added enum19 max_underlying_value_of

arBmind · arBmind · commit 300f82e814e9 · 2022-12-08T16:38:48.000+01:00
diff --git a/src/enum19.lib/enum19/Enum.max.h b/src/enum19.lib/enum19/Enum.max.h
@@ -0,0 +1,17 @@
+#pragma once
+#include "Enum.h"
+
+namespace enum19 {
+
+template<class T>
+constexpr auto max_underlying_value_of = []() -> std::underlying_type_t<T> {
+    using V = std::underlying_type_t<T>;
+    auto result = V{};
+    for (auto& member : meta_enum_for<T>.members) {
+        const auto v = static_cast<V>(member.value);
+        if (result < v) result = v;
+    }
+    return result;
+}();
+
+} // namespace enum19
diff --git a/src/enum19.lib/enum19/Enum.max.test.cpp b/src/enum19.lib/enum19/Enum.max.test.cpp
@@ -0,0 +1,17 @@
+#include "Enum.max.h"
+
+#include <gtest/gtest.h>
+
+using namespace enum19;
+
+namespace my_test {
+
+ENUM19(Color, int, green = 0x0f0, red = 0xf00, brown = green + red);
+ENUM19(List, int, Base, Apple, Banana, Orange, Pinapple);
+
+} // namespace my_test
+
+TEST(Enum_max, example) {
+    static_assert(enum19::max_underlying_value_of<my_test::Color> == 0xff0);
+    static_assert(enum19::max_underlying_value_of<my_test::List> == 4);
+}
diff --git a/src/enum19.lib/enum19/enum19.qbs b/src/enum19.lib/enum19/enum19.qbs
@@ -15,6 +15,7 @@ Product {
         "Enum.extras.ostream.h",
         "Enum.fmt.h",
         "Enum.h",
+        "Enum.max.h",
         "Enum.names.h",
         "Enum.ostream.h",
         "visitEnumMemberNames.h",
diff --git a/src/enum19.lib/enum19/enum19.tests.qbs b/src/enum19.lib/enum19/enum19.tests.qbs
@@ -12,5 +12,6 @@ Application {
     files: [
         "Enum.ostream.test.cpp",
         "Enum.test.cpp",
+        "Enum.max.test.cpp",
     ]
 }

Original file line number	Diff line number	Diff line change
`@@ -12,5 +12,6 @@ Application {`
`12`	`12`	`files: [`
`13`	`13`	`"Enum.ostream.test.cpp",`
`14`	`14`	`"Enum.test.cpp",`
	`15`	`+ "Enum.max.test.cpp",`
`15`	`16`	`]`
`16`	`17`	`}`