refactor: memcpy -> std::ranges::copy

I think there is no issue of passing a nullptr here, but it makes sense to use the std-lib copy for consistency.

Recommended in #305 (review)

Author: marco

include/mp/type-char.h

@@ -7,6 +7,9 @@
 
 #include <mp/util.h>
 
+#include <algorithm>
+#include <ranges>
+
 namespace mp {
 template <typename Output, size_t size>
 void CustomBuildField(TypeList<const unsigned char*>,
@@ -16,7 +19,7 @@ void CustomBuildField(TypeList<const unsigned char*>,
     Output&& output)
 {
     auto result = output.init(size);
-    memcpy(result.begin(), value, size);
+    std::ranges::copy(value, result.begin());
 }
 
 template <size_t size, typename Input, typename ReadDest>
@@ -27,8 +30,7 @@ decltype(auto) CustomReadField(TypeList<unsigned char[size]>,
     ReadDest&& read_dest)
 {
     return read_dest.update([&](auto& value) {
-        auto data = input.get();
-        memcpy(value, data.begin(), size);
+        std::ranges::copy(input.get(), std::ranges::begin(value));
     });
 }
 } // namespace mp

include/mp/type-string.h

@@ -7,6 +7,9 @@
 
 #include <mp/util.h>
 
+#include <algorithm>
+#include <ranges>
+
 namespace mp {
 template <typename Value, typename Output>
 void CustomBuildField(TypeList<std::string>,
@@ -16,7 +19,7 @@ void CustomBuildField(TypeList<std::string>,
     Output&& output)
 {
     auto result = output.init(value.size());
-    memcpy(result.begin(), value.data(), value.size());
+    std::ranges::copy(value, result.begin());
 }
 
 template <typename Input, typename ReadDest>