unite process/shared_memory datafacades into a single type using an allocator scheme

src/engine/datafacade/shared_memory_allocator.cpp

@@ -0,0 +1,34 @@
+#include "engine/datafacade/shared_memory_allocator.hpp"
+#include "util/log.hpp"
+
+#include "boost/assert.hpp"
+
+namespace osrm
+{
+namespace engine
+{
+namespace datafacade
+{
+
+SharedMemoryAllocator::SharedMemoryAllocator(storage::SharedDataType data_region)
+{
+    util::Log(logDEBUG) << "Loading new data for region " << regionToString(data_region);
+
+    BOOST_ASSERT(storage::SharedMemory::RegionExists(data_region));
+    m_large_memory = storage::makeSharedMemory(data_region);
+}
+
+SharedMemoryAllocator::~SharedMemoryAllocator() {}
+
+storage::DataLayout &SharedMemoryAllocator::GetLayout()
+{
+    return *reinterpret_cast<storage::DataLayout *>(m_large_memory->Ptr());
+}
+char *SharedMemoryAllocator::GetMemory()
+{
+    return reinterpret_cast<char *>(m_large_memory->Ptr()) + sizeof(storage::DataLayout);
+}
+
+} // namespace datafacade
+} // namespace engine
+} // namespace osrm