boost/spirit/home/support/string_traits.hpp
/*=============================================================================
Copyright (c) 2001-2011 Joel de Guzman
Copyright (c) 2001-2011 Hartmut Kaiser
Copyright (c) 2010 Bryce Lelbach
Distributed under the Boost Software License, Version 1.0. (See accompanying
file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
================================================_==============================*/
#if !defined(BOOST_SPIRIT_STRING_TRAITS_OCTOBER_2008_1252PM)
#define BOOST_SPIRIT_STRING_TRAITS_OCTOBER_2008_1252PM
#if defined(_MSC_VER)
#pragma once
#endif
#include <boost/spirit/home/support/container.hpp>
#include <string>
#include <boost/mpl/bool.hpp>
#include <boost/mpl/identity.hpp>
#include <boost/mpl/if.hpp>
#include <boost/proto/proto_fwd.hpp>
#include <boost/type_traits/is_const.hpp>
#if defined(__GNUC__) && (__GNUC__ < 4)
#include <boost/type_traits/add_const.hpp>
#endif
namespace boost { namespace spirit { namespace traits
{
///////////////////////////////////////////////////////////////////////////
// Determine if T is a character type
///////////////////////////////////////////////////////////////////////////
template <typename T>
struct is_char : mpl::false_ {};
template <typename T>
struct is_char<T const> : is_char<T> {};
template <>
struct is_char<char> : mpl::true_ {};
template <>
struct is_char<wchar_t> : mpl::true_ {};
///////////////////////////////////////////////////////////////////////////
// Determine if T is a string
///////////////////////////////////////////////////////////////////////////
template <typename T>
struct is_string : mpl::false_ {};
template <typename T>
struct is_string<T const> : is_string<T> {};
template <>
struct is_string<char const*> : mpl::true_ {};
template <>
struct is_string<wchar_t const*> : mpl::true_ {};
template <>
struct is_string<char*> : mpl::true_ {};
template <>
struct is_string<wchar_t*> : mpl::true_ {};
template <std::size_t N>
struct is_string<char[N]> : mpl::true_ {};
template <std::size_t N>
struct is_string<wchar_t[N]> : mpl::true_ {};
template <std::size_t N>
struct is_string<char const[N]> : mpl::true_ {};
template <std::size_t N>
struct is_string<wchar_t const[N]> : mpl::true_ {};
template <std::size_t N>
struct is_string<char(&)[N]> : mpl::true_ {};
template <std::size_t N>
struct is_string<wchar_t(&)[N]> : mpl::true_ {};
template <std::size_t N>
struct is_string<char const(&)[N]> : mpl::true_ {};
template <std::size_t N>
struct is_string<wchar_t const(&)[N]> : mpl::true_ {};
template <typename T, typename Traits, typename Allocator>
struct is_string<std::basic_string<T, Traits, Allocator> > : mpl::true_ {};
///////////////////////////////////////////////////////////////////////////
// Get the underlying char type of a string
///////////////////////////////////////////////////////////////////////////
template <typename T>
struct char_type_of;
template <typename T>
struct char_type_of<T const> : char_type_of<T> {};
template <>
struct char_type_of<char> : mpl::identity<char> {};
template <>
struct char_type_of<wchar_t> : mpl::identity<wchar_t> {};
template <>
struct char_type_of<char const*> : mpl::identity<char const> {};
template <>
struct char_type_of<wchar_t const*> : mpl::identity<wchar_t const> {};
template <>
struct char_type_of<char*> : mpl::identity<char> {};
template <>
struct char_type_of<wchar_t*> : mpl::identity<wchar_t> {};
template <std::size_t N>
struct char_type_of<char[N]> : mpl::identity<char> {};
template <std::size_t N>
struct char_type_of<wchar_t[N]> : mpl::identity<wchar_t> {};
template <std::size_t N>
struct char_type_of<char const[N]> : mpl::identity<char const> {};
template <std::size_t N>
struct char_type_of<wchar_t const[N]> : mpl::identity<wchar_t const> {};
template <std::size_t N>
struct char_type_of<char(&)[N]> : mpl::identity<char> {};
template <std::size_t N>
struct char_type_of<wchar_t(&)[N]> : mpl::identity<wchar_t> {};
template <std::size_t N>
struct char_type_of<char const(&)[N]> : mpl::identity<char const> {};
template <std::size_t N>
struct char_type_of<wchar_t const(&)[N]> : mpl::identity<wchar_t const> {};
template <typename T, typename Traits, typename Allocator>
struct char_type_of<std::basic_string<T, Traits, Allocator> >
: mpl::identity<T> {};
///////////////////////////////////////////////////////////////////////////
// Get the C string from a string
///////////////////////////////////////////////////////////////////////////
template <typename String>
struct extract_c_string;
template <typename String>
struct extract_c_string
{
typedef typename char_type_of<String>::type char_type;
template <typename T>
static T const* call (T* str)
{
return (T const*)str;
}
template <typename T>
static T const* call (T const* str)
{
return str;
}
};
// Forwarder that strips const
template <typename T>
struct extract_c_string<T const>
{
typedef typename extract_c_string<T>::char_type char_type;
static typename extract_c_string<T>::char_type const* call (T const str)
{
return extract_c_string<T>::call(str);
}
};
// Forwarder that strips references
template <typename T>
struct extract_c_string<T&>
{
typedef typename extract_c_string<T>::char_type char_type;
static typename extract_c_string<T>::char_type const* call (T& str)
{
return extract_c_string<T>::call(str);
}
};
// Forwarder that strips const references
template <typename T>
struct extract_c_string<T const&>
{
typedef typename extract_c_string<T>::char_type char_type;
static typename extract_c_string<T>::char_type const* call (T const& str)
{
return extract_c_string<T>::call(str);
}
};
template <typename T, typename Traits, typename Allocator>
struct extract_c_string<std::basic_string<T, Traits, Allocator> >
{
typedef T char_type;
typedef std::basic_string<T, Traits, Allocator> string;
static T const* call (string const& str)
{
return str.c_str();
}
};
template <typename T>
typename extract_c_string<T*>::char_type const*
get_c_string (T* str)
{
return extract_c_string<T*>::call(str);
}
template <typename T>
typename extract_c_string<T const*>::char_type const*
get_c_string (T const* str)
{
return extract_c_string<T const*>::call(str);
}
template <typename String>
typename extract_c_string<String>::char_type const*
get_c_string (String& str)
{
return extract_c_string<String>::call(str);
}
template <typename String>
typename extract_c_string<String>::char_type const*
get_c_string (String const& str)
{
return extract_c_string<String>::call(str);
}
///////////////////////////////////////////////////////////////////////////
// Get the begin/end iterators from a string
///////////////////////////////////////////////////////////////////////////
// Implementation for C-style strings.
// gcc 3.x.x has problems resolving ambiguities here
#if defined(__GNUC__) && (__GNUC__ < 4)
template <typename T>
inline typename add_const<T>::type * get_begin(T* str) { return str; }
template <typename T>
inline typename add_const<T>::type* get_end(T* str)
{
T* last = str;
while (*last)
last++;
return last;
}
#else
template <typename T>
inline T const* get_begin(T const* str) { return str; }
template <typename T>
inline T* get_begin(T* str) { return str; }
template <typename T>
inline T const* get_end(T const* str)
{
T const* last = str;
while (*last)
last++;
return last;
}
template <typename T>
inline T* get_end(T* str)
{
T* last = str;
while (*last)
last++;
return last;
}
#endif
// Implementation for containers (includes basic_string).
template <typename T, typename Str>
inline typename Str::const_iterator get_begin(Str const& str)
{ return str.begin(); }
template <typename T, typename Str>
inline typename Str::iterator
get_begin(Str& str BOOST_PROTO_DISABLE_IF_IS_CONST(Str))
{ return str.begin(); }
template <typename T, typename Str>
inline typename Str::const_iterator get_end(Str const& str)
{ return str.end(); }
template <typename T, typename Str>
inline typename Str::iterator
get_end(Str& str BOOST_PROTO_DISABLE_IF_IS_CONST(Str))
{ return str.end(); }
// Default implementation for other types: try a C-style string
// conversion.
// These overloads are explicitly disabled for containers,
// as they would be ambiguous with the previous ones.
template <typename T, typename Str>
inline typename disable_if<is_container<Str>
, T const*>::type get_begin(Str const& str)
{ return str; }
template <typename T, typename Str>
inline typename disable_if<is_container<Str>
, T const*>::type get_end(Str const& str)
{ return get_end(get_begin<T>(str)); }
}
namespace result_of
{
template <typename Char, typename T, typename Enable = void>
struct get_begin
{
typedef typename traits::char_type_of<T>::type char_type;
typedef typename mpl::if_<
is_const<char_type>
, char_type const
, char_type
>::type* type;
};
template <typename Char, typename Str>
struct get_begin<Char, Str
, typename enable_if<traits::is_container<Str> >::type>
{
typedef typename mpl::if_<
is_const<Str>
, typename Str::const_iterator
, typename Str::iterator
>::type type;
};
template <typename Char, typename T>
struct get_end : get_begin<Char, T> {};
}
}}
#endif
