1 files changed, 34 insertions, 0 deletions
diff --git a/include/o3tl/safeint.hxx b/include/o3tl/safeint.hxx
index 80a152b83290..4ab31b13ec8f 100644
--- a/include/o3tl/safeint.hxx
+++ b/include/o3tl/safeint.hxx
@@ -10,7 +10,11 @@
 #ifndef INCLUDED_O3TL_SAFEINT_HXX
 #define INCLUDED_O3TL_SAFEINT_HXX
 
+#include <sal/config.h>
+
 #include <limits>
+#include <type_traits>
+
 #if defined(_MSC_VER)
 #include <safeint.h>
 #else
@@ -22,6 +26,36 @@
 namespace o3tl
 {
 
+template<typename T> inline
+typename std::enable_if<std::is_signed<T>::value, T>::type saturating_add(
+    T a, T b)
+{
+    if (b >= 0) {
+        if (a <= std::numeric_limits<T>::max() - b) {
+            return a + b;
+        } else {
+            return std::numeric_limits<T>::max();
+        }
+    } else {
+        if (a >= std::numeric_limits<T>::min() + b) {
+            return a - b;
+        } else {
+            return std::numeric_limits<T>::min();
+        }
+    }
+}
+
+template<typename T> inline
+typename std::enable_if<std::is_unsigned<T>::value, T>::type saturating_add(
+    T a, T b)
+{
+    if (a <= std::numeric_limits<T>::max() - b) {
+        return a + b;
+    } else {
+        return std::numeric_limits<T>::max();
+    }
+}
+
 #if defined(_MSC_VER)
 
 template<typename T> inline bool checked_multiply(T a, T b, T& result)