Method read

guava/src/com/google/common/io/ByteStreams.java:933–952

Reads some bytes from an input stream and stores them into the buffer array {@code b}. This method blocks until {@code len} bytes of input data have been read into the array, or end of file is detected. The number of bytes read is returned, possibly zero. Does not close the stream. <p>A caller can

(InputStream in, byte[] b, int off, int len)

   *     {@code off + len} is greater than {@code b.length}
   */
  @CanIgnoreReturnValue
  // Sometimes you don't care how many bytes you actually read, I guess.
  // (You know that it's either going to read len bytes or stop at EOF.)
  public static int read(InputStream in, byte[] b, int off, int len) throws IOException {
    checkNotNull(in);
    checkNotNull(b);
    if (len < 0) {
      throw new IndexOutOfBoundsException(String.format("len (%s) cannot be negative", len));
    }
    checkPositionIndexes(off, off + len, b.length);
    int total = 0;
    while (total < len) {
      int result = in.read(b, off + total, len - total);
      if (result == -1) {
        break;
      }
      total += result;
    }
    return total;
  }

  /** Compares the contents of the two {@link InputStream}s for equality. */
  static boolean contentsEqual(InputStream in1, InputStream in2) throws IOException {