ip.ts

export class IPv4 {
  static from(input: string) {
    const [, a, b, c, d] = /(\d+)\.(\d+)\.(\d+)\.(\d+)/.exec(input)!;

    const address = ((Number(a) << 24) | (Number(b) << 16) | ((Number(c) << 8) | Number(d))) >>> 0;

    console.log(address.toString());
    console.log(address.toString(2));
    console.log(address.toString(16));

    return new IPv4(address);
  }

  constructor(private readonly value: number) {}

  toString() {
    return this[Symbol.toPrimitive]('string');
  }

  [Symbol.toPrimitive](hint: 'number'): number;
  [Symbol.toPrimitive](hint: 'string'): string;
  [Symbol.toPrimitive](hint: 'number' | 'string'): string | number | null {
    if (hint === 'number') {
      return this.value;
    }

    if (hint === 'string') {
      return `${(this.value >> 24) & 0xff}.${(this.value >> 16) & 0xff}.${
        (this.value >> 8) & 0xff
      }.${this.value & 0xff}`;
    }

    console.log(hint);
    return null;
  }
}

export class CIDRBlock {
  static parse(cidr: string) {
    const variable = 32 - Number.parseInt(/\/(\d+)/.exec(cidr)![1]!, 10);

    const address = IPv4.from(cidr);

    let mask = 0;
    for (let i = 0; i < variable; i++) {
      mask |= (1 << i) >>> 0;
    }

    return { start: address, end: (address | mask) >>> 0, mask };
  }

  readonly start: IPv4;
  readonly end: IPv4;
  readonly mask: number;

  constructor(address: string) {
    const { start, end, mask } = CIDRBlock.parse(address);
    this.start = start;
    this.end = new IPv4(end);
    this.mask = mask;
  }
}