bit_width.h 943 B

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  1. //===----------------------------------------------------------------------===//
  2. //
  3. // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
  4. // See https://llvm.org/LICENSE.txt for license information.
  5. // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
  6. //
  7. //===----------------------------------------------------------------------===//
  8. #ifndef _LIBCPP___BIT_BIT_WIDTH_H
  9. #define _LIBCPP___BIT_BIT_WIDTH_H
  10. #include <__bit/bit_log2.h>
  11. #include <__concepts/arithmetic.h>
  12. #include <__config>
  13. #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
  14. # pragma GCC system_header
  15. #endif
  16. #if _LIBCPP_STD_VER >= 20
  17. _LIBCPP_BEGIN_NAMESPACE_STD
  18. template <__libcpp_unsigned_integer _Tp>
  19. _LIBCPP_NODISCARD_EXT _LIBCPP_HIDE_FROM_ABI constexpr int bit_width(_Tp __t) noexcept {
  20. return __t == 0 ? 0 : std::__bit_log2(__t) + 1;
  21. }
  22. _LIBCPP_END_NAMESPACE_STD
  23. #endif // _LIBCPP_STD_VER >= 20
  24. #endif // _LIBCPP___BIT_BIT_WIDTH_H