byte[] buffer = new byte[4];
        pdis.readFully(buffer);
        assertArrayEquals(data, buffer);
    }

    @Test
    public void testReadFullyWithOffset() throws IOException {
        byte[] data = new byte[] { 0x01, 0x02, 0x03, 0x04 };
        PacDataInputStream pdis = createInputStream(data);
        byte[] buffer = new byte[6];
        pdis.readFully(buffer, 1, 4);

                this.checksum = new byte[12];
                break;
            default:
                this.checksum = new byte[bufferStream.available()];
                break;
            }
            bufferStream.readFully(this.checksum);
        } catch (final IOException e) {
            throw new PACDecodingException("Malformed PAC signature", e);
        }
    }

    /**
     * Gets the checksum type of this signature.
     *

        excludesFilters = FilterPath.compile(Set.of(fetchContext.excludes()));
    }

    private BytesReference read300BytesExample() throws IOException {
        return Streams.readFully(FetchSourcePhaseBenchmark.class.getResourceAsStream("300b_example.json"));
    }

    private BytesReference buildBigExample(String extraText) throws IOException {
        String bigger = read300BytesExample().utf8ToString();

	if err != nil {
		return nil, nil, err
	}
	defer f.Close()

	st, err := f.Stat()
	if err != nil {
		return nil, nil, err
	}

	dst := make([]byte, st.Size())
	_, err = io.ReadFull(f, dst)
	return dst, st, err
}

// ReadFile reads the named file and returns the contents.
// A successful call returns err == nil, not err == EOF.

			return n, cr.err
		}
	}

	if cap(cr.buffer) < size {
		cr.buffer = make([]byte, size)
	} else {
		cr.buffer = cr.buffer[:size]
	}

	// Now, we read the payload.
	_, err = io.ReadFull(cr.reader, cr.buffer)
	if err == io.EOF && size != 0 {
		err = io.ErrUnexpectedEOF
	}
	if err != nil && err != io.EOF {
		cr.err = err
		return n, cr.err
	}

	const (
		MaxMetadataSize = 1 << 20 // max. size of the metadata
		Version         = 1
	)

	var header [5]byte
	if _, err := io.ReadFull(ciphertext, header[:]); err != nil {
		return nil, err
	}
	if header[0] != Version {
		return nil, fmt.Errorf("config: unknown ciphertext version %d", header[0])
	}
	size := binary.LittleEndian.Uint32(header[1:])

// also returned.
func cmpReaders(r1, r2 io.Reader) (bool, string) {
	bufLen := 32 * 1024
	b1, b2 := make([]byte, bufLen), make([]byte, bufLen)
	for i := 0; true; i++ {
		n1, e1 := io.ReadFull(r1, b1)
		n2, e2 := io.ReadFull(r2, b2)
		if n1 != n2 {
			return false, fmt.Sprintf("Read %d != %d bytes from the readers", n1, n2)
		}
		if !bytes.Equal(b1[:n1], b2[:n2]) {

	if random == nil {
		random = rand.Reader
	}
	if len(extKey) != 32 { // safety check
		logger.CriticalIf(context.Background(), errors.New("crypto: invalid key length"))
	}
	var nonce [32]byte
	if _, err := io.ReadFull(random, nonce[:]); err != nil {
		logger.CriticalIf(context.Background(), errOutOfEntropy)
	}

	const Context = "object-encryption-key generation"
	mac := hmac.New(sha256.New, extKey)
	mac.Write([]byte(Context))

		}
	}
	if offset != b.currOffset {
		// Can never happen unless there are programmer bugs
		return 0, errUnexpected
	}
	b.h.Reset()
	_, err = io.ReadFull(b.rc, b.hashBytes)
	if err != nil {
		return 0, err
	}
	_, err = io.ReadFull(b.rc, buf)
	if err != nil {
		return 0, err
	}
	b.h.Write(buf)
	if !bytes.Equal(b.h.Sum(nil), b.hashBytes) {
		return 0, errFileCorrupt
	}

	if cap(dst) < skip {
		dst = make([]byte, 0, skip+1024)
	}
	dst = dst[:skip]
	if skip > 0 {
		n, err := io.ReadFull(r.buf, dst)
		if err != nil && err != io.ErrUnexpectedEOF {
			// If an EOF happens after reading some but not all the bytes,
			// ReadFull returns ErrUnexpectedEOF.
			return dst[:n], err
		}
		dst = dst[:n]
		if err == io.ErrUnexpectedEOF {
			return dst, io.EOF
		}
	}