Added support for work/movements, fixes #834

src/libs/core/impl/String.cpp

@@ -418,6 +418,44 @@ namespace lms::core::stringUtils
         }
     }
 
+    std::string toRomanNumeral(std::size_t n)
+    {
+        if (n == 0 || n > 3999)
+            return {};
+
+        static constexpr struct
+        {
+            std::size_t val;
+            const char* sym;
+        } table[]{
+            { 1000, "m" },
+            { 900, "cm" },
+            { 500, "d" },
+            { 400, "cd" },
+            { 100, "c" },
+            { 90, "xc" },
+            { 50, "l" },
+            { 40, "xl" },
+            { 10, "x" },
+            { 9, "ix" },
+            { 5, "v" },
+            { 4, "iv" },
+            { 1, "i" }
+        };
+
+        std::string res;
+        for (const auto& [val, sym] : table)
+        {
+            while (n >= val)
+            {
+                res += sym;
+                n -= val;
+            }
+        }
+
+        return res;
+    }
+
     std::string replaceInString(std::string_view str, std::string_view from, std::string_view to)
     {
         std::string res{ str };

src/libs/core/include/core/String.hpp

@@ -65,6 +65,9 @@ namespace lms::core::stringUtils
 
     void capitalize(std::string& str);
 
+    // returns empty string if invalid input
+    [[nodiscard]] std::string toRomanNumeral(std::size_t n);
+
     template<typename T>
     [[nodiscard]] std::optional<T> readAs(std::string_view str)
     {

src/libs/core/test/String.cpp

@@ -17,6 +17,8 @@
  * along with LMS.  If not, see <http://www.gnu.org/licenses/>.
  */
 
+#include <limits>
+
 #include <gtest/gtest.h>
 
 #include <Wt/WDate.h>
@@ -412,4 +414,32 @@ namespace lms::core::stringUtils::tests
         EXPECT_EQ(stringFromHex("3132333435"), "12345");
         EXPECT_EQ(stringFromHex("54657374"), "Test");
     }
+
+    TEST(StringUtils, toRomanNumeral)
+    {
+        EXPECT_EQ(toRomanNumeral(1), "i");
+        EXPECT_EQ(toRomanNumeral(2), "ii");
+        EXPECT_EQ(toRomanNumeral(3), "iii");
+        EXPECT_EQ(toRomanNumeral(4), "iv");
+        EXPECT_EQ(toRomanNumeral(5), "v");
+        EXPECT_EQ(toRomanNumeral(6), "vi");
+        EXPECT_EQ(toRomanNumeral(7), "vii");
+        EXPECT_EQ(toRomanNumeral(8), "viii");
+        EXPECT_EQ(toRomanNumeral(9), "ix");
+        EXPECT_EQ(toRomanNumeral(10), "x");
+        EXPECT_EQ(toRomanNumeral(11), "xi");
+        EXPECT_EQ(toRomanNumeral(14), "xiv");
+        EXPECT_EQ(toRomanNumeral(16), "xvi");
+        EXPECT_EQ(toRomanNumeral(40), "xl");
+        EXPECT_EQ(toRomanNumeral(50), "l");
+        EXPECT_EQ(toRomanNumeral(90), "xc");
+        EXPECT_EQ(toRomanNumeral(99), "xcix");
+        EXPECT_EQ(toRomanNumeral(444), "cdxliv");
+        EXPECT_EQ(toRomanNumeral(1994), "mcmxciv");
+        EXPECT_EQ(toRomanNumeral(3999), "mmmcmxcix");
+        EXPECT_EQ(toRomanNumeral(0), "");
+        EXPECT_EQ(toRomanNumeral(4000), "");
+        EXPECT_EQ(toRomanNumeral(static_cast<std::size_t>(-1)), ""); // underflows to SIZE_MAX
+        EXPECT_EQ(toRomanNumeral(std::numeric_limits<std::size_t>::max()), "");
+    }
 } // namespace lms::core::stringUtils::tests