/*
**      PJL C++ Library
**      less.h
**
**      Copyright (C) 1998  Paul J. Lucas
**
**      This program is free software; you can redistribute it and/or modify
**      it under the terms of the GNU General Public License as published by
**      the Free Software Foundation; either version 2 of the License, or
**      (at your option) any later version.
**
**      This program is distributed in the hope that it will be useful,
**      but WITHOUT ANY WARRANTY; without even the implied warranty of
**      MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
**      GNU General Public License for more details.
**
**      You should have received a copy of the GNU General Public License
**      along with this program; if not, write to the Free Software
**      Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
*/

#ifndef less_H
#define less_H

// standard
#include <cstring>
#include <functional>

namespace std {

//*****************************************************************************
//
// SYNOPSIS
//
        template<> struct less< char const* > :
            std::binary_function< char const*, char const*, bool >
//
// DESCRIPTION
//
//      Specialize the binary_function "less" so that C-style strings (char
//      const*) will work properly with STL containers.
//
// SEE ALSO
//
//      binary_function(3), less(3), strcmp(3)
//
//      Bjarne Stroustrup.  "The C++ Programming Language, 3rd ed."
//      Addison-Wesley, Reading, MA, 1997.  p. 468.
//
//*****************************************************************************
{
    less() { }
    // This default constructor doesn't need to be defined, but g++ 2.8.0
    // complains if it isn't and you try to define a "const less" object.

    result_type
    operator()( first_argument_type a, second_argument_type b ) const {
        return std::strcmp( a, b ) < 0;
    }
};

//*****************************************************************************
//
// SYNOPSIS
//
        template< class T > struct less_n;

        template<> struct less_n< char const* > : less< char const* >
//
// DESCRIPTION
//
//      A less_n is-a less< char const* > that compares C-style strings, but
//      only for a certain maximum length.
//
// SEE ALSO
//
//      less(3), strncmp(3)
//
//*****************************************************************************
{
    less_n< char const* >( int len ) : n_( len ) { }

    result_type
    operator()( first_argument_type a, second_argument_type b ) const {
        return std::strncmp( a, b, n_ ) < 0;
    }
private:
    int const n_;
};

} // namespace std

#endif  /* less_H */
/* vim:set et sw=4 ts=4: */