public int getInt(int off) {
    checkOffsets(off, off + 4);
    return (getByte0(off) << 24)
        | (getUnsignedByte0(off + 1) << 16)
        | (getUnsignedByte0(off + 2) << 8)
        | getUnsignedByte0(off + 3);
  }
Gets the {@code signed int} value at a particular offset.

@param off {@code >= 0, < (size() - 3);} offset to fetch
@return {@code signed int} at that offset
android/android_framework/dex-maker/src/main/java/com/android/dx/util/ByteArray.java