binary-format/sample/ico/ico.node.js

Two-way custom binary seralization

var fs = require('fs');
var jParser = require('../../src/jparser.js');

fs.readFile('favicon.ico', function (err, buffer) {
	var parser = new jParser(buffer, {
		uint4: function () {
			// By default, we can only parse 8 bits at a time.
			// When uint4 is called, it will parse 8 bits,
			// return the first 4 and cache the 4 others for
			// the next call.
			if (this.hasUint4Buffer) {
				this.hasUint4Buffer = false;
				return this.uint4Buffer;
			} else {
				this.hasUint4Buffer = true;
				var uint8 = this.parse('uint8');
				this.uint4Buffer = uint8 >>> 4;
				return uint8 & 0x0f;
			}
		},

		rgba: {
			r: 'uint8',
			g: 'uint8',
			b: 'uint8',
			a: 'uint8'
		},

		header: {
			reserved: 'uint8',
			type: 'uint8',
			imageCount: 'uint8',
			padding: ['array', 'uint8', 3]
		},

		image: {
			width: 'uint8',
			height: 'uint8',
			paletteCount: 'uint8',
			reserved: 'uint8',
			colorPlanes: 'uint16',
			bitsPerPixel: 'uint16',
			size: 'uint32',
			offset: 'uint32',
			content: function () {
				var that = this;
				return that.seek(that.current.offset, function () {
					return that.parse({
						palette: ['array', 'rgba', that.current.paletteCount],
						pixels: [
							'array',
							['array', 'uint' + that.current.bitsPerPixel, that.current.width],
							that.current.height
						]
					});
				});
			}
		},

		file: {
			header: 'header',
			images: ['array', 'image', function () { return this.current.header.imageCount; }]
		}
	});

	var ico = parser.parse('file');
	console.log(require('util').inspect(ico, false, 10));
});