}
	}
	n := copy(d.window[d.windowEnd:], b)
	d.windowEnd += n
	return n
}

func (d *compressor) writeBlock(tokens []token, index int) error {
	if index > 0 {
		var window []byte
		if d.blockStart <= index {
			window = d.window[d.blockStart:index]
		}
		d.blockStart = index
		d.w.writeBlock(tokens, false, window)
		return d.w.err
	}
	return nil
}

	return n
}

// countMutex returns the number of records in the mutex profile.
func countMutex() int {
	n, _ := runtime.MutexProfile(nil)
	return n
}

// writeBlock writes the current blocking profile to w.
func writeBlock(w io.Writer, debug int) error {
	return writeProfileInternal(w, debug, "contention", pprof_blockProfileInternal)
}

// writeMutex writes the current mutex profile to w.

func writeDatblkToOutBuf(ctxt *Link, out *OutBuf, addr int64, size int64) {
	writeBlocks(ctxt, out, ctxt.outSem, ctxt.loader, ctxt.datap, addr, size, zeros[:])
}

func dwarfblk(ctxt *Link, out *OutBuf, addr int64, size int64) {
	// Concatenate the section symbol lists into a single list to pass
	// to writeBlocks.
	//
	// NB: ideally we would do a separate writeBlocks call for each

		}
		err = fd.eofError(n, err)
		return n, oobn, sysflags, err
	}
}

// Write implements io.Writer.
func (fd *FD) Write(p []byte) (int, error) {
	if err := fd.writeLock(); err != nil {
		return 0, err
	}
	defer fd.writeUnlock()
	if err := fd.pd.prepareWrite(fd.isFile); err != nil {
		return 0, err
	}
	var nn int
	for {
		max := len(p)
		if fd.IsStream && max-nn > maxRW {
			max = nn + maxRW

func SendFile(dstFD *FD, src int, remain int64) (written int64, err error, handled bool) {
	defer func() {
		TestHookDidSendFile(dstFD, src, written, err, handled)
	}()
	if err := dstFD.writeLock(); err != nil {
		return 0, err, false
	}
	defer dstFD.writeUnlock()

	if err := dstFD.pd.prepareWrite(dstFD.isFile); err != nil {
		return 0, err, false
	}

	dst := dstFD.Sysfd
	for remain > 0 {
		n := maxSendfileSize

func SendFile(dstFD *FD, src int, pos, remain int64) (written int64, err error, handled bool) {
	defer func() {
		TestHookDidSendFile(dstFD, src, written, err, handled)
	}()
	if err := dstFD.writeLock(); err != nil {
		return 0, err, false
	}
	defer dstFD.writeUnlock()

	if err := dstFD.pd.prepareWrite(dstFD.isFile); err != nil {
		return 0, err, false
	}

	dst := dstFD.Sysfd
	for remain > 0 {
		n := maxSendfileSize

func SendFile(dstFD *FD, src int, pos, remain int64) (written int64, err error, handled bool) {
	defer func() {
		TestHookDidSendFile(dstFD, src, written, err, handled)
	}()
	if err := dstFD.writeLock(); err != nil {
		return 0, err, false
	}
	defer dstFD.writeUnlock()

	if err := dstFD.pd.prepareWrite(dstFD.isFile); err != nil {
		return 0, err, false
	}

	dst := dstFD.Sysfd
	for remain > 0 {
		n := maxSendfileSize

		return 0, syscall.ESPIPE
	}
	if ft, _ := syscall.GetFileType(src); ft == syscall.FILE_TYPE_PIPE {
		return 0, syscall.ESPIPE
	}

	if err := fd.writeLock(); err != nil {
		return 0, err
	}
	defer fd.writeUnlock()

	o := &fd.wop
	o.handle = src

	// TODO(brainman): skip calling syscall.Seek if OS allows it
	curpos, err := syscall.Seek(o.handle, 0, io.SeekCurrent)
	if err != nil {

	// locks for both file descriptors (and why this whole machinery is
	// in the internal/poll package to begin with).
	if err := dst.writeLock(); err != nil {
		return 0, err
	}
	defer dst.writeUnlock()
	if err := src.readLock(); err != nil {
		return 0, err
	}
	defer src.readUnlock()
	var n int
	for {
		n, err = unix.CopyFileRange(src.Sysfd, nil, dst.Sysfd, nil, max, 0)

// Since Plan 9 preserves message boundaries, never allow
// a zero-byte write.
func (f *File) write(b []byte) (n int, err error) {
	if err := f.writeLock(); err != nil {
		return 0, err
	}
	defer f.writeUnlock()
	if len(b) == 0 {
		return 0, nil
	}
	return fixCount(syscall.Write(f.fd, b))
}

// pwrite writes len(b) bytes to the File starting at byte offset off.