Benchmark speed and standard deviation between md5 (2 bytes of) and crc for a hash key.

index.js

"use strict";
//
// Benchmark speed and standard deviation between md5 (2 bytes of) and crc for a hash key.
//
// Version: 0.0.1
// Author: Mark W. B. Ashcroft (mark [at] fluidecho [dot] com)
// License: MIT or Apache 2.0.
//
// Copyright (c) 2017 Mark W. B. Ashcroft.
// Copyright (c) 2017 FluidEcho.
//


//const preview = require('preview')('md5vscrc');
const crypto = require('crypto');
const crc = require('crc');
const Sse4Crc32 = require("sse4_crc32");
const stats = require('stats-lite');

// NOTES:
// crc32c (hardware) is the fastest and has the best SD, crc16-CCITT however is as good as md5
// and twice as fast. crc16-CCITT is in JS, so will recomend that. crc16 has poorer SD for 
// sequential keys.


var x = 1000000;

md5(x, function() {
  crc16(x, function() {
    crc32(x);
  });
});



// MD5
function md5(x, cb) {

  var slices = new Array(65536);
  slices.fill(0);  
  var start = Date.now();
  
  for ( var y = 0; y < x; y++ ) {
    
    //var key = process.hrtime()[1].toString();
    //var key = crypto.randomBytes(10);
    //var key = y.toString();
    
    var key = "";
    for( var i=0; i < 3; i++ ) { 
      key += "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789".charAt(Math.floor(Math.random() * 62)); 
    }
    key += y.toString();

    var hased_key = crypto.createHash('md5').update(key).digest().slice(0, 2);

   // preview('hased_key: ', hased_key);

    var SLICE = ((hased_key[0] << 8) + (hased_key[1])) >>> 0;
    //preview('SLICE: ', SLICE);

    slices[SLICE]++;

  }
  report('MD5', start, slices);
  return cb();
}


// CRC16-ccitt
function crc16(x, cb) {
  
  var slices = new Array(65536);
  slices.fill(0);  
  var start = Date.now();
  
  for ( var y = 0; y < x; y++ ) {

    //var key = process.hrtime()[1].toString();
    //var key = crypto.randomBytes(10);
    //var key = y.toString();
    
    var key = "";
    for( var i=0; i < 3; i++ ) { 
      key += "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789".charAt(Math.floor(Math.random() * 62)); 
    }   
    key += y.toString();

    var SLICE = crc.crc16ccitt(key);   // crc16modbus and crc16 are less consitant
  
    var hashed_key = new Buffer(2);
    hashed_key[0] = SLICE >>> 8 & 0xff;
    hashed_key[1] = SLICE & 0xff;  
  
    //preview('hased_key: ', hased_key);

    //var SLICE = ((hased_key[0] << 8) + (hased_key[1])) >>> 0;
    
    //preview('SLICE: ', SLICE);

    slices[SLICE]++;

  }
  report('CRC16', start, slices);
  return cb();
}



// CRC32C
function crc32(x) {
  
  var slices = new Array(65536);
  slices.fill(0);  
  var start = Date.now();
  
  for ( var y = 0; y < x; y++ ) {

    //var key = process.hrtime()[1].toString();
    //var key = crypto.randomBytes(10);
    //var key = y.toString();
    
    var key = "";
    for( var i=0; i < 3; i++ ) { 
      key += "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789".charAt(Math.floor(Math.random() * 62)); 
    }
    key += y.toString();


    var crc = Sse4Crc32.calculate(key);

    //preview('crc32', crc32);

    var hashed_key = new Buffer(2);
    hashed_key[0] = crc >>> 8 & 0xff;
    hashed_key[1] = crc & 0xff;  

    var SLICE = ((hashed_key[0] << 8) + (hashed_key[1])) >>> 0;
  
  
    //preview('hased_key: ', hased_key);

    //var SLICE = ((hased_key[0] << 8) + (hased_key[1])) >>> 0;
    
    //preview('SLICE: ', SLICE);

    slices[SLICE]++;

  }
  report('CRC32', start, slices);
}


function report(testing, start, slices) {

  let ms = Date.now() - start;
  console.log(testing + ', completed in: ' + ms + ' ms');
  console.log('slices: ',slices);

  console.log("sum: %s", stats.sum(slices))
  console.log("mean: %s", stats.mean(slices))
  console.log("median: %s", stats.median(slices))
  console.log("mode: %s", stats.mode(slices))
  console.log("variance: %s", stats.variance(slices))
  console.log("standard deviation: %s", stats.stdev(slices))
  console.log("85th percentile: %s", stats.percentile(slices, 0.85))

}