adler-32 simple vs optimized vs full length (v6)

Revision 6 of this benchmark created by kvaruni on

Description

This new version adds a new function which defers the modulo operation till the end. This avoids excessive modulo operations and avoids some bookkeeping, further contributing to the speed of the implementation.

Preparation HTML

<script>
  //--------------------------------------------------
  // simple impl
  //--------------------------------------------------
  function adler32_simple(array) {
    return adler32_simple_update(1, array);
  }

  function adler32_simple_update(adler, array) {
    var s1 = adler & 0xffff,
        s2 = (adler >>> 16) & 0xffff;

    for (var i = 0, l = array.length; i < l; i++) {
      s1 = (s1 + array[i]) % 65521;
      s2 = (s2 + s1) % 65521;
    }

    return ((s2 << 16) | s1) >>> 0;
  }

  //--------------------------------------------------
  // optimized impl
  //--------------------------------------------------
  function adler32_opti(array, param) {
    return adler32_opti_update(1, array, param);
  }

  function adler32_opti_update(adler, array, param) {
    var s1 = adler & 0xffff,
        s2 = (adler >>> 16) & 0xffff;
    var len = array.length;
    var tlen;
    var i = 0;

    while (len > 0) {
      tlen = len > param ? param : len;
      len -= tlen;
      do {
        s1 += array[i++];
        s2 += s1;
      } while (--tlen);

      s1 %= 65521;
      s2 %= 65521;
    }

    return ((s2 << 16) | s1) >>> 0;
  }

function adler32_fulllength(array) {
  var a = 1;
  var b = 0;

  var len = array.length;

  for (var i = 0; i < len; i++) {
    a += array[i];
    b += a;
  }

  a %= 65521;
  b %= 65521;

  return (b << 16) | a;
}
</script>

Setup

var testData = [];
    var num = 100000;
    
    for (var i = 0; i < num; ++i) {
      testData[i] = (i * 2) & 0xff;
    }

Test runner

Ready to run.

Testing in
TestOps/sec
simple
adler32_simple(testData);
ready
opti(16)
adler32_opti(testData, 16);
 
ready
opti(32)
adler32_opti(testData, 32);
 
ready
opti(64)
adler32_opti(testData, 64);
 
ready
opti(128)
adler32_opti(testData, 128);
 
ready
opti(256)
adler32_opti(testData, 256);
 
ready
opti(512)
adler32_opti(testData, 512);
 
ready
opti(1024)
adler32_opti(testData, 1024);
 
ready
opti(2048)
adler32_opti(testData, 2048);
 
ready
opti(4096)
adler32_opti(testData, 4096);
 
ready
opti(5550)
adler32_opti(testData, 5550);
 
ready
full-length
adler32_fulllength(testData);
ready

Revisions

You can edit these tests or add more tests to this page by appending /edit to the URL.