From 1dc1e7466865433d64fb0bf2bfd00c4f746195f9 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Ion=20Gazta=C3=B1aga?= <igaztanaga@gmail.com>
Date: Fri, 15 Jan 2021 20:43:27 +0100
Subject: [PATCH] Remove std::pair dependency for multiallocation_chain

---
 .../container/detail/multiallocation_chain.hpp | 18 ++++++++++--------
 .../container/detail/pool_common_alloc.hpp     |  2 +-
 include/boost/container/stable_vector.hpp      |  8 ++++----
 3 files changed, 15 insertions(+), 13 deletions(-)

diff --git a/include/boost/container/detail/multiallocation_chain.hpp b/include/boost/container/detail/multiallocation_chain.hpp
index 1031de2..192e14d 100644
--- a/include/boost/container/detail/multiallocation_chain.hpp
+++ b/include/boost/container/detail/multiallocation_chain.hpp
@@ -31,7 +31,7 @@
 // intrusive
 #include <boost/intrusive/slist.hpp>
 #include <boost/intrusive/pointer_traits.hpp>
-#include <boost/intrusive/detail/minimal_pair_header.hpp>
+#include <boost/intrusive/detail/twin.hpp>
 // move
 #include <boost/move/utility_core.hpp>
 
@@ -80,6 +80,7 @@ class basic_multiallocation_chain
    typedef VoidPointer                       void_pointer;
    typedef typename slist_impl_t::iterator   iterator;
    typedef typename slist_impl_t::size_type  size_type;
+   typedef boost::intrusive::twin<void_pointer> pointer_pair;
 
    basic_multiallocation_chain()
       :  slist_impl_()
@@ -171,17 +172,17 @@ class basic_multiallocation_chain
    static iterator iterator_to(const void_pointer &p)
    {  return slist_impl_t::s_iterator_to(to_node(p));   }
 
-   std::pair<void_pointer, void_pointer> extract_data()
+   pointer_pair extract_data()
    {
       if(BOOST_LIKELY(!slist_impl_.empty())){
-         std::pair<void_pointer, void_pointer> ret
+         pointer_pair ret
             (slist_impl_.begin().operator->()
             ,slist_impl_.last().operator->());
          slist_impl_.clear();
          return ret;
       }
       else {
-         return std::pair<void_pointer, void_pointer>();
+         return pointer_pair();
       }
    }
 };
@@ -218,8 +219,9 @@ class transform_multiallocation_chain
    public:
    typedef transform_iterator
       < typename MultiallocationChain::iterator
-      , dtl::cast_functor <T> >             iterator;
+      , dtl::cast_functor <T> >                          iterator;
    typedef typename MultiallocationChain::size_type      size_type;
+   typedef boost::intrusive::twin<pointer>               pointer_pair;
 
    transform_multiallocation_chain()
       : MultiallocationChain()
@@ -284,10 +286,10 @@ class transform_multiallocation_chain
    static iterator iterator_to(const pointer &p)
    {  return iterator(MultiallocationChain::iterator_to(p));  }
 
-   std::pair<pointer, pointer> extract_data()
+   pointer_pair extract_data()
    {
-      std::pair<void_pointer, void_pointer> data(this->MultiallocationChain::extract_data());
-      return std::pair<pointer, pointer>(cast(data.first), cast(data.second));
+      typename MultiallocationChain::pointer_pair data(this->MultiallocationChain::extract_data());
+      return pointer_pair(cast(data.first), cast(data.second));
    }
 /*
    MultiallocationChain &extract_multiallocation_chain()
diff --git a/include/boost/container/detail/pool_common_alloc.hpp b/include/boost/container/detail/pool_common_alloc.hpp
index bfb82f5..f58c5e7 100644
--- a/include/boost/container/detail/pool_common_alloc.hpp
+++ b/include/boost/container/detail/pool_common_alloc.hpp
@@ -49,7 +49,7 @@ struct fake_segment_manager
    static void deallocate_many(multiallocation_chain &chain)
    {
       std::size_t size = chain.size();
-      std::pair<void*, void*> ptrs = chain.extract_data();
+      multiallocation_chain::pointer_pair ptrs = chain.extract_data();
       dlmalloc_memchain dlchain;
       BOOST_CONTAINER_MEMCHAIN_INIT_FROM(&dlchain, ptrs.first, ptrs.second, size);
       dlmalloc_multidealloc(&dlchain);
diff --git a/include/boost/container/stable_vector.hpp b/include/boost/container/stable_vector.hpp
index d62fb52..68be7c0 100644
--- a/include/boost/container/stable_vector.hpp
+++ b/include/boost/container/stable_vector.hpp
@@ -2005,7 +2005,7 @@ class stable_vector
       this->allocate_individual(n, m);
       holder.splice_after(holder.before_begin(), m, m.before_begin(), m.last(), n);
       this->internal_data.pool_size += n;
-      std::pair<node_ptr, node_ptr> data(holder.extract_data());
+      typename multiallocation_chain::pointer_pair data(holder.extract_data());
       pool_first_ref = data.first;
       pool_last_ref = data.second;
    }
@@ -2021,7 +2021,7 @@ class stable_vector
                               , internal_data.pool_size);
       holder.push_front(p);
       ++this->internal_data.pool_size;
-      std::pair<node_ptr, node_ptr> ret(holder.extract_data());
+      typename multiallocation_chain::pointer_pair ret(holder.extract_data());
       pool_first_ref = ret.first;
       pool_last_ref  = ret.second;
    }
@@ -2035,7 +2035,7 @@ class stable_vector
                           , node_ptr_traits::static_cast_from(pool_last_ref)
                           , internal_data.pool_size);
       this->internal_data.pool_size = ch.size();
-      const std::pair<node_ptr, node_ptr> ret(ch.extract_data());
+      const typename multiallocation_chain::pointer_pair ret(ch.extract_data());
       pool_first_ref = ret.first;
       pool_last_ref  = ret.second;
    }
@@ -2057,7 +2057,7 @@ class stable_vector
          pool_first_ref = pool_last_ref = node_ptr();
       }
       else{
-         const std::pair<node_ptr, node_ptr> data(holder.extract_data());
+         const typename multiallocation_chain::pointer_pair data(holder.extract_data());
          pool_first_ref = data.first;
          pool_last_ref  = data.second;
       }