interface IteratorValue {
  skip(length: number): void;
  value: Uint8Array;
}

/**
 * Iterate over a buffer with the specified size. This will yield a part of the buffer starting at an increment of the
 * specified size, until the end of the buffer is reached.
 *
 * Calling the `skip` function will make it skip the specified number of bytes.
 *
 * @param buffer The buffer to iterate over.
 * @param [size] The number of bytes to iterate with.
 */
export const iterate = function* (
  buffer: Uint8Array,
  size = 32
): Generator<IteratorValue, IteratorValue, IteratorValue> {
  for (let pointer = 0; pointer < buffer.length; pointer += size) {
    const skip = (length: number) => {
      if (length % size !== 0) {
        throw new Error('Length must be divisible by size');
      }

      pointer += length;
    };

    const value = buffer.subarray(pointer);

    yield { skip, value };
  }

  return {
    skip: () => undefined,
    value: new Uint8Array()
  };
};