String::fromNumber gave a wrong result with uint8_t and int8_t values

texus · May 8, 2024 · 0414021 · 0414021
1 parent 151ff95
commit 0414021
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Showing 2 changed files with 23 additions and 4 deletions.
diff --git a/include/TGUI/String.hpp b/include/TGUI/String.hpp
@@ -321,10 +321,20 @@ TGUI_MODULE_EXPORT namespace tgui
         template <typename T>
         TGUI_NODISCARD static String fromNumber(T value)
         {
-            std::ostringstream oss;
-            oss.imbue(std::locale::classic());
-            oss << value;
-            return {oss.str()};
+            // If the value is a floating point then we can't use std::to_string because its result depends on the locale.
+            // If the value is an 8-bit type (e.g. uint8_t and int8_t) then using std::ostringstream results in the wrong result,
+            // as it will be interpreted as a character instead of a number.
+            TGUI_IF_CONSTEXPR (std::is_integral<T>::value)
+            {
+                return {std::to_string(value)};
+            }
+            else
+            {
+                std::ostringstream oss;
+                oss.imbue(std::locale::classic());
+                oss << value;
+                return {oss.str()};
+            }
         }
 
 
@@ -339,6 +349,12 @@ TGUI_MODULE_EXPORT namespace tgui
         template <typename T>
         TGUI_NODISCARD static String fromNumberRounded(T value, unsigned int decimals)
         {
+            // Precision is ignored by std::ostringstream for integers, so we use std::to_string for integers instead.
+            // If the value is an 8-bit type (e.g. uint8_t and int8_t) then using std::ostringstream results in the wrong result,
+            // as it will be interpreted as a character instead of a number. Which is why this separate branch for integers exists.
+            TGUI_IF_CONSTEXPR (std::is_integral<T>::value)
+                return {std::to_string(value)};
+
             std::ostringstream oss;
             oss.imbue(std::locale::classic());
             oss << std::fixed << std::setprecision(static_cast<int>(decimals));

diff --git a/tests/String.cpp b/tests/String.cpp
@@ -1474,13 +1474,16 @@ TEST_CASE("[String]")
         REQUIRE(tgui::String::fromNumber(15) == "15");
         REQUIRE(tgui::String::fromNumber(-3) == "-3");
         REQUIRE(tgui::String::fromNumber(0.5) == "0.5");
+        REQUIRE(tgui::String::fromNumber(uint8_t(5)) == "5");
     }
 
     SECTION("fromNumberRounded")
     {
         REQUIRE(tgui::String::fromNumberRounded(15.001f, 0) == "15");
         REQUIRE(tgui::String::fromNumberRounded(-3.0015f, 3) == "-3.001");
         REQUIRE(tgui::String::fromNumberRounded(0.5f, 2) == "0.50");
+        REQUIRE(tgui::String::fromNumberRounded(15, 2) == "15");
+        REQUIRE(tgui::String::fromNumberRounded(uint8_t(5), 2) == "5");
     }
 
     SECTION("trim")