type ReaderFunc func([]byte) (int, error)

// Delegates the call to the WriterFunc while implementing io.Reader
func (r ReaderFunc) Read(b []byte) (int, error) {
	return r(b)
}

// Returns a reader that will delegate calls to Read(...) while ensuring
// that the output buffer will never be smaller than the required size
// and will be downsized to a multiple of the required size if larger
func BlockReader(reader io.Reader, size int) io.Reader {
// Returns a reader that delegates calls to Read(...) while ensuring
// that the output buffer is never smaller than the required size
// and is downsized to a multiple of the required size if larger
func SizedReader(reader io.Reader, size int) io.Reader {
	var buffer []byte = make([]byte, 0, size)

	return ReaderFunc(func(output []byte) (int, error) {
		var (
			readCount int
			err       error
		)

func TestBlockReader(t *testing.T) {
	var (
		input  []byte = []byte{0, 1, 2, 3, 4, 5, 6, 7}
		output []byte = make([]byte, 16)

		reader *bytes.Reader = bytes.NewReader(input)
		min    io.Reader     = BlockReader(reader, 4)
		min    io.Reader     = SizedReader(reader, 4)
	)

	// Expecting a read count of 2
	count, err := min.Read(output[:2])
	if count != 2 {
		t.Error("Invalid read count from MinReader", count)
	}

		t.Error("Invalid read count from MinReader", count)
	}
	if err != nil {
		t.Error("Unexpected error from MinReader", err)
	}

	// Expecting a read count of 0 with an EOF as the buffer should be empty
	count, err = min.Read(output[:4])
	count, err = min.Read(output[:1])
	if count != 0 {
		t.Error("Invalid read count from MinReader", count)
	}
	if err != io.EOF {
		t.Error("Unexpected error from MinReader", err)
	}
}

// Returns an io.Reader implementation that wraps the provided io.Reader
// and decompresses data according to the predictor algorithm
func Decompressor(reader io.Reader) io.Reader {
	var ctx context
	ctx.input = make([]byte, 0, 8)

	return iou.BlockReader(iou.ReaderFunc(func(output []byte) (int, error) {
	return iou.SizedReader(iou.ReaderFunc(func(output []byte) (int, error) {
		var (
			err               error
			flags, predicted  byte
			rc, total, copied int
		)

		// Read the next prediction header