DeflateCompressorInputStream.java
- /*
- * 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.compressors.deflate;
- import java.io.IOException;
- import java.io.InputStream;
- import java.util.zip.Inflater;
- import java.util.zip.InflaterInputStream;
- import org.apache.commons.compress.compressors.CompressorInputStream;
- import org.apache.commons.compress.utils.InputStreamStatistics;
- import org.apache.commons.io.input.BoundedInputStream;
- /**
- * Deflate decompressor.
- *
- * @since 1.9
- */
- public class DeflateCompressorInputStream extends CompressorInputStream implements InputStreamStatistics {
- private static final int MAGIC_1 = 0x78;
- private static final int MAGIC_2a = 0x01;
- private static final int MAGIC_2b = 0x5e;
- private static final int MAGIC_2c = 0x9c;
- private static final int MAGIC_2d = 0xda;
- /**
- * Checks if the signature matches what is expected for a zlib / deflated file with the zlib header.
- *
- * @param signature the bytes to check
- * @param length the number of bytes to check
- * @return true, if this stream is zlib / deflate compressed with a header stream, false otherwise
- *
- * @since 1.10
- */
- public static boolean matches(final byte[] signature, final int length) {
- return length > 3 && signature[0] == MAGIC_1
- && (signature[1] == (byte) MAGIC_2a || signature[1] == (byte) MAGIC_2b || signature[1] == (byte) MAGIC_2c || signature[1] == (byte) MAGIC_2d);
- }
- private final BoundedInputStream countingStream;
- private final InputStream in;
- private final Inflater inflater;
- /**
- * Creates a new input stream that decompresses Deflate-compressed data from the specified input stream.
- *
- * @param inputStream where to read the compressed data
- */
- public DeflateCompressorInputStream(final InputStream inputStream) {
- this(inputStream, new DeflateParameters());
- }
- /**
- * Creates a new input stream that decompresses Deflate-compressed data from the specified input stream.
- *
- * @param inputStream where to read the compressed data
- * @param parameters parameters
- */
- public DeflateCompressorInputStream(final InputStream inputStream, final DeflateParameters parameters) {
- inflater = new Inflater(!parameters.withZlibHeader());
- in = new InflaterInputStream(countingStream = BoundedInputStream.builder().setInputStream(inputStream).asSupplier().get(), inflater);
- }
- /** {@inheritDoc} */
- @Override
- public int available() throws IOException {
- return in.available();
- }
- /** {@inheritDoc} */
- @Override
- public void close() throws IOException {
- try {
- in.close();
- } finally {
- inflater.end();
- }
- }
- /**
- * @since 1.17
- */
- @Override
- public long getCompressedCount() {
- return countingStream.getCount();
- }
- /** {@inheritDoc} */
- @Override
- public int read() throws IOException {
- final int ret = in.read();
- count(ret == -1 ? 0 : 1);
- return ret;
- }
- /** {@inheritDoc} */
- @Override
- public int read(final byte[] buf, final int off, final int len) throws IOException {
- if (len == 0) {
- return 0;
- }
- final int ret = in.read(buf, off, len);
- count(ret);
- return ret;
- }
- /** {@inheritDoc} */
- @Override
- public long skip(final long n) throws IOException {
- return org.apache.commons.io.IOUtils.skip(in, n);
- }
- }