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Diffstat (limited to 'mobile/android/thirdparty/ch/boye/httpclientandroidlib/client/entity/DeflateInputStream.java')
| -rw-r--r-- | mobile/android/thirdparty/ch/boye/httpclientandroidlib/client/entity/DeflateInputStream.java | 228 |
1 files changed, 228 insertions, 0 deletions
diff --git a/mobile/android/thirdparty/ch/boye/httpclientandroidlib/client/entity/DeflateInputStream.java b/mobile/android/thirdparty/ch/boye/httpclientandroidlib/client/entity/DeflateInputStream.java new file mode 100644 index 000000000..392a28a74 --- /dev/null +++ b/mobile/android/thirdparty/ch/boye/httpclientandroidlib/client/entity/DeflateInputStream.java @@ -0,0 +1,228 @@ +/* + * ==================================================================== + * 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 + * <http://www.apache.org/>. + * + */ +package ch.boye.httpclientandroidlib.client.entity; + +import java.io.IOException; +import java.io.InputStream; +import java.io.PushbackInputStream; +import java.util.zip.DataFormatException; +import java.util.zip.Inflater; +import java.util.zip.InflaterInputStream; + +/** 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 InputStream sourceStream; + + public DeflateInputStream(final InputStream wrapped) + throws IOException + { + /* + * A zlib stream will have a header. + * + * CMF | FLG [| DICTID ] | ...compressed data | ADLER32 | + * + * * CMF is one byte. + * + * * FLG is one byte. + * + * * DICTID is four bytes, and only present if FLG.FDICT is set. + * + * Sniff the content. Does it look like a zlib stream, with a CMF, etc? c.f. RFC1950, + * section 2.2. http://tools.ietf.org/html/rfc1950#page-4 + * + * We need to see if it looks like a proper zlib stream, or whether it is just a deflate + * stream. RFC2616 calls zlib streams deflate. Confusing, isn't it? That's why some servers + * implement deflate Content-Encoding using deflate streams, rather than zlib streams. + * + * We could start looking at the bytes, but to be honest, someone else has already read + * the RFCs and implemented that for us. So we'll just use the JDK libraries and exception + * handling to do this. If that proves slow, then we could potentially change this to check + * the first byte - does it look like a CMF? What about the second byte - does it look like + * a FLG, etc. + */ + + /* We read a small buffer to sniff the content. */ + final byte[] peeked = new byte[6]; + + final PushbackInputStream pushback = new PushbackInputStream(wrapped, peeked.length); + + final int headerLength = pushback.read(peeked); + + if (headerLength == -1) { + throw new IOException("Unable to read the response"); + } + + /* We try to read the first uncompressed byte. */ + final byte[] dummy = new byte[1]; + + final Inflater inf = new Inflater(); + + try { + int n; + while ((n = inf.inflate(dummy)) == 0) { + if (inf.finished()) { + + /* Not expecting this, so fail loudly. */ + throw new IOException("Unable to read the response"); + } + + if (inf.needsDictionary()) { + + /* Need dictionary - then it must be zlib stream with DICTID part? */ + break; + } + + if (inf.needsInput()) { + inf.setInput(peeked); + } + } + + if (n == -1) { + throw new IOException("Unable to read the response"); + } + + /* + * We read something without a problem, so it's a valid zlib stream. Just need to reset + * and return an unused InputStream now. + */ + pushback.unread(peeked, 0, headerLength); + sourceStream = new DeflateStream(pushback, new Inflater()); + } catch (final DataFormatException e) { + + /* Presume that it's an RFC1951 deflate stream rather than RFC1950 zlib stream and try + * again. */ + pushback.unread(peeked, 0, headerLength); + sourceStream = new DeflateStream(pushback, new Inflater(true)); + } finally { + inf.end(); + } + + } + + /** 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(); + } + + } + +} |