/*
- * Copyright 2017 Facebook, Inc.
+ * Copyright 2017-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.
namespace detail {
template <typename T>
-constexpr T constexpr_log2(T a, T e) {
- return e == T(1) ? a : constexpr_log2(a + T(1), e / T(2));
+constexpr T constexpr_log2_(T a, T e) {
+ return e == T(1) ? a : constexpr_log2_(a + T(1), e / T(2));
+}
+
+template <typename T>
+constexpr T constexpr_log2_ceil_(T l2, T t) {
+ return l2 + T(T(1) << l2 < t ? 1 : 0);
+}
+
+template <typename T>
+constexpr T constexpr_square_(T t) {
+ return t * t;
}
} // namespace detail
template <typename T>
constexpr T constexpr_log2(T t) {
- return detail::constexpr_log2(T(0), t);
+ return detail::constexpr_log2_(T(0), t);
+}
+
+template <typename T>
+constexpr T constexpr_log2_ceil(T t) {
+ return detail::constexpr_log2_ceil_(constexpr_log2(t), t);
+}
+
+template <typename T>
+constexpr T constexpr_ceil(T t, T round) {
+ return round == T(0)
+ ? t
+ : ((t + (t < T(0) ? T(0) : round - T(1))) / round) * round;
+}
+
+template <typename T>
+constexpr T constexpr_pow(T base, std::size_t exp) {
+ return exp == 0
+ ? T(1)
+ : exp == 1 ? base
+ : detail::constexpr_square_(constexpr_pow(base, exp / 2)) *
+ (exp % 2 ? base : T(1));
}
} // namespace folly