Merge pull request #21 from iris-cpp/fixed_string

Add `fixed_string`

Author: saki7

include/iris/fixed_string.hpp

@@ -0,0 +1,45 @@
+#ifndef IRIS_FIXED_STRING_HPP
+#define IRIS_FIXED_STRING_HPP
+
+// SPDX-License-Identifier: MIT
+
+#include <algorithm>
+#include <array>
+#include <string>
+#include <string_view>
+
+namespace iris {
+
+template<class CharT, std::size_t N, class Traits = std::char_traits<CharT>>
+struct basic_fixed_string
+{
+    using storage_type = std::array<CharT, N + 1>;
+
+    storage_type data{};
+
+    using traits_type = Traits;
+    using value_type = CharT;
+    using iterator = storage_type::iterator;
+    using const_iterator = storage_type::const_iterator;
+    using string_view_type = std::basic_string_view<CharT, Traits>;
+
+    constexpr basic_fixed_string() noexcept = default;
+    constexpr basic_fixed_string(CharT const (&str)[N + 1]) { std::ranges::copy(str, data.begin()); }
+
+    [[nodiscard]] constexpr iterator begin() noexcept { return data.begin(); }
+    [[nodiscard]] constexpr const_iterator begin() const noexcept { return data.begin(); }
+    [[nodiscard]] constexpr iterator end() noexcept { return data.end() - 1; }
+    [[nodiscard]] constexpr const_iterator end() const noexcept { return data.end() - 1; }
+
+    [[nodiscard]] constexpr operator string_view_type() const { return {this->begin(), this->end()}; }
+};
+
+template<class CharT, std::size_t N>
+basic_fixed_string(CharT const (&)[N]) -> basic_fixed_string<CharT, N - 1>;
+
+template<std::size_t N>
+using fixed_string = basic_fixed_string<char, N>;
+
+}  // iris
+
+#endif

test/core.cpp

@@ -5,10 +5,12 @@
 #include <iris/type_traits.hpp>
 #include <iris/requirements.hpp>
 #include <iris/compare.hpp>
+#include <iris/fixed_string.hpp>
 
 #include <concepts>
 #include <utility>
 #include <type_traits>
+#include <ranges>
 
 namespace unit_test {
 
@@ -431,4 +433,11 @@ TEST_CASE("synth_three_way")
     STATIC_CHECK(iris::cmp::synth_three_way{}(NoThreeWay{0}, NoThreeWay{1}) == std::weak_ordering::less);
 }
 
+TEST_CASE("fixed_string")
+{
+    using namespace std::string_view_literals;
+    constexpr iris::fixed_string str = "foobar";
+    CHECK((std::ranges::equal(str, "foobar"sv)));
+}
+
 } // unit_test

test/enum.cpp

@@ -31,7 +31,7 @@ enum class SpellType : std::uint8_t
     ATTR_THUNDER = 1 << 4,
 };
 
-template <>
+template<>
 struct iris::bitops_enabled<MyFlags> : std::true_type
 {
     static MyFlags parse(std::string_view sv) noexcept
@@ -44,7 +44,7 @@ struct iris::bitops_enabled<MyFlags> : std::true_type
     }
 };
 
-template <>
+template<>
 struct iris::bitops_enabled<SpellType> : std::true_type
 {
     static constexpr int min_bit = 2;