utility/functional/contains.hpp

0001 /*
0002  *          Copyright Andrey Semashev 2007 - 2015.
0003  * Distributed under the Boost Software License, Version 1.0.
0004  *    (See accompanying file LICENSE_1_0.txt or copy at
0005  *          http://www.boost.org/LICENSE_1_0.txt)
0006  */
0007 /*!
0008  * \file   contains.hpp
0009  * \author Andrey Semashev
0010  * \date   30.03.2008
0011  *
0012  * This header contains a predicate for checking if the provided string contains a substring.
0013  */
0014
0015 #ifndef BOOST_LOG_UTILITY_FUNCTIONAL_CONTAINS_HPP_INCLUDED_
0016 #define BOOST_LOG_UTILITY_FUNCTIONAL_CONTAINS_HPP_INCLUDED_
0017
0018 #include <boost/log/detail/config.hpp>
0019 #include <boost/log/detail/header.hpp>
0020
0021 #ifdef BOOST_HAS_PRAGMA_ONCE
0022 #pragma once
0023 #endif
0024
0025 namespace boost {
0026
0027 BOOST_LOG_OPEN_NAMESPACE
0028
0029 //! The \c contains functor
0030 struct contains_fun
0031 {
0032     typedef bool result_type;
0033
0034     template< typename T, typename U >
0035     bool operator() (T const& left, U const& right) const
0036     {
0037         typedef typename T::const_iterator left_iterator;
0038         typedef typename U::const_iterator right_iterator;
0039
0040         typename U::size_type const right_size = right.size();
0041         if (left.size() >= right_size)
0042         {
0043             const left_iterator search_end = left.end() - right_size + 1;
0044             const right_iterator right_end = right.end();
0045             for (left_iterator it = left.begin(); it != search_end; ++it)
0046             {
0047                 left_iterator left_it = it;
0048                 right_iterator right_it = right.begin();
0049                 for (; right_it != right_end; ++left_it, ++right_it)
0050                 {
0051                     if (*left_it != *right_it)
0052                         break;
0053                 }
0054                 if (right_it == right_end)
0055                     return true;
0056             }
0057         }
0058
0059         return false;
0060     }
0061 };
0062
0063 BOOST_LOG_CLOSE_NAMESPACE // namespace log
0064
0065 } // namespace boost
0066
0067 #include <boost/log/detail/footer.hpp>
0068
0069 #endif // BOOST_LOG_UTILITY_FUNCTIONAL_CONTAINS_HPP_INCLUDED_