/*
- * Copyright 2016 Facebook, Inc.
+ * Copyright 2016-present Facebook, Inc.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* limitations under the License.
*/
-#ifndef FOLLY_CONSTEXPR_H_
-#define FOLLY_CONSTEXPR_H_
+#pragma once
#include <cstdint>
#include <cstring>
+#include <type_traits>
namespace folly {
-template <typename T>
-constexpr T constexpr_max(T a, T b) {
- return a > b ? a : b;
-}
+namespace detail {
-template <typename T>
-constexpr T constexpr_min(T a, T b) {
- return a < b ? a : b;
+template <typename Char>
+constexpr size_t constexpr_strlen_internal(const Char* s, size_t len) {
+ return *s == Char(0) ? len : constexpr_strlen_internal(s + 1, len + 1);
}
-
-#ifdef _MSC_VER
-constexpr size_t constexpr_strlen_internal(const char* s, size_t len) {
- return *s == '\0' ? len : constexpr_strlen_internal(s + 1, len + 1);
+static_assert(
+ constexpr_strlen_internal("123456789", 0) == 9,
+ "Someone appears to have broken constexpr_strlen...");
+} // namespace detail
+
+template <typename Char>
+constexpr size_t constexpr_strlen(const Char* s) {
+ return detail::constexpr_strlen_internal(s, 0);
}
-static_assert(constexpr_strlen_internal("123456789", 0) == 9,
- "Someone appears to have broken constexpr_strlen...");
-#endif
+template <>
constexpr size_t constexpr_strlen(const char* s) {
#if defined(__clang__)
return __builtin_strlen(s);
-#elif defined(_MSC_VER)
- return s == nullptr ? 0 : constexpr_strlen_internal(s, 0);
+#elif defined(_MSC_VER) || defined(__CUDACC__)
+ return detail::constexpr_strlen_internal(s, 0);
#else
return std::strlen(s);
#endif
}
-}
-
-#endif
+} // namespace folly