| //===----------------------------------------------------------------------===// |
| // |
| // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. |
| // See https://llvm.org/LICENSE.txt for license information. |
| // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception |
| // |
| //===----------------------------------------------------------------------===// |
| |
| #ifndef _LIBCPP___STRING_CONSTEXPR_C_FUNCTIONS_H |
| #define _LIBCPP___STRING_CONSTEXPR_C_FUNCTIONS_H |
| |
| #include <__config> |
| #include <__type_traits/is_constant_evaluated.h> |
| #include <__type_traits/is_equality_comparable.h> |
| #include <__type_traits/is_same.h> |
| #include <cstddef> |
| |
| #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER) |
| # pragma GCC system_header |
| #endif |
| |
| _LIBCPP_BEGIN_NAMESPACE_STD |
| |
| inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 size_t __constexpr_strlen(const char* __str) { |
| // GCC currently doesn't support __builtin_strlen for heap-allocated memory during constant evaluation. |
| // https://gcc.gnu.org/bugzilla/show_bug.cgi?id=70816 |
| #ifdef _LIBCPP_COMPILER_GCC |
| if (__libcpp_is_constant_evaluated()) { |
| size_t __i = 0; |
| for (; __str[__i] != '\0'; ++__i) |
| ; |
| return __i; |
| } |
| #endif |
| return __builtin_strlen(__str); |
| } |
| |
| template <class _Tp, class _Up> |
| _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 int |
| __constexpr_memcmp(const _Tp* __lhs, const _Up* __rhs, size_t __count) { |
| static_assert(__libcpp_is_trivially_equality_comparable<_Tp, _Up>::value, |
| "_Tp and _Up have to be trivially equality comparable"); |
| |
| if (__libcpp_is_constant_evaluated()) { |
| #ifdef _LIBCPP_COMPILER_CLANG_BASED |
| if (sizeof(_Tp) == 1 && !is_same<_Tp, bool>::value) |
| return __builtin_memcmp(__lhs, __rhs, __count); |
| #endif |
| |
| while (__count != 0) { |
| if (*__lhs < *__rhs) |
| return -1; |
| if (*__rhs < *__lhs) |
| return 1; |
| |
| __count -= sizeof(_Tp); |
| ++__lhs; |
| ++__rhs; |
| } |
| return 0; |
| } else { |
| return __builtin_memcmp(__lhs, __rhs, __count); |
| } |
| } |
| |
| inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 const char* |
| __constexpr_char_memchr(const char* __str, int __char, size_t __count) { |
| #if __has_builtin(__builtin_char_memchr) |
| return __builtin_char_memchr(__str, __char, __count); |
| #else |
| if (!__libcpp_is_constant_evaluated()) |
| return static_cast<const char*>(__builtin_memchr(__str, __char, __count)); |
| for (; __count; --__count) { |
| if (*__str == __char) |
| return __str; |
| ++__str; |
| } |
| return nullptr; |
| #endif |
| } |
| |
| _LIBCPP_END_NAMESPACE_STD |
| |
| #endif // _LIBCPP___STRING_CONSTEXPR_C_FUNCTIONS_H |