| /* |
| * Licensed to the Apache Software Foundation (ASF) under one or more |
| * contributor license agreements. See the NOTICE file distributed with |
| * this work for additional information regarding copyright ownership. |
| * The ASF licenses this file to You under the Apache License, Version 2.0 |
| * (the "License"); you may not use this file except in compliance with |
| * the License. You may obtain a copy of the License at |
| * |
| * http://www.apache.org/licenses/LICENSE-2.0 |
| * |
| * Unless required by applicable law or agreed to in writing, software |
| * distributed under the License is distributed on an "AS IS" BASIS, |
| * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| * See the License for the specific language governing permissions and |
| * limitations under the License. |
| * |
| */ |
| package org.apache.commons.compress.utils; |
| |
| import java.io.IOException; |
| import java.io.InputStream; |
| import java.util.zip.Checksum; |
| |
| /** |
| * A stream that calculates the checksum of the data read. |
| * @NotThreadSafe |
| * @since 1.14 |
| */ |
| public class ChecksumCalculatingInputStream extends InputStream { |
| private final InputStream in; |
| private final Checksum checksum; |
| |
| public ChecksumCalculatingInputStream(final Checksum checksum, final InputStream in) { |
| |
| if ( checksum == null ){ |
| throw new NullPointerException("Parameter checksum must not be null"); |
| } |
| |
| if ( in == null ){ |
| throw new NullPointerException("Parameter in must not be null"); |
| } |
| |
| this.checksum = checksum; |
| this.in = in; |
| } |
| |
| /** |
| * Reads a single byte from the stream |
| * @throws IOException if the underlying stream throws or the |
| * stream is exhausted and the Checksum doesn't match the expected |
| * value |
| */ |
| @Override |
| public int read() throws IOException { |
| final int ret = in.read(); |
| if (ret >= 0) { |
| checksum.update(ret); |
| } |
| return ret; |
| } |
| |
| /** |
| * Reads a byte array from the stream |
| * @throws IOException if the underlying stream throws or the |
| * stream is exhausted and the Checksum doesn't match the expected |
| * value |
| */ |
| @Override |
| public int read(final byte[] b) throws IOException { |
| return read(b, 0, b.length); |
| } |
| |
| /** |
| * Reads from the stream into a byte array. |
| * @throws IOException if the underlying stream throws or the |
| * stream is exhausted and the Checksum doesn't match the expected |
| * value |
| */ |
| @Override |
| public int read(final byte[] b, final int off, final int len) throws IOException { |
| final int ret = in.read(b, off, len); |
| if (ret >= 0) { |
| checksum.update(b, off, ret); |
| } |
| return ret; |
| } |
| |
| @Override |
| public long skip(final long n) throws IOException { |
| // Can't really skip, we have to hash everything to verify the checksum |
| if (read() >= 0) { |
| return 1; |
| } |
| return 0; |
| } |
| |
| /** |
| * Returns the calculated checksum. |
| * @return the calculated checksum. |
| */ |
| public long getValue() { |
| return checksum.getValue(); |
| } |
| |
| } |