From 7d315c8095766bb33082998e168c6409200d0eb3 Mon Sep 17 00:00:00 2001
From: Danny Robson <danny@nerdcruft.net>
Date: Fri, 18 May 2018 16:51:42 +1000
Subject: [PATCH] allow/raw/linear: add typed offset query

---
 alloc/raw/linear.hpp | 10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/alloc/raw/linear.hpp b/alloc/raw/linear.hpp
index 5d73cb96..da11fa8e 100644
--- a/alloc/raw/linear.hpp
+++ b/alloc/raw/linear.hpp
@@ -82,6 +82,16 @@ namespace util::alloc::raw {
 
         size_t offset (const void*) const;
 
+        template <typename ValueT>
+        size_t
+        offset (ValueT const *ptr) const
+        {
+            CHECK_MOD (reinterpret_cast<uintptr_t> (ptr),     sizeof (ValueT));
+            CHECK_MOD (reinterpret_cast<uintptr_t> (data ()), sizeof (ValueT));
+
+            return ptr - util::cast::alignment<ValueT const*> (data ());
+        }
+
         template <typename T>
         size_t
         offset (util::view<T*> ptr) const