@thi.ng/random/sfc32.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 SFC32 extends ARandom {
  buffer;
  constructor(seed = DEFAULT_SEED_128) {
    super();
    this.buffer = new Uint32Array(4);
    this.seed(seed);
  }
  copy() {
    return new SFC32(this.buffer);
  }
  bytes() {
    return new Uint8Array(this.buffer.buffer);
  }
  int() {
    const s = this.buffer;
    const t = (s[0] + s[1] >>> 0) + s[3] >>> 0;
    s[3] = s[3] + 1 >>> 0;
    s[0] = s[1] ^ s[1] >>> 9;
    s[1] = s[2] + (s[2] << 3) >>> 0;
    s[2] = (s[2] << 21 | s[2] >>> 11) + t >>> 0;
    return t;
  }
  seed(seed) {
    this.buffer.set(seed);
    return this;
  }
}
export {
  SFC32
};