/**

	@constructor

	@example

	var _index = new Hash();

	_index.set("a", "apple");

	_index.set("b", "blue");

	_index.set("c", "coffee");

	for (var p = _index.first(); p; p = _index.next()) {

		print(p.key+" is for "+p.value);

	}

 */

var Hash = function() {

	this._map = {};

	this._keys = [];

	this._vals = [];

	this.reset();

}

Hash.prototype.set = function(k, v) {

	if (k != "") {

		this._keys.push(k);

		this._map["="+k] = this._vals.length;

		this._vals.push(v);

	}

}

Hash.prototype.replace = function(k, k2, v) {

	if (k == k2) return;

	var offset = this._map["="+k];

	this._keys[offset] = k2;

	if (typeof v != "undefined") this._vals[offset] = v;

	this._map["="+k2] = offset;

	delete(this._map["="+k]);

}

Hash.prototype.drop = function(k) {

	if (k != "") {

		var offset = this._map["="+k];

		this._keys.splice(offset, 1);

		this._vals.splice(offset, 1);

		delete(this._map["="+k]);

		for (var p in this._map) {

			if (this._map[p] >= offset) this._map[p]--;

		}

		if (this._cursor >= offset && this._cursor > 0) this._cursor--;

	}

}

Hash.prototype.get = function(k) {

	if (k != "") {

		return this._vals[this._map["="+k]];

	}

}

Hash.prototype.keys = function() {

	return this._keys;

}

Hash.prototype.hasKey = function(k) {

	if (k != "") {

		return (typeof this._map["="+k] != "undefined");

	}

}

Hash.prototype.values = function() {

	return this._vals;

}

Hash.prototype.reset = function() {

	this._cursor = 0;

}

Hash.prototype.first = function() {

	this.reset();

	return this.next();

}

Hash.prototype.next = function() {

	if (this._cursor++ < this._keys.length)

		return {key: this._keys[this._cursor-1], value: this._vals[this._cursor-1]};

}