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