[OptionalReference] Add value_or() function

teslamotors · Sep 19, 2024 · 1ad10a6 · 1ad10a6
1 parent 89923df
commit 1ad10a6
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diff --git a/include/fixed_containers/optional_reference.hpp b/include/fixed_containers/optional_reference.hpp
@@ -86,6 +86,16 @@ class OptionalReference
         return *val();
     }
 
+    [[nodiscard]] constexpr reference value_or(reference default_value) const&
+    {
+        if (!has_value())
+        {
+            return default_value;
+        }
+
+        return *val();
+    }
+
     constexpr explicit operator bool() const noexcept { return has_value(); }
     [[nodiscard]] constexpr bool has_value() const noexcept { return val() != nullptr; }
 

diff --git a/test/optional_reference_test.cpp b/test/optional_reference_test.cpp
@@ -97,6 +97,29 @@ TEST(OptionalReference, Value)
     }
 }
 
+TEST(OptionalReference, ValueOr)
+{
+    {
+        int fallback_value = 99;
+
+        using T = OptionalReference<int>;
+        const T val1{};
+        int& result = val1.value_or(fallback_value);
+        EXPECT_EQ(99, result);
+        result = 88;
+        EXPECT_EQ(88, result);
+        EXPECT_EQ(88, fallback_value);
+    }
+    {
+        const int fallback_value = 77;
+
+        constexpr int ENTRY_1 = 5;
+        const OptionalReference<const int> val1(ENTRY_1);
+        const int& result = val1.value_or(fallback_value);
+        EXPECT_EQ(5, result);
+    }
+}
+
 TEST(OptionalReference, DereferenceOperator)
 {
     {