Changeset 2239 for trunk/yat/utility/stl_utility.h

Timestamp:

Apr 11, 2010, 1:05:12 AM (12 years ago)

Author:

Peter

Message:

closes #612

File:

• trunk/yat/utility/stl_utility.h (modified) (1 diff)

trunk/yat/utility/stl_utility.h

@@ -499 +499 @@
 
 
-
+  /**
+     Adaptor class that can be used to compare pointers, T*, when you
+     want to compare them with respect to the objects they point to.
+
+     Example:
+     \code
+     std::vector<MyClass*> vec(18);
+     ...
+     PtrCompare<MyClass, std::greater<MyClass> > ptr_compare;
+     std::sort(vec.begin(), vec.end(), ptr_compare);
+     \endcode
+
+     The class Compare must be a <a
+     href="http://www.sgi.com/tech/stl/BinaryFunction.html">binary
+     functor</a> that takes two \c const \c T& and returns \c bool.
+
+     \since New in yat 0.7
+   */
+  template<typename T, class Compare = std::less<T> >
+  class PtrCompare : std::binary_function<T const* const, T const* const, bool>
+  {
+  public:
+    /**
+       \brief Constructor.
+
+       Creates an instance of Compare using its default constructor.
+     */
+    PtrCompare(void)
+    {
+      BOOST_CONCEPT_ASSERT((boost::BinaryFunction<Compare, bool, const T&, 
+                            const T&>));
+    }
+
+    /**
+       \brief Constructor.
+
+       Creates a copy of \a c that will be used later.
+     */
+    PtrCompare(Compare c)
+      : compare_(c) 
+    {
+      BOOST_CONCEPT_ASSERT((boost::BinaryFunction<Compare, bool, const T&, 
+                            const T&>));
+    }
+
+    /**
+       \return true iff Compare(* \a lhs, * \a rhs ) is true.
+     */
+    bool operator()(T const* const lhs, T const* const rhs) const
+    { 
+      return compare_(*lhs, *rhs); 
+    }
+  private:
+    Compare compare_;
+
+    // using compiler generated copy
+    // PtrCompare(const PtrCompare&)
+    // PtrCompare& operator=(const PtrCompare&)
+  };
 
   ///