Add BooleanBitSet

gab1one · abranhe · commit 210f65c54e60 · 2020-10-06T16:49:25.000-04:00
diff --git a/bit-manipulation/BooleanBitSet.java b/bit-manipulation/BooleanBitSet.java
@@ -0,0 +1,56 @@
+
+/**
+ * BooleanBitSet that encodes bits in longs, thus saving memory compared to a
+ * boolean[] array.
+ */
+public class BooleanBitSet {
+
+    final long[] storage;
+
+    public BooleanBitSet(int size) {
+        storage = new long[(int)Math.ceil(size / 64.0)];
+    }
+
+    public void set(int adress, boolean value){
+
+        // translate adress to holding long
+        int pos = (int)Math.floor(adress/ 64.0);
+        long holder = storage[pos];
+        int offset = adress % 64;
+
+        if(value){
+            holder |= 1 << offset;
+        } else {
+            holder &= ~(1 << offset);
+        }
+        storage[pos] = holder;
+    }
+
+    public boolean get(int adress){
+
+        long holder = storage[(int)Math.floor(adress/ 64.0)];
+        int offset = adress % 64;
+
+        return ((holder >> offset) & 1) == 1;
+    }
+
+    public static void main(String...strings){
+
+        BooleanBitSet b = new BooleanBitSet(20);
+        b.set(0, true);
+        b.set(1, true);
+        b.set(3, true);
+        b.set(5, true);
+
+        System.out.println(b.get(0));
+        System.out.println(b.get(1));
+        System.out.println(b.get(2));
+        System.out.println(b.get(3));
+        System.out.println(b.get(4));
+        System.out.println(b.get(5));
+        System.out.println(b.get(6));
+    }
+
+
+
+}
