96 lines
2.4 KiB
Java
96 lines
2.4 KiB
Java
package eu.siacs.conversations.utils.zlib;
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import java.io.IOException;
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import java.io.OutputStream;
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import java.lang.reflect.InvocationTargetException;
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import java.lang.reflect.Method;
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import java.security.NoSuchAlgorithmException;
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import java.util.zip.Deflater;
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import java.util.zip.DeflaterOutputStream;
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/**
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* <p>
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* Android 2.2 includes Java7 FLUSH_SYNC option, which will be used by this
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* Implementation, preferable via reflection. The @hide was remove in API level
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* 19. This class might thus go away in the future.
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* </p>
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* <p>
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* Please use {@link ZLibOutputStream#SUPPORTED} to check for flush
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* compatibility.
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* </p>
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*/
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public class ZLibOutputStream extends DeflaterOutputStream {
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/**
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* The reflection based flush method.
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*/
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private final static Method method;
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/**
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* SUPPORTED is true if a flush compatible method exists.
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*/
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public final static boolean SUPPORTED;
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/**
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* Static block to initialize {@link #SUPPORTED} and {@link #method}.
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*/
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static {
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Method m = null;
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try {
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m = Deflater.class.getMethod("deflate", byte[].class, int.class,
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int.class, int.class);
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} catch (SecurityException e) {
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} catch (NoSuchMethodException e) {
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}
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method = m;
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SUPPORTED = (method != null);
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}
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/**
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* Create a new ZLib compatible output stream wrapping the given low level
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* stream. ZLib compatiblity means we will send a zlib header.
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*
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* @param os
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* OutputStream The underlying stream.
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* @throws IOException
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* In case of a lowlevel transfer problem.
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* @throws NoSuchAlgorithmException
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* In case of a {@link Deflater} error.
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*/
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public ZLibOutputStream(OutputStream os) throws IOException,
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NoSuchAlgorithmException {
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super(os, new Deflater(Deflater.BEST_COMPRESSION));
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}
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/**
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* Flush the given stream, preferring Java7 FLUSH_SYNC if available.
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*
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* @throws IOException
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* In case of a lowlevel exception.
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*/
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@Override
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public void flush() throws IOException {
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if (!SUPPORTED) {
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super.flush();
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return;
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}
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try {
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int count = 0;
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do {
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count = (Integer) method.invoke(def, buf, 0, buf.length, 3);
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if (count > 0) {
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out.write(buf, 0, count);
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}
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} while (count > 0);
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} catch (IllegalArgumentException e) {
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throw new IOException("Can't flush");
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} catch (IllegalAccessException e) {
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throw new IOException("Can't flush");
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} catch (InvocationTargetException e) {
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throw new IOException("Can't flush");
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}
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super.flush();
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}
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}
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