Find wrappers for map/multimap; suggested by Olaf; Refs #5227; No docs yet.

[SVN r79385]

include/boost/algorithm/wrappers.hpp

@@ -0,0 +1,52 @@
+/* 
+   Copyright (c) Marshall Clow 2012.
+
+   Distributed under the Boost Software License, Version 1.0. (See accompanying
+   file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+   
+   Alternate interfaces (aka "wrappers") for algorithms.
+*/
+
+#ifndef	BOOST_ALGORITHM_WRAPPERS_HPP
+#define	BOOST_ALGORITHM_WRAPPERS_HPP
+
+namespace boost { namespace algorithm {
+
+/// \fn find_ptr ( Container &c, Key k )
+/// \return a pointer to the value matching the key in the container, 
+///	or NULL if the key does not exist in the container.
+///
+///	\note: This is a wrapper around Container::find, with a useful interface.
+///	Suggested by Olaf van der Spek 
+/// 
+/// \param c    The container to be searched
+/// \param k	The key value to search with
+template <class Container, class Key>
+typename Container::value_type::second_type* 
+find_ptr ( Container &c, Key k )
+{
+	typename Container::iterator iter = c.find ( k );
+	return iter == c.end() ? NULL : &iter->second;
+}
+
+/// \fn find_ptr ( const Container &c, Key k )
+/// \return a pointer to the value matching the key in the container, 
+///	or NULL if the key does not exist in the container.
+///
+///	\note: This is a wrapper around Container::find, with a useful interface.
+///	Suggested by Olaf van der Spek 
+/// 
+/// \param c    The container to be searched
+/// \param k	The key value to search with
+template <class Container, class Key>
+const typename Container::value_type::second_type* 
+find_ptr ( const Container &c, Key k )
+{
+	typename Container::const_iterator iter = c.find ( k );
+	return iter == c.end() ? NULL : &iter->second;
+}
+
+
+}}
+
+#endif

test/Jamfile.v2

@@ -46,6 +46,9 @@ import testing ;
      [ run hex_test3.cpp        : : : : hex_test3 ]
      [ run hex_test4.cpp        : : : : hex_test4 ]
 	 [ compile-fail hex_fail1.cpp ]
+
+# Wrapper tests
+     [ run wrapper_test1.cpp        : : : : wrapper_test1 ]
    ;
 }
 

test/wrapper_test1.cpp

@@ -0,0 +1,75 @@
+/* 
+   Copyright (c) Marshall Clow 2012.
+
+   Distributed under the Boost Software License, Version 1.0. (See accompanying
+   file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+
+    For more information, see http://www.boost.org
+*/
+
+#include <boost/config.hpp>
+#include <boost/algorithm/wrappers.hpp>
+#include <boost/test/included/test_exec_monitor.hpp>
+
+#include <functional>
+#include <string>
+#include <map>
+
+namespace ba = boost::algorithm;
+
+void test_int ()
+{
+	std::map<int, int> m;
+	std::multimap<int, int> mm;
+	
+	int *ptr;
+	
+//	try with an empty map
+	BOOST_CHECK ( ba::find_ptr ( m , 3 ) == NULL );
+	BOOST_CHECK ( ba::find_ptr ( mm, 3 ) == NULL );
+	
+	m.insert  ( std::make_pair <int, int> ( 5, 5 ));
+	mm.insert ( std::make_pair <int, int> ( 9, 9 ));
+	BOOST_CHECK ( ba::find_ptr ( m , 3 ) == NULL );
+	BOOST_CHECK ( ba::find_ptr ( mm, 3 ) == NULL );
+
+	ptr = ba::find_ptr ( m, 5 );
+	BOOST_CHECK ( ptr != NULL && *ptr == 5 );
+	BOOST_CHECK ( ba::find_ptr ( m , 9 ) == NULL );
+
+	ptr = ba::find_ptr ( mm, 9 );
+	BOOST_CHECK ( ptr != NULL && *ptr == 9 );
+	BOOST_CHECK ( ba::find_ptr ( mm, 5 ) == NULL );
+	
+}
+
+void test_str ()
+{
+	std::map<int, std::string> m;
+	std::multimap<int, std::string> mm;
+	std::string *ptr;
+
+//	try with an empty map
+	BOOST_CHECK ( ba::find_ptr ( m , 31 ) == NULL );
+	BOOST_CHECK ( ba::find_ptr ( mm, 31 ) == NULL );
+	
+	m.insert  ( std::make_pair <int, std::string> ( 55, "fifty-five" ));
+	mm.insert ( std::make_pair <int, std::string> ( 66, "sixty-six" ));
+	BOOST_CHECK ( ba::find_ptr ( m , 3 ) == NULL );
+	BOOST_CHECK ( ba::find_ptr ( mm, 3 ) == NULL );
+
+	ptr = ba::find_ptr ( m, 55 );
+	BOOST_CHECK ( ptr != NULL && *ptr == "fifty-five" );
+	BOOST_CHECK ( ba::find_ptr ( m , 66 ) == NULL );
+
+	ptr = ba::find_ptr ( mm, 66 );
+	BOOST_CHECK ( ptr != NULL && *ptr == "sixty-six" );
+	BOOST_CHECK ( ba::find_ptr ( mm, 55 ) == NULL );
+}
+
+int test_main( int , char* [] )
+{
+  test_int ();
+  test_str ();
+  return 0;
+}