added more methods to bitarray.rb

git-svn-id: http://biopieces.googlecode.com/svn/trunk@1583 74ccb610-7750-0410-82ae-013aeee3265d

diff --git a/code_ruby/lib/maasha/bitarray.rb b/code_ruby/lib/maasha/bitarray.rb
index e65ab3ca4429f9be7da258c6bb8a2f1f8b0dc673..1b2bc9ea212268c5650f44c63c58f2a6d6ceaf99 100644 (file)
--- a/code_ruby/lib/maasha/bitarray.rb
+++ b/code_ruby/lib/maasha/bitarray.rb
@@ -155,6 +155,63 @@ class BitArray
 
   alias :to_string :to_s
 
+  # Method to set the bits to "on" in an interval in a bit array.
+  # Returns the number of bits set.
+  def interval_set(start, stop)
+    raise BitArrayError, "interval start < 0 (#{start} < 0)"                      if start < 0
+    raise BitArrayError, "interval stop > bit array size (#{stop} > #{self.size})" if stop  > self.size
+    raise BitArrayError, "interval stop < interval start (#{stop} < #{start})"    if stop  < start
+
+    (start ... stop).each do |pos|
+      self.bit_set(pos)
+    end
+
+    stop - start
+  end
+
+  # Method to set the bits to "off" in an interval in a bit array.
+  # Returns the number of bits unset.
+  def interval_unset(start, stop)
+    raise BitArrayError, "interval start < 0 (#{start} < 0)"                      if start < 0
+    raise BitArrayError, "interval stop > bit array size (#{stop} > #{self.size})" if stop  > self.size
+    raise BitArrayError, "interval stop < interval start (#{stop} < #{start})"    if stop  < start
+
+    (start ... stop).each do |pos|
+      self.bit_unset(pos)
+    end
+
+    stop - start
+  end
+
+  # Method to locate intervals of bits set to "on" in a bit array.
+  #   BitArray.each_interval -> Array
+  #   BitArray.each_interval { |start, stop| } -> Fixnum
+  def each_interval
+    intervals = []
+    start     = 0
+    stop      = 0
+
+    while start < self.size
+      if self.bit_set?(start)
+        stop = start
+
+        while stop < self.size and self.bit_set?(stop)
+          stop += 1
+        end
+
+        if block_given?
+          yield start, stop
+        else
+          intervals << [start, stop]
+        end
+      end
+
+      stop > start ? start = stop : start += 1
+    end
+
+    return intervals unless block_given?
+  end
+
   private
 
   # Method to initialize the byte array (string) that constitutes the bit array.

diff --git a/code_ruby/test/maasha/test_bitarray.rb b/code_ruby/test/maasha/test_bitarray.rb
index 182ec27eee95f49aa9e139a73216c46bf21a1688..6c410be7fb1bf38f8dfc787f95f705ac4ab8d358 100755 (executable)
--- a/code_ruby/test/maasha/test_bitarray.rb
+++ b/code_ruby/test/maasha/test_bitarray.rb
@@ -123,7 +123,7 @@ class TestBitArray < Test::Unit::TestCase
     @ba.bit_set(5)
     ba.bit_set(5)
     ba.bit_set(6)
-    assert_equal( "0000010000", (@ba & ba).to_s)
+    assert_equal("0000010000", (@ba & ba).to_s)
   end
 
   def test_BitArray_OR_with_uneven_sizes_raises
@@ -137,7 +137,7 @@ class TestBitArray < Test::Unit::TestCase
     @ba.bit_set(5)
     ba.bit_set(5)
     ba.bit_set(6)
-    assert_equal( "0000111000", (@ba | ba).to_s)
+    assert_equal("0000111000", (@ba | ba).to_s)
   end
 
   def test_BitArray_XOR_with_uneven_sizes_raises
@@ -151,14 +151,46 @@ class TestBitArray < Test::Unit::TestCase
     @ba.bit_set(5)
     ba.bit_set(5)
     ba.bit_set(6)
-    assert_equal( "0000101000", (@ba ^ ba).to_s)
+    assert_equal("0000101000", (@ba ^ ba).to_s)
   end
 
   def test_BitArray_FLIP_returns_correctly
     @ba.bit_set(0)
     @ba.bit_set(9)
 
-    assert_equal( "0111111110", (~@ba).to_s)
+    assert_equal("0111111110", (~@ba).to_s)
+  end
+
+  def test_interval_set_with_bad_interval_raises
+    assert_raise(BitArrayError) { @ba.interval_set(-1, 4) }
+    assert_raise(BitArrayError) { @ba.interval_set(1, 14) }
+    assert_raise(BitArrayError) { @ba.interval_set(4, 2) }
+  end
+
+  def test_interval_set_returns_correctly
+    @ba.interval_set(1, 9)
+
+    assert_equal("0111111110", @ba.to_s)
+  end
+
+  def test_interval_unset_with_bad_interval_raises
+    assert_raise(BitArrayError) { @ba.interval_unset(-1, 4) }
+    assert_raise(BitArrayError) { @ba.interval_unset(1, 14) }
+    assert_raise(BitArrayError) { @ba.interval_unset(4, 2) }
+  end
+
+  def test_interval_unset_returns_correctly
+    ~@ba
+    @ba.interval_unset(1, 9)
+
+    assert_equal("1000000001", @ba.to_s)
+  end
+
+  def test_each_interval_returns_correctly
+    @ba.fill!
+    @ba.bit_unset(4)
+    
+    assert_equal([[0, 4], [5, 10]], @ba.each_interval.to_a)
   end
 end