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/**
* Copyright 2010 JogAmp Community. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without modification, are
* permitted provided that the following conditions are met:
*
* 1. Redistributions of source code must retain the above copyright notice, this list of
* conditions and the following disclaimer.
*
* 2. 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.
*
* THIS SOFTWARE IS PROVIDED BY JogAmp Community ``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 JogAmp Community 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 PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON
* ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
* NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
* ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*
* The views and conclusions contained in the software and documentation are those of the
* authors and should not be interpreted as representing official policies, either expressed
* or implied, of JogAmp Community.
*/
package jogamp.opengl;
import java.nio.ByteBuffer;
import java.util.HashMap;
/**
*
*/
public class MemoryObject {
private long addr;
private long size;
private int hash32;
private ByteBuffer buffer=null;
public MemoryObject(long addr, long size) {
this.addr = addr;
this.size = size;
this.hash32 = getHash32(addr, size);
}
public void setBuffer(ByteBuffer buffer) {
this.buffer = buffer;
}
public ByteBuffer getBuffer() {
return this.buffer;
}
/**
* @return the 32bit hash value generated via {@link #getHash32(long, long)}
*/
public int hashCode() {
return hash32;
}
/**
* Ignores the optional attached <code>ByteBuffer</code> intentionally.<br>
*
* @return true of reference is equal or <code>obj</code> is of type <code>MemoryObject</code>
* and <code>addr</code> and <code>size</code> is equal.<br>
*/
public boolean equals(Object obj) {
if(this == obj) { return true; }
if(obj instanceof MemoryObject) {
MemoryObject m = (MemoryObject) obj;
return addr == m.addr && size == m.size ;
}
return false;
}
/**
* Generates a 32bit hash value by <code>addr</code> and <code>size</code>.<br>
* Ignores the optional attached <code>ByteBuffer</code> intentionally.<br>
*/
public static int getHash32(long addr, long size) {
// avoid xor collisions of eg low/high parts
// 31 * x == (x << 5) - x
int hash = 31 + (int) addr ; // lo addr
hash = ((hash << 5) - hash) + (int) ( addr >>> 32 ) ; // hi addr
hash = ((hash << 5) - hash) + (int) size ; // lo size
hash = ((hash << 5) - hash) + (int) ( size >>> 32 ) ; // hi size
return hash;
}
/**
* Generates a 64bit hash value by <code>addr</code> and <code>size</code>.<br>
* Ignores the optional attached <code>ByteBuffer</code> intentionally.<br>
*/
public static long getHash64(long addr, long size) {
// 31 * x == (x << 5) - x
final long hash = 31 + addr;
return ((hash << 5) - hash) + size;
}
public String toString() {
return "MemoryObject[addr 0x"+Long.toHexString(addr)+", size 0x"+Long.toHexString(size)+", hash32: 0x"+Integer.toHexString(hash32)+"]";
}
/**
* Verifies the hash map operation, ie
* <ul>
* <li>slow add: if !map.contains(obj0), the values are verified (slow)</li>
* <li>fast get: if map.contains(obj0), the mapped value is compared with equals (fast) </li>
* </ul>
* In case the above verification fails, a RuntimeException is thrown.<br>
* In such case the calculation of the hash value should either be tuned,<br>
* or we just cannot use hash mapping.<br>
*
* @param map the identity HashMap mapping MemoryObject to MemoryObject
* @param obj0 the MemoryObject to get or add in the map
* @return either the already mapped one where <code>obj0</code> != <code>return</code>,
* or the added <code>obj0</code> == <code>return</code>.
* @throws RuntimeException if hash collision occurs
*/
public static MemoryObject getOrAddSafe(HashMap/*<MemoryObject,MemoryObject>*/ map, MemoryObject obj0) {
MemoryObject obj1 = (MemoryObject) map.get(obj0); // get identity (fast)
if(null == obj1) {
// verify hash collision (slow)
if( map.values().contains(obj0) ) {
throw new RuntimeException("Hash collision, hash !exist, but in values: "+obj0);
}
map.put(obj0, obj0);
obj1 = obj0;
} else {
// verify hash collision (ok)
if( !obj1.equals(obj0) ) {
throw new RuntimeException("Hash collision, hash equals, but objects not: query "+obj0+" != contained "+obj1);
}
}
return obj1;
}
}
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