Bufferer

bufferer.js

var Bufferer = function() {
	this.buffer = new Buffer(0);
	this.expects = [];
	return this;
};
Bufferer.prototype.receive = function(buffer) {
	var new_buffer = new Buffer(this.buffer.length + buffer.length);
	this.buffer.copy(new_buffer);
	buffer.copy(new_buffer, this.buffer.length);
	this.buffer = new_buffer;
	this.tryFlush();
	return this;
};
Bufferer.prototype.expect = function(requirement, callback) {
	this.expects.push({requirement: requirement, callback: callback});
	this.tryFlush();
	return this;
};
Bufferer.prototype.tryFlush = function() {
	if(this.expects.length < 1) return;
	if(typeof this.expects[0].requirement === "number") {
		if(this.buffer.length >= this.expects[0].requirement) {
			var expects = this.expects.shift();
			if(typeof expects.callback == "function") {
				process.nextTick(expects.callback.bind(this, this.buffer.slice(0, expects.requirement)));
			}
			this.chop(expects.requirement);
		}
	} else if(typeof this.expects[0].requirement === "function") {
		var result = this.expects[0].requirement(this.buffer);
		if(!result) return;
		var expects = this.expects.shift();
		if(typeof expects.callback == "function") {
			process.nextTick(expects.callback.bind(this, result));
		}
		this.chop(result.size || 0);
	}
	return this;
};
Bufferer.prototype.read = function(size) {
	if(this.buffer.length < size) return false;
	var result = this.buffer.slice(0, size);
	this.chop(size);
	return result;
};
Bufferer.prototype.chop = function(size) {
	if(this.buffer.length > size)
		this.buffer = this.buffer.slice(size);
	else
		this.buffer = new Buffer(0);
	process.nextTick(this.tryFlush.bind(this));
};

module.exports = Bufferer;