137 lines
2.9 KiB
Java
137 lines
2.9 KiB
Java
/* Copyright (C) 1998, 1999 Cygnus Solutions
|
|
|
|
This file is part of libgcj.
|
|
|
|
This software is copyrighted work licensed under the terms of the
|
|
Libgcj License. Please consult the file "LIBGCJ_LICENSE" for
|
|
details. */
|
|
|
|
package java.io;
|
|
|
|
/**
|
|
* @author Warren Levy <warrenl@cygnus.com>
|
|
* @date October 16, 1998.
|
|
*/
|
|
/* Written using "Java Class Libraries", 2nd edition, ISBN 0-201-31002-3
|
|
* "The Java Language Specification", ISBN 0-201-63451-1
|
|
* plus online API docs for JDK 1.2 beta from http://www.javasoft.com.
|
|
* Status: Believed complete and correct.
|
|
*/
|
|
|
|
public class PushbackReader extends FilterReader
|
|
{
|
|
/* Internal buffer array for data. */
|
|
private char[] buf;
|
|
|
|
/* The current position in the buffer. */
|
|
private int pos;
|
|
|
|
public PushbackReader(Reader in)
|
|
{
|
|
this(in, 1);
|
|
}
|
|
|
|
public PushbackReader(Reader in, int size)
|
|
{
|
|
super(in);
|
|
if (size < 0)
|
|
throw new IllegalArgumentException();
|
|
buf = new char[size];
|
|
pos = buf.length;
|
|
}
|
|
|
|
public void close() throws IOException
|
|
{
|
|
synchronized (lock)
|
|
{
|
|
buf = null;
|
|
super.close();
|
|
}
|
|
}
|
|
|
|
public boolean markSupported()
|
|
{
|
|
return false;
|
|
}
|
|
|
|
public int read() throws IOException
|
|
{
|
|
synchronized (lock)
|
|
{
|
|
if (buf == null)
|
|
throw new IOException();
|
|
|
|
if (pos < buf.length)
|
|
return ((int) buf[pos++]) & 0xFFFF;
|
|
|
|
return super.read();
|
|
}
|
|
}
|
|
|
|
public int read(char[] b, int off, int len) throws IOException
|
|
{
|
|
synchronized (lock)
|
|
{
|
|
if (buf == null)
|
|
throw new IOException();
|
|
|
|
if (off < 0 || len < 0 || off + len > b.length)
|
|
throw new ArrayIndexOutOfBoundsException();
|
|
|
|
int numBytes = Math.min(buf.length - pos, len);
|
|
for (int i = 0; i < numBytes; i++)
|
|
b[off++] = buf[pos++];
|
|
|
|
return numBytes + super.read(b, off, len - numBytes);
|
|
}
|
|
}
|
|
|
|
public boolean ready() throws IOException
|
|
{
|
|
synchronized (lock)
|
|
{
|
|
if (buf == null)
|
|
throw new IOException();
|
|
|
|
if (buf.length - pos > 0)
|
|
return true;
|
|
|
|
return super.ready();
|
|
}
|
|
}
|
|
|
|
public void unread(int b) throws IOException
|
|
{
|
|
synchronized (lock)
|
|
{
|
|
if (buf == null || pos <= 0)
|
|
throw new IOException();
|
|
|
|
buf[--pos] = (char) b;
|
|
}
|
|
}
|
|
|
|
public void unread(char[] b) throws IOException
|
|
{
|
|
unread(b, 0, b.length);
|
|
}
|
|
|
|
public void unread(char[] b, int off, int len) throws IOException
|
|
{
|
|
synchronized (lock)
|
|
{
|
|
if (buf == null || pos < len)
|
|
throw new IOException();
|
|
|
|
// Note the order that these chars are being added is the opposite
|
|
// of what would be done if they were added to the buffer one at a time.
|
|
// See the Java Class Libraries book p. 1397.
|
|
System.arraycopy(b, off, buf, pos - len, len);
|
|
|
|
// Don't put this into the arraycopy above, an exception might be thrown
|
|
// and in that case we don't want to modify pos.
|
|
pos -= len;
|
|
}
|
|
}
|
|
}
|