// be checked afterwards.
type bitReader struct {
	r    io.ByteReader
	n    uint64
	bits uint
	err  error
}

// newBitReader returns a new bitReader reading from r. If r is not
// already an io.ByteReader, it will be converted via a bufio.Reader.
func newBitReader(r io.Reader) bitReader {
	byter, ok := r.(io.ByteReader)
	if !ok {
		byter = bufio.NewReader(r)
	}
	return bitReader{r: byter}
}

	case '-':
		neg = true
	case '+':
		// nothing to do
	default:
		r.UnreadByte()
	}
	return
}

// byteReader is a local wrapper around fmt.ScanState;
// it implements the ByteReader interface.
type byteReader struct {
	fmt.ScanState
}

func (r byteReader) ReadByte() (byte, error) {
	ch, size, err := r.ReadRune()
	if size != 1 && err == nil {
		err = fmt.Errorf("invalid rune %#U", ch)
	}

// license that can be found in the LICENSE file.

package strings

import (
	"errors"
	"io"
	"unicode/utf8"
)

// A Reader implements the [io.Reader], [io.ReaderAt], [io.ByteReader], [io.ByteScanner],
// [io.RuneReader], [io.RuneScanner], [io.Seeker], and [io.WriterTo] interfaces by reading
// from a string.
// The zero value for Reader operates like a Reader of an empty string.
type Reader struct {

		f.Reset(encodedReader, nil)
		if f.r != encodedReader {
			t.Fatalf("provided io.ByteReader should be used directly")
		}
	})
	t.Run("BufferIsCreatedAfterByteReader", func(t *testing.T) {
		for i, r := range []io.Reader{encodedReader, bufio.NewReader(encodedReader)} {
			f := NewReader(r).(*decompressor)
			if f.r != r {
				t.Fatalf("provided io.ByteReader should be used directly, i=%d", i)
			}
			f.Reset(encodedNotByteReader, nil)

// The error is [io.EOF] only if no bytes were read.
// If an [io.EOF] happens after reading some but not all the bytes,
// ReadUvarint returns [io.ErrUnexpectedEOF].
func ReadUvarint(r io.ByteReader) (uint64, error) {
	var x uint64
	var s uint
	for i := 0; i < MaxVarintLen64; i++ {
		b, err := r.ReadByte()
		if err != nil {
			if i > 0 && err == io.EOF {
				err = io.ErrUnexpectedEOF
			}

	decoderInvalidCode = 0xffff
	flushBuffer        = 1 << maxWidth
)

// Reader is an io.Reader which can be used to read compressed data in the
// LZW format.
type Reader struct {
	r        io.ByteReader
	bits     uint32
	nBits    uint
	width    uint
	read     func(*Reader) (uint16, error) // readLSB or readMSB
	litWidth int                           // width in bits of literal codes
	err      error

}

// NewDecoder returns a new decoder that reads from the [io.Reader].
// If r does not also implement [io.ByteReader], it will be wrapped in a
// [bufio.Reader].
func NewDecoder(r io.Reader) *Decoder {
	dec := new(Decoder)
	// We use the ability to read bytes as a plausible surrogate for buffering.
	if _, ok := r.(io.ByteReader); !ok {
		r = bufio.NewReader(r)
	}
	dec.r = r
	dec.wireType = make(map[typeId]*wireType)

	return b.exp == event.NoExperiment && len(b.data) > 0 && event.Type(b.data[0]) == go122.EvFrequency
}

// readBatch reads the next full batch from r.
func readBatch(r interface {
	io.Reader
	io.ByteReader
}) (batch, uint64, error) {
	// Read batch header byte.
	b, err := r.ReadByte()
	if err != nil {
		return batch{}, 0, err
	}
	if typ := event.Type(b); typ != go122.EvEventBatch && typ != go122.EvExperimentalBatch {

	buf          [512]byte
	err          error
	multistream  bool
}

// NewReader creates a new [Reader] reading the given reader.
// If r does not also implement [io.ByteReader],
// the decompressor may read more data than necessary from r.
//
// It is the caller's responsibility to call Close on the [Reader] when done.
//
// The [Reader.Header] fields will be valid in the [Reader] returned.

	Reset(r io.Reader, dict []byte) error
}

// NewReader creates a new ReadCloser.
// Reads from the returned ReadCloser read and decompress data from r.
// If r does not implement [io.ByteReader], the decompressor may read more
// data than necessary from r.
// It is the caller's responsibility to call Close on the ReadCloser when done.
//
// The [io.ReadCloser] returned by NewReader also implements [Resetter].