boost/xpressive/traits/c_regex_traits.hpp
//////////////////////////////////////////////////////////////////////////////
/// \file c_regex_traits.hpp
/// Contains the definition of the c_regex_traits\<\> template, which is a
/// wrapper for the C locale functions that can be used to customize the
/// behavior of static and dynamic regexes.
//
// Copyright 2008 Eric Niebler. 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)
#ifndef BOOST_XPRESSIVE_TRAITS_C_REGEX_TRAITS_HPP_EAN_10_04_2005
#define BOOST_XPRESSIVE_TRAITS_C_REGEX_TRAITS_HPP_EAN_10_04_2005
// MS compatible compilers support #pragma once
#if defined(_MSC_VER) && (_MSC_VER >= 1020)
# pragma once
#endif
#include <cstdlib>
#include <boost/config.hpp>
#include <boost/assert.hpp>
#include <boost/xpressive/traits/detail/c_ctype.hpp>
namespace boost { namespace xpressive
{
namespace detail
{
///////////////////////////////////////////////////////////////////////////////
// empty_locale
struct empty_locale
{
};
///////////////////////////////////////////////////////////////////////////////
// c_regex_traits_base
template<typename Char, std::size_t SizeOfChar = sizeof(Char)>
struct c_regex_traits_base
{
protected:
template<typename Traits>
void imbue(Traits const &tr)
{
}
};
template<typename Char>
struct c_regex_traits_base<Char, 1>
{
protected:
template<typename Traits>
static void imbue(Traits const &)
{
}
};
#ifndef BOOST_XPRESSIVE_NO_WREGEX
template<std::size_t SizeOfChar>
struct c_regex_traits_base<wchar_t, SizeOfChar>
{
protected:
template<typename Traits>
static void imbue(Traits const &)
{
}
};
#endif
template<typename Char>
Char c_tolower(Char);
template<typename Char>
Char c_toupper(Char);
template<>
inline char c_tolower(char ch)
{
using namespace std;
return static_cast<char>(tolower(static_cast<unsigned char>(ch)));
}
template<>
inline char c_toupper(char ch)
{
using namespace std;
return static_cast<char>(toupper(static_cast<unsigned char>(ch)));
}
#ifndef BOOST_XPRESSIVE_NO_WREGEX
template<>
inline wchar_t c_tolower(wchar_t ch)
{
using namespace std;
return towlower(ch);
}
template<>
inline wchar_t c_toupper(wchar_t ch)
{
using namespace std;
return towupper(ch);
}
#endif
} // namespace detail
///////////////////////////////////////////////////////////////////////////////
// regex_traits_version_1_tag
//
struct regex_traits_version_1_tag;
///////////////////////////////////////////////////////////////////////////////
// c_regex_traits
//
/// \brief Encapsaulates the standard C locale functions for use by the
/// \c basic_regex\<\> class template.
template<typename Char>
struct c_regex_traits
: detail::c_regex_traits_base<Char>
{
typedef Char char_type;
typedef std::basic_string<char_type> string_type;
typedef detail::empty_locale locale_type;
typedef typename detail::char_class_impl<Char>::char_class_type char_class_type;
typedef regex_traits_version_2_tag version_tag;
typedef detail::c_regex_traits_base<Char> base_type;
/// Initialize a c_regex_traits object to use the global C locale.
///
c_regex_traits(locale_type const &loc = locale_type())
: base_type()
{
this->imbue(loc);
}
/// Checks two c_regex_traits objects for equality
///
/// \return true.
bool operator ==(c_regex_traits<char_type> const &) const
{
return true;
}
/// Checks two c_regex_traits objects for inequality
///
/// \return false.
bool operator !=(c_regex_traits<char_type> const &) const
{
return false;
}
/// Convert a char to a Char
///
/// \param ch The source character.
/// \return ch if Char is char, std::btowc(ch) if Char is wchar_t.
static char_type widen(char ch);
/// Returns a hash value for a Char in the range [0, UCHAR_MAX]
///
/// \param ch The source character.
/// \return a value between 0 and UCHAR_MAX, inclusive.
static unsigned char hash(char_type ch)
{
return static_cast<unsigned char>(std::char_traits<Char>::to_int_type(ch));
}
/// No-op
///
/// \param ch The source character.
/// \return ch
static char_type translate(char_type ch)
{
return ch;
}
/// Converts a character to lower-case using the current global C locale.
///
/// \param ch The source character.
/// \return std::tolower(ch) if Char is char, std::towlower(ch) if Char is wchar_t.
static char_type translate_nocase(char_type ch)
{
return detail::c_tolower(ch);
}
/// Converts a character to lower-case using the current global C locale.
///
/// \param ch The source character.
/// \return std::tolower(ch) if Char is char, std::towlower(ch) if Char is wchar_t.
static char_type tolower(char_type ch)
{
return detail::c_tolower(ch);
}
/// Converts a character to upper-case using the current global C locale.
///
/// \param ch The source character.
/// \return std::toupper(ch) if Char is char, std::towupper(ch) if Char is wchar_t.
static char_type toupper(char_type ch)
{
return detail::c_toupper(ch);
}
/// Returns a \c string_type containing all the characters that compare equal
/// disregrarding case to the one passed in. This function can only be called
/// if <tt>has_fold_case\<c_regex_traits\<Char\> \>::value</tt> is \c true.
///
/// \param ch The source character.
/// \return \c string_type containing all chars which are equal to \c ch when disregarding
/// case
//typedef array<char_type, 2> fold_case_type;
string_type fold_case(char_type ch) const
{
BOOST_MPL_ASSERT((is_same<char_type, char>));
char_type ntcs[] = {
detail::c_tolower(ch)
, detail::c_toupper(ch)
, 0
};
if(ntcs[1] == ntcs[0])
ntcs[1] = 0;
return string_type(ntcs);
}
/// Checks to see if a character is within a character range.
///
/// \param first The bottom of the range, inclusive.
/// \param last The top of the range, inclusive.
/// \param ch The source character.
/// \return first <= ch && ch <= last.
static bool in_range(char_type first, char_type last, char_type ch)
{
return first <= ch && ch <= last;
}
/// Checks to see if a character is within a character range, irregardless of case.
///
/// \param first The bottom of the range, inclusive.
/// \param last The top of the range, inclusive.
/// \param ch The source character.
/// \return in_range(first, last, ch) || in_range(first, last, tolower(ch)) || in_range(first,
/// last, toupper(ch))
/// \attention The default implementation doesn't do proper Unicode
/// case folding, but this is the best we can do with the standard
/// C locale functions.
static bool in_range_nocase(char_type first, char_type last, char_type ch)
{
return c_regex_traits::in_range(first, last, ch)
|| c_regex_traits::in_range(first, last, detail::c_tolower(ch))
|| c_regex_traits::in_range(first, last, detail::c_toupper(ch));
}
/// Returns a sort key for the character sequence designated by the iterator range [F1, F2)
/// such that if the character sequence [G1, G2) sorts before the character sequence [H1, H2)
/// then v.transform(G1, G2) < v.transform(H1, H2).
///
/// \attention Not currently used
template<typename FwdIter>
static string_type transform(FwdIter begin, FwdIter end)
{
BOOST_ASSERT(false); // BUGBUG implement me
}
/// Returns a sort key for the character sequence designated by the iterator range [F1, F2)
/// such that if the character sequence [G1, G2) sorts before the character sequence [H1, H2)
/// when character case is not considered then
/// v.transform_primary(G1, G2) < v.transform_primary(H1, H2).
///
/// \attention Not currently used
template<typename FwdIter>
static string_type transform_primary(FwdIter begin, FwdIter end)
{
BOOST_ASSERT(false); // BUGBUG implement me
}
/// Returns a sequence of characters that represents the collating element
/// consisting of the character sequence designated by the iterator range [F1, F2).
/// Returns an empty string if the character sequence is not a valid collating element.
///
/// \attention Not currently used
template<typename FwdIter>
static string_type lookup_collatename(FwdIter begin, FwdIter end)
{
BOOST_ASSERT(false); // BUGBUG implement me
}
/// For the character class name represented by the specified character sequence,
/// return the corresponding bitmask representation.
///
/// \param begin A forward iterator to the start of the character sequence representing
/// the name of the character class.
/// \param end The end of the character sequence.
/// \param icase Specifies whether the returned bitmask should represent the case-insensitive
/// version of the character class.
/// \return A bitmask representing the character class.
template<typename FwdIter>
static char_class_type lookup_classname(FwdIter begin, FwdIter end, bool icase)
{
return detail::char_class_impl<char_type>::lookup_classname(begin, end, icase);
}
/// Tests a character against a character class bitmask.
///
/// \param ch The character to test.
/// \param mask The character class bitmask against which to test.
/// \pre mask is a bitmask returned by lookup_classname, or is several such masks bit-or'ed
/// together.
/// \return true if the character is a member of any of the specified character classes, false
/// otherwise.
static bool isctype(char_type ch, char_class_type mask)
{
return detail::char_class_impl<char_type>::isctype(ch, mask);
}
/// Convert a digit character into the integer it represents.
///
/// \param ch The digit character.
/// \param radix The radix to use for the conversion.
/// \pre radix is one of 8, 10, or 16.
/// \return -1 if ch is not a digit character, the integer value of the character otherwise. If
/// char_type is char, std::strtol is used for the conversion. If char_type is wchar_t,
/// std::wcstol is used.
static int value(char_type ch, int radix);
/// No-op
///
locale_type imbue(locale_type loc)
{
this->base_type::imbue(*this);
return loc;
}
/// No-op
///
static locale_type getloc()
{
locale_type loc;
return loc;
}
};
///////////////////////////////////////////////////////////////////////////////
// c_regex_traits<>::widen specializations
/// INTERNAL ONLY
template<>
inline char c_regex_traits<char>::widen(char ch)
{
return ch;
}
#ifndef BOOST_XPRESSIVE_NO_WREGEX
/// INTERNAL ONLY
template<>
inline wchar_t c_regex_traits<wchar_t>::widen(char ch)
{
using namespace std;
return btowc(ch);
}
#endif
///////////////////////////////////////////////////////////////////////////////
// c_regex_traits<>::hash specializations
/// INTERNAL ONLY
template<>
inline unsigned char c_regex_traits<char>::hash(char ch)
{
return static_cast<unsigned char>(ch);
}
#ifndef BOOST_XPRESSIVE_NO_WREGEX
/// INTERNAL ONLY
template<>
inline unsigned char c_regex_traits<wchar_t>::hash(wchar_t ch)
{
return static_cast<unsigned char>(ch);
}
#endif
///////////////////////////////////////////////////////////////////////////////
// c_regex_traits<>::value specializations
/// INTERNAL ONLY
template<>
inline int c_regex_traits<char>::value(char ch, int radix)
{
using namespace std;
BOOST_ASSERT(8 == radix || 10 == radix || 16 == radix);
char begin[2] = { ch, '\0' }, *end = 0;
int val = strtol(begin, &end, radix);
return begin == end ? -1 : val;
}
#ifndef BOOST_XPRESSIVE_NO_WREGEX
/// INTERNAL ONLY
template<>
inline int c_regex_traits<wchar_t>::value(wchar_t ch, int radix)
{
using namespace std;
BOOST_ASSERT(8 == radix || 10 == radix || 16 == radix);
wchar_t begin[2] = { ch, L'\0' }, *end = 0;
int val = wcstol(begin, &end, radix);
return begin == end ? -1 : val;
}
#endif
// Narrow C traits has fold_case() member function.
template<>
struct has_fold_case<c_regex_traits<char> >
: mpl::true_
{
};
}}
#endif