From eb0d01126a573a204c4382cbdde3a0bf8aa1924c Mon Sep 17 00:00:00 2001
From: Andrey Semashev <andrey.semashev@gmail.com>
Date: Thu, 13 Jan 2022 16:59:46 +0300
Subject: [PATCH] Added support for int128 to counting_iterator.

---
 include/boost/iterator/counting_iterator.hpp | 29 ++++++++++++++++++--
 test/counting_iterator_test.cpp              |  8 ++++--
 2 files changed, 33 insertions(+), 4 deletions(-)

diff --git a/include/boost/iterator/counting_iterator.hpp b/include/boost/iterator/counting_iterator.hpp
index 45d4c83..65c11e9 100644
--- a/include/boost/iterator/counting_iterator.hpp
+++ b/include/boost/iterator/counting_iterator.hpp
@@ -67,11 +67,21 @@ namespace detail
 
 #  if defined(BOOST_HAS_LONG_LONG)
   template <>
-  struct is_numeric< ::boost::long_long_type>
+  struct is_numeric<boost::long_long_type>
     : boost::true_type {};
 
   template <>
-  struct is_numeric< ::boost::ulong_long_type>
+  struct is_numeric<boost::ulong_long_type>
+    : boost::true_type {};
+#  endif
+
+#  if defined(BOOST_HAS_INT128)
+  template <>
+  struct is_numeric<boost::int128_type>
+    : boost::true_type {};
+
+  template <>
+  struct is_numeric<boost::uint128_type>
     : boost::true_type {};
 #  endif
 
@@ -86,6 +96,21 @@ namespace detail
       typedef typename boost::detail::numeric_traits<T>::difference_type type;
   };
 
+#  if defined(BOOST_HAS_INT128)
+  // std::numeric_limits, which is used by numeric_traits, is not specialized for __int128 in some standard libraries
+  template <>
+  struct numeric_difference<boost::int128_type>
+  {
+      typedef boost::int128_type type;
+  };
+
+  template <>
+  struct numeric_difference<boost::uint128_type>
+  {
+      typedef boost::int128_type type;
+  };
+#  endif
+
   template <class Incrementable, class CategoryOrTraversal, class Difference>
   struct counting_iterator_base
   {
diff --git a/test/counting_iterator_test.cpp b/test/counting_iterator_test.cpp
index ac382f0..09d4295 100644
--- a/test/counting_iterator_test.cpp
+++ b/test/counting_iterator_test.cpp
@@ -271,8 +271,12 @@ int main()
     test_integer<long>();
     test_integer<unsigned long>();
 #if defined(BOOST_HAS_LONG_LONG)
-    test_integer< ::boost::long_long_type>();
-    test_integer< ::boost::ulong_long_type>();
+    test_integer<boost::long_long_type>();
+    test_integer<boost::ulong_long_type>();
+#endif
+#if defined(BOOST_HAS_INT128)
+    test_integer<boost::int128_type>();
+    test_integer<boost::uint128_type>();
 #endif
 
     // Test user-defined type.