buf := make([]byte, len(expect))
	r, err := os.Open(file)
	if err != nil {
		// Test did not create profile, which is OK.
		return
	}
	defer r.Close()

	n, err := io.ReadFull(r, buf)
	if n == 0 {
		return
	}
	if err != nil || string(buf) != expect {
		fmt.Fprintf(ew, "error: test wrote malformed coverage profile %s.\n", file)
		return
	}
	_, err = io.Copy(coverMerge.f, r)

			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
	}

import (
	"bytes"
	"fmt"
	"io"
	"os"
)

func main() {
	f, err := os.Open(os.Args[1])
	if err != nil {
		fmt.Fprintln(os.Stderr, err)
		os.Exit(1)
	}
	buf := make([]byte, 100)
	io.ReadFull(f, buf)
	f.Close()
	if !bytes.HasPrefix(buf, []byte("!<arch>\n")) {
		fmt.Fprintf(os.Stderr, "file %s exists but is not an archive\n", os.Args[1])
		os.Exit(1)
	}

		rbuf := make([]byte, 2500)
		n, err := io.ReadFull(resp.Body, rbuf)
		checkErr(err, "2500 byte ReadFull")
		if n != 2500 {
			fatalf("ReadFull only read %d bytes", n)
		}
		if test.compressed == false && !bytes.Equal(bytes.Repeat([]byte{'x'}, 2500), rbuf) {
			fatalf("ReadFull didn't read 2500 'x'; got %q", string(rbuf))
		}
		resp.Body.Close()

		rest, err := io.ReadAll(bufr)
		checkErr(err, "ReadAll on remainder")

	_, err := w.Write(buf[0:binary.MaxVarintLen64])
	return err
}

// readInt reads an int x from r using buf to buffer the read and returns x.
func readInt(r io.Reader, buf []byte) (int64, error) {
	_, err := io.ReadFull(r, buf[0:binary.MaxVarintLen64]) // ok to continue with error
	x, _ := binary.Varint(buf)
	return x, err
}

// writeSlice writes data[:n] to w and returns n.
// It uses buf to buffer the write.

		toread := r.fileView[r.off:]
		if len(toread) < 1 {
			return 0, io.EOF
		}
		if len(toread) < amt {
			amt = len(toread)
		}
		copy(p, toread)
		r.off += int64(amt)
		return amt, nil
	}
	return io.ReadFull(r.rdr, p)
}

func (r *MReader) ReadByte() (byte, error) {
	if r.fileView != nil {
		toread := r.fileView[r.off:]
		if len(toread) < 1 {
			return 0, io.EOF
		}
		rv := toread[0]
		r.off++

	"bufio"
	"fmt"
	"io"
	"strconv"
	"strings"
)

func readGopackHeader(r *bufio.Reader) (name string, size int, err error) {
	// See $GOROOT/include/ar.h.
	hdr := make([]byte, 16+12+6+6+8+10+2)
	_, err = io.ReadFull(r, hdr)
	if err != nil {
		return
	}
	// leave for debugging
	if false {
		fmt.Printf("header: %s", hdr)
	}
	s := strings.TrimSpace(string(hdr[16+12+6+6+8:][:10]))
	size, err = strconv.Atoi(s)

			// Flush and Close on the transmitter side.
			if _, err := io.ReadFull(zr, b[:1]); err != nil {
				if err == io.EOF {
					break // The transmitter closed the stream
				}
				log.Fatal(err)
			}

			// Read the message content.
			n := int(b[0])
			if _, err := io.ReadFull(zr, b[:n]); err != nil {
				log.Fatal(err)
			}

	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))

	r, w := Pipe()
	go func() {
		w.Write([]byte{})
		w.Close()
	}()
	var b [2]byte
	ReadFull(r, b[0:2])
	r.Close()
}

func TestWriteNil(t *testing.T) {
	r, w := Pipe()
	go func() {
		w.Write(nil)
		w.Close()
	}()
	var b [2]byte
	ReadFull(r, b[0:2])
	r.Close()
}

func TestWriteAfterWriterClose(t *testing.T) {
	r, w := Pipe()
	defer r.Close()