/*
* Copyright (c) 1997, 1999, Oracle and/or its affiliates. All rights reserved.
* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
*
* This code is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License version 2 only, as
* published by the Free Software Foundation. Oracle designates this
* particular file as subject to the "Classpath" exception as provided
* by Oracle in the LICENSE file that accompanied this code.
*
* This code 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
* version 2 for more details (a copy is included in the LICENSE file that
* accompanied this code).
*
* You should have received a copy of the GNU General Public License version
* 2 along with this work; if not, write to the Free Software Foundation,
* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
*
* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
* or visit www.oracle.com if you need additional information or have any
* questions.
*/
package sun.rmi.log;
import java.io.*;
public
class LogInputStream extends InputStream {
private InputStream in;
private int length;
/**
* Creates a log input file with the specified system dependent
* file descriptor.
* @param fd the system dependent file descriptor
* @param length the total number of bytes allowed to be read
* @exception IOException If an I/O error has occurred.
*/
public LogInputStream(InputStream in, int length) throws IOException {
this.in = in;
this.length = length;
}
/**
* Reads a byte of data. This method will block if no input is
* available.
* @return the byte read, or -1 if the end of the log or end of the
* stream is reached.
* @exception IOException If an I/O error has occurred.
*/
public int read() throws IOException {
if (length == 0)
return -1;
int c = in.read();
length = (c != -1) ? length - 1 : 0;
return c;
}
/**
* Reads data into an array of bytes.
* This method blocks until some input is available.
* @param b the buffer into which the data is read
* @return the actual number of bytes read, or -1 if the end of the log
* or 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 data into an array of bytes.
* This method blocks until some input is available.
* @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, or -1 if the end of the log or
* end of the stream is reached.
* @exception IOException If an I/O error has occurred.
*/
public int read(byte b[], int off, int len) throws IOException {
if (length == 0)
return -1;
len = (length < len) ? length : len;
int n = in.read(b, off, len);
length = (n != -1) ? length - n : 0;
return n;
}
/**
* Skips n bytes of input.
* @param n the number of bytes to be skipped
* @return the actual number of bytes skipped.
* @exception IOException If an I/O error has occurred.
*/
public long skip(long n) throws IOException {
if (n > Integer.MAX_VALUE)
throw new IOException("Too many bytes to skip - " + n);
if (length == 0)
return 0;
n = (length < n) ? length : n;
n = in.skip(n);
length -= n;
return n;
}
/**
* Returns the number of bytes that can be read without blocking.
* @return the number of available bytes, which is initially
* equal to the file size.
*/
public int available() throws IOException {
int avail = in.available();
return (length < avail) ? length : avail;
}
/**
* Closes the input stream. No further input can be read.
* the stream.
*/
public void close() {
length = 0;
}
/**
* Closes the stream when garbage is collected.
*/
protected void finalize() throws IOException {
close();
}
}