Full merge from trunk at revision 41356 of entire boost-root tree.

[SVN r41370]

example/doc_vectorstream.cpp

@@ -0,0 +1,113 @@
+//////////////////////////////////////////////////////////////////////////////
+//
+// (C) Copyright Ion Gaztanaga 2006-2007. 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/interprocess for documentation.
+//
+//////////////////////////////////////////////////////////////////////////////
+#include <boost/interprocess/detail/config_begin.hpp>
+#include <boost/interprocess/detail/workaround.hpp>
+//[doc_vectorstream
+#include <boost/interprocess/containers/vector.hpp>
+#include <boost/interprocess/containers/string.hpp>
+#include <boost/interprocess/allocators/allocator.hpp>
+#include <boost/interprocess/managed_shared_memory.hpp>
+#include <boost/interprocess/streams/vectorstream.hpp>
+#include <iterator>
+
+using namespace boost::interprocess;
+
+typedef allocator<int, managed_shared_memory::segment_manager> 
+   IntAllocator;
+typedef allocator<char, managed_shared_memory::segment_manager> 
+   CharAllocator;
+typedef vector<int, IntAllocator>   MyVector;
+typedef basic_string
+   <char, std::char_traits<char>, CharAllocator>   MyString;
+typedef basic_vectorstream<MyString>               MyVectorStream;
+
+int main ()
+{
+   //Create shared memory
+   shared_memory_object::remove("MySharedMemory");
+   try{
+      managed_shared_memory segment(
+         create_only, 
+         "MySharedMemory", //segment name
+         65536);           //segment size in bytes
+
+      //Construct shared memory vector
+      MyVector *myvector = 
+         segment.construct<MyVector>("MyVector")
+         (IntAllocator(segment.get_segment_manager()));
+
+      //Fill vector
+      myvector->reserve(100);
+      for(int i = 0; i < 100; ++i){
+         myvector->push_back(i);
+      }
+
+      //Create the vectorstream. To create the internal shared memory
+      //basic_string we need to pass the shared memory allocator as
+      //a constructor argument
+      MyVectorStream myvectorstream(CharAllocator(segment.get_segment_manager()));
+
+      //Reserve the internal string
+      myvectorstream.reserve(100*5);
+
+      //Write all vector elements as text in the internal string
+      //Data will be directly written in shared memory, because
+      //internal string's allocator is a shared memory allocator
+      for(std::size_t i = 0, max = myvector->size(); i < max; ++i){
+         myvectorstream << (*myvector)[i] << std::endl;
+      }
+
+      //Auxiliary vector to compare original data
+      MyVector *myvector2 =
+         segment.construct<MyVector>("MyVector2")
+         (IntAllocator(segment.get_segment_manager()));
+
+      //Avoid reallocations
+      myvector2->reserve(100);
+
+      //Extract all values from the internal 
+      //string directly to a shared memory vector.
+      std::istream_iterator<int> it(myvectorstream), itend;
+      std::copy(it, itend, std::back_inserter(*myvector2));
+
+      //Compare vectors
+      assert(std::equal(myvector->begin(), myvector->end(), myvector2->begin()));
+
+      //Create a copy of the internal string
+      MyString stringcopy (myvectorstream.vector());
+
+      //Now we create a new empty shared memory string...
+      MyString *mystring = 
+         segment.construct<MyString>("MyString")
+         (CharAllocator(segment.get_segment_manager()));
+
+      //...and we swap vectorstream's internal string
+      //with the new one: after this statement mystring
+      //will be the owner of the formatted data.
+      //No reallocations, no data copies
+      myvectorstream.swap_vector(*mystring);
+
+      //Let's compare both strings
+      assert(stringcopy == *mystring);
+
+      //Done, destroy and delete vectors and string from the segment
+      segment.destroy_ptr(myvector2);
+      segment.destroy_ptr(myvector);
+      segment.destroy_ptr(mystring);
+   }
+   catch(...){
+      shared_memory_object::remove("MySharedMemory");
+      throw;
+   }
+   shared_memory_object::remove("MySharedMemory");
+   return 0;
+}
+//]
+#include <boost/interprocess/detail/config_end.hpp>