ci_less.h

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/* +---------------------------------------------------------------------------+
   |                     Mobile Robot Programming Toolkit (MRPT)               |
   |                          http://www.mrpt.org/                             |
   |                                                                           |
   | Copyright (c) 2005-2017, Individual contributors, see AUTHORS file        |
   | See: http://www.mrpt.org/Authors - All rights reserved.                   |
   | Released under BSD License. See details in http://www.mrpt.org/License    |
   +---------------------------------------------------------------------------+ */
#pragma once

#include <functional>  // binary_function
#include <cctype>  // tolower
#include <string>

namespace mrpt
{
        namespace utils
        {
                /** \addtogroup stlext_grp STL extensions and metaprogramming 
                  * \ingroup mrpt_base_grp
                  * @{ */

                /** A case-insensitive comparator struct for usage within STL containers, eg: map<string,string,ci_less>
                  * \note Defined in #include <mrpt/utils/ci_less.h>
                  */
                struct ci_less : std::binary_function<std::string,std::string,bool>
                {
                        // case-independent (ci) compare_less binary function
                        struct nocase_compare : public std::binary_function<char,char,bool> {
                                bool operator()(const char c1, const char c2) const { return tolower(c1)<tolower(c2); }
                        };
                        bool operator() (const std::string & s1, const std::string & s2) const {
                                return std::lexicographical_compare(s1.begin(),s1.end(), s2.begin(),s2.end(), nocase_compare());
                        }
                }; // end of ci_less

                /** @} */  // end of grouping
        } // End of namespace
} // End of namespace