// Read the first 4 bytes of the file.

	f, err := os.Open(name)
	if err != nil {
		return nil, fmt.Errorf("error opening %s: %v", name, err)
	}
	defer f.Close()

	var header [4]byte
	if _, err = io.ReadFull(f, header[:]); err != nil {
		return nil, fmt.Errorf("error reading magic number from %s: %v", name, err)
	}

	elfMagic := string(header[:])

	// Match against supported file types.

	}
	f, err := os.Open(c.fileName(id, "a"))
	if err != nil {
		return missing(err)
	}
	defer f.Close()
	entry := make([]byte, entrySize+1) // +1 to detect whether f is too long
	if n, err := io.ReadFull(f, entry); n > entrySize {
		return missing(errors.New("too long"))
	} else if err != io.ErrUnexpectedEOF {
		if err == io.EOF {
			return missing(errors.New("file is empty"))
		}
		return missing(err)

		t.Fatal(err)
	}

	if _, err := stdin.Write([]byte("O:hi\n")); err != nil {
		t.Fatal(err)
	}
	buf := make([]byte, 5)
	n, err := io.ReadFull(stdout, buf)
	if n != len(buf) || err != nil || string(buf) != "O:hi\n" {
		t.Fatalf("ReadFull = %d, %v, %q", n, err, buf[:n])
	}
	go cancel()

	if err := c.Wait(); err == nil {
		t.Fatal("expected Wait failure")
	}
}

			}
			bb := make([]byte, len(b))
			if *fast {
				clientConn.SetReadDeadline(time.Now().Add(1 * time.Second))
			} else {
				clientConn.SetReadDeadline(time.Now().Add(1 * time.Minute))
			}
			n, err := io.ReadFull(clientConn, bb)
			if err != nil {
				t.Fatalf("%s #%d: %s\nRead %d, wanted %d, got %x, wanted %x\n", test.name, i+1, err, n, len(bb), bb[:n], b)
			}
			if !bytes.Equal(b, bb) {

		c.sendAlert(alertIllegalParameter)
		return errors.New("tls: TLS 1.3 client supports illegal compression methods")
	}

	hs.hello.random = make([]byte, 32)
	if _, err := io.ReadFull(c.config.rand(), hs.hello.random); err != nil {
		c.sendAlert(alertInternalError)
		return err
	}

	if len(hs.clientHello.secureRenegotiation) != 0 {
		c.sendAlert(alertHandshakeFailure)

	c.mutex.RUnlock()
	defer c.mutex.RLock()
	c.mutex.Lock()
	defer c.mutex.Unlock()
	if c.SessionTicketKey == [32]byte{} {
		if _, err := io.ReadFull(c.rand(), c.SessionTicketKey[:]); err != nil {
			panic(fmt.Sprintf("tls: unable to generate random session ticket key: %v", err))
		}
		// Write the deprecated prefix at the beginning so we know we created

// Read reads data into p.
// It returns the number of bytes read into p.
// The bytes are taken from at most one Read on the underlying [Reader],
// hence n may be less than len(p).
// To read exactly len(p) bytes, use io.ReadFull(b, p).
// If the underlying [Reader] can return a non-zero count with io.EOF,
// then this Read method can do so as well; see the [io.Reader] docs.
func (b *Reader) Read(p []byte) (n int, err error) {
	n = len(p)

	var ctype string
	if !haveType {
		ctype = mime.TypeByExtension(filepath.Ext(name))
		if ctype == "" {
			// read a chunk to decide between utf-8 text and binary
			var buf [sniffLen]byte
			n, _ := io.ReadFull(content, buf[:])
			ctype = DetectContentType(buf[:n])
			_, err := content.Seek(0, io.SeekStart) // rewind to output whole file
			if err != nil {
				serveError(w, "seeker can't seek", StatusInternalServerError)

		err = rb.WriteByte(0)
		done <- err
		_, err = rb.TryWrite([]byte("world"))
		done <- err
		err = rb.TryWriteByte(0)
		done <- err
	}()

	buf := make([]byte, 100)
	n, err := io.ReadFull(rb, buf)
	if err != nil && err != io.ErrUnexpectedEOF {
		t.Fatalf("got: %q; want: %q", err, io.ErrUnexpectedEOF)
	}
	for writeErr := range done {
		if writeErr != ErrWriteOnClosed {

func (r *readRune) readByte() (b byte, err error) {
	if r.pending > 0 {
		b = r.pendBuf[0]
		copy(r.pendBuf[0:], r.pendBuf[1:])
		r.pending--
		return
	}
	n, err := io.ReadFull(r.reader, r.pendBuf[:1])
	if n != 1 {
		return 0, err
	}
	return r.pendBuf[0], err
}

// ReadRune returns the next UTF-8 encoded code point from the
// io.Reader inside r.