From c54e7c974beb59153ad90234e1ea7a9bdc2b2dc8 Mon Sep 17 00:00:00 2001
From: Laurent Rineau <laurent.rineau@cgal.org>
Date: Tue, 2 Apr 2019 10:29:01 +0200
Subject: [PATCH 1/3] Fix AppleClang -Wnull-pointer-arithmetic warning

---
 STL_Extension/include/CGAL/Compact_container.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/STL_Extension/include/CGAL/Compact_container.h b/STL_Extension/include/CGAL/Compact_container.h
index b4960af00c4..c1927dd9c3f 100644
--- a/STL_Extension/include/CGAL/Compact_container.h
+++ b/STL_Extension/include/CGAL/Compact_container.h
@@ -815,7 +815,7 @@ private:
 
   static char * clean_pointer(char * p)
   {
-    return ((p - (char *) NULL) & ~ (std::ptrdiff_t) START_END) + (char *) NULL;
+    return reinterpret_cast<char*>((p - (char *) NULL) & ~ (std::ptrdiff_t) START_END);
   }
 
   // Returns the pointee, cleaned up from the squatted bits.

From 68f6ebf42d74e99c0397803825d7909bbcd4ed42 Mon Sep 17 00:00:00 2001
From: Laurent Rineau <laurent.rineau@cgal.org>
Date: Wed, 3 Apr 2019 14:52:12 +0200
Subject: [PATCH 2/3] More reinterpret_cast to avoid undefined behavior

---
 STL_Extension/include/CGAL/Compact_container.h | 10 +++++++---
 1 file changed, 7 insertions(+), 3 deletions(-)

diff --git a/STL_Extension/include/CGAL/Compact_container.h b/STL_Extension/include/CGAL/Compact_container.h
index c1927dd9c3f..1b7ea962e78 100644
--- a/STL_Extension/include/CGAL/Compact_container.h
+++ b/STL_Extension/include/CGAL/Compact_container.h
@@ -28,6 +28,7 @@
 #include <CGAL/Default.h>
 
 #include <cmath>
+#include <cstdint>
 #include <iterator>
 #include <algorithm>
 #include <vector>
@@ -815,7 +816,8 @@ private:
 
   static char * clean_pointer(char * p)
   {
-    return reinterpret_cast<char*>((p - (char *) NULL) & ~ (std::ptrdiff_t) START_END);
+    return reinterpret_cast<char*>(reinterpret_cast<std::uintptr_t>(p) &
+                                   ~ (std::uintptr_t) START_END);
   }
 
   // Returns the pointee, cleaned up from the squatted bits.
@@ -828,7 +830,8 @@ private:
   static Type type(const_pointer ptr)
   {
     char * p = (char *) Traits::pointer(*ptr);
-    return (Type) (p - clean_pointer(p));
+    return (Type) (reinterpret_cast<std::uintptr_t>(p) -
+                   reinterpret_cast<std::uintptr_t>(clean_pointer(p)));
   }
 
   // Sets the pointer part and the type of the pointee.
@@ -837,7 +840,8 @@ private:
     // This out of range compare is always true and causes lots of
     // unnecessary warnings.
     // CGAL_precondition(0 <= t && t < 4);
-    Traits::pointer(*ptr) = (void *) ((clean_pointer((char *) p)) + (int) t);
+    Traits::pointer(*ptr) = reinterpret_cast<void *>
+      (reinterpret_cast<std::uintptr_t>(clean_pointer((char *) p)) + (int) t);
   }
 
 public:

From 34cf27b47e9d3218a2cdd240dea10338793049ba Mon Sep 17 00:00:00 2001
From: Laurent Rineau <laurent.rineau@cgal.org>
Date: Wed, 3 Apr 2019 14:56:21 +0200
Subject: [PATCH 3/3] Use std::ptrdiff_t, because the target branch is not
 C++11

`std::uintptr_t` was introduced by C++11, but the target branch if
CGAL-4.13-branch, does not require C++11.
---
 STL_Extension/include/CGAL/Compact_container.h | 12 ++++++------
 1 file changed, 6 insertions(+), 6 deletions(-)

diff --git a/STL_Extension/include/CGAL/Compact_container.h b/STL_Extension/include/CGAL/Compact_container.h
index 1b7ea962e78..6064a81c6d9 100644
--- a/STL_Extension/include/CGAL/Compact_container.h
+++ b/STL_Extension/include/CGAL/Compact_container.h
@@ -28,7 +28,7 @@
 #include <CGAL/Default.h>
 
 #include <cmath>
-#include <cstdint>
+#include <cstddef>
 #include <iterator>
 #include <algorithm>
 #include <vector>
@@ -816,8 +816,8 @@ private:
 
   static char * clean_pointer(char * p)
   {
-    return reinterpret_cast<char*>(reinterpret_cast<std::uintptr_t>(p) &
-                                   ~ (std::uintptr_t) START_END);
+    return reinterpret_cast<char*>(reinterpret_cast<std::ptrdiff_t>(p) &
+                                   ~ (std::ptrdiff_t) START_END);
   }
 
   // Returns the pointee, cleaned up from the squatted bits.
@@ -830,8 +830,8 @@ private:
   static Type type(const_pointer ptr)
   {
     char * p = (char *) Traits::pointer(*ptr);
-    return (Type) (reinterpret_cast<std::uintptr_t>(p) -
-                   reinterpret_cast<std::uintptr_t>(clean_pointer(p)));
+    return (Type) (reinterpret_cast<std::ptrdiff_t>(p) -
+                   reinterpret_cast<std::ptrdiff_t>(clean_pointer(p)));
   }
 
   // Sets the pointer part and the type of the pointee.
@@ -841,7 +841,7 @@ private:
     // unnecessary warnings.
     // CGAL_precondition(0 <= t && t < 4);
     Traits::pointer(*ptr) = reinterpret_cast<void *>
-      (reinterpret_cast<std::uintptr_t>(clean_pointer((char *) p)) + (int) t);
+      (reinterpret_cast<std::ptrdiff_t>(clean_pointer((char *) p)) + (int) t);
   }
 
 public: