Adding com.jogamp.common.util.IntBitfield: Simple bitfield holder class using an int[] storage.

IntBitfield comes in handy to store bit states of a wide value range w/o being a memory hog an O(1) access,
e.g. keyCode -> isPressed maps etc.

1 files changed, 71 insertions, 0 deletions

diff --git a/src/java/com/jogamp/common/util/IntBitfield.java b/src/java/com/jogamp/common/util/IntBitfield.java
new file mode 100644
index 0000000..5220063
--- /dev/null
+++ b/src/java/com/jogamp/common/util/IntBitfield.java
@@ -0,0 +1,71 @@
+/**
+ * Copyright 2012 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 IntBitfield {
+    /** Unit size in bits, here 32 bits for one int unit. */
+    public static final int UNIT_SIZE = 32;
+    
+    final int[] storage;
+    final long bits;
+    
+    /**
+     * @param bits
+     */
+    public IntBitfield(long bits) {
+        final int units = (int) ( ( bits + 7L ) / (long)UNIT_SIZE );
+        this.storage = new int[units];
+        this.bits = units * (long)UNIT_SIZE;
+    }
+    
+    private final void check(long bitnum) {
+        if( 0 > bitnum || bitnum >= bits ) {
+            throw new ArrayIndexOutOfBoundsException("Bitnum should be within [0.."+(bits-1)+"], but is "+bitnum);
+        }
+    }
+    
+    public final long capacity() { return bits; }
+    
+    public final boolean get(long bitnum) {
+        check(bitnum);
+        final int u = (int) ( bitnum / UNIT_SIZE );
+        final int b = (int) ( bitnum - ( u * UNIT_SIZE ) );
+        return 0 != ( storage[u] & ( 1 << b ) ) ;
+    }
+    
+    public final void put(long bitnum, boolean bit) {        
+        check(bitnum);
+        final int u = (int) ( bitnum / UNIT_SIZE );
+        final int b = (int) ( bitnum - ( u * UNIT_SIZE ) );
+        if(bit) {
+            storage[u] |=    1 << b;
+        } else {
+            storage[u] &= ~( 1 << b );
+        }
+    }
+}