@thi.ng/random/xoshiro128.js

Pseudo-random number generators w/ unified API, distributions, weighted choices, ID generation

import { ARandom } from "./arandom.js";
import { DEFAULT_SEED_128 } from "./constants.js";
class Xoshiro128 extends ARandom {
  buffer;
  constructor(seed = DEFAULT_SEED_128) {
    super();
    this.buffer = new Uint32Array(4);
    this.seed(seed);
  }
  copy() {
    return new Xoshiro128(this.buffer);
  }
  bytes() {
    return new Uint8Array(this.buffer.buffer);
  }
  seed(seed) {
    this.buffer.set(seed);
    return this;
  }
  int() {
    const s = this.buffer;
    let t = s[0] + s[3];
    const res = (t << 7 | t >>> 25) >>> 0;
    t = s[1] << 9;
    s[2] ^= s[0];
    s[3] ^= s[1];
    s[1] ^= s[2];
    s[0] ^= s[3];
    s[2] ^= t;
    t = s[3];
    s[3] = (t << 11 | t >>> 21) >>> 0;
    return res;
  }
}
export {
  Xoshiro128
};