public long readRawLittleEndian64() throws IOException
    {
        final byte[] buffer = this.buffer;
        int offset = this.offset;

        final byte b1 = buffer[offset++];
        final byte b2 = buffer[offset++];
        final byte b3 = buffer[offset++];
        final byte b4 = buffer[offset++];
        final byte b5 = buffer[offset++];
        final byte b6 = buffer[offset++];
        final byte b7 = buffer[offset++];
        final byte b8 = buffer[offset++];

        this.offset = offset;

        return (((long) b1 & 0xff)) |
                (((long) b2 & 0xff) << 8) |
                (((long) b3 & 0xff) << 16) |
                (((long) b4 & 0xff) << 24) |
                (((long) b5 & 0xff) << 32) |
                (((long) b6 & 0xff) << 40) |
                (((long) b7 & 0xff) << 48) |
                (((long) b8 & 0xff) << 56);
    }
Read a 64-bit little-endian integer from the internal byte buffer.
protostuff-core/src/main/java/io/protostuff/ByteArrayInput.java