boost/log/utility/functional/contains.hpp

   1 /*
   2  *          Copyright Andrey Semashev 2007 - 2014.
   3  * Distributed under the Boost Software License, Version 1.0.
   4  *    (See accompanying file LICENSE_1_0.txt or copy at
   5  *          http://www.boost.org/LICENSE_1_0.txt)
   6  */
   7 /*!
   8  * \file   contains.hpp
   9  * \author Andrey Semashev
  10  * \date   30.03.2008
  11  *
  12  * This header contains a predicate for checking if the provided string contains a substring.
  13  */
  14
  15 #ifndef BOOST_LOG_UTILITY_FUNCTIONAL_CONTAINS_HPP_INCLUDED_
  16 #define BOOST_LOG_UTILITY_FUNCTIONAL_CONTAINS_HPP_INCLUDED_
  17
  18 #include <boost/log/detail/config.hpp>
  19 #include <boost/log/detail/header.hpp>
  20
  21 #ifdef BOOST_HAS_PRAGMA_ONCE
  22 #pragma once
  23 #endif
  24
  25 namespace boost {
  26
  27 BOOST_LOG_OPEN_NAMESPACE
  28
  29 //! The \c contains functor
  30 struct contains_fun
  31 {
  32     typedef bool result_type;
  33
  34     template< typename T, typename U >
  35     bool operator() (T const& left, U const& right) const
  36     {
  37         typedef typename T::const_iterator left_iterator;
  38         typedef typename U::const_iterator right_iterator;
  39
  40         typename U::size_type const right_size = right.size();
  41         if (left.size() >= right_size)
  42         {
  43             const left_iterator search_end = left.end() - right_size + 1;
  44             const right_iterator right_end = right.end();
  45             for (left_iterator it = left.begin(); it != search_end; ++it)
  46             {
  47                 left_iterator left_it = it;
  48                 right_iterator right_it = right.begin();
  49                 for (; right_it != right_end; ++left_it, ++right_it)
  50                 {
  51                     if (*left_it != *right_it)
  52                         break;
  53                 }
  54                 if (right_it == right_end)
  55                     return true;
  56             }
  57         }
  58
  59         return false;
  60     }
  61 };
  62
  63 BOOST_LOG_CLOSE_NAMESPACE // namespace log
  64
  65 } // namespace boost
  66
  67 #include <boost/log/detail/footer.hpp>
  68
  69 #endif // BOOST_LOG_UTILITY_FUNCTIONAL_CONTAINS_HPP_INCLUDED_