Better return type for find

BrainStone · Oct 29, 2023 · ccfa141 · ccfa141
1 parent da64dcc
commit ccfa141
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Showing 3 changed files with 14 additions and 12 deletions.
diff --git a/src/static_string_map.hpp b/src/static_string_map.hpp
@@ -1,5 +1,6 @@
 #include <algorithm>
 #include <array>
+#include <optional>
 #include <string_view>
 #include <utility>
 
@@ -10,6 +11,7 @@ class static_string_map {
 	using entry_t = std::pair<str_t, str_t>;
 	using map_t = std::array<entry_t, N>;
 	using it_t = typename map_t::const_iterator;
+	using find_t = std::optional<str_t>;
 
 	// Mimic std::map's size functions
 	static constexpr std::size_t size = N;
@@ -29,22 +31,22 @@ class static_string_map {
 	constexpr explicit static_string_map(const map_t& map) : sorted_map{sort_map(map)} {}
 	constexpr explicit static_string_map(const entry_t (&&entries)[N]) : static_string_map{std::to_array(entries)} {}
 
-	[[nodiscard]] constexpr std::pair<bool, it_t> find(str_t key) const {
+	[[nodiscard]] constexpr find_t find(str_t key) const {
 		const it_t begin = sorted_map.cbegin();
 		const it_t end = sorted_map.end();
 
 		const it_t result =
 		    std::lower_bound(begin, end, key, [](const entry_t& a, const std::string_view& b) { return a.first < b; });
 
-		return std::make_pair((result != end) && (result->first == key), result);
+		return (result != end) && (result->first == key) ? std::make_optional(result->second) : std::nullopt;
 	}
 
 	[[nodiscard]] constexpr str_t at(str_t key) const {
-		const std::pair<bool, it_t> search_result = find(key);
+		const find_t search_result = find(key);
 
-		if (search_result.first) [[likely]] {
+		if (search_result) [[likely]] {
 			// Found key
-			return search_result.second->second;
+			return *search_result;
 		} else {
 			using namespace std::literals::string_literals;
 			// Key not found
@@ -53,7 +55,7 @@ class static_string_map {
 	}
 
 	[[nodiscard]] constexpr bool contains(str_t key) const {
-		return find(key).first;
+		return find(key).has_value();
 	}
 
 	[[nodiscard]] constexpr str_t operator[](str_t key) const {

diff --git a/test/test_constexpr.cpp b/test/test_constexpr.cpp
@@ -35,8 +35,8 @@ TEST(TestConstexpr, Find) {
 	constexpr auto hello = map.find("hello");
 	constexpr auto hi = map.find("hi");
 
-	EXPECT_TRUE(hello.first);
-	EXPECT_EQ(hello.second->second, "world");
+	EXPECT_TRUE(hello);
+	EXPECT_EQ(*hello, "world");
 
-	EXPECT_FALSE(hi.first);
+	EXPECT_FALSE(hi);
 }
diff --git a/test/test_dynamic.cpp b/test/test_dynamic.cpp
@@ -34,8 +34,8 @@ TEST(TestDynamic, Find) {
 	const auto hello = map.find("hello");
 	const auto hi = map.find("hi");
 
-	EXPECT_TRUE(hello.first);
-	EXPECT_EQ(hello.second->second, "world");
+	EXPECT_TRUE(hello);
+	EXPECT_EQ(*hello, "world");
 
-	EXPECT_FALSE(hi.first);
+	EXPECT_FALSE(hi);
 }