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/**
* Author: Sven Gothel <sgothel@jausoft.com>
* Copyright (c) 2021 Gothel Software e.K.
*
* Permission is hereby granted, free of charge, to any person obtaining
* a copy of this software and associated documentation files (the
* "Software"), to deal in the Software without restriction, including
* without limitation the rights to use, copy, modify, merge, publish,
* distribute, sublicense, and/or sell copies of the Software, and to
* permit persons to whom the Software is furnished to do so, subject to
* the following conditions:
*
* The above copyright notice and this permission notice shall be
* included in all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
* NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
* LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
* OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
* WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
*/
package org.jau.io;
import java.nio.Buffer;
import java.nio.ByteBuffer;
import java.nio.ByteOrder;
import java.nio.CharBuffer;
import java.nio.DoubleBuffer;
import java.nio.FloatBuffer;
import java.nio.IntBuffer;
import java.nio.LongBuffer;
import java.nio.ShortBuffer;
import org.jau.lang.UnsafeUtil;
import org.jau.sys.Debug;
import org.jau.sys.PlatformProps;
/**
* Utility methods allowing easy {@link java.nio.Buffer} manipulations.
*/
public class Buffers {
static final boolean DEBUG = Debug.debug("NioUtil");
public static final int SIZEOF_BYTE = 1;
public static final int SIZEOF_SHORT = 2;
public static final int SIZEOF_CHAR = 2;
public static final int SIZEOF_INT = 4;
public static final int SIZEOF_FLOAT = 4;
public static final int SIZEOF_LONG = 8;
public static final int SIZEOF_DOUBLE = 8;
private Buffers() {}
/**
* Allocates a new direct ByteBuffer with the specified number of
* elements. The returned buffer will have its byte order set to
* the host platform's native byte order.
*/
public static ByteBuffer newDirectByteBuffer(final int size) {
return ByteBuffer.allocateDirect( size ).order( ByteOrder.nativeOrder() );
}
/**
* Helper routine to set a ByteBuffer to the native byte order, if
* that operation is supported by the underlying NIO
* implementation.
*/
public static ByteBuffer nativeOrder(final ByteBuffer buf) {
return buf.order(ByteOrder.nativeOrder());
}
/**
* Helper routine to tell whether a buffer is direct or not. Null
* pointers <b>are</b> considered direct.
*/
public static boolean isDirect(final Object buf) {
if (buf == null) {
return true;
}
if (buf instanceof Buffer) {
return ((Buffer) buf).isDirect();
}
throw new IllegalArgumentException("Unexpected buffer type " + buf.getClass().getName());
}
/**
* Helper routine to get the Buffer byte offset by taking into
* account the Buffer position and the underlying type. This is
* the total offset for Direct Buffers.
*
* Return value is of type `long` only to cover the `int` multiple of the position and element type size.<br/>
* For ByteBuffer, the return value can be safely cast to `int`.
*/
public static long getDirectBufferByteOffset(final Object buf) {
if (buf == null) {
return 0;
}
if (buf instanceof Buffer) {
final long pos = ((Buffer) buf).position();
if (buf instanceof ByteBuffer) {
return pos;
} else if (buf instanceof FloatBuffer) {
return pos * SIZEOF_FLOAT;
} else if (buf instanceof IntBuffer) {
return pos * SIZEOF_INT;
} else if (buf instanceof ShortBuffer) {
return pos * SIZEOF_SHORT;
} else if (buf instanceof DoubleBuffer) {
return pos * SIZEOF_DOUBLE;
} else if (buf instanceof LongBuffer) {
return pos * SIZEOF_LONG;
} else if (buf instanceof CharBuffer) {
return pos * SIZEOF_CHAR;
}
}
throw new IllegalArgumentException("Disallowed array backing store type in buffer " + buf.getClass().getName());
}
/**
* Access to NIO {@link sun.misc.Cleaner}, allowing caller to deterministically clean a given {@link sun.nio.ch.DirectBuffer}.
*/
public static class Cleaner {
private static final boolean hasCleaner;
/** OK to be lazy on thread synchronization, just for early out **/
private static volatile boolean cleanerError;
static {
hasCleaner = UnsafeUtil.hasInvokeCleaner();
cleanerError = !hasCleaner;
if( DEBUG ) {
System.err.println("Buffers.Cleaner.init: hasCleaner: "+hasCleaner+", cleanerError "+cleanerError);
}
}
/**
* If {@code b} is an direct NIO buffer, i.e {@link sun.nio.ch.DirectBuffer},
* calls it's {@link sun.misc.Cleaner} instance {@code clean()} method once.
* @return {@code true} if successful, otherwise {@code false}.
*/
public static boolean clean(final ByteBuffer bb) {
if( !hasCleaner && ( cleanerError || !bb.isDirect() ) ) {
return false;
}
if( PlatformProps.JAVA_9 ) {
UnsafeUtil.invokeCleaner(bb);
} else {
return false;
}
return true;
}
}
}
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