approach 3

Author: grisumbras

include/boost/json/detail/digest.hpp

@@ -32,15 +32,23 @@ digest(
 #endif
     hash += salt;
 
-    char const* const end = s + n;
-    for(;s < end;)
+    constexpr std::size_t step = sizeof(std::size_t);
+    auto const m = n - (n % step);
+    n -= m;
+
+    char const* const end = s + m;
+    for(; s < end; s += step)
     {
-        std::size_t step = (std::min)(sizeof(std::size_t),
-            static_cast<std::size_t>(end - s));
-        std::size_t batch = 0;
+        std::size_t batch;
         std::memcpy(&batch, s, step);
         hash = (batch ^ hash) * prime;
-        s += step;
+    }
+
+    if(n)
+    {
+        std::size_t batch = 0;
+        std::memcpy(&batch, s, n);
+        hash = (batch ^ hash) * prime;
     }
 
     return hash;