From f7a468ea1e15ab810f4bdece2b776981787fc0f7 Mon Sep 17 00:00:00 2001
From: Gary Talent <gary@drinkingtea.net>
Date: Tue, 14 Jan 2025 21:10:18 -0600
Subject: [PATCH] [ox/std] Add spancpy

---
 deps/ox/src/ox/std/span.hpp       | 20 ++++++++++++++++----
 deps/ox/src/ox/std/typetraits.hpp | 10 ++++++++--
 2 files changed, 24 insertions(+), 6 deletions(-)

diff --git a/deps/ox/src/ox/std/span.hpp b/deps/ox/src/ox/std/span.hpp
index ddd978a9..3114aa0f 100644
--- a/deps/ox/src/ox/std/span.hpp
+++ b/deps/ox/src/ox/std/span.hpp
@@ -14,7 +14,7 @@
 #include "iterator.hpp"
 #include "vector.hpp"
 
-OX_CLANG_NOWARN_BEGIN(-Wunsafe-buffer-usage)
+OX_ALLOW_UNSAFE_BUFFERS_BEGIN
 
 namespace ox {
 
@@ -133,7 +133,7 @@ class Span {
 			return m_items[i];
 		}
 
-		constexpr const T &operator[](std::size_t i) const noexcept {
+		constexpr T const&operator[](std::size_t i) const noexcept {
 			ox::primitiveAssert(__FILE__, __LINE__, i < size(), "Span access overflow");
 			return m_items[i];
 		}
@@ -168,8 +168,20 @@ class Span {
 };
 
 template<typename T>
-using SpanView = Span<const T>;
+using SpanView = Span<T const>;
+
+template<typename T>
+constexpr void spancpy(ox::Span<T> const dst, ox::SpanView<T> const src) noexcept {
+	auto const sz = ox::min(dst.size(), src.size());
+	if (std::is_constant_evaluated() || std::is_trivially_copyable_v<T>) {
+		for (size_t i{}; i < sz; ++i) {
+			dst.data()[i] = src.data()[i];
+		}
+	} else {
+		memcpy(dst.data(), src.data(), sz * sizeof(T));
+	}
+}
 
 }
 
-OX_CLANG_NOWARN_END
+OX_ALLOW_UNSAFE_BUFFERS_END
diff --git a/deps/ox/src/ox/std/typetraits.hpp b/deps/ox/src/ox/std/typetraits.hpp
index 720ac05a..f123ed0d 100644
--- a/deps/ox/src/ox/std/typetraits.hpp
+++ b/deps/ox/src/ox/std/typetraits.hpp
@@ -19,12 +19,15 @@
 namespace std {
 
 template<typename T>
-constexpr bool is_union_v = __is_union(T);
+inline constexpr bool is_union_v = __is_union(T);
 
-constexpr bool is_constant_evaluated() noexcept {
+inline constexpr bool is_constant_evaluated() noexcept {
 	return __builtin_is_constant_evaluated();
 }
 
+template<typename T>
+inline constexpr bool is_trivially_copyable_v = __is_trivially_copyable(T);
+
 }
 
 #endif
@@ -156,6 +159,9 @@ static_assert(is_class<int>::value == false);
 template<typename T>
 constexpr bool is_class_v = is_class<T>();
 
+template<typename T>
+inline constexpr bool is_trivially_copyable_v = std::is_trivially_copyable_v<T>;
+
 template<typename T>
 constexpr bool is_signed_v = integral_constant<bool, T(-1) < T(0)>::value;