bloomFilter in Javascript.

bloomFilter.js

var bloomFilter = (function(exports) {
	var typedArrays = typeof ArrayBuffer !== "undefined";

	var popcnt = function (v) {
		v -= v >> 1 & 1431655765;
		v = (v & 858993459) + (v >> 2 & 858993459);
		return (v + (v >> 4) & 252645135) * 16843009 >> 24
	}

	var fnv_1a = function (v) {
		var n = v.length,
			a = 2166136261,
			c, d, i = -1;
		while (++i < n) {
			c = v.charCodeAt(i);
			if (d = c & 4278190080) {
				a ^= d >> 24;
				a += (a << 1) + (a << 4) + (a << 7) + (a << 8) + (a << 24)
			}
			if (d = c & 16711680) {
				a ^= d >> 16;
				a += (a << 1) + (a << 4) + (a << 7) + (a << 8) + (a << 24)
			}
			if (d = c & 65280) {
				a ^= d >> 8;
				a += (a << 1) + (a << 4) + (a << 7) + (a << 8) + (a << 24)
			}
			a ^= c & 255;
			a += (a << 1) + (a << 4) + (a << 7) + (a << 8) + (a << 24)
		}
		a += a << 13;
		a ^= a >> 7;
		a += a << 3;
		a ^= a >> 17;
		a += a << 5;
		return a & 4294967295
	}

	var fnv_1a_b = function (a) {
		a += (a << 1) + (a << 4) + (a << 7) + (a << 8) + (a << 24);
		a += a << 13;
		a ^= a >> 7;
		a += a << 3;
		a ^= a >> 17;
		a += a << 5;
		return a & 4294967295
	}

	var BloomFilter = function (m, k) {
		var a;
		if (typeof m !== "number") a = m, m = a.length * 32;
		this.m = m;
		this.k = k;
		var n = Math.ceil(m / 32),
			i = -1;
		if (typedArrays) {
			var kbytes = 1 << Math.ceil(Math.log(Math.ceil(Math.log(m) / Math.LN2 / 8)) / Math.LN2),
				array = kbytes === 1 ? Uint8Array : kbytes === 2 ? Uint16Array : Uint32Array,
				kbuffer = new ArrayBuffer(kbytes * k),
				buckets = this.buckets = new Int32Array(n);
			if (a)
				while (++i <
					n) buckets[i] = a[i];
			this._locations = new array(kbuffer)
		} else {
			var buckets = this.buckets = [];
			if (a)
				while (++i < n) buckets[i] = a[i];
			else
				while (++i < n) buckets[i] = 0;
			this._locations = []
		}
	}
	BloomFilter.prototype.locations = function(v) {
		var k = this.k,
			m = this.m,
			r = this._locations,
			a = fnv_1a(v),
			b = fnv_1a_b(a),
			i = -1,
			x = a % m;
		while (++i < k) {
			r[i] = x < 0 ? x + m : x;
			x = (x + b) % m
		}
		return r
	};
	BloomFilter.prototype.add = function(v) {
		var l = this.locations(v + ""),
			i = -1,
			k = this.k,
			buckets = this.buckets;
		while (++i < k) buckets[Math.floor(l[i] / 32)] |= 1 << l[i] % 32
	};
	BloomFilter.prototype.test =
		function(v) {
			var l = this.locations(v + ""),
				i = -1,
				k = this.k,
				b, buckets = this.buckets;
			while (++i < k) {
				b = l[i];
				if ((buckets[Math.floor(b / 32)] & 1 << b % 32) === 0) return false
			}
			return true
	};
	BloomFilter.prototype.size = function() {
		var buckets = this.buckets,
			bits = 0;
		for (var i = 0, n = buckets.length; i < n; ++i) bits += popcnt(buckets[i]);
		return -this.m * Math.log(1 - bits / this.m) / this.k
	};

	return BloomFilter
})();

var bloom = bloomFilter( 32 * 256, 16 );

// Add elements to the filter
bloom.add("foo");
bloom.add("bar");

// Will be true if the element is probably in the set
// or false if the item is definitely not in the set.
bloom.test("foo");   // true
bloom.test("bar");   // true
bloom.test("\\o//"); // false