org.apache.http.client.entity.DeflateInputStream Maven / Gradle / Ivy

Go to download
Show more of this group Show more artifacts with this name
Show all versions of httpclient Show documentation
Builds the httpclient. Requires the commons logging to be built first and be excluded from any other poms requiring it.
The newest version!
/*
 * ====================================================================
 * 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.
 * ====================================================================
 *
 * This software consists of voluntary contributions made by many
 * individuals on behalf of the Apache Software Foundation.  For more
 * information on the Apache Software Foundation, please see
 * .
 *
 */
package org.apache.http.client.entity;

import java.io.IOException;
import java.io.InputStream;
import java.io.PushbackInputStream;
import java.util.zip.Inflater;
import java.util.zip.InflaterInputStream;
import java.util.zip.ZipException;

/**
 * Deflate input stream.    This class includes logic needed for various Rfc's in order
 * to reasonably implement the "deflate" compression style.
 */
public class DeflateInputStream extends InputStream {

    private final InputStream sourceStream;

    public DeflateInputStream(final InputStream wrapped) throws IOException {

        final PushbackInputStream pushback = new PushbackInputStream(wrapped, 2);
        final int i1 = pushback.read();
        final int i2 = pushback.read();
        if (i1 == -1 || i2 == -1) {
            throw new ZipException("Unexpected end of stream");
        }

        pushback.unread(i2);
        pushback.unread(i1);

        boolean nowrap = true;
        final int b1 = i1 & 0xFF;
        final int compressionMethod = b1 & 0xF;
        final int compressionInfo = b1 >> 4 & 0xF;
        final int b2 = i2 & 0xFF;
        if (compressionMethod == 8 && compressionInfo <= 7 && ((b1 << 8) | b2) % 31 == 0) {
            nowrap = false;
        }
        sourceStream = new DeflateStream(pushback, new Inflater(nowrap));
    }

    /**
     * Read a byte.
     */
    @Override
    public int read() throws IOException {
        return sourceStream.read();
    }

    /**
     * Read lots of bytes.
     */
    @Override
    public int read(final byte[] b) throws IOException {
        return sourceStream.read(b);
    }

    /**
     * Read lots of specific bytes.
     */
    @Override
    public int read(final byte[] b, final int off, final int len) throws IOException {
        return sourceStream.read(b, off, len);
    }

    /**
     * Skip
     */
    @Override
    public long skip(final long n) throws IOException {
        return sourceStream.skip(n);
    }

    /**
     * Get available.
     */
    @Override
    public int available() throws IOException {
        return sourceStream.available();
    }

    /**
     * Mark.
     */
    @Override
    public void mark(final int readLimit) {
        sourceStream.mark(readLimit);
    }

    /**
     * Reset.
     */
    @Override
    public void reset() throws IOException {
        sourceStream.reset();
    }

    /**
     * Check if mark is supported.
     */
    @Override
    public boolean markSupported() {
        return sourceStream.markSupported();
    }

    /**
     * Close.
     */
    @Override
    public void close() throws IOException {
        sourceStream.close();
    }

    static class DeflateStream extends InflaterInputStream {

        private boolean closed = false;

        public DeflateStream(final InputStream in, final Inflater inflater) {
            super(in, inflater);
        }

        @Override
        public void close() throws IOException {
            if (closed) {
                return;
            }
            closed = true;
            inf.end();
            super.close();
        }

    }

}