Fix setting a 0-bit to 0

peterc · Jul 11, 2018 · cff29e5 · cff29e5
1 parent 6018faa
commit cff29e5
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Showing 2 changed files with 9 additions and 5 deletions.
diff --git a/lib/bitarray.rb b/lib/bitarray.rb
@@ -15,7 +15,7 @@ def []=(position, value)
     if value == 1
       @field.setbyte(position >> 3, @field.getbyte(position >> 3) | (1 << (position % 8)))
     else
-      @field.setbyte(position >> 3, @field.getbyte(position >> 3) ^ (1 << (position % 8)))
+      @field.setbyte(position >> 3, @field.getbyte(position >> 3) & ~(1 << (position % 8)))
     end
   end
 

diff --git a/test/test_bitarray.rb b/test/test_bitarray.rb
@@ -30,15 +30,19 @@ def test_random_setting_and_unsetting
 
   def test_multiple_setting
     1.upto(999) do |pos|
-      2.times { @public_ba[pos] = 1 }
-      assert_equal 1, @public_ba[pos]
+      2.times do
+        @public_ba[pos] = 1
+        assert_equal 1, @public_ba[pos]
+      end
     end
   end
 
   def test_multiple_unsetting
     1.upto(999) do |pos|
-      2.times { @public_ba[pos] = 0 }
-      assert_equal 0, @public_ba[pos]
+      2.times do
+        @public_ba[pos] = 0
+        assert_equal 0, @public_ba[pos]
+      end
     end
   end