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/*
** 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: */
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