implement BitSet.clear(bitIndex)

monmohan · Nov 23, 2013 · 0d34344 · 0d34344
1 parent 4402fc7
commit 0d34344
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Showing 2 changed files with 43 additions and 20 deletions.
diff --git a/lib/BitSet.js b/lib/BitSet.js
@@ -20,11 +20,7 @@
         var actualIndex = bitIndex & 0X1F;
         if (wordIndex < this._wordsUsed) {
             this._words[wordIndex] |= 1 << actualIndex;
-        } else {
-            throw new Error('Attempt to set bit, ' + bitIndex +
-                ' ,beyond the BitSet size, ' + this.size());
         }
-
     };
 
     BitSet.prototype.get = function (bitIndex) {
@@ -36,6 +32,16 @@
 
     };
 
+    BitSet.prototype.clear = function (bitIndex) {
+        var wordIndex = _getWordIndex(bitIndex);
+        var actualIndex = bitIndex & 0X1F;
+
+        if (wordIndex < this._wordsUsed) {
+            this._words[wordIndex] &= ~(1 << actualIndex);
+        }
+
+    };
+
     BitSet.prototype.size = function () {
         return this._wordsUsed * BITS_PER_WORD;
     };

diff --git a/tests/TestBitSet.js b/tests/TestBitSet.js
@@ -1,27 +1,44 @@
 var BitSet = require('../lib/BitSet.js'), assert = require('assert'), fs = require('fs');
-(function(){
-    function testBasic(){
-       var bs=new BitSet();
-       bs.set(15);
-       assert.equal(bs.get(15),true,'setting bit failed');
-       assert.equal(bs.get(19),false,'wrong value set');
-       assert.equal(bs.size(),32,'wrong size');
+(function () {
+    function testBasic() {
+        var bs = new BitSet();
+        bs.set(15);
+        assert.equal(bs.get(15), true, 'setting bit failed');
+        assert.equal(bs.get(19), false, 'wrong value set');
+        assert.equal(bs.size(), 32, 'wrong size');
+        assert.throws(function () {
+            bs.set(-1);
+        });
+        assert.equal(bs.get(19), false, 'wrong value set');
+        bs.clear(19);
+        assert.equal(bs.get(19), false, 'clearing problem');
+        bs.set(19);
+        assert.equal(bs.get(19), true, 'set after clear failed');
 
     }
 
-    function testLargeBitSet(){
-        var bs=new BitSet(200);
+    function testLargeBitSet() {
+        var bs = new BitSet(200);
         bs.set(156);
-        assert.equal(bs.get(156),true,'setting bit failed');
-        assert.equal(bs.get(19),false,'wrong value set');
-        assert.equal(bs.size(),224,'wrong size');
+        assert.equal(bs.get(156), true, 'setting bit failed');
+        bs.clear(156);
+        assert.equal(bs.get(156), false, 'clearing bit failed');
+
+        assert.equal(bs.size(), 224, 'wrong size');
         bs.set(32);
-        assert.equal(bs.get(32),true,'setting bit failed');
-        assert.throws(function(){bs.set(235);});
-        assert.doesNotThrow(function(){bs.get(235);});
-        assert.equal(bs.get(235),false,'wrong value set');
+        assert.equal(bs.get(32), true, 'setting bit failed');
+        bs.clear(32);
+        assert.equal(bs.get(32), false, 'clearing bit failed');
+        assert.doesNotThrow(function () {
+            bs.set(235);
+        });
+        assert.doesNotThrow(function () {
+            bs.get(235);
+        });
+        assert.equal(bs.get(235), false, 'wrong value set');
 
     }
+
     testBasic();
     testLargeBitSet();