add boost on mac

macx64/include/boost/poly_collection/detail/segment_split.hpp

@@ -0,0 +1,154 @@
+/* Copyright 2016-2017 Joaquin M Lopez Munoz.
+ * Distributed under the Boost Software License, Version 1.0.
+ * (See accompanying file LICENSE_1_0.txt or copy at
+ * http://www.boost.org/LICENSE_1_0.txt)
+ *
+ * See http://www.boost.org/libs/poly_collection for library home page.
+ */
+
+#ifndef BOOST_POLY_COLLECTION_DETAIL_SEGMENT_SPLIT_HPP
+#define BOOST_POLY_COLLECTION_DETAIL_SEGMENT_SPLIT_HPP
+
+#if defined(_MSC_VER)
+#pragma once
+#endif
+
+#include <boost/iterator/iterator_facade.hpp>
+#include <boost/poly_collection/detail/iterator_traits.hpp>
+#include <typeinfo>
+#include <utility>
+
+namespace boost{
+
+namespace poly_collection{
+
+namespace detail{
+
+/* breakdown of an iterator range into local_base_iterator segments */
+
+template<typename PolyCollectionIterator>
+class segment_splitter
+{
+  using traits=iterator_traits<PolyCollectionIterator>;
+  using local_base_iterator=typename traits::local_base_iterator;
+  using base_segment_info_iterator=typename traits::base_segment_info_iterator;
+
+public:
+  struct info
+  {
+    const std::type_info& type_info()const noexcept{return *pinfo_;}
+    local_base_iterator   begin()const noexcept{return begin_;}
+    local_base_iterator   end()const noexcept{return end_;}
+
+    const std::type_info* pinfo_;
+    local_base_iterator   begin_,end_;
+  };
+
+  struct iterator:iterator_facade<iterator,info,std::input_iterator_tag,info>
+  {
+    iterator()=default;
+
+  private:
+    friend class segment_splitter;
+    friend class boost::iterator_core_access;
+
+    iterator(
+      base_segment_info_iterator it,
+      const PolyCollectionIterator& first,const PolyCollectionIterator& last):
+      it{it},pfirst{&first},plast{&last}{}
+    iterator(
+      const PolyCollectionIterator& first,const PolyCollectionIterator& last):
+      it{traits::base_segment_info_iterator_from(first)},
+      pfirst{&first},plast{&last}
+      {}
+
+    info dereference()const noexcept
+    {
+      return {
+        &it->type_info(),
+        it==traits::base_segment_info_iterator_from(*pfirst)?
+          traits::local_base_iterator_from(*pfirst):it->begin(),
+        it==traits::base_segment_info_iterator_from(*plast)?
+          traits::local_base_iterator_from(*plast):it->end()
+      };
+    }
+
+    bool equal(const iterator& x)const noexcept{return it==x.it;}
+    void increment()noexcept{++it;}
+
+    base_segment_info_iterator    it;
+    const PolyCollectionIterator* pfirst;
+    const PolyCollectionIterator* plast;
+  };
+
+  segment_splitter(
+    const PolyCollectionIterator& first,const PolyCollectionIterator& last):
+    pfirst{&first},plast{&last}{}
+
+  iterator begin()const noexcept{return {*pfirst,*plast};}
+
+  iterator end()const noexcept
+  {
+    auto slast=traits::base_segment_info_iterator_from(*plast);
+    if(slast!=traits::end_base_segment_info_iterator_from(*plast))++slast;
+    return {slast,*plast,*plast};
+  }
+
+private:
+  const PolyCollectionIterator* pfirst;
+  const PolyCollectionIterator* plast;
+};
+
+template<typename PolyCollectionIterator>
+segment_splitter<PolyCollectionIterator>
+segment_split(
+  const PolyCollectionIterator& first,const PolyCollectionIterator& last)
+{
+  return {first,last};
+}
+
+#if 1
+/* equivalent to for(auto i:segment_split(first,last))f(i) */
+
+template<typename PolyCollectionIterator,typename F>
+void for_each_segment(
+  const PolyCollectionIterator& first,const PolyCollectionIterator& last,F&& f)
+{
+  using traits=iterator_traits<PolyCollectionIterator>;
+  using info=typename segment_splitter<PolyCollectionIterator>::info;
+
+  auto sfirst=traits::base_segment_info_iterator_from(first),
+       slast=traits::base_segment_info_iterator_from(last),
+       send=traits::end_base_segment_info_iterator_from(last);
+  auto lbfirst=traits::local_base_iterator_from(first),
+       lblast=traits::local_base_iterator_from(last);
+
+  if(sfirst!=slast){
+    for(;;){
+      f(info{&sfirst->type_info(),lbfirst,sfirst->end()});
+      ++sfirst;
+      if(sfirst==slast)break;
+      lbfirst=sfirst->begin();
+    }
+    if(sfirst!=send)f(info{&sfirst->type_info(),sfirst->begin(),lblast});
+  }
+  else if(sfirst!=send){
+    f(info{&sfirst->type_info(),lbfirst,lblast});
+  }
+}
+#else
+template<typename PolyCollectionIterator,typename F>
+void for_each_segment(
+  const PolyCollectionIterator& first,const PolyCollectionIterator& last,F&& f)
+{
+  for(auto i:segment_split(first,last))f(i);  
+}
+#endif
+
+} /* namespace poly_collection::detail */
+
+} /* namespace poly_collection */
+
+} /* namespace boost */
+
+#endif