| /******************************************************************************* |
| * Copyright (c) 2000, 2006 IBM Corporation and others. |
| * All rights reserved. This program and the accompanying materials |
| * are made available under the terms of the Eclipse Public License v1.0 |
| * which accompanies this distribution, and is available at |
| * http://www.eclipse.org/legal/epl-v10.html |
| * |
| * Contributors: |
| * IBM Corporation - initial API and implementation |
| *******************************************************************************/ |
| package org.eclipse.core.internal.runtime.auth; |
| |
| import java.io.*; |
| |
| /** |
| * Decrypts a stream of data that was encrypted using the |
| * <code>Cipher</code> or <code>CipherOutputStream</code>. |
| * |
| * @see Cipher |
| * @see CipherOutputStream |
| */ |
| public class CipherInputStream extends FilterInputStream { |
| private static final int SKIP_BUFFER_SIZE = 2048; |
| private Cipher cipher; |
| |
| /** |
| * Constructs a new <code>CipherInputStream</code> that decrypts the |
| * data in the given <code>InputStream</code>. The data can only be |
| * decrypted if the given password is the same as that which was used |
| * to encrypt it. |
| * |
| * @param is |
| * @param password |
| */ |
| public CipherInputStream(InputStream is, String password) { |
| super(is); |
| cipher = new Cipher(Cipher.DECRYPT_MODE, password); |
| } |
| |
| /** |
| * @see InputStream#markSupported() |
| */ |
| public boolean markSupported() { |
| return false; |
| } |
| |
| /** |
| * @see InputStream#read() |
| */ |
| public int read() throws IOException { |
| int b = super.read(); |
| if (b == -1) |
| return -1; |
| try { |
| return (cipher.cipher((byte) b)) & 0x00ff; |
| } catch (Exception e) { |
| throw new IOException(e.getMessage()); |
| } |
| } |
| |
| /** |
| * @see InputStream#read(byte[], int, int) |
| */ |
| public int read(byte b[], int off, int len) throws IOException { |
| int bytesRead = in.read(b, off, len); |
| if (bytesRead == -1) |
| return -1; |
| try { |
| byte[] result = cipher.cipher(b, off, bytesRead); |
| for (int i = 0; i < result.length; ++i) |
| b[i + off] = result[i]; |
| return bytesRead; |
| } catch (Exception e) { |
| throw new IOException(e.getMessage()); |
| } |
| } |
| |
| /** |
| * @see InputStream#skip(long) |
| */ |
| public long skip(long n) throws IOException { |
| byte[] buffer = new byte[SKIP_BUFFER_SIZE]; |
| |
| int bytesRead = 0; |
| long bytesRemaining = n; |
| |
| while (bytesRead != -1 && bytesRemaining > 0) { |
| bytesRead = read(buffer, 0, (int) Math.min(SKIP_BUFFER_SIZE, bytesRemaining)); |
| if (bytesRead > 0) { |
| bytesRemaining -= bytesRead; |
| } |
| } |
| |
| return n - bytesRemaining; |
| } |
| } |