diff --git a/common/include/ntstring.h b/common/include/ntstring.h
index e9d66ea10..d4b06f5f5 100644
--- a/common/include/ntstring.h
+++ b/common/include/ntstring.h
@@ -11,48 +11,53 @@ class ntstring :
 	public prohibit_void_ptr<ntstring<L>>,
 	public array<char, L + 1>
 {
+	static char terminator() { return 0; }
 public:
 	typedef array<char, L + 1> array_t;
 	typedef char elements_t[L + 1];
 	using array_t::operator[];
 	typename array_t::reference operator[](int i) { return array_t::operator[](i); }
 	typename array_t::reference operator[](unsigned i) { return array_t::operator[](i); }
-	bool _copy_n(std::size_t offset, const char *ib, std::size_t N)
+	__attribute_nonnull()
+	std::size_t _copy_n(std::size_t offset, const char *ib, std::size_t N)
 	{
+		if (offset >= this->size())
+			return 0;
 		auto eb = ib;
-		bool r = (offset + N) <= L;
+		std::size_t r = (offset + N) <= L ? N : 0;
 		if (r)
 			eb += N;
 		auto ob = std::next(this->begin(), offset);
 		auto oc = std::copy(ib, eb, ob);
-		std::fill(oc, this->end(), 0);
+		std::fill(oc, this->end(), terminator());
 		return r;
 	}
 	template <std::size_t N>
-		bool _copy(std::size_t offset, const char *i)
+		__attribute_nonnull()
+		std::size_t _copy(std::size_t offset, const char *i)
 		{
 			static_assert(N <= L, "string too long");
 			return _copy_n(offset, i, N);
 		}
 	template <typename I>
-		bool copy_if(I &&i)
+		std::size_t copy_if(I &&i)
 		{
 			return copy_if(static_cast<std::size_t>(0), static_cast<I &&>(i));
 		}
 	template <typename I>
-		bool copy_if(I &&i, std::size_t N)
+		std::size_t copy_if(I &&i, std::size_t N)
 		{
 			return copy_if(static_cast<std::size_t>(0), static_cast<I &&>(i), N);
 		}
 	template <typename I>
-		bool copy_if(std::size_t out_offset, I &&i)
+		std::size_t copy_if(std::size_t out_offset, I &&i)
 		{
 			return copy_if(out_offset, static_cast<I &&>(i), this->size());
 		}
 	template <std::size_t N>
 		void copy_if(std::size_t, const ntstring<N> &, std::size_t = 0) = delete;
 	template <std::size_t N>
-		bool copy_if(std::size_t out_offset, const array<char, N> &i, std::size_t n = N)
+		std::size_t copy_if(std::size_t out_offset, const array<char, N> &i, std::size_t n = N)
 		{
 #ifdef DXX_HAVE_BUILTIN_CONSTANT_P
 			if (__builtin_constant_p(n > N) && n > N)
@@ -61,20 +66,69 @@ public:
 			return copy_if(out_offset, i.data(), n);
 		}
 	template <std::size_t N>
-		bool copy_if(std::size_t out_offset, const char (&i)[N])
+		std::size_t copy_if(std::size_t out_offset, const char (&i)[N])
 		{
 			static_assert(N <= L + 1, "string too long");
 			return copy_if(out_offset, i, N);
 		}
-	bool copy_if(std::size_t offset, const char *i, std::size_t N)
+	__attribute_nonnull()
+	std::size_t copy_if(std::size_t offset, const char *i, std::size_t N)
 	{
 		const std::size_t d =
 #ifdef DXX_HAVE_BUILTIN_CONSTANT_P
 			(__builtin_constant_p(i[N - 1]) && !i[N - 1]) ? N - 1 :
 #endif
-			std::distance(i, std::find(i, i + N, 0));
+			std::distance(i, std::find(i, i + N, terminator()));
 		return _copy_n(offset, i, d);
 	}
+	__attribute_nonnull()
+	std::size_t _copy_out(const std::size_t src_offset, char *const dst_base, const std::size_t dst_offset, const std::size_t max_copy) const
+	{
+		char *const dst = dst_base + dst_offset;
+		if (L > max_copy || src_offset >= this->size())
+		{
+			/* Some outputs might not fit or nothing to copy */
+			*dst = terminator();
+			return 1;
+		}
+		const auto ie = std::prev(this->end());
+		const auto ib = std::next(this->begin(), src_offset);
+		auto ii = std::find(ib, ie, terminator());
+		if (ii != ie)
+			/* Only copy null if string is short  */
+			++ ii;
+		const std::size_t r = std::distance(ib, ii);
+		if (r > max_copy)
+		{
+			/* This output does not fit */
+			*dst = terminator();
+			return 1;
+		}
+		std::copy(ib, ii, dst);
+		return r;
+	}
+	__attribute_nonnull()
+	std::size_t copy_out(std::size_t src_offset, char *dst, std::size_t dst_offset, std::size_t dst_size) const
+	{
+		if (dst_size <= dst_offset)
+			return 0;
+		return _copy_out(src_offset, dst, dst_offset, dst_size - dst_offset);
+	}
+	__attribute_nonnull()
+	std::size_t copy_out(std::size_t src_offset, char *dst, std::size_t dst_size) const
+	{
+		return copy_out(src_offset, dst, 0, dst_size);
+	}
+	template <std::size_t N>
+		std::size_t copy_out(std::size_t src_offset, array<char, N> &dst, std::size_t dst_offset) const
+		{
+			return copy_out(src_offset, dst.data(), dst_offset, N);
+		}
+	template <std::size_t N>
+		std::size_t copy_out(std::size_t src_offset, array<uint8_t, N> &dst, std::size_t dst_offset) const
+		{
+			return copy_out(src_offset, reinterpret_cast<char *>(dst.data()), dst_offset, N);
+		}
 	operator bool() const = delete;
 	operator char *() const = delete;
 	operator elements_t &() const = delete;
diff --git a/similar/main/net_udp.cpp b/similar/main/net_udp.cpp
index 31f99b22f..f09035f36 100644
--- a/similar/main/net_udp.cpp
+++ b/similar/main/net_udp.cpp
@@ -198,14 +198,13 @@ static bool operator!=(const _sockaddr &l, const _sockaddr &r)
 template <std::size_t N>
 static void copy_from_ntstring(uint8_t *const buf, uint_fast32_t &len, const ntstring<N> &in)
 {
-	std::memcpy(&buf[exchange(len, len + N)], in.data(), N);
+	len += in.copy_out(0, reinterpret_cast<char *>(&buf[len]), N);
 }
 
 template <std::size_t N>
 static void copy_to_ntstring(const uint8_t *const buf, uint_fast32_t &len, ntstring<N> &out)
 {
-	std::memcpy(out.data(), &buf[exchange(len, len + N)], N);
-	out.back() = 0;
+	len += out.copy_if(reinterpret_cast<const char *>(&buf[len]), N);
 }
 
 static void net_udp_prepare_request_game_info(array<uint8_t, UPID_GAME_INFO_REQ_SIZE> &buf, int lite)