[core] util::wrap(): std::fmod is not lossless

1 files changed, 9 insertions, 2 deletions

diff --git a/include/mbgl/math/wrap.hpp b/include/mbgl/math/wrap.hpp
index 16dc598c22..3076225384 100644
--- a/include/mbgl/math/wrap.hpp
+++ b/include/mbgl/math/wrap.hpp
@@ -9,8 +9,15 @@ namespace util {
 // arithmetic.
 template <typename T>
 T wrap(T value, T min, T max) {
-    T d = max - min;
-    return std::fmod((std::fmod((value - min), d) + d), d) + min;
+    if (value >= min && value < max) {
+        return value;
+    } else if (value == max) {
+        return min;
+    }
+
+    const T delta = max - min;
+    const T wrapped = min + std::fmod(value - min, delta);
+    return value < min ? wrapped + delta : wrapped;
 }
 
 } // namespace util