Info

Looking for the fastest hash function to get a unique id of a string.

Preparation code

 
<script>
  Benchmark.prototype.setup = function() {
    function bitwise(str){
        var hash = 0,i,char,len = str.length;
        if ( len == 0) return hash;
        for (i = 0; i < len; i++) {
            char = str.charCodeAt(i);
            hash = ((hash<<5)-hash)+char;
        }
        return hash;
    }
    
    function numbers(str) {
       var res = 0,
           len = str.length;
    if ( len == 0) return res;
       for (var i = 0; i < len; i++) {
            char = str.charCodeAt(i);
        res = res * 31 + char;
       }
       return res;
      }
    
    function bitwiseconv(str){
        var hash = 0;
        if (str.length == 0) return hash;
        for (i = 0; i < str.length; i++) {
            char = str.charCodeAt(i);
            hash = ((hash<<5)-hash)+char;
            hash = hash & hash; // Convert to 32bit integer
        }
        return hash;
    }
    
    function numbersconv(str) {
       var res = 0,
           len = str.length;
       for (var i = 0; i < len; i++) {
        res = res * 31 + str.charCodeAt(i);
        res = res & res;
       }
       return res;
      }
    
    function murmurhash3_32_gc(key, seed) {
        var remainder, bytes, h1, h1b, c1, c1b, c2, c2b, k1, i;
    
        remainder = key.length & 3; // key.length % 4
        bytes = key.length - remainder;
        h1 = seed;
        c1 = 0xcc9e2d51;
        c2 = 0x1b873593;
        i = 0;
    
        while (i < bytes) {
                k1 = 
                  ((key.charCodeAt(i) & 0xff)) |
                  ((key.charCodeAt(++i) & 0xff) << 8) |
                  ((key.charCodeAt(++i) & 0xff) << 16) |
                  ((key.charCodeAt(++i) & 0xff) << 24);
                ++i;
    
                k1 = ((((k1 & 0xffff) * c1) + ((((k1 >>> 16) * c1) & 0xffff) << 16))) & 0xffffffff;
                k1 = (k1 << 15) | (k1 >>> 17);
                k1 = ((((k1 & 0xffff) * c2) + ((((k1 >>> 16) * c2) & 0xffff) << 16))) & 0xffffffff;
    
                h1 ^= k1;
            h1 = (h1 << 13) | (h1 >>> 19);
                h1b = ((((h1 & 0xffff) * 5) + ((((h1 >>> 16) * 5) & 0xffff) << 16))) & 0xffffffff;
                h1 = (((h1b & 0xffff) + 0x6b64) + ((((h1b >>> 16) + 0xe654) & 0xffff) << 16));
        }
    
        k1 = 0;
    
        switch (remainder) {
                case 3: k1 ^= (key.charCodeAt(i + 2) & 0xff) << 16;
                case 2: k1 ^= (key.charCodeAt(i + 1) & 0xff) << 8;
                case 1: k1 ^= (key.charCodeAt(i) & 0xff);
    
                k1 = (((k1 & 0xffff) * c1) + ((((k1 >>> 16) * c1) & 0xffff) << 16)) & 0xffffffff;
                k1 = (k1 << 15) | (k1 >>> 17);
                k1 = (((k1 & 0xffff) * c2) + ((((k1 >>> 16) * c2) & 0xffff) << 16)) & 0xffffffff;
                h1 ^= k1;
        }
    
        h1 ^= key.length;
    
        h1 ^= h1 >>> 16;
        h1 = (((h1 & 0xffff) * 0x85ebca6b) + ((((h1 >>> 16) * 0x85ebca6b) & 0xffff) << 16)) & 0xffffffff;
        h1 ^= h1 >>> 13;
        h1 = ((((h1 & 0xffff) * 0xc2b2ae35) + ((((h1 >>> 16) * 0xc2b2ae35) & 0xffff) << 16))) & 0xffffffff;
        h1 ^= h1 >>> 16;
    
        return h1 >>> 0;
    }
  };
</script>

Test runner

Warning! For accurate results, please disable Firebug before running the tests. (Why?)

Java applet disabled.

bitwise('notsolongstring');

numbers('notsolongstring');

bitwiseconv('notsolongstring');

numbersconv('notsolongstring');

murmurhash3_32_gc('[LOG] This is a a not-too-long log message, once that will commonly pop up in my application', 'test');

Compare results of other browsers

Revisions

You can edit these tests or add even more tests to this page by appending /edit to the URL. Here’s a list of current revisions for this page:

• Revision 1: published by Jelle De Loecker on 29th June 2012
• Revision 2: published on 26th July 2012
• Revision 5: published on 13th September 2012
• Revision 6: published on 14th September 2012
• Revision 8: published on 29th December 2012
• Revision 10: published on 22nd February 2013
• Revision 11: published on 6th March 2013
• Revision 12: published by Erwinus on 17th April 2013
• Revision 13: published by Yehor on 17th April 2013
• Revision 14: published 1 week ago

0 comments