gistfile1.txt

void CorrectFileCase(const wchar_t* srcFileName, wchar_t* dstFileName, int maxLength)
{

    struct FILE_NAME_INFORMATION
    {
        ULONG FileNameLength;
        WCHAR FileName[1024 + 1];
    };
    typedef NTSTATUS (NTAPI *_NtQueryInformationFile)(HANDLE, PIO_STATUS_BLOCK, PVOID, ULONG, FILE_INFORMATION_CLASS);

    bool useFallback = false;

    DWORD flagsAndAttributes = FILE_FLAG_BACKUP_SEMANTICS; // Allows us to open directories.
    HANDLE hFile = CreateFile(srcFileName, GENERIC_READ, FILE_SHARE_READ | FILE_SHARE_WRITE | FILE_SHARE_DELETE, nullptr, OPEN_EXISTING, flagsAndAttributes, nullptr);

    bool result = false;
    if (hFile != INVALID_HANDLE_VALUE)
    {
        static _NtQueryInformationFile NtQueryInformationFile = nullptr;
        if (NtQueryInformationFile == nullptr)
        {
            HMODULE hDll = LoadLibraryW(L"ntdll.dll");
            NtQueryInformationFile = (_NtQueryInformationFile)GetProcAddress(hDll, "NtQueryInformationFile");
            if (NtQueryInformationFile == nullptr)
            {
                Log_Error(2, "Couldn't get NtQueryInformationFile function");
            }
        }

        IO_STATUS_BLOCK iosb;
        FILE_NAME_INFORMATION nameInformation;

        NTSTATUS status = NtQueryInformationFile(hFile, &iosb, &nameInformation,
            sizeof(nameInformation), (FILE_INFORMATION_CLASS)9); // FileNameInformation
        CloseHandle(hFile);

        if (status == 0)
        {
            nameInformation.FileName[nameInformation.FileNameLength / sizeof(WCHAR)] = 0;

            // Fix up the slashes.
            for (int i = 0; nameInformation.FileName[i] != 0; ++i)
            {
                if (nameInformation.FileName[i] == L'\\')
                {
                    nameInformation.FileName[i] = L'/';
                }
            }

            dstFileName[0] = 0;
            int length = 0;

            // We don't get the volume label, so just use that from the original file name.
            // There are ways of getting the proper volume label case, but it's more expensive and complex.
            const WCHAR* volumeLabelEnd = wcschr(srcFileName, L':');
            if (volumeLabelEnd != nullptr)
            {
                length = volumeLabelEnd - srcFileName + 1;
                wcsncpy(dstFileName, srcFileName, volumeLabelEnd - srcFileName + 1);
            }

            int appendLength = Min(maxLength - length - 1, nameInformation.FileNameLength);
            wcsncpy(dstFileName + length, nameInformation.FileName, appendLength);
            dstFileName[appendLength] = 0;

            int srcLength = wcslen(srcFileName);
            int dstLength = wcslen(dstFileName);
            if (srcLength > 0 && srcFileName[srcLength - 1] == L'/' || srcFileName[srcLength - 1] == L'\\')
            {
                // Make sure we have a trailing slash.
                if (dstLength > 0 && dstFileName[dstLength - 1] != '/')
                {
                    if (dstLength + 1 < maxLength)
                    {
                        dstFileName[dstLength] = '/';
                        dstFileName[dstLength + 1] = 0;
                    }
                }

            }

        }
        else
        {
            Log_Message(2, "Using fallback method for testing file name case");
            useFallback = true;
        }

    }
    else if (GetLastError() != ERROR_FILE_NOT_FOUND)
    {
        useFallback = true;
    }

    if (useFallback)
    {
        wchar_t shortFileName[1025];
        if (GetShortPathName(srcFileName, shortFileName, countof(shortFileName) - 1) != 0)
        {
            GetLongPathName(shortFileName, dstFileName, maxLength - 1);
        }
        else
        {
            wcsncpy(dstFileName, srcFileName, maxLength - 1);
        }
    }

}