Fix reheap method. [bug]

Author: trans

.ruby

@@ -44,7 +44,7 @@ revision: 0
 created: '2001-03-10'
 summary: Queue of Prioritized Elements
 title: PQueue
-version: 2.0.1
+version: 2.0.2
 name: pqueue
 description: ! 'A priority queue is like a standard queue, except that each inserted
   elements

HISTORY.rdoc

@@ -1,5 +1,21 @@
 = CHANGE HISTORY
 
+== 2.0.2 / 2011-10-29
+
+It's been one of those days. I went to to get a wash cloth for the shower,
+on my way through the kitchen realized the chilling cookie dough needed to
+be put in the oven, bit I forgot to put flower in the batter, so they burnt
+in minute and made a mess that took almost an hour to clean-up. Then I discover
+the shower still running, hot water was all but gone, and my bedroom felt like
+a suana. And to top it all off, it was at this point I realized my binary
+search algrithm didn't work. Sigh. And fuck if my grandmother won't stop making
+me food I don't want to eat. Yea, one of those days.
+
+Changes:
+
+* Fixed #reheap method.
+
+
 == 2.0.1 / 2011-10-29
 
 Quick fix to remove old legacy library that was supposed to be 

lib/pqueue.rb

@@ -261,31 +261,9 @@ def reheap(k)
     que = @que.dup
 
     v = que.delete_at(k)
+    i = binary_index(que, v)
 
-    i = que.size.div(2)
-    q = i
-    r = nil
-
-    loop do
-      case @cmp.call(v, que[i])
-      when 0, nil
-        r = i
-        break
-      when 1, true
-        i = (que.size + i).div(2)
-        i += 1 if i == q  # don't repeat yourself
-      when -1, false
-        i = (i).div(2)
-        i -= 1 if i == q  # don't repeat yourself
-      else
-        warn "bad comparison procedure in #{self.inspect}"
-        r = i
-        break
-      end
-      q = i
-    end
-
-    que.insert(r, v)
+    que.insert(i, v)
 
     @que = que
 
@@ -314,4 +292,26 @@ def sort!
   #
   alias heapify sort!
 
+  #
+  def binary_index(que, target)
+    upper = que.size - 1
+    lower = 0
+
+    while(upper >= lower) do
+      idx  = lower + (upper - lower) / 2
+      comp = @cmp.call(target, que[idx])
+
+      case comp
+      when 0, nil
+        return idx
+      when 1, true
+        lower = idx + 1
+      when -1, false
+        upper = idx - 1
+      else
+      end
+    end
+    lower
+  end
+
 end # class PQueue

meta/version

@@ -1 +1 @@
-2.0.1
+2.0.2

test/test_pqueue.rb

@@ -1,9 +1,10 @@
 require 'microtest'
+require 'ae'
 require 'ae/legacy'
 
 require 'pqueue'
 
-class TC_PQueue < MicroTest::TestCase
+class PQueueTest < MicroTest::TestCase
   include AE::Legacy::Assertions
 
   ARY_TEST   = [2,6,1,3,8,15,0,-4,7,8,10]
@@ -152,5 +153,26 @@ def test_array_copied
     q.pop
     assert_not_equal(q, r)
   end
-end
 
+  def test_reheap
+    q = PQueue.new([2,4,5])
+    q << 6
+    q.to_a.assert == [2,4,5,6]
+    q << 1
+    q.to_a.assert == [1,2,4,5,6]
+    q << 3
+    q.to_a.assert == [1,2,3,4,5,6]
+
+    q = PQueue.new([100,5,25])
+    q.to_a.assert == [5,25,100]
+    q << 17
+    q.to_a.assert == [5,17,25,100]
+    q << 0
+    q.to_a.assert == [0,5,17,25,100]
+    q << -5
+    q.to_a.assert == [-5,0,5,17,25,100]
+    q << 100
+    q.to_a.assert == [-5,0,5,17,25,100,100]
+  end
+
+end