Core/Misc: Modernize comparison operators

(cherry picked from commit f0a862e71bc12d86a898901ef773475a7c964832)

4 files changed, 36 insertions, 27 deletions

diff --git a/src/common/Utilities/SmartEnum.h b/src/common/Utilities/SmartEnum.h
index 24e3c60bd30..3c58d433406 100644
--- a/src/common/Utilities/SmartEnum.h
+++ b/src/common/Utilities/SmartEnum.h
@@ -85,13 +85,10 @@ class EnumUtils
                 Iterator() : _index(EnumUtils::Count<Enum>()) {}
                 explicit Iterator(size_t index) : _index(index) { }
 
-                bool operator==(const Iterator& other) const { return other._index == _index; }
-                bool operator!=(const Iterator& other) const { return !operator==(other); }
+                bool operator==(const Iterator& other) const = default;
+                std::strong_ordering operator<=>(const Iterator& other) const = default;
+
                 difference_type operator-(Iterator const& other) const { return _index - other._index; }
-                bool operator<(const Iterator& other) const { return _index < other._index; }
-                bool operator<=(const Iterator& other) const { return _index <= other._index; }
-                bool operator>(const Iterator& other) const { return _index > other._index; }
-                bool operator>=(const Iterator& other) const { return _index >= other._index; }
 
                 value_type operator[](difference_type d) const { return FromIndex<Enum>(_index + d); }
                 value_type operator*() const { return operator[](0); }
diff --git a/src/common/Utilities/TaskScheduler.h b/src/common/Utilities/TaskScheduler.h
index 4d6761780be..3af5fc70a12 100644
--- a/src/common/Utilities/TaskScheduler.h
+++ b/src/common/Utilities/TaskScheduler.h
@@ -95,18 +95,13 @@ class TC_COMMON_API TaskScheduler
         Task& operator= (Task&& right) = delete;
 
         // Order tasks by its end
-        inline bool operator< (Task const& other) const
+        std::weak_ordering operator<=> (Task const& other) const
         {
-            return _end < other._end;
-        }
-
-        inline bool operator> (Task const& other) const
-        {
-            return _end > other._end;
+            return _end <=> other._end;
         }
 
         // Compare tasks with its end
-        inline bool operator== (Task const& other)
+        bool operator== (Task const& other) const
         {
             return _end == other._end;
         }
@@ -126,7 +121,7 @@ class TC_COMMON_API TaskScheduler
         bool operator() (TaskContainer const& left, TaskContainer const& right) const
         {
             return (*left.get()) < (*right.get());
-        };
+        }
     };
 
     class TC_COMMON_API TaskQueue
diff --git a/src/common/Utilities/Util.h b/src/common/Utilities/Util.h
index d37b86f85e5..62c8655b65f 100644
--- a/src/common/Utilities/Util.h
+++ b/src/common/Utilities/Util.h
@@ -417,18 +417,6 @@ public:
         part[2] = p3;
     }
 
-    inline bool operator<(flag96 const& right) const
-    {
-        for (uint8 i = 3; i > 0; --i)
-        {
-            if (part[i - 1] < right.part[i - 1])
-                return true;
-            else if (part[i - 1] > right.part[i - 1])
-                return false;
-        }
-        return false;
-    }
-
     inline bool operator==(flag96 const& right) const
     {
         return
diff --git a/src/common/Utilities/advstd.h b/src/common/Utilities/advstd.h
index ff2717c9755..4a26e00df52 100644
--- a/src/common/Utilities/advstd.h
+++ b/src/common/Utilities/advstd.h
@@ -18,9 +18,38 @@
 #ifndef TRINITY_ADVSTD_H
 #define TRINITY_ADVSTD_H
 
+#include <version>
+
+#ifdef __cpp_lib_bit_cast
+#include <bit>
+#else
+#include <cstring> // for memcpy
+#endif
+#include <compare>
+
 // this namespace holds implementations of upcoming stdlib features that our c++ version doesn't have yet
 namespace advstd
 {
+// libc++ is missing these two
+[[nodiscard]] constexpr bool is_eq(std::partial_ordering cmp) noexcept { return cmp == 0; }
+[[nodiscard]] constexpr bool is_neq(std::partial_ordering cmp) noexcept { return cmp != 0; }
+
+#ifdef __cpp_lib_bit_cast
+using std::bit_cast;
+#else
+// libstdc++ v10 is missing this
+template <typename To, typename From,
+    std::enable_if_t<std::conjunction_v<
+    std::bool_constant<sizeof(To) == sizeof(From)>,
+    std::is_trivially_copyable<To>,
+    std::is_trivially_copyable<From>>, int> = 0>
+    [[nodiscard]] constexpr To bit_cast(From const& from) noexcept
+{
+    To to;
+    std::memcpy(&to, &from, sizeof(To));
+    return to;
+}
+#endif
 }
 
 #endif