initial checkin

[SVN r1155]
2003-04-17 06:07:41 +00:00
parent aa052cb7ec
commit 53d67cf875
3 changed files with 413 additions and 0 deletions
@@ -0,0 +1,109 @@
+// (C) 2003, Jan Langer (jan@langernetz.de).
+// 
+// This material is provided "as is", with absolutely no warranty expressed
+// or implied. Any use is at your own risk.
+// 
+// Permission to use or copy this software for any purpose is hereby granted
+// without fee, provided the above notices are retained on all copies.
+// Permission to modify the code and to distribute modified code is granted,
+// provided the above notices are retained, and a notice that the code was
+// modified is included with the above copyright notice.
+ 
+#ifndef BOOST_UTILITY_LEXICOGRAPHIC_HPP
+#define BOOST_UTILITY_LEXICOGRAPHIC_HPP
+
+namespace boost
+{
+
+  class lexicographic
+  {
+    public:
+      enum result_type { minus = -1, equivalent, plus };
+    
+    private:
+      typedef void (lexicographic::*unspecified_bool_type) ();
+      void safe_bool_conversion () {}
+        
+      template <typename T1, typename T2>
+      result_type do_compare (T1 const &a, T2 const &b) const
+      {
+          if (a < b)
+              return minus;
+          else if (b < a)
+              return plus;
+          else 
+              return equivalent;
+      }
+      template <typename T1, typename T2, typename Cmp>
+      result_type do_compare (T1 const &a, T2 const &b, Cmp cmp) const
+      {
+          if (cmp (a, b))
+              return minus;
+          else if (cmp (b, a))
+              return plus;
+          else 
+              return equivalent;
+      }
+      
+    public:
+      lexicographic () : m_value (equivalent) {}
+
+      template <typename T1, typename T2>
+      lexicographic (T1 const &a, T2 const &b) 
+          : m_value (do_compare (a, b))
+      {}
+      template <typename T1, typename T2, typename Cmp>
+      lexicographic (T1 const &a, T2 const &b, Cmp cmp) 
+          : m_value (do_compare (a, b, cmp))
+      {}
+    
+      template <typename T1, typename T2>
+      lexicographic &operator () (T1 const &a, T2 const &b)
+      {
+          if (m_value == equivalent) 
+            m_value = do_compare (a, b);
+          return *this;
+      }
+      template <typename T1, typename T2, typename Cmp>
+      lexicographic &operator () (T1 const &a, T2 const &b, Cmp cmp)
+      {
+          if (m_value == equivalent) 
+            m_value = do_compare (a, b, cmp); 
+          return *this;
+      }
+
+      result_type result () const 
+      { 
+          return m_value; 
+      }
+      
+      operator unspecified_bool_type () const 
+      { 
+          return (m_value == minus) 
+                      ? &lexicographic::safe_bool_conversion 
+                      : 0; 
+      }
+      
+      // somehow only needed old compilers
+      bool operator ! () const
+      {
+          return m_value != minus;
+      }
+
+    private:
+      result_type m_value;
+  };
+
+  bool operator == (lexicographic l1, lexicographic l2)
+  {
+      return l1.result () == l2.result ();
+  }
+  
+  bool operator != (lexicographic l1, lexicographic l2)
+  {
+      return l1.result () != l2.result ();
+  }
+  
+} // namespace boost
+
+#endif // BOOST_UTILITY_LEXICOGRAPHIC_HPP