YT-22642: Fix unaligned access UB

378099ca41e7698fba0ceda68b8d2b554e61b6ea

2 files changed, 54 insertions, 0 deletions

diff --git a/library/cpp/yt/misc/unaligned-inl.h b/library/cpp/yt/misc/unaligned-inl.h
new file mode 100644
index 0000000000..68e1c9b499
--- /dev/null
+++ b/library/cpp/yt/misc/unaligned-inl.h
@@ -0,0 +1,31 @@
+#ifndef UNALIGNED_INL_H_
+#error "Direct inclusion of this file is not allowed, include unaligned.h"
+// For the sake of sane code completion.
+#include "unaligned.h"
+#endif
+
+#include <cstring>
+
+namespace NYT {
+
+////////////////////////////////////////////////////////////////////////////////
+
+template <class T>
+    requires std::is_trivial_v<T>
+T UnalignedLoad(const T* ptr)
+{
+    T value;
+    std::memcpy(&value, ptr, sizeof(T));
+    return value;
+}
+
+template <class T>
+    requires std::is_trivial_v<T>
+void UnalignedStore(T* ptr, const T& value)
+{
+    std::memcpy(ptr, &value, sizeof(T));
+}
+
+////////////////////////////////////////////////////////////////////////////////
+
+} // namespace NYT
diff --git a/library/cpp/yt/misc/unaligned.h b/library/cpp/yt/misc/unaligned.h
new file mode 100644
index 0000000000..68c124183f
--- /dev/null
+++ b/library/cpp/yt/misc/unaligned.h
@@ -0,0 +1,23 @@
+#pragma once
+
+#include <type_traits>
+
+namespace NYT {
+
+////////////////////////////////////////////////////////////////////////////////
+
+template <class T>
+    requires std::is_trivial_v<T>
+T UnalignedLoad(const T* ptr);
+
+template <class T>
+    requires std::is_trivial_v<T>
+void UnalignedStore(T* ptr, const T& value);
+
+////////////////////////////////////////////////////////////////////////////////
+
+} // namespace NYT
+
+#define UNALIGNED_INL_H_
+#include "unaligned-inl.h"
+#undef UNALIGNED_INL_H_