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;
      if (str.length == 0) return hash;
      for (i = 0; i < str.length; i++) {
        char = str.charCodeAt(i);
        hash = ((hash << 5) - hash) + char;
      }
      return hash;
    }
    
    function numbers(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 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 hashcode(str) {
      var hash = 0;
      if (str.length == 0) return hash;
      for (var i = 0; i < str.length; i++) {
        var char = str.charCodeAt(i);
        hash = ((hash << 5) - hash) + char;
      }
      hash = hash & hash; // Convert to 32bit integer
      return hash;
    }
  };
</script>

Test runner

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

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

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

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

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

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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 2 weeks ago

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