is_character.hpp 2.1 KB

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  1. // Copyright Kevlin Henney, 2000-2005.
  2. // Copyright Alexander Nasonov, 2006-2010.
  3. // Copyright Antony Polukhin, 2011-2019.
  4. //
  5. // Distributed under the Boost Software License, Version 1.0. (See
  6. // accompanying file LICENSE_1_0.txt or copy at
  7. // http://www.boost.org/LICENSE_1_0.txt)
  8. //
  9. // what: lexical_cast custom keyword cast
  10. // who: contributed by Kevlin Henney,
  11. // enhanced with contributions from Terje Slettebo,
  12. // with additional fixes and suggestions from Gennaro Prota,
  13. // Beman Dawes, Dave Abrahams, Daryle Walker, Peter Dimov,
  14. // Alexander Nasonov, Antony Polukhin, Justin Viiret, Michael Hofmann,
  15. // Cheng Yang, Matthew Bradbury, David W. Birdsall, Pavel Korzh and other Boosters
  16. // when: November 2000, March 2003, June 2005, June 2006, March 2011 - 2014
  17. #ifndef BOOST_LEXICAL_CAST_DETAIL_IS_CHARACTER_HPP
  18. #define BOOST_LEXICAL_CAST_DETAIL_IS_CHARACTER_HPP
  19. #include <boost/config.hpp>
  20. #ifdef BOOST_HAS_PRAGMA_ONCE
  21. # pragma once
  22. #endif
  23. #include <boost/type_traits/integral_constant.hpp>
  24. #include <boost/type_traits/is_same.hpp>
  25. namespace boost {
  26. namespace detail // is_character<...>
  27. {
  28. // returns true, if T is one of the character types
  29. template < typename T >
  30. struct is_character
  31. {
  32. typedef BOOST_DEDUCED_TYPENAME boost::integral_constant<
  33. bool,
  34. boost::is_same< T, char >::value ||
  35. #if !defined(BOOST_NO_STRINGSTREAM) && !defined(BOOST_NO_STD_WSTRING)
  36. boost::is_same< T, wchar_t >::value ||
  37. #endif
  38. #ifndef BOOST_NO_CXX11_CHAR16_T
  39. boost::is_same< T, char16_t >::value ||
  40. #endif
  41. #ifndef BOOST_NO_CXX11_CHAR32_T
  42. boost::is_same< T, char32_t >::value ||
  43. #endif
  44. boost::is_same< T, unsigned char >::value ||
  45. boost::is_same< T, signed char >::value
  46. > type;
  47. BOOST_STATIC_CONSTANT(bool, value = (type::value) );
  48. };
  49. }
  50. }
  51. #endif // BOOST_LEXICAL_CAST_DETAIL_IS_CHARACTER_HPP