is_character.hpp 1.6 KB

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  1. // Copyright Kevlin Henney, 2000-2005.
  2. // Copyright Alexander Nasonov, 2006-2010.
  3. // Copyright Antony Polukhin, 2011-2025.
  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 <type_traits>
  20. #include <boost/config.hpp>
  21. #ifdef BOOST_HAS_PRAGMA_ONCE
  22. # pragma once
  23. #endif
  24. namespace boost { namespace detail {
  25. // returns true, if T is one of the character types
  26. template < typename T >
  27. using is_character = std::integral_constant<
  28. bool,
  29. std::is_same< T, char >::value ||
  30. #if !defined(BOOST_NO_STRINGSTREAM) && !defined(BOOST_NO_STD_WSTRING)
  31. std::is_same< T, wchar_t >::value ||
  32. #endif
  33. #ifndef BOOST_NO_CXX11_CHAR16_T
  34. std::is_same< T, char16_t >::value ||
  35. #endif
  36. #ifndef BOOST_NO_CXX11_CHAR32_T
  37. std::is_same< T, char32_t >::value ||
  38. #endif
  39. std::is_same< T, unsigned char >::value ||
  40. std::is_same< T, signed char >::value
  41. >;
  42. }}
  43. #endif // BOOST_LEXICAL_CAST_DETAIL_IS_CHARACTER_HPP