OCC22278 No any sorting algorithm implemented for NCollection templates Developen by : KGV

src/NCollection/NCollection_QuickSort.hxx

@@ -0,0 +1,97 @@
+// File       NCollection_QuickSort.hxx
+// Created    27 January 2011
+// Author     KGV
+// Copyright  OpenCASCADE 2011
+
+#ifndef _NCollection_QuickSort_HeaderFile
+#define _NCollection_QuickSort_HeaderFile
+
+#include <NCollection_Comparator.hxx>
+#include <Standard_Integer.hxx>
+
+/**
+ * Perform sorting of enumerable collection with QuickSort algorithm.
+ * Enumerable collection should provide the random access to its values
+ * by index number with methods Value(theId) and ChangeValue(theId).
+ * Currently it supposed to be used with NCollection_Sequence and NCollection_Vector.
+ *
+ * Usage sample:
+ *   // input sequence
+ *   NCollection_Sequence<Standard_Real> aSequence;
+ *   // perform sorting for the whole sequence.
+ *   NCollection_QuickSort<NCollection_Sequence<Standard_Real>, Standard_Real>
+ *     ::Perform (aSequence, NCollection_Comparator<Standard_Real>(),
+ *                1, aSequence.Size());
+ */
+template<class TheCollType, class TheItemType>
+class NCollection_QuickSort
+{
+public:
+
+  //! Main entry call to perform sorting
+  static void Perform (TheCollType& theEnumColl,
+                       const NCollection_Comparator<TheItemType>& theComparator,
+                       const Standard_Integer theLower,
+                       const Standard_Integer theUpper)
+  {
+    if (theLower < theUpper)
+    {
+      Standard_Integer aPivotPosition = Partition (theEnumColl, theComparator,
+                                                   theLower, theUpper);
+      if (theLower < aPivotPosition)
+      {
+        // recursive call
+        Perform (theEnumColl, theComparator,
+                 theLower, aPivotPosition - 1);
+      }
+      // recursive call
+      Perform (theEnumColl, theComparator,
+               aPivotPosition + 1, theUpper);
+    }
+  }
+
+private:
+
+  //! Auxiliary function
+  static void SwapValues (TheItemType& x, TheItemType& y)
+  {
+    TheItemType aCopy = x;
+    x = y;
+    y = aCopy;
+  }
+
+  static Standard_Integer Partition (TheCollType& theEnumColl,
+                                     const NCollection_Comparator<TheItemType>& theComparator,
+                                     const Standard_Integer theLower,
+                                     const Standard_Integer theUpper)
+  {
+    Standard_Integer anIdLeft (theLower), anIdRight (theUpper);
+    const TheItemType aPivot = theEnumColl.Value (theLower);
+
+    while (anIdLeft < anIdRight)
+    {
+      while (theComparator.IsGreater (theEnumColl.Value (anIdRight), aPivot))
+      {
+        --anIdRight;
+      }
+      while ((anIdLeft < anIdRight) &&
+             theComparator.IsLowerEqual (theEnumColl.Value (anIdLeft), aPivot))
+      {
+        ++anIdLeft;
+      }
+
+      if (anIdLeft < anIdRight)
+      {
+        SwapValues (theEnumColl.ChangeValue (anIdLeft),
+                    theEnumColl.ChangeValue (anIdRight));
+      }
+    }
+
+    theEnumColl.ChangeValue (theLower) = theEnumColl.Value (anIdRight);
+    theEnumColl.ChangeValue (anIdRight) = aPivot;
+    return anIdRight;
+  }
+
+};
+
+#endif /*_NCollection_QuickSort_HeaderFile*/