From a1aef36c836844cbe0ee52e1482550d4c13fd928 Mon Sep 17 00:00:00 2001
From: Martchus <martchus@gmx.net>
Date: Fri, 29 Jul 2022 22:01:51 +0200
Subject: [PATCH] Add `checkFlagEnum()` and tests for `flagenumclass.h`

---
 misc/flagenumclass.h | 11 +++++++++++
 tests/misctests.cpp  | 33 +++++++++++++++++++++++++++++++++
 2 files changed, 44 insertions(+)

diff --git a/misc/flagenumclass.h b/misc/flagenumclass.h
index b72f15e..e7e4a38 100644
--- a/misc/flagenumclass.h
+++ b/misc/flagenumclass.h
@@ -85,6 +85,17 @@ constexpr FlagEnumClass &modFlagEnum(FlagEnumClass &flagVariable, FlagEnumClass
     return value ? (flagVariable += relevantFlags) : (flagVariable -= relevantFlags);
 }
 
+/*!
+ * \brief Returns whether the specified \a flagVariable has set all flags specified via \a flagsToCheck to true.
+ */
+template <typename FlagEnumClass, Traits::EnableIf<IsFlagEnumClass<FlagEnumClass>> * = nullptr>
+constexpr bool checkFlagEnum(FlagEnumClass flagVariable, FlagEnumClass flagsToCheck)
+{
+    return (static_cast<typename std::underlying_type<FlagEnumClass>::type>(flagVariable)
+               & static_cast<typename std::underlying_type<FlagEnumClass>::type>(flagsToCheck))
+        == static_cast<typename std::underlying_type<FlagEnumClass>::type>(flagsToCheck);
+}
+
 } // namespace CppUtilities
 
 #endif // CPP_UTILITIES_FLAG_ENUM_CLASS_H
diff --git a/tests/misctests.cpp b/tests/misctests.cpp
index 0dc1992..65a2126 100644
--- a/tests/misctests.cpp
+++ b/tests/misctests.cpp
@@ -1,3 +1,4 @@
+#include "../misc/flagenumclass.h"
 #include "../misc/levenshtein.h"
 #include "../misc/multiarray.h"
 
@@ -171,3 +172,35 @@ void MiscTests::testTestUtilities()
 
     TESTUTILS_ASSERT_LIKE("assert like works", ".*foo.*", "   foo   ");
 }
+
+// test flagenumclass.h
+
+namespace FlagEnumTests {
+enum class TestFlags { None, Foo = 1, Bar = 2, Baz = 4, Biz = 8 };
+}
+
+CPP_UTILITIES_MARK_FLAG_ENUM_CLASS(FlagEnumTests, FlagEnumTests::TestFlags);
+
+namespace FlagEnumTests {
+
+constexpr bool testFlagEnumClass()
+{
+    // test const operations
+    const auto testFlags = TestFlags::Foo | TestFlags::Baz;
+    static_assert(testFlags & TestFlags::Foo);
+    static_assert(!(testFlags & TestFlags::Bar));
+    static_assert(testFlags & TestFlags::Baz);
+    static_assert(checkFlagEnum(testFlags, TestFlags::Foo | TestFlags::Baz));
+    static_assert(checkFlagEnum(testFlags, TestFlags::Foo));
+    static_assert(!checkFlagEnum(testFlags, TestFlags::Foo | TestFlags::Bar));
+
+    // test modifying
+    auto nonConstFlags = TestFlags::Foo | TestFlags::Biz;
+    modFlagEnum(nonConstFlags, TestFlags::Foo | TestFlags::Bar, false);
+    nonConstFlags += TestFlags::Bar;
+    modFlagEnum(nonConstFlags, TestFlags::Baz | TestFlags::Biz, true);
+    return nonConstFlags == (TestFlags::Bar | TestFlags::Baz | TestFlags::Biz);
+}
+static_assert(testFlagEnumClass());
+
+} // namespace FlagEnumTests