/*
*
*
* Copyright 1990-2007 Sun Microsystems, Inc. All Rights Reserved.
* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER
*
* This program 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.
*
* 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 version 2 for more details (a copy is
* included at /legal/license.txt).
*
* 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 Sun Microsystems, Inc., 4150 Network Circle, Santa
* Clara, CA 95054 or visit www.sun.com if you need additional
* information or have any questions.
*/
package com.sun.cldc.io;
import java.io.IOException;
import java.io.InputStream;
import java.util.Vector;
/**
* Input stream class for accessing resource files in classpath.
*/
public class ResourceInputStream extends InputStream {
private Object fileDecoder;
private Object savedDecoder; // used for mark/reset functionality
/**
* Fixes the resource name to be conformant with the CLDC 1.0
* specification. We are not allowed to use "../" to get outside
* of the .jar file.
*
* @param name the name of the resource in classpath to access.
* @return the fixed string.
* @exception IOException if the resource name points to a
* classfile, as determined by the resource name's
* extension.
*/
private static String fixResourceName(String name) throws IOException {
Vector dirVector = new Vector();
int startIdx = 0;
int endIdx = 0;
String curDir;
while ((endIdx = name.indexOf('/', startIdx)) != -1) {
if (endIdx == startIdx) {
// We have a leading '/' or two consecutive '/'s
startIdx++;
continue;
}
curDir = name.substring(startIdx, endIdx);
startIdx = endIdx + 1;
if (curDir.equals(".")) {
// Ignore a single '.' directory
continue;
}
if (curDir.equals("..")) {
// Go up a level
try {
dirVector.removeElementAt(dirVector.size()-1);
} catch (ArrayIndexOutOfBoundsException aioobe) {
// "/../resource" Not allowed!
throw new IOException();
}
continue;
}
dirVector.addElement(curDir);
}
// save directory structure
StringBuffer dirName = new StringBuffer();
int nelements = dirVector.size();
for (int i = 0; i < nelements; ++i) {
dirName.append((String)dirVector.elementAt(i));
dirName.append("/");
}
// save filename
if (startIdx < name.length()) {
String filename = name.substring(startIdx);
// Throw IOE if the resource ends with ".class", but, not
// if the entire name is ".class"
if ((filename.endsWith(".class")) &&
(! ".class".equals(filename))) {
throw new IOException();
}
dirName.append(name.substring(startIdx));
}
return dirName.toString();
}
/**
* Construct a resource input stream for accessing objects in the jar file.
*
* @param name the name of the resource in classpath to access. The
* name must not have a leading '/'.
* @exception IOException if an I/O error occurs.
*/
public ResourceInputStream(String name) throws IOException {
String fixedName = fixResourceName(name);
fileDecoder = open(fixedName);
if (fileDecoder == null) {
throw new IOException();
}
}
/**
* Reads the next byte of data from the input stream.
*
* @return the next byte of data, or <code>-1</code> if the end
* of the stream is reached.
* @exception IOException if an I/O error occurs.
*/
public int read() throws IOException {
// Fix for CR 6303054
if (fileDecoder == null) {
throw new IOException();
}
return readByte(fileDecoder);
}
/**
* Gets the number of bytes remaining to be read.
*
* @return the number of bytes remaining in the resource.
* @exception IOException if an I/O error occurs.
*/
public int available() throws IOException {
if (fileDecoder == null) {
throw new IOException();
}
return bytesRemain(fileDecoder);
}
/**
* Reads bytes into a byte array.
*
* @param b the buffer to read into.
* @param off offset to start at in the buffer.
* @param len number of bytes to read.
* @return the number of bytes read, or <code>-1</code> if the end
* of the stream is reached.
* @exception IOException if an I/O error occurs.
*/
public int read(byte b[], int off, int len) throws IOException {
// Fix for CR 6303054
if (fileDecoder == null) {
throw new IOException();
}
if (b == null) {
throw new NullPointerException();
} else if ((off < 0) || (off > b.length) || (len < 0) ||
((off + len) > b.length) || ((off + len) < 0)) {
throw new IndexOutOfBoundsException();
}
return readBytes(fileDecoder, b, off, len);
}
public void close() throws IOException {
fileDecoder = null;
}
/**
* Remembers current position in ResourceInputStream so that
* subsequent call to <code>reset</code> will rewind the stream
* to the saved position.
*
* @param readlimit affects nothing
* @see java.io.InputStream#reset()
*/
public void mark(int readlimit) {
if (fileDecoder != null) {
savedDecoder = clone(fileDecoder);
}
}
/**
* Repositions this stream to the position at the time the
* <code>mark</code> method was last called on this input stream.
*
* @exception IOException if this stream has not been marked
* @see java.io.InputStream#mark(int)
*/
public void reset() throws IOException {
if (fileDecoder == null || savedDecoder == null) {
throw new IOException();
}
fileDecoder = clone(savedDecoder);
}
/**
* Indicates that this ResourceInputStream supports mark/reset
* functionality
*
* @return true
*/
public boolean markSupported() {
return true;
}
// OS-specific interface to underlying file system.
private static native Object open(String name);
private static native int bytesRemain(Object fileDecoder);
private static native int readByte(Object fileDecoder);
private static native int readBytes(Object fileDecoder,
byte b[], int off, int len);
/*
* Copies all fields from one FileDecoder object to another -
* used remember or restore current ResourceInputStream state.
*/
private static native Object clone(Object source);
}
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