////////////////////////////////////////////////////////////////////////////////
/// DISCLAIMER
///
/// Copyright 2014-2016 ArangoDB GmbH, Cologne, Germany
/// Copyright 2004-2014 triAGENS GmbH, Cologne, Germany
///
/// Licensed under the Apache License, Version 2.0 (the "License");
/// you may not use this file except in compliance with the License.
/// You may obtain a copy of the License at
///
///     http://www.apache.org/licenses/LICENSE-2.0
///
/// Unless required by applicable law or agreed to in writing, software
/// distributed under the License is distributed on an "AS IS" BASIS,
/// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
/// See the License for the specific language governing permissions and
/// limitations under the License.
///
/// Copyright holder is ArangoDB GmbH, Cologne, Germany
///
/// @author Dr. Oreste Costa-Panaia
////////////////////////////////////////////////////////////////////////////////

#ifndef ARANGODB_BASICS_MEMORY__MAP_H
#define ARANGODB_BASICS_MEMORY__MAP_H 1

#include "ApplicationFeatures/PageSizeFeature.h"
#include "Basics/Common.h"

////////////////////////////////////////////////////////////////////////////////
/// @brief wrapper macro for anonymous memory mapping
///
/// it might or might not be defined by one of the following includes
/// if still empty after the includes, no anonymous memory mapping is available
/// on the platform
////////////////////////////////////////////////////////////////////////////////

#undef TRI_MMAP_ANONYMOUS

////////////////////////////////////////////////////////////////////////////////
/// @brief posix memory map
////////////////////////////////////////////////////////////////////////////////

#ifdef TRI_HAVE_POSIX_MMAP
#include "Basics/memory-map-posix.h"
#endif

////////////////////////////////////////////////////////////////////////////////
/// @brief windows memory map
////////////////////////////////////////////////////////////////////////////////

#ifdef TRI_HAVE_WIN32_MMAP
#include "Basics/memory-map-win32.h"
#endif

////////////////////////////////////////////////////////////////////////////////
/// @brief flushes changes made in memory back to disk
////////////////////////////////////////////////////////////////////////////////

int TRI_FlushMMFile(int fileDescriptor, void* startingAddress,
                    size_t numOfBytesToFlush, int flags);

////////////////////////////////////////////////////////////////////////////////
/// @brief maps a file on disk onto memory
////////////////////////////////////////////////////////////////////////////////

int TRI_MMFile(void* memoryAddress, size_t numOfBytesToInitialize,
               int memoryProtection, int flags, int fileDescriptor,
               void** mmHandle, int64_t offset, void** result);

////////////////////////////////////////////////////////////////////////////////
/// @brief 'unmaps' or removes memory associated with a memory mapped file
////////////////////////////////////////////////////////////////////////////////

int TRI_UNMMFile(void* memoryAddress, size_t numOfBytesToUnMap,
                 int fileDescriptor, void** mmHandle);

////////////////////////////////////////////////////////////////////////////////
/// @brief sets various protection levels with the memory mapped file
////////////////////////////////////////////////////////////////////////////////

int TRI_ProtectMMFile(void* memoryAddress, size_t numOfBytesToProtect,
                      int flags, int fileDescriptor);

////////////////////////////////////////////////////////////////////////////////
/// @brief gives hints about upcoming memory usage
////////////////////////////////////////////////////////////////////////////////

int TRI_MMFileAdvise(void* memoryAddress, size_t numOfBytes, int advice);

////////////////////////////////////////////////////////////////////////////////
/// @brief locks a region in memory
////////////////////////////////////////////////////////////////////////////////

int TRI_MMFileLock(void* memoryAddress, size_t numOfBytes);

////////////////////////////////////////////////////////////////////////////////
/// @brief unlocks a mapped region from memory
////////////////////////////////////////////////////////////////////////////////

int TRI_MMFileUnlock(void* memoryAddress, size_t numOfBytes);

////////////////////////////////////////////////////////////////////////////////
/// @brief msyncs a memory block between begin (incl) and end (excl)
////////////////////////////////////////////////////////////////////////////////

static inline int TRI_MSync(int fd, char const* begin, char const* end) {
  size_t pageSize = arangodb::PageSizeFeature::getPageSize();
  uintptr_t p = (uintptr_t)begin;
  uintptr_t g = (uintptr_t)pageSize;

  char* b = (char*)((p / g) * g);

  return TRI_FlushMMFile(fd, b, end - b, MS_SYNC);
}

#endif