From 14550beb3b7b97195e483fb74b5efb906395c31e Mon Sep 17 00:00:00 2001 From: Abseil Team Date: Tue, 30 Jul 2019 20:47:29 -0700 Subject: Export of internal Abseil changes. -- 8f685654a7d04eb8a0cb82d31e44e391e906b609 by Derek Mauro : Support constexpr construction of absl::string_view from a string literal in MSVC 2017+. Fixes https://github.com/abseil/abseil-cpp/issues/352 PiperOrigin-RevId: 260853160 -- a3c4c5168ce2a491134d7c87cf7fdc75d1ee2533 by Derek Mauro : Make SwissTable's at() throw when exceptions are enabled Fixes https://github.com/abseil/abseil-cpp/issues/355 PiperOrigin-RevId: 260788026 GitOrigin-RevId: 8f685654a7d04eb8a0cb82d31e44e391e906b609 Change-Id: I9ed498e181faa9c9d16e9b1b01404969d99b8ea9 --- absl/strings/string_view.h | 30 +++++++++++++++++++----------- 1 file changed, 19 insertions(+), 11 deletions(-) (limited to 'absl/strings/string_view.h') diff --git a/absl/strings/string_view.h b/absl/strings/string_view.h index f8b20015df6a..65b1772de747 100644 --- a/absl/strings/string_view.h +++ b/absl/strings/string_view.h @@ -172,19 +172,9 @@ class string_view { // Implicit constructor of a `string_view` from nul-terminated `str`. When // accepting possibly null strings, use `absl::NullSafeStringView(str)` // instead (see below). -#if ABSL_HAVE_BUILTIN(__builtin_strlen) || \ - (defined(__GNUC__) && !defined(__clang__)) - // GCC has __builtin_strlen according to - // https://gcc.gnu.org/onlinedocs/gcc-4.7.0/gcc/Other-Builtins.html, but - // ABSL_HAVE_BUILTIN doesn't detect that, so we use the extra checks above. - // __builtin_strlen is constexpr. constexpr string_view(const char* str) // NOLINT(runtime/explicit) : ptr_(str), - length_(CheckLengthInternal(str ? __builtin_strlen(str) : 0)) {} -#else - constexpr string_view(const char* str) // NOLINT(runtime/explicit) - : ptr_(str), length_(CheckLengthInternal(str ? strlen(str) : 0)) {} -#endif + length_(str ? CheckLengthInternal(StrlenInternal(str)) : 0) {} // Implicit constructor of a `string_view` from a `const char*` and length. constexpr string_view(const char* data, size_type len) @@ -495,6 +485,24 @@ class string_view { return ABSL_ASSERT(len <= kMaxSize), len; } + static constexpr size_type StrlenInternal(const char* str) { +#if defined(_MSC_VER) && _MSC_VER >= 1910 && !defined(__clang__) + // MSVC 2017+ can evaluate this at compile-time. + const char* begin = str; + while (*str != '\0') ++str; + return str - begin; +#elif ABSL_HAVE_BUILTIN(__builtin_strlen) || \ + (defined(__GNUC__) && !defined(__clang__)) + // GCC has __builtin_strlen according to + // https://gcc.gnu.org/onlinedocs/gcc-4.7.0/gcc/Other-Builtins.html, but + // ABSL_HAVE_BUILTIN doesn't detect that, so we use the extra checks above. + // __builtin_strlen is constexpr. + return __builtin_strlen(str); +#else + return str ? strlen(str) : 0; +#endif + } + const char* ptr_; size_type length_; }; -- cgit 1.4.1