// Copyright 2010 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.

package cipher

import 

// The Stream* objects are so simple that all their members are public. Users
// can create them themselves.

// StreamReader wraps a Stream into an io.Reader. It calls XORKeyStream
// to process each slice of data which passes through.
type StreamReader struct {
	S Stream
	R io.Reader
}

func ( StreamReader) ( []byte) ( int,  error) {
	,  = .R.Read()
	.S.XORKeyStream([:], [:])
	return
}

// StreamWriter wraps a Stream into an io.Writer. It calls XORKeyStream
// to process each slice of data which passes through. If any Write call
// returns short then the StreamWriter is out of sync and must be discarded.
// A StreamWriter has no internal buffering; Close does not need
// to be called to flush write data.
type StreamWriter struct {
	S   Stream
	W   io.Writer
	Err error // unused
}

func ( StreamWriter) ( []byte) ( int,  error) {
	 := make([]byte, len())
	.S.XORKeyStream(, )
	,  = .W.Write()
	if  != len() &&  == nil { // should never happen
		 = io.ErrShortWrite
	}
	return
}

// Close closes the underlying Writer and returns its Close return value, if the Writer
// is also an io.Closer. Otherwise it returns nil.
func ( StreamWriter) () error {
	if ,  := .W.(io.Closer);  {
		return .Close()
	}
	return nil
}