEAN: 5,
	TYPE: 'application/octet-stream',

	pointer: function() {
		this.index = 0;
		this.top = 0;
		this.stack = [];
	},

	pack: function(value) {
		var object = new DataView(new ArrayBuffer(4));
		object.setUint32(0, value, true);
		return object.buffer;
	},

	pack8: function(value) {
		var object = new DataView(new ArrayBuffer(1));
		object.setUint8(0, value, true);
		return object.buffer;
	},

	prefix: function(value) {
		return new Blob([Serializer.pack(value.size || value.length || value.byteLength), value], { type: Serializer.TYPE });
	},

	serialize: function(stream) {
		var parts = [];
		var size = 4;
		for (i in stream) {
			if (stream.hasOwnProperty(i)) {
				var tag;
				var head = Serializer.prefix(i);
				var body;
				switch (typeof(stream[i])) {
				case 'number':
					tag = Serializer.TAG_INT;
					body = Serializer.pack(stream[i]);
					break;
				case 'string':
					tag = Serializer.TAG_STRING;
					body = Serializer.prefix(stream[i]);
					break;
				case 'object':
					if (stream[i].type == Serializer.TYPE) {
						tag = Serializer.TAG_BLOB;
						body = stream[i];
					} else {
						tag = Serializer.TAG_STRUCT;
						body = Serializer.serialize(stream[i]);
					}
					break;
				case 'boolean':
					tag = Serializer.TAG_BOOLEAN;
					body = Serializer.pack8(stream[i]);
					break;
				default:
					console.log(stream[i]);
					break;
				}
				size += 1 + head.size + (body.size || body.byteLength || body.length);
				parts.push(Serializer.pack8(tag));
				parts.push(head);
				parts.push(body);
			}
		}
		parts.unshift(Serializer.pack(size));
		return new Blob(parts);
	},

	deserialize: function(blob, callback) {
		var reader = new FileReader();
		reader.onload = function(data) {
			callback(Serializer.deserealizeStream(new DataView(data.target.result), new Serializer.pointer));
		}
		reader.readAsArrayBuffer(blob);
	},

	deserealizeStream: function(view, pointer) {
		pointer.push();
		var object = {};
		var remaining = view.getUint32(pointer.advance(4), true);
		while (pointer.mark() < remaining) {
			var tag = view.getUint8(pointer.advance(1));
			var head = pointer.readString(view);
			var body;
			switch (tag) {
			case Serializer.TAG_INT:
				body = view.getUint32(pointer.advance(4), true);
				break;
			case Serializer.TAG_STRING:
				body = pointer.readString(view);
				break;
			case Serializer.TAG_STRUCT:
				body = Serializer.deserealizeStream(view, pointer);
				break;
			case Serializer.TAG_BLOB:
				var size = view.getUint32(pointer.advance(4), true);
				body = view.buffer.slice(pointer.advance(size), pointer.advance(0));
				break;
			case Serializer.TAG_BOOLEAN:
				body = !!view.getUint8(pointer.advance(1));
				break;
			}
			object[head] = body;
		}
		if (pointer.mark() > remaining) {
			throw "Size of serialized data exceeded";
		}
		pointer.pop();
		return object;
	},

	serializePNG: function(blob, base, callback) {
		var canvas = document.createElement('canvas');
		var context = canvas.getContext('2d');
		var pixels = base.getContext('2d').getImageData(0, 0, base.width, base.height);
		var transparent = 0;
		for (var y = 0; y < base.height; ++y) {
			for (var x = 0; x < base.width; ++x) {
				if (!pixels.data[(x + y * base.width) * 4 + 3]) {
					++transparent;
				}
			}
		}
		var bytesInCanvas = transparent * 3 + (base.width * base.height - transparent);
		for (var multiplier = 1; (bytesInCanvas * multiplier * multiplier) < blob.size; ++multiplier);
		var edges = bytesInCanvas * multiplier * multiplier - blob.size;
		var padding = Math.ceil(edges / (base.width * multiplier));
		canvas.setAttribute('width', base.width * multiplier);
		canvas.setAttribute('height', base.height * multiplier + padding);

		var reader = new FileReader();
		reader.onload = function(data) {
			var view = new Uint8Array(data.target.result);
			var pointer = 0;
			var pixelPointer = 0;
			var newPixels = context.createImageData(canvas.width, canvas.height + padding);
			for (var y = 0; y < canvas.height; ++y) {
				for (var x = 0; x < canvas.width; ++x) {
					var oldY = (y / multiplier) | 0;
					var oldX = (x / multiplier) | 0;
					if (oldY > base.height || !pixels.data[(oldX + oldY * base.width) * 4 + 3]) {
						newPixels.data[pixelPointer++] = view[pointer++];
						newPixels.data[pixelPointer++] = view[pointer++];
						newPixels.data[pixelPointer++] = view[pointer++];
						newPixels.data[pixelPointer++] = 0;
					} else {
						var byte = view[pointer++];
						newPixels.data[pixelPointer++] = pixels.data[(oldX + oldY * base.width) * 4 + 0] | (byte & 7);
						newPixels.data[pixelPointer++] = pixels.data[(oldX + oldY * base.width) * 4 + 1] | ((byte >> 3) & 7);
						newPixels.data[pixelPointer++] = pixels.data[(oldX + oldY * base.width) * 4 + 2] | ((byte >> 6) & 7);
						newPixels.data[pixelPointer++] = pixels.data[(oldX + oldY * base.width) * 4 + 3];
					}
				}
			}
			context.putImageData(newPixels, 0, 0);
			callback(canvas.toDataURL('image/png'));
		}
		reader.readAsArrayBuffer(blob);
		return canvas;
	},

	deserializePNG: function(blob, callback) {
		var reader = new FileReader();
		reader.onload = function(data) {
			var image = document.createElement('img');
			image.setAttribute('src', data.target.result);
			var canvas = document.createElement('canvas');
			canvas.setAttribute('height', image.height);
			canvas.setAttribute('width', image.width);
			var context = canvas.getContext('2d');
			context.drawImage(image, 0, 0);
			var pixels = context.getImageData(0, 0, canvas.width, canvas.height);
			var data = [];
			for (var y = 0; y < canvas.height; ++y) {
				for (var x = 0; x < canvas.width; ++x) {
					if (!pixels.data[(x + y * canvas.width) * 4 + 3]) {
						data.push(pixels.data[(x + y * canvas.width) * 4 + 0]);
						data.push(pixels.data[(x + y * canvas.width) * 4 + 1]);
						data.push(pixels.data[(x + y * canvas.width) * 4 + 2]);
					} else {
						var byte = 0;
						byte |= pixels.data[(x + y * canvas.width) * 4 + 0] & 7;
						byte |= (pixels.data[(x + y * canvas.width) * 4 + 1] & 7) << 3;
						byte |= (pixels.data[(x + y * canvas.width) * 4 + 2] & 7) << 6;
						data.push(byte);
					}
				}
			}
			newBlob = new Blob(data.map(function (byte) {
				var array = new Uint8Array(1);
				array[0] = byte;
				return array;
			}), { type: Serializer.TYPE});
			Serializer.deserialize(newBlob, callback);
		}
		reader.readAsDataURL(blob);
	}
};

Serializer.pointer.prototype.advance = function(amount) {
	var index = this.index;
	this.index += amount;
	return index;
};

Serializer.pointer.prototype.mark = function() {
	return this.index - this.top;
};

Serializer.pointer.prototype.push = function() {
	this.stack.push(this.top);
	this.top = this.index;
};

Serializer.pointer.prototype.pop = function() {
	this.top = this.stack.pop();
};

Serializer.pointer.prototype.readString = function(view) {
	var length = view.getUint32(this.advance(4), true);
	var bytes = [];
	for (var i = 0; i < length; ++i) {
		bytes.push(String.fromCharCode(view.getUint8(this.advance(1))));
	}
	return bytes.join('');
};