Add stew/saturation_arith

stew/saturating_arith.nim

@@ -0,0 +1,8 @@
+## This module may hold various saturating arithmetic definitions.
+## It will be expanded on demand as more definitions are requred.
+
+func saturate*(T: type int64, u: uint64): T =
+  if u > high(int64).uint64:
+    high(int64)
+  else:
+    int64(u)

stew/saturation_arith.nim

@@ -0,0 +1,8 @@
+## This module may hold various saturating arithmetic definitions.
+## It will be expanded on demand as Status project require its definition
+
+func saturate*(T: type int64, u: uint64): T =
+  if u > high(int64).uint64:
+    high(int64)
+  else:
+    int64(u)