From b1c2576c2097482d3dab912dd6e7e462dcb40c1f Mon Sep 17 00:00:00 2001
From: Jason Volk <jason@zemos.net>
Date: Sat, 25 Mar 2023 18:36:32 -0700
Subject: [PATCH] ircd::util: Add sign cast convenience suite.

---
 include/ircd/util/typography.h | 28 ++++++++++++++++++++++++++++
 1 file changed, 28 insertions(+)

diff --git a/include/ircd/util/typography.h b/include/ircd/util/typography.h
index 87c49a016..7d8ce65b2 100644
--- a/include/ircd/util/typography.h
+++ b/include/ircd/util/typography.h
@@ -140,6 +140,34 @@ struct is_specialization_of<T<args...>, T>
 :std::true_type
 {};
 
+//
+// Convenience signedness cast template
+//
+
+template<class T>
+using enable_if_s2u = std::enable_if<std::is_signed<T>::value, typename std::make_unsigned<T>::type>;
+
+template<class T>
+[[using gnu: always_inline, gnu_inline, artificial]]
+extern inline typename enable_if_s2u<T>::type *
+sign_cast(T *const t)
+{
+	using type = typename std::make_unsigned<T>::type;
+	return reinterpret_cast<type *>(t);
+}
+
+template<class T>
+using enable_if_u2s = std::enable_if<std::is_unsigned<T>::value, typename std::make_signed<T>::type>;
+
+template<class T>
+[[using gnu: always_inline, gnu_inline, artificial]]
+extern inline typename enable_if_u2s<T>::type *
+sign_cast(T *const t)
+{
+	using type = typename std::make_signed<T>::type;
+	return reinterpret_cast<type *>(t);
+}
+
 //
 // Convenience const_cast deduction template
 //