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