Changeset 1053 for cpp

Timestamp:

12/27/20 19:35:00 (4 years ago)

Author:

Maciej Komosinski

Message:

Implemented missing ffs(int) for Windows compilers

File:

• cpp/common/nonstd_math.h (modified) (2 diffs)

cpp/common/nonstd_math.h

@@ -78 +78 @@
 void fpExceptDisable();
 
-// std::lerp can be used since c++20 (and has some guaranteed properties probably better than this basic formula) but apparently it is not a template
+// std::lerp can be used since C++20 (and has some guaranteed properties probably better than this basic formula) but apparently it is not a template
 template <typename Value, typename Linear> Value universal_lerp(Value a,Value b,Linear t) {return a*(1-t)+b*t;}
 
@@ -86 +86 @@
 }
 
+//in C++20, related: https://en.cppreference.com/w/cpp/numeric/countl_zero
+#ifdef _WIN32 //visual studio is missing ffs()
+static inline unsigned ffs(int x)
+{
+        if (x == 0) return 0u;
+        unsigned r = 1;
+        while ((x & 1) == 0)
+                x >>= 1, ++r;
+        return r;
+}
 #endif
+
+
+#endif