diff options
Diffstat (limited to 'libstdc++-v3/include/bits/char_traits.h')
| -rw-r--r-- | libstdc++-v3/include/bits/char_traits.h | 101 |
1 files changed, 90 insertions, 11 deletions
diff --git a/libstdc++-v3/include/bits/char_traits.h b/libstdc++-v3/include/bits/char_traits.h index 75db5b89321..3ecc30e46cb 100644 --- a/libstdc++-v3/include/bits/char_traits.h +++ b/libstdc++-v3/include/bits/char_traits.h @@ -40,6 +40,10 @@ #include <bits/postypes.h> // For streampos #include <cwchar> // For WEOF, wmemmove, wmemset, etc. +#ifndef _GLIBCXX_ALWAYS_INLINE +#define _GLIBCXX_ALWAYS_INLINE inline __attribute__((__always_inline__)) +#endif + namespace __gnu_cxx _GLIBCXX_VISIBILITY(default) { _GLIBCXX_BEGIN_NAMESPACE_VERSION @@ -139,7 +143,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION { return !eq_int_type(__c, eof()) ? __c : to_int_type(char_type()); } }; -// #define __cpp_lib_constexpr_char_traits 201611 +#define __cpp_lib_constexpr_char_traits 201611 template<typename _CharT> _GLIBCXX14_CONSTEXPR int @@ -212,6 +216,42 @@ namespace std _GLIBCXX_VISIBILITY(default) { _GLIBCXX_BEGIN_NAMESPACE_VERSION +#if __cplusplus > 201402 + /** + * @brief Determine whether the characters of a NULL-terminated + * string are known at compile time. + * @param __s The string. + * + * Assumes that _CharT is a built-in character type. + */ + template<typename _CharT> + static _GLIBCXX_ALWAYS_INLINE constexpr bool + __constant_string_p(const _CharT* __s) + { + while (__builtin_constant_p(*__s) && *__s) + __s++; + return __builtin_constant_p(*__s); + } + + /** + * @brief Determine whether the characters of a character array are + * known at compile time. + * @param __a The character array. + * @param __n Number of characters. + * + * Assumes that _CharT is a built-in character type. + */ + template<typename _CharT> + static _GLIBCXX_ALWAYS_INLINE constexpr bool + __constant_char_array_p(const _CharT* __a, size_t __n) + { + size_t __i = 0; + while (__builtin_constant_p(__a[__i]) && __i < __n) + __i++; + return __i == __n; + } +#endif + // 21.1 /** * @brief Basis for explicit traits specializations. @@ -256,21 +296,39 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION < static_cast<unsigned char>(__c2)); } - static /* _GLIBCXX17_CONSTEXPR */ int + static _GLIBCXX17_CONSTEXPR int compare(const char_type* __s1, const char_type* __s2, size_t __n) { +#if __cplusplus > 201402 + if (__builtin_constant_p(__n) + && __constant_char_array_p(__s1, __n) + && __constant_char_array_p(__s2, __n)) + return __gnu_cxx::char_traits<char_type>::compare(__s1, __s2, __n); +#endif if (__n == 0) return 0; return __builtin_memcmp(__s1, __s2, __n); } - static /* _GLIBCXX17_CONSTEXPR */ size_t + static _GLIBCXX17_CONSTEXPR size_t length(const char_type* __s) - { return __builtin_strlen(__s); } + { +#if __cplusplus > 201402 + if (__constant_string_p(__s)) + return __gnu_cxx::char_traits<char_type>::length(__s); +#endif + return __builtin_strlen(__s); + } - static /* _GLIBCXX17_CONSTEXPR */ const char_type* + static _GLIBCXX17_CONSTEXPR const char_type* find(const char_type* __s, size_t __n, const char_type& __a) { +#if __cplusplus > 201402 + if (__builtin_constant_p(__n) + && __builtin_constant_p(__a) + && __constant_char_array_p(__s, __n)) + return __gnu_cxx::char_traits<char_type>::find(__s, __n, __a); +#endif if (__n == 0) return 0; return static_cast<const char_type*>(__builtin_memchr(__s, __a, __n)); @@ -347,24 +405,45 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION lt(const char_type& __c1, const char_type& __c2) _GLIBCXX_NOEXCEPT { return __c1 < __c2; } - static /* _GLIBCXX17_CONSTEXPR */ int + static _GLIBCXX17_CONSTEXPR int compare(const char_type* __s1, const char_type* __s2, size_t __n) { +#if __cplusplus > 201402 + if (__builtin_constant_p(__n) + && __constant_char_array_p(__s1, __n) + && __constant_char_array_p(__s2, __n)) + return __gnu_cxx::char_traits<char_type>::compare(__s1, __s2, __n); +#endif if (__n == 0) return 0; - return wmemcmp(__s1, __s2, __n); + else + return wmemcmp(__s1, __s2, __n); } - static /* _GLIBCXX17_CONSTEXPR */ size_t + static _GLIBCXX17_CONSTEXPR size_t length(const char_type* __s) - { return wcslen(__s); } + { +#if __cplusplus > 201402 + if (__constant_string_p(__s)) + return __gnu_cxx::char_traits<char_type>::length(__s); + else +#endif + return wcslen(__s); + } - static /* _GLIBCXX17_CONSTEXPR */ const char_type* + static _GLIBCXX17_CONSTEXPR const char_type* find(const char_type* __s, size_t __n, const char_type& __a) { +#if __cplusplus > 201402 + if (__builtin_constant_p(__n) + && __builtin_constant_p(__a) + && __constant_char_array_p(__s, __n)) + return __gnu_cxx::char_traits<char_type>::find(__s, __n, __a); +#endif if (__n == 0) return 0; - return wmemchr(__s, __a, __n); + else + return wmemchr(__s, __a, __n); } static char_type* |