lwjgl2-arm64/src/java/org/lwjgl/BufferUtils.java

/* 
 * Copyright (c) 2002-2004 LWJGL Project
 * All rights reserved.
 * 
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are 
 * met:
 * 
 * * Redistributions of source code must retain the above copyright 
 *   notice, this list of conditions and the following disclaimer.
 *
 * * Redistributions in binary form must reproduce the above copyright
 *   notice, this list of conditions and the following disclaimer in the
 *   documentation and/or other materials provided with the distribution.
 *
 * * Neither the name of 'LWJGL' nor the names of 
 *   its contributors may be used to endorse or promote products derived 
 *   from this software without specific prior written permission.
 * 
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR 
 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, 
 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, 
 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR 
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 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */
package org.lwjgl;

import java.nio.*;
import java.nio.ByteBuffer;
import java.nio.ByteOrder;
import java.nio.FloatBuffer;
import java.nio.DoubleBuffer;
import java.nio.IntBuffer;
import java.nio.ShortBuffer;

/**
 * $Id$
 *
 * Some often-used Buffer code for creating native buffers of the appropriate size.

 * @author $Author$
 * @version $Revision$
 */

public final class BufferUtils {
	
	/**
	 * Construct a direct native-ordered bytebuffer with the specified size.
	 * @param size The size, in bytes
	 * @return a ByteBuffer
	 */	
	public static ByteBuffer createByteBuffer(int size) {
		return ByteBuffer.allocateDirect(size).order(ByteOrder.nativeOrder());
	}
	
	/**
	 * Construct a direct native-order shortbuffer with the specified number
	 * of elements.
	 * @param size The size, in shorts
	 * @return a ShortBuffer
	 */
	public static ShortBuffer createShortBuffer(int size) {
		return createByteBuffer(size << 1).asShortBuffer();
	}

	/**
	 * Construct a direct native-order intbuffer with the specified number
	 * of elements.
	 * @param size The size, in ints
	 * @return an IntBuffer
	 */
	public static IntBuffer createIntBuffer(int size) {
		return createByteBuffer(size << 2).asIntBuffer();
	}

	/**
	 * Construct a direct native-order floatbuffer with the specified number
	 * of elements.
	 * @param size The size, in floats
	 * @return a FloatBuffer
	 */
	public static FloatBuffer createFloatBuffer(int size) {
		return createByteBuffer(size << 2).asFloatBuffer();
	}

	/**
	 * Construct a direct native-order doublebuffer with the specified number
	 * of elements.
	 * @param size The size, in floats
	 * @return a FloatBuffer
	 */
	public static DoubleBuffer createDoubleBuffer(int size) {
		return createByteBuffer(size << 3).asDoubleBuffer();
	}
	
	/**
	 * A helper function which is used to get the byte offset in an arbitrary buffer
	 * based on its position
	 * @return the position of the buffer, in BYTES
	 */
	public static int getOffset(Buffer buffer) {
		if (buffer instanceof FloatBuffer || buffer instanceof IntBuffer)
			return buffer.position() << 2;
		else if (buffer instanceof ShortBuffer || buffer instanceof CharBuffer)
			return buffer.position() << 1;
		else if (buffer instanceof DoubleBuffer || buffer instanceof LongBuffer)
			return buffer.position() << 3;
		else
			return buffer.position();
	}

}