'use strict';
/**
* @author schukai GmbH
*/
import {Monster, getGlobal} from '../types/global.js';
/**
* this function uses crypt and returns a random number.
*
* you can call the method via the monster namespace `Monster.Math.random()`.
*
* ```
* <script type="module">
* import {Monster} from 'https://cdn.jsdelivr.net/npm/@schukai/monster@1.6.0/dist/modules/math/random.js';
* console.log(Monster.Math.random(1,10)) // ↦ 5
* </script>
* ```
*
* Alternatively, you can also integrate this function individually.
*
* ```
* <script type="module">
* import {random} from 'https://cdn.jsdelivr.net/npm/@schukai/monster@1.6.0/dist/modules/math/random.js';
* console.log(random(1,10)) // ↦ 5
* </script>
* ```
*
* @param {number} min starting value of the definition set (default is 0)
* @param {number} max end value of the definition set (default is 1000000000)
* @returns {number}
* @memberOf Monster/Math
* @since 1.0.0
* @copyright schukai GmbH
*/
function random(min, max) {
if (min === undefined) {
min = 0;
}
if (max === undefined) {
max = MAX;
}
if (max < min) {
throw new Error("max must be greater than min");
}
return Math.round(create(min, max));
}
/**
* @private
* @type {number}
*/
var MAX = 1000000000;
Math.log2 = Math.log2 || function (n) {
return Math.log(n) / Math.log(2);
};
/**
*
* @param min
* @param max
* @returns {*}
* @private
*/
function create(min, max) {
let crypt;
let globalReference = getGlobal();
crypt = globalReference?.['crypto'] || globalReference?.['msCrypto'] || globalReference?.['crypto'] || undefined;
if (typeof crypt === "undefined") {
throw new Error("missing crypt")
}
let rval = 0;
const range = max - min;
if (range < 2) {
return min;
}
const bitsNeeded = Math.ceil(Math.log2(range));
if (bitsNeeded > 53) {
throw new Error("we cannot generate numbers larger than 53 bits.");
}
const bytesNeeded = Math.ceil(bitsNeeded / 8);
const mask = Math.pow(2, bitsNeeded) - 1;
const byteArray = new Uint8Array(bytesNeeded);
crypt.getRandomValues(byteArray);
let p = (bytesNeeded - 1) * 8;
for (var i = 0; i < bytesNeeded; i++) {
rval += byteArray[i] * Math.pow(2, p);
p -= 8;
}
rval = rval & mask;
if (rval >= range) {
return create(min, max);
}
return min + rval;
}
Monster.assignToNamespace('Monster.Math', random);
export {Monster, random}