fix hang when using very large angles for hue in hsl colors

Author: kkaefer

csscolorparser.cpp

@@ -262,8 +262,9 @@ optional<Color> parse(const std::string& css_str) {
             }
 
             float h = parseFloat(params[0]) / 360.0f;
-            while (h < 0.0f) h++;
-            while (h > 1.0f) h--;
+            float i;
+            // Normalize the hue to [0..1[
+            h = std::modf(h, &i);
 
             // NOTE(deanm): According to the CSS spec s/l should only be
             // percentages, but we don't bother and let float or percentage.

test.cpp

@@ -47,6 +47,10 @@ int main() {
         ASSERT_EQUAL({}, "hsla(900, 15%, 90%)");
         ASSERT_EQUAL(Color{ 226, 233, 233, 1 }, "hsl(900, 15%, 90%)");
         ASSERT_EQUAL(Color{ 226, 233, 233, 1 }, "hsl(900, 0.15, 90%)"); // NOTE: not spec compliamt.
+        ASSERT_EQUAL(Color{ 0, 0, 0, 1 }, "hsl(9999999999999999999, 0, 0)"); // NOTE: float precision loss
+        ASSERT_EQUAL(Color{ 255, 191, 0, 1 }, "hsl(45, 100%, 50%)");
+        ASSERT_EQUAL(Color{ 255, 191, 0, 1 }, "hsl(-315, 100%, 50%)");
+        ASSERT_EQUAL(Color{ 255, 191, 0, 1 }, "hsl(-675, 100%, 50%)");
 
         // Out of range:
         ASSERT_EQUAL({}, "xxx");