random-id-generator.js

random-id-generator.js

function RandomIdGenerator() {
    var self = this;
    var lut = RandomIdGenerator.lut;

    var myCounter = ++RandomIdGenerator.counter;
    var idCounter = 0;

    self.get = function() {
        ++idCounter;

        var d0 = Date.now();
        var d1 = (idCounter & 0xffff) | (myCounter<<16 & 0xffff0000);
        var d2 = Math.random()*0x100000000>>>0;
        var d3 = Math.random()*0x100000000>>>0;
   
        return lut[d0>>24&0xff]+lut[d0>>16&0xff]+lut[d0>>8&0xff]+lut[d0&0xff]+'-'+
               lut[d1>>8&0xff]+lut[d1&0xff]+'-'+
               lut[d1>>24&0x0f|0x40]+lut[d1>>16&0xff]+'-'+
               lut[d2&0x3f|0x80]+lut[d2>>8&0xff]+'-'+
               lut[d2>>16&0xff]+lut[d2>>24&0xff]+lut[d3&0xff]+lut[d3>>8&0xff]+lut[d3>>16&0xff]+lut[d3>>24&0xff];
    }
}
RandomIdGenerator.counter = 0;
RandomIdGenerator.lut = []; for (var i=0; i<256; i++) { RandomIdGenerator.lut[i] = (i<16?'0':'')+(i).toString(16); }