support/traits/string_traits.hpp

0001 /*=============================================================================
0002     Copyright (c) 2001-2014 Joel de Guzman
0003     Copyright (c) 2001-2011 Hartmut Kaiser
0004     Copyright (c)      2010 Bryce Lelbach
0005
0006     Distributed under the Boost Software License, Version 1.0. (See accompanying
0007     file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
0008 ================================================_==============================*/
0009 #if !defined(BOOST_SPIRIT_X3_STRING_TRAITS_OCTOBER_2008_1252PM)
0010 #define BOOST_SPIRIT_X3_STRING_TRAITS_OCTOBER_2008_1252PM
0011
0012 #include <string>
0013 #include <boost/mpl/bool.hpp>
0014
0015 namespace boost { namespace spirit { namespace x3 { namespace traits
0016 {
0017     ///////////////////////////////////////////////////////////////////////////
0018     // Get the C string from a string
0019     ///////////////////////////////////////////////////////////////////////////
0020     template <typename String>
0021     struct extract_c_string;
0022
0023     template <typename String>
0024     struct extract_c_string
0025     {
0026         template <typename T>
0027         static T const* call (T* str)
0028         {
0029             return (T const*)str;
0030         }
0031
0032         template <typename T>
0033         static T const* call (T const* str)
0034         {
0035             return str;
0036         }
0037     };
0038
0039     // Forwarder that strips const
0040     template <typename T>
0041     struct extract_c_string<T const>
0042     {
0043         static decltype(auto) call(T const str)
0044         {
0045             return extract_c_string<T>::call(str);
0046         }
0047     };
0048
0049     // Forwarder that strips references
0050     template <typename T>
0051     struct extract_c_string<T&>
0052     {
0053         static decltype(auto) call(T& str)
0054         {
0055             return extract_c_string<T>::call(str);
0056         }
0057     };
0058
0059     // Forwarder that strips const references
0060     template <typename T>
0061     struct extract_c_string<T const&>
0062     {
0063         static decltype(auto) call(T const& str)
0064         {
0065             return extract_c_string<T>::call(str);
0066         }
0067     };
0068
0069     template <typename T, typename Traits, typename Allocator>
0070     struct extract_c_string<std::basic_string<T, Traits, Allocator> >
0071     {
0072         typedef std::basic_string<T, Traits, Allocator> string;
0073
0074         static T const* call (string const& str)
0075         {
0076             return str.c_str();
0077         }
0078     };
0079
0080     template <typename T>
0081     decltype(auto) get_c_string(T* str)
0082     {
0083         return extract_c_string<T*>::call(str);
0084     }
0085
0086     template <typename T>
0087     decltype(auto) get_c_string(T const* str)
0088     {
0089         return extract_c_string<T const*>::call(str);
0090     }
0091
0092     template <typename String>
0093     decltype(auto) get_c_string(String& str)
0094     {
0095         return extract_c_string<String>::call(str);
0096     }
0097
0098     template <typename String>
0099     decltype(auto) get_c_string(String const& str)
0100     {
0101         return extract_c_string<String>::call(str);
0102     }
0103
0104     ///////////////////////////////////////////////////////////////////////////
0105     // Get the begin/end iterators from a string
0106     ///////////////////////////////////////////////////////////////////////////
0107
0108     // Implementation for C-style strings.
0109
0110     template <typename T>
0111     inline T const* get_string_begin(T const* str) { return str; }
0112
0113     template <typename T>
0114     inline T* get_string_begin(T* str) { return str; }
0115
0116     template <typename T>
0117     inline T const* get_string_end(T const* str)
0118     {
0119         T const* last = str;
0120         while (*last)
0121             last++;
0122         return last;
0123     }
0124
0125     template <typename T>
0126     inline T* get_string_end(T* str)
0127     {
0128         T* last = str;
0129         while (*last)
0130             last++;
0131         return last;
0132     }
0133
0134     // Implementation for containers (includes basic_string).
0135     template <typename T, typename Str>
0136     inline typename Str::const_iterator get_string_begin(Str const& str)
0137     { return str.begin(); }
0138
0139     template <typename T, typename Str>
0140     inline typename Str::iterator
0141     get_string_begin(Str& str)
0142     { return str.begin(); }
0143
0144     template <typename T, typename Str>
0145     inline typename Str::const_iterator get_string_end(Str const& str)
0146     { return str.end(); }
0147
0148     template <typename T, typename Str>
0149     inline typename Str::iterator
0150     get_string_end(Str& str)
0151     { return str.end(); }
0152 }}}}
0153
0154 #endif