From 3bf42c6ff3805a0d42bbc661794a95ff31bedc26 Mon Sep 17 00:00:00 2001
From: untodesu <kirill@untode.su>
Date: Sat, 15 Mar 2025 16:22:09 +0500
Subject: Add whatever I was working on for the last month

---
 deps/include/entt/core/bit.hpp | 69 ++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 69 insertions(+)
 create mode 100644 deps/include/entt/core/bit.hpp

(limited to 'deps/include/entt/core/bit.hpp')

diff --git a/deps/include/entt/core/bit.hpp b/deps/include/entt/core/bit.hpp
new file mode 100644
index 0000000..6a28058
--- /dev/null
+++ b/deps/include/entt/core/bit.hpp
@@ -0,0 +1,69 @@
+#ifndef ENTT_CORE_BIT_HPP
+#define ENTT_CORE_BIT_HPP
+
+#include <cstddef>
+#include <limits>
+#include <type_traits>
+#include "../config/config.h"
+
+namespace entt {
+
+/**
+ * @brief Returns the number of set bits in a value (waiting for C++20 and
+ * `std::popcount`).
+ * @tparam Type Unsigned integer type.
+ * @param value A value of unsigned integer type.
+ * @return The number of set bits in the value.
+ */
+template<typename Type>
+[[nodiscard]] constexpr std::enable_if_t<std::is_unsigned_v<Type>, int> popcount(const Type value) noexcept {
+    return value ? (int(value & 1) + popcount(static_cast<Type>(value >> 1))) : 0;
+}
+
+/**
+ * @brief Checks whether a value is a power of two or not (waiting for C++20 and
+ * `std::has_single_bit`).
+ * @tparam Type Unsigned integer type.
+ * @param value A value of unsigned integer type.
+ * @return True if the value is a power of two, false otherwise.
+ */
+template<typename Type>
+[[nodiscard]] constexpr std::enable_if_t<std::is_unsigned_v<Type>, bool> has_single_bit(const Type value) noexcept {
+    return value && ((value & (value - 1)) == 0);
+}
+
+/**
+ * @brief Computes the smallest power of two greater than or equal to a value
+ * (waiting for C++20 and `std::bit_ceil`).
+ * @tparam Type Unsigned integer type.
+ * @param value A value of unsigned integer type.
+ * @return The smallest power of two greater than or equal to the given value.
+ */
+template<typename Type>
+[[nodiscard]] constexpr std::enable_if_t<std::is_unsigned_v<Type>, Type> next_power_of_two(const Type value) noexcept {
+    ENTT_ASSERT_CONSTEXPR(value < (Type{1u} << (std::numeric_limits<Type>::digits - 1)), "Numeric limits exceeded");
+    Type curr = value - (value != 0u);
+
+    for(int next = 1; next < std::numeric_limits<Type>::digits; next = next * 2) {
+        curr |= (curr >> next);
+    }
+
+    return ++curr;
+}
+
+/**
+ * @brief Fast module utility function (powers of two only).
+ * @tparam Type Unsigned integer type.
+ * @param value A value of unsigned integer type.
+ * @param mod _Modulus_, it must be a power of two.
+ * @return The common remainder.
+ */
+template<typename Type>
+[[nodiscard]] constexpr std::enable_if_t<std::is_unsigned_v<Type>, Type> fast_mod(const Type value, const std::size_t mod) noexcept {
+    ENTT_ASSERT_CONSTEXPR(has_single_bit(mod), "Value must be a power of two");
+    return value & (mod - 1u);
+}
+
+} // namespace entt
+
+#endif
-- 
cgit