Method readFromSync

io/buffer.ts:474–496

Reads data from `r` until EOF (`null`) and appends it to the buffer, * growing the buffer as needed. It returns the number of bytes read. If the * buffer becomes too large, `.readFromSync()` will throw an error. * * Based on Go Lang's * {@link https://golang.org/pkg/bytes/#Buffer.Read

(r: ReaderSync)

   * @returns The number of bytes read.
   */
  readFromSync(r: ReaderSync): number {
    let n = 0;
    const tmp = new Uint8Array(MIN_READ);
    while (true) {
      const shouldGrow = this.capacity - this.length < MIN_READ;
      // read into tmp buffer if there's not enough room
      // otherwise read directly into the internal buffer
      const buf = shouldGrow
        ? tmp
        : new Uint8Array(this.#buf.buffer, this.length);

      const nread = r.readSync(buf);
      if (nread === null) {
        return n;
      }

      // write will grow if needed
      if (shouldGrow) this.writeSync(buf.subarray(0, nread));
      else this.#reslice(this.length + nread);

      n += nread;
    }
  }
}