#pragma region CPL License
/*
Nuclex Native Framework
Copyright (C) 2002-2013 Nuclex Development Labs

This library is free software; you can redistribute it and/or
modify it under the terms of the IBM Common Public License as
published by the IBM Corporation; either version 1.0 of the
License, or (at your option) any later version.

This library is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
IBM Common Public License for more details.

You should have received a copy of the IBM Common Public
License along with this library
*/
#pragma endregion // CPL License

// If the library is compiled as a DLL, this ensures symbols are exported
#define NUCLEX_STORAGE_SOURCE 1

#include "DateHelper.h"

#if defined(NUCLEX_STORAGE_WIN32)

namespace Nuclex { namespace Storage { namespace FileSystem { namespace Windows {

  // ------------------------------------------------------------------------------------------- //

  std::time_t DateHelper::PosixTimeFromFileTime(const ::FILETIME &fileTime) {
    return PosixTimeFromFileTime(
      (static_cast<std::uint64_t>(fileTime.dwHighDateTime) << 32) |
      (fileTime.dwLowDateTime)
    );
  }

  // ------------------------------------------------------------------------------------------- //
#if 0
  std::time_t DateHelper::PosixTimeFromFileTime(
    std::uint32_t fileTimeHigh, std::uint32_t fileTimeLow
  ) {
    return PosixTimeFromFileTime(
      (static_cast<std::uint64_t>(fileTimeHigh) << 32) |
      (fileTimeLow)
    );
  }
#endif
  // ------------------------------------------------------------------------------------------- //

  std::time_t DateHelper::PosixTimeFromFileTime(std::uint64_t fileTime) {
    const std::uint64_t tenthMicrosecondsPerSecond = 10000000;
    const std::uint64_t secondsPerDay = 86400;
    const std::uint64_t secondsSinceJanuaryFirst1601OnJanuaryFirst1970 = 134774 * secondsPerDay;

    // Make sure to round up if the fraction is 0.5 seconds or more
    fileTime += (tenthMicrosecondsPerSecond / 2);

    // Convert to seconds and rebase to 1970-01-01
    std::uint64_t secondsSinceJanuaryFirst1601 = fileTime / tenthMicrosecondsPerSecond;
    return secondsSinceJanuaryFirst1601 - secondsSinceJanuaryFirst1601OnJanuaryFirst1970;
  }

  // ------------------------------------------------------------------------------------------- //

}}}} // namespace Nuclex::Storage::FileSystem::Windows

#endif // defined(NUCLEX_STORAGE_WIN32)