numerics.ts

function wrap(value: number, max: number, min: number): number {
  while (value > max || value < min) {
    value = value > max ? value - (max + 1) : value < min ? value + (max + 1) : value;
  }
  return value;
}

function wrap_u8(value: number = 0): number {
  return wrap(value, 255, 0);
}

function wrap_u16(value: number = 0): number {
  return wrap(value, 65535, 0);
}

function split_u16(u: u16): [u8, u8] {
  let v = u.cast();
  let v1 = v >> 8; // first section
  let vo = v1 << 8; // add 0 bytes
  let v2 = vo ^ v; // last section;
  return [new u8(v1), new u8(v2)];
}

export class u16 extends Number {
  constructor(value?: number) {
    super(wrap_u16(value));
  }
  public add(value: number): u16 {
    return new u16(this.valueOf() + value);
  }
  public sub(value: number): u16 {
    return new u16(this.valueOf() - value);
  }
  public neg(): u16 {
    return new u16(-this.valueOf());
  }
  public clone(): u16 {
    return new u16(this.valueOf());
  }
  public static MAX(): u16 {
    return new u16(65535);
  }
  public static MIN(): u16 {
    return new u16();
  }
  public static from_be(be: [u8, u8]): u16 {
    return u16.from_le([be[1], be[0]]);
  }
  public static from_le(le: [u8, u8]): u16 {
    const hi = le[1].toString(16);
    const lo = le[0].toString(16);
    return new u16(parseInt(`${lo}${hi}`, 16));
  }
  public split(): [u8, u8] {
    return split_u16(this);
  }
  public as_u8(): u8 {
    return new u8(this.valueOf());
  }
  public cast(): number {
    return this as unknown as number;
  }
}

export class u8 extends Number {
  constructor(value?: number) {
    super(wrap_u8(value));
  }
  public static MAX(): u8 {
    return new u8(255);
  }
  public static MIN(): u8 {
    return new u8();
  }
  public add(value: number): u8 {
    return new u8(this.valueOf() + value);
  }
  public sub(value: number): u8 {
    return new u8(this.valueOf() - value);
  }
  public neg(): u8 {
    return new u8(-this.valueOf());
  }
  public clone(): u8 {
    return new u8(this.valueOf());
  }
  public as_u16(): u16 {
    return u16.from_le([u8.MIN(), this]);
  }
  public cast(): number {
    return this as unknown as number;
  }
}