#pragma region CPL License
/*
Nuclex Native Framework
Copyright (C) 2002-2021 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 "PathHelper.h"

#if defined(NUCLEX_STORAGE_WIN32)

#include "../../Helpers/Utf8/checked.h"

#include <vector> // for std::vector

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

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

  /// <summary>Converts a UTF-8 path into a UTF-16 path</summary>
  /// <param name="utf8String">String containing a UTF-8 path</param>
  /// <returns>The UTF-16 path with magic prefix to eliminate the path length limit</returns>
  std::wstring PathHelper::PrefixedUtf16FromUtf8Path(const std::string &utf8Path) {
    if(utf8Path.empty()) {
      return std::wstring();
    }

    // We guess that we need as many UTF-16 characters as we needed UTF-8 characters
    // based on the assumption that most text will only use ascii characters.
    std::wstring utf16Path;
    utf16Path.reserve(utf8Path.length() + 4);

    // According to Microsoft, this is how you lift the 260 char MAX_PATH limit.
    // Also skips the internal call to GetFullPathName() every API method does internally,
    // so paths have to be normalized and 
    const wchar_t prefix[] = L"\\\\?\\";
    utf16Path.push_back(prefix[0]);
    utf16Path.push_back(prefix[1]);
    utf16Path.push_back(prefix[2]);
    utf16Path.push_back(prefix[3]);

    // Do the conversions. If the vector was too short, it will be grown in factors
    // of 2 usually (depending on the standard library implementation)
    utf8::utf8to16(utf8Path.begin(), utf8Path.end(), std::back_inserter(utf16Path));

    return utf16Path;
  }

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

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

#endif // defined(NUCLEX_STORAGE_WIN32)