/*
* @(#)SocketInputStream.java 1.11 95/11/06 Jonathan Payne
*
* Copyright (c) 1994 Sun Microsystems, Inc. All Rights Reserved.
*
* Permission to use, copy, modify, and distribute this software
* and its documentation for NON-COMMERCIAL purposes and without
* fee is hereby granted provided that this copyright notice
* appears in all copies. Please refer to the file "copyright.html"
* for further important copyright and licensing information.
*
* SUN MAKES NO REPRESENTATIONS OR WARRANTIES ABOUT THE SUITABILITY OF
* THE SOFTWARE, EITHER EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED
* TO THE IMPLIED WARRANTIES OF MERCHANTABILITY, FITNESS FOR A
* PARTICULAR PURPOSE, OR NON-INFRINGEMENT. SUN SHALL NOT BE LIABLE FOR
* ANY DAMAGES SUFFERED BY LICENSEE AS A RESULT OF USING, MODIFYING OR
* DISTRIBUTING THIS SOFTWARE OR ITS DERIVATIVES.
*/
package java.net;
import java.io.IOException;
import java.io.FileInputStream;
/**
* This stream extends FileInputStream to implement a
* SocketInputStream. Note that this class should <b>NOT</b> be
* public.
*
* @version 1.11, 06 Nov 1995
* @author Jonathan Payne
* @author Arthur van Hoff
*/
class SocketInputStream extends FileInputStream
{
private boolean eof;
private SocketImpl impl;
private byte temp[] = new byte[1];
/**
* Creates a new SocketInputStream. Can only be called
* by a Socket. This method needs to hang on to the owner Socket so
* that the fd will not be closed.
* @param impl the implemented socket input stream
*/
SocketInputStream(SocketImpl impl) throws IOException {
super(impl.getFileDescriptor());
this.impl = impl;
}
/**
* Reads into an array of bytes at the specified offset using
* the received socket primitive.
* @param b the buffer into which the data is read
* @param off the start offset of the data
* @param len the maximum number of bytes read
* @return the actual number of bytes read, -1 is
* returned when the end of the stream is reached.
* @exception IOException If an I/O error has occurred.
*/
private native int socketRead(byte b[], int off, int len)
throws IOException;
/**
* Reads into a byte array data from the socket.
* @param b the buffer into which the data is read
* @return the actual number of bytes read, -1 is
* returned when the end of the stream is reached.
* @exception IOException If an I/O error has occurred.
*/
public int read(byte b[]) throws IOException {
return read(b, 0, b.length);
}
/**
* Reads into a byte array <i>b</i> at offset <i>off</i>,
* <i>length</i> bytes of data.
* @param b the buffer into which the data is read
* @param off the start offset of the data
* @param len the maximum number of bytes read
* @return the actual number of bytes read, -1 is
* returned when the end of the stream is reached.
* @exception IOException If an I/O error has occurred.
*/
public int read(byte b[], int off, int length) throws IOException {
if (eof) {
return -1;
}
int n = socketRead(b, off, length);
if (n <= 0) {
eof = true;
return -1;
}
return n;
}
/**
* Reads a single byte from the socket.
*/
public int read() throws IOException {
if (eof) {
return -1;
}
int n = read(temp, 0, 1);
if (n <= 0) {
return -1;
}
return temp[0] & 0xff;
}
/**
* Skips n bytes of input.
* @param n the number of bytes to skip
*/
public int skip(int numbytes) throws IOException {
int n = numbytes;
byte data[] = new byte[n];
while (n > 0) {
n -= read(data, 0, n);
}
return numbytes;
}
/**
* Returns the number of bytes that can be read without blocking.
* @return the number of immediately available bytes
*/
public int available() throws IOException {
return impl.available();
}
/**
* Closes the stream.
*/
public void close() throws IOException {
impl.close();
}
/**
* Overrides finalize, the fd is closed by the Socket.
*/
protected void finalize() {}
}