Fix Long*HashMap impl. of IntIntHashMap: Better 64bit hash value, using new HashUtil.

Introduce markup: /*keyHash*/(.*)/*keyHash*/ allowing Long*HashMap to inject hash function for 64bit value.

2 files changed, 79 insertions, 12 deletions

diff --git a/src/java/com/jogamp/common/util/HashUtil.java b/src/java/com/jogamp/common/util/HashUtil.java
new file mode 100644
index 0000000..c5a3bff
--- /dev/null
+++ b/src/java/com/jogamp/common/util/HashUtil.java
@@ -0,0 +1,66 @@
+/**
+ * Copyright 2013 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 com.jogamp.common.util;
+
+public class HashUtil {
+    /**
+     * Generates a 32bit equally distributed identity hash value 
+     * from <code>addr</code> avoiding XOR collision.
+     */
+    public static int getAddrHash32_EqualDist(long addr) {
+        // avoid xor collisions of low/high parts
+        // 31 * x == (x << 5) - x
+        int  hash = 31 +              (int)   addr          ; // lo addr
+        return ((hash << 5) - hash) + (int) ( addr >>> 32 ) ; // hi addr
+    }
+    
+    /**
+     * Generates a 32bit equally distributed identity hash value 
+     * from <code>addr</code> and <code>size</code> avoiding XOR collision.
+     */
+    public static int getAddrSizeHash32_EqualDist(long addr, long size) {
+        // avoid xor collisions of 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
+        return ((hash << 5) - hash) + (int) ( size >>> 32 ) ; // hi size
+    }
+    
+    /**
+     * Generates a 64bit equally distributed hash value 
+     * from <code>addr</code> and <code>size</code> avoiding XOR collisions.
+     */
+    public static long getHash64(long addr, long size) {
+        // 31 * x == (x << 5) - x
+        final long hash = 31 + addr;
+        return ((hash << 5) - hash) + size;
+    }
+
+    
+}
diff --git a/src/java/com/jogamp/common/util/IntIntHashMap.java b/src/java/com/jogamp/common/util/IntIntHashMap.java
index bd5529e..7909478 100644
--- a/src/java/com/jogamp/common/util/IntIntHashMap.java
+++ b/src/java/com/jogamp/common/util/IntIntHashMap.java
@@ -207,8 +207,8 @@ public class /*name*/IntIntHashMap/*name*/ implements Cloneable,
 
 //    @SuppressWarnings(value="cast")
     public boolean containsKey(/*key*/int/*key*/ key) {
-        Entry[] t = this.table;
-        int index = (int) (key & mask);
+        final Entry[] t = this.table;
+        final int index = /*keyHash*/key/*keyHash*/ & mask;
         for (Entry e = t[index]; e != null; e = e.next) {
             if (e.key == key) {
                 return true;
@@ -223,8 +223,8 @@ public class /*name*/IntIntHashMap/*name*/ implements Cloneable,
      */
 //    @SuppressWarnings(value="cast")
     public /*value*/int/*value*/ get(/*key*/int/*key*/ key) {
-        Entry[] t = this.table;
-        int index = (int) (key & mask);
+        final Entry[] t = this.table;
+        final int index = /*keyHash*/key/*keyHash*/ & mask;
         for (Entry e = t[index]; e != null; e = e.next) {
             if (e.key == key) {
                 return e.value;
@@ -240,7 +240,7 @@ public class /*name*/IntIntHashMap/*name*/ implements Cloneable,
 //    @SuppressWarnings(value="cast")
     public /*value*/int/*value*/ put(/*key*/int/*key*/ key, /*value*/int/*value*/ value) {
         final Entry[] t = this.table;
-        int index = (int) (key & mask);
+        final int index = /*keyHash*/key/*keyHash*/ & mask;
         // Check if key already exists.
         for (Entry e = t[index]; e != null; e = e.next) {
             if (e.key != key) {
@@ -254,18 +254,18 @@ public class /*name*/IntIntHashMap/*name*/ implements Cloneable,
 
         if (size++ >= threshold) {
             // Rehash.
-            int newCapacity = 2 * capacity;
+            final int newCapacity = 2 * capacity;
             final Entry[] newTable = new Entry[newCapacity];
-            /*key*/int/*key*/ bucketmask = newCapacity - 1;
+            final int newMask = newCapacity - 1;
             for (int j = 0; j < t.length; j++) {
                 Entry e = t[j];
                 if (e != null) {
                     t[j] = null;
                     do {
                         Entry next = e.next;
-                        index = (int) (e.key & bucketmask);
-                        e.next = newTable[index];
-                        newTable[index] = e;
+                        final int index2 = /*keyHash*/e.key/*keyHash*/ & newMask;
+                        e.next = newTable[index2];
+                        newTable[index2] = e;
                         e = next;
                     } while (e != null);
                 }
@@ -273,7 +273,7 @@ public class /*name*/IntIntHashMap/*name*/ implements Cloneable,
             table = newTable;
             capacity = newCapacity;
             threshold = (int) (newCapacity * loadFactor);
-            mask = capacity - 1;
+            mask = newMask;
         }
         return keyNotFoundValue;
     }
@@ -296,9 +296,10 @@ public class /*name*/IntIntHashMap/*name*/ implements Cloneable,
 //    @SuppressWarnings(value="cast")
     public /*value*/int/*value*/ remove(/*key*/int/*key*/ key) {
         final Entry[] t = this.table;
-        final int index = (int) (key & mask);
+        final int index = /*keyHash*/key/*keyHash*/ & mask;
         Entry prev = t[index];
         Entry e = prev;
+        
         while (e != null) {
             Entry next = e.next;
             if (e.key == key) {