[ox/std] Add missing + and += operators to Span

deps/ox/src/ox/std/span.hpp

@@ -116,6 +116,7 @@ class SpanView {
 		}
 
 		constexpr SpanView operator+=(size_t i) noexcept {
+			ox::primitiveAssert(__FILE__, __LINE__, i < size(), "Span access overflow");
 			m_items += i;
 			m_size -= i;
 			return *this;
@@ -143,7 +144,7 @@ class Span {
 
 	private:
 		T *m_items{};
-		const std::size_t m_size{};
+		std::size_t m_size{};
 
 	public:
 		using value_type = T;
@@ -243,6 +244,18 @@ class Span {
 			return m_items[i];
 		}
 
+		constexpr Span operator+(size_t i) const noexcept {
+			ox::primitiveAssert(__FILE__, __LINE__, i < size(), "Span access overflow");
+			return {m_items + i, m_size - i};
+		}
+
+		constexpr Span operator+=(size_t i) noexcept {
+			ox::primitiveAssert(__FILE__, __LINE__, i < size(), "Span access overflow");
+			m_items += i;
+			m_size -= i;
+			return *this;
+		}
+
 		[[nodiscard]]
 		constexpr auto data() const noexcept {
 			return m_items;