diff --git a/include/rexy/binary.hpp b/include/rexy/binary.hpp
index 2f1a840..bb0af5b 100644
--- a/include/rexy/binary.hpp
+++ b/include/rexy/binary.hpp
@@ -41,6 +41,7 @@ namespace rexy{
 	public:
 	protected:
 		constexpr binary_base(void)noexcept = default;
+		constexpr binary_base(size_t len)noexcept;
 		constexpr binary_base(char* data, size_t size)noexcept;
 		constexpr binary_base(char* data, size_t size, size_t cap)noexcept;
 		constexpr binary_base(const binary_base& b)noexcept;
diff --git a/include/rexy/binary.tpp b/include/rexy/binary.tpp
index 874c18a..2cb8e4d 100644
--- a/include/rexy/binary.tpp
+++ b/include/rexy/binary.tpp
@@ -34,6 +34,8 @@
 
 namespace rexy{
 
+	constexpr binary_base::binary_base(size_t len)noexcept:
+		m_cap(len){}
 	constexpr binary_base::binary_base(char* data, size_t size)noexcept:
 		m_data(data), m_cap(size){}
 	constexpr binary_base::binary_base(char* data, size_t size, size_t cap)noexcept:
@@ -140,7 +142,7 @@ namespace rexy{
 	}
 	template<class Allocator>
 	binary_data<Allocator>& binary_data<Allocator>::operator=(const binary_base& b)
-		noexcept(noexcept(Allocator::copy(b.m_data, b.m_size)))
+		noexcept(noexcept(Allocator::copy(b.get(), b.size())))
 	{
 		return _copy_data(b.get(), b.size());
 	}