/*
 * PROJECT:     ReactOS user32.dll and win32k.sys
 * LICENSE:     GPL-2.0-or-later (https://spdx.org/licenses/GPL-2.0-or-later)
 * PURPOSE:     RtlGetExpWinVer function
 * COPYRIGHT:   Copyright 2019 James Tabor <james.tabor@reactos.org>
 *              Copyright 2024 Katayama Hirofumi MZ <katayama.hirofumi.mz@gmail.com>
 */

#ifdef _WIN32K_
#include <win32k.h>
DBG_DEFAULT_CHANNEL(UserMisc);
#else
#include <user32.h>
#include <wine/debug.h>
WINE_DEFAULT_DEBUG_CHANNEL(user32);
#endif

/* Get the expected OS version from the application module */
ULONG
RtlGetExpWinVer(_In_ PVOID BaseAddress)
{
    ULONG dwMajorVersion = 3, dwMinorVersion = 10; /* Set default to Windows 3.10 (WINVER_WIN31) */
    PIMAGE_NT_HEADERS pNTHeader;
    ULONG_PTR AlignedAddress = (ULONG_PTR)BaseAddress;

    TRACE("(%p)\n", BaseAddress);

    /* Remove the magic flag for non-mapped images */
    if (AlignedAddress & 1)
        AlignedAddress = (AlignedAddress & ~1);

    if (AlignedAddress && !LOWORD(AlignedAddress))
    {
        pNTHeader = RtlImageNtHeader((PVOID)AlignedAddress);
        if (pNTHeader)
        {
            dwMajorVersion = pNTHeader->OptionalHeader.MajorSubsystemVersion;
            if (dwMajorVersion == 1)
                dwMajorVersion = 3;
            else
                dwMinorVersion = pNTHeader->OptionalHeader.MinorSubsystemVersion;
        }
    }

    return MAKEWORD(dwMinorVersion, dwMajorVersion);
}