Add mmap allocator

src/engine/datafacade/mmap_memory_allocator.cpp

@@ -0,0 +1,53 @@
+#include "engine/datafacade/mmap_memory_allocator.hpp"
+
+#include "storage/storage.hpp"
+
+#include "util/log.hpp"
+#include "util/mmap_file.hpp"
+
+#include "boost/assert.hpp"
+
+namespace osrm
+{
+namespace engine
+{
+namespace datafacade
+{
+
+MMapMemoryAllocator::MMapMemoryAllocator(const storage::StorageConfig &config,
+                                         const boost::filesystem::path &memory_file)
+{
+    storage::Storage storage(config);
+
+    if (!boost::filesystem::exists(memory_file))
+    {
+        storage::DataLayout initial_layout;
+        storage.PopulateLayout(initial_layout);
+
+        auto data_size = initial_layout.GetSizeOfLayout();
+        auto total_size = data_size + sizeof(storage::DataLayout);
+
+        mapped_memory = util::mmapFile<char>(memory_file, mapped_memory_file, total_size);
+
+        data_layout = reinterpret_cast<storage::DataLayout *>(mapped_memory.data());
+        *data_layout = initial_layout;
+        storage.PopulateData(*data_layout, GetMemory());
+    }
+    else
+    {
+        mapped_memory = util::mmapFile<char>(memory_file, mapped_memory_file);
+        data_layout = reinterpret_cast<storage::DataLayout *>(mapped_memory.data());
+    }
+}
+
+MMapMemoryAllocator::~MMapMemoryAllocator() {}
+
+storage::DataLayout &MMapMemoryAllocator::GetLayout() { return *data_layout; }
+char *MMapMemoryAllocator::GetMemory()
+{
+    return mapped_memory.data() + sizeof(storage::DataLayout);
+}
+
+} // namespace datafacade
+} // namespace engine
+} // namespace osrm