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Common Lisp implementation running on the JVM
/*
* EchoStream.java
*
* Copyright (C) 2004-2005 Peter Graves
* $Id$
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version 2
* of the License, or (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
*
* As a special exception, the copyright holders of this library give you
* permission to link this library with independent modules to produce an
* executable, regardless of the license terms of these independent
* modules, and to copy and distribute the resulting executable under
* terms of your choice, provided that you also meet, for each linked
* independent module, the terms and conditions of the license of that
* module. An independent module is a module which is not derived from
* or based on this library. If you modify this library, you may extend
* this exception to your version of the library, but you are not
* obligated to do so. If you do not wish to do so, delete this
* exception statement from your version.
*/
package org.armedbear.lisp;
import static org.armedbear.lisp.Lisp.*;
public final class EchoStream extends Stream
{
private final Stream in;
private final Stream out;
private int unreadChar = -1;
public EchoStream(Stream in, Stream out)
{
super(Symbol.ECHO_STREAM);
this.in = in;
this.out = out;
}
public EchoStream(Stream in, Stream out, boolean interactive)
{
super(Symbol.ECHO_STREAM);
this.in = in;
this.out = out;
setInteractive(interactive);
}
@Override
public LispObject getElementType()
{
LispObject itype = in.getElementType();
LispObject otype = out.getElementType();
if (itype.equal(otype))
return itype;
return Symbol.NULL; // FIXME
}
public Stream getInputStream()
{
return in;
}
public Stream getOutputStream()
{
return out;
}
@Override
public LispObject typeOf()
{
return Symbol.ECHO_STREAM;
}
@Override
public LispObject classOf()
{
return BuiltInClass.ECHO_STREAM;
}
@Override
public LispObject typep(LispObject type)
{
if (type == Symbol.ECHO_STREAM)
return T;
if (type == BuiltInClass.ECHO_STREAM)
return T;
return super.typep(type);
}
@Override
public boolean isInputStream()
{
return true;
}
@Override
public boolean isOutputStream()
{
return true;
}
@Override
public boolean isCharacterInputStream()
{
return in.isCharacterInputStream();
}
@Override
public boolean isBinaryInputStream()
{
return in.isBinaryInputStream();
}
@Override
public boolean isCharacterOutputStream()
{
return out.isCharacterOutputStream();
}
@Override
public boolean isBinaryOutputStream()
{
return out.isBinaryOutputStream();
}
// Returns -1 at end of file.
@Override
protected int _readChar() throws java.io.IOException
{
int n = in._readChar();
if (n >= 0) {
// Not at end of file.
if (unreadChar < 0)
out._writeChar((char)n);
else
unreadChar = -1;
}
return n;
}
@Override
protected void _unreadChar(int n) throws java.io.IOException
{
in._unreadChar(n);
unreadChar = n;
}
@Override
protected boolean _charReady() throws java.io.IOException
{
return in._charReady();
}
@Override
public void _writeChar(char c)
{
out._writeChar(c);
}
@Override
public void _writeChars(char[] chars, int start, int end)
{
out._writeChars(chars, start, end);
}
@Override
public void _writeString(String s)
{
out._writeString(s);
}
@Override
public void _writeLine(String s)
{
out._writeLine(s);
}
// Reads an 8-bit byte.
@Override
public int _readByte()
{
int n = in._readByte();
if (n >= 0)
out._writeByte(n);
return n;
}
// Writes an 8-bit byte.
@Override
public void _writeByte(int n)
{
out._writeByte(n);
}
@Override
public void _finishOutput()
{
out._finishOutput();
}
@Override
public void _clearInput()
{
in._clearInput();
}
@Override
public LispObject close(LispObject abort)
{
// "The effect of CLOSE on a constructed stream is to close the
// argument stream only. There is no effect on the constituents of
// composite streams."
setOpen(false);
return T;
}
@Override
public LispObject listen()
{
return in.listen();
}
@Override
public LispObject freshLine()
{
return out.freshLine();
}
// ### make-echo-stream
// input-stream output-stream => echo-stream
private static final Primitive MAKE_ECHO_STREAM =
new Primitive("make-echo-stream", "input-stream output-stream")
{
@Override
public LispObject execute(LispObject first, LispObject second)
{
if (!(first instanceof Stream))
return type_error(first, Symbol.STREAM);
if (!(second instanceof Stream))
return type_error(second, Symbol.STREAM);
return new EchoStream((Stream) first, (Stream) second);
}
};
// ### echo-stream-input-stream
// echo-stream => input-stream
private static final Primitive ECHO_STREAM_INPUT_STREAM =
new Primitive("echo-stream-input-stream", "echo-stream")
{
@Override
public LispObject execute(LispObject arg)
{
if (arg instanceof EchoStream)
return ((EchoStream)arg).getInputStream();
return type_error(arg, Symbol.ECHO_STREAM);
}
};
// ### echo-stream-output-stream
// echo-stream => output-stream
private static final Primitive ECHO_STREAM_OUTPUT_STREAM =
new Primitive("echo-stream-output-stream", "echo-stream")
{
@Override
public LispObject execute(LispObject arg)
{
if (arg instanceof EchoStream)
return ((EchoStream)arg).getOutputStream();
return type_error(arg, Symbol.ECHO_STREAM);
}
};
}