This file details an interface to be used to supply locale/language-specific
function for display, keyboard handling, etc, within text setup.

The goals are as follows:

1) Provide a straightforward means for supporting fully localized text display,
   keyboard handling, and other features, in various locales, especially
   Far Eastern ones.

2) Avoid impacting setupdd.sys's size or performance when such function is not
   required.

To this end features such as DBCS font support, locale-specific keyboard detection,
and various other features are to be removed and placed into an export driver.
Setupdd.sys will be linked such that this driver is automatically referenced
and loaded when setupdd.sys is loaded. Setupdd.sys will itself export a set of
routines for use by the language-specific driver when carrying out its function.

Language-specific drivers will be built in the setup\textmode\spddlang directory.
Such drivers are logically part of setupdd.sys. No special set of include files
will be created for the interfaces below; they will be contained in various
header files in setup\textmode\kernel. Language-specific drivers' SOURCES files
should be set up so they include setup\textmode\kernel in their INCLUDES and
#include spprecmp.h.

*******************************************************************************

The functions listed below must be exported from every language-specific driver.

NTSTATUS
SplangInitializeFontSupport(
    IN PCWSTR BootDevicePath,
    IN PCWSTR DirectoryOnBootDevice
    );

/*++

Routine Description:

    This routine is called by setupdd.sys to allow the language-specific
    font support to be initialized. The language-specific driver should
    load any font it requires and perform any additioanl initialization.

Arguments:

    BootDevicePath - supplies the path of the device from which the system
        booted. This is a full NT-style path that includes a directory spec.

    DirectoryOnBootDevice - supplies directory relative to root of boot
        device.

Return Value:

    NT Status code indicating outcome. If this routine returns a non-success
    status code, then setupdd.sys will not switch into non-US character mode.
    The implementation of this routine is free to call SpBugCheck or otherwise
    inform the user of any errors if it wishes to halt setup if font
    initialization fails.

--*/


NTSTATUS
SplangTerminateFontSupport(
    VOID
    );

/*++

Routine Description:

    This routine may be called in certain conditions to cause font support
    for a particular language to be terminated. The implementation should
    clean up any resources allocated during SplangInitializeFontSupport().

Arguments:

    None.

Return Value:

    NT Status code indicating outcome.

--*/


PVIDEO_FUNCTION_VECTOR
SplangGetVideoFunctionVector(
    IN SpVideoType VideoType,
    IN PSP_VIDEO_VARS VideoVariableBlock
    );

/*++

Routine Description:

    This routine is called by setupdd.sys upon successful return from
    SplangInitializeFontSupport, to request a pointer to a vector of
    language-specific display support routines for a given display
    type (vga or frame buffer).

Arguments:

    VideoType - a value from the SpVideoType enum indicating which display
        vector is requested. Currently one of SpVideoVga or SpVideoFrameBuffer.

    VideoVariableBlock - supplies a pointer to a block of video variables that
        are shared between the high-level code in setup\textmode\spvideo.c and
        the display-specific code.

Return Value:

    Pointer to the language-specific video functions vector to use for
    displaying text. NULL if the requested type is not supported. In this case
    the display will not be switched into non-US character mode.

--*/


ULONG
SplangGetColumnCount(
    IN PCWSTR String
    );

/*++

Routine Description:

    This routine is called by setupdd.sys to determine how many columns
    on the screen a particular string will occupy. This may be different
    than the number of characters in the string due to full/half width
    characters in the character set, etc. Full width chars occupy two columns
    whereas half-width chars occupy one column. If the font in use is
    fixed-pitch or does not support DBCS, the number of columns is by
    definition equal to the number of characters in the string.

Arguments:

    String - points to unicode string whose width in columns is desired.

Return Value:

    Number of columns occupied by the string.

--*/


PWSTR
SplangPadString(
    IN int    Size,
    IN PCWSTR String
    );

/*++

Routine Description:

    This routine is called by setupdd.sys to generate a padded string
    appropriate for SBCS or DBCS as appropriate.

Arguments:

    Size - specifies the length to which to pad the string.

    String - points to unicode string that needs to be padded.

Return Value:

    Pointer to padded string. Note that this is a static buffer and thus
    the caller must duplicate the string if it is needed across multiple
    calls to this routine.

--*/


VOID
SplangSelectKeyboard(
    IN BOOLEAN UnattendedMode,
    IN PVOID SifHandle,
    IN PHARDWARE_COMPONENT *HwComponents
    );

/*++

Routine Description:

    This routine is called by setupdd.sys to allow language-specific processing
    for the keyboard selection. The implementation can confirm a keyboard
    type at this time.

Arguments:

    UnattendedMode - supplies a flag indicating whether we are running in
        unattended mode. If so, the implementation may wish to do nothing,
        since the user will not be entering any paths.

    SifHandle - supplies handle to open setup information file (txtsetup.sif).

    HwComponents - supplies the address of the master hardware components
        array.

Return Value:

    None. If a failure occurs, it is up to the implementation to decide whether
    to continue or to SpBugCheck.

--*/


VOID
SplangReinitializeKeyboard(
    IN BOOLEAN UnattendedMode,
    IN PVOID SifHandle,
    IN PWSTR Directory,
    OUT PVOID *KeyboardVector,
    IN PHARDWARE_COMPONENT *HwComponents
    );

/*++

Routine Description:

    This routine is called by setupdd.sys to allow language-specific processing
    for the keyboard. The implementation can reinitialize the keyboard layout
    at this time.

    This routine will be called before the user is asked to enter any paths
    or other text that includes typing anything other than keys such as
    ENTER, function keys, backspace, escape, etc.

Arguments:

    UnattendedMode - supplies a flag indicating whether we are running in
        unattended mode. If so, the implementation may wish to do nothing,
        since the user will not be entering any paths.

    SifHandle - supplies handle to open setup information file (txtsetup.sif).

    Directory - supplies the directory on the boot device from which the
        new layout dll is to be loaded.

    KeyboardVector - supplies the address of a pointer to the keyboard
        vector table. The implementation should overwrite this value with
        whatever is returned from SpLoadKbdLayoutDll().

    HwComponents - supplies the address of the master hardware components
        array.

Return Value:

    None. If a failure occurs the implementation must leave the currently active
    keybaord in place.

--*/


WCHAR
SplangGetLineDrawChar(
    IN LineCharIndex WhichChar
    );

/*++

Routine Description:

    This routine is called by setupdd.sys to retreive the unicode value for
    a particular line drawing character. An implementation must make these
    characters available in the character set somehow.

Arguments:

    WhichChar - supplies the index of the character desired.

Return Value:

    Unicode value for the character in question. Because the character
    will be displayed using the language-specific module, the implementation
    can materialize this character by playing whatever tricks it needs to,
    such as overlaying a hardcoded glyph into the character set, etc.

--*/


WCHAR
SplangGetCursorChar(
    VOID
    );

/*++

Routine Description:

    This routine is called by setupdd.sys to retreive the unicode value
    of a character to be used as the cursor when the user is asked to
    enter text.

Arguments:

    None.

Return Value:

    Unicode value for the character to be used as the cursor.

--*/


NTSTATUS
SplangSetRegistryData(
    IN PVOID  SifHandle,
    IN HANDLE ControlSetKeyHandle,
    IN PHARDWARE_COMPONENT *HwComponents
    );

/*++

Routine Description:

    This routine is called by setupdd.sys to cause language-specific
    information to be written into the current control set in the registry.

Arguments:

    SifHandle - supplies a handle to the open setup information file
        (txtsetup.sif).

    ControlSetKeyHandle - supplies a handle to the current control set
        root in the registry (ie, HKEY_LOCAL_MACHINE\CurrentControlSet).

    HwComponents - supplies the address of the master hardware components
        array.

Return Value:

    NT Status value indicating outcome. A non-success status is considered
    critical and causes Setup to abort.

--*/


BOOLEAN
SplangQueryMinimizeExtraSpacing(
    VOID
    );

/*++

Routine Description:

    This routine is called by setupdd.sys to determine whether to
    eliminate uses of extra spacing on the screen to set off things
    like menus and lists from text. Languages whose text takes up
    a lot of room on the screen might opt to eliminate such spacing
    to allow menus to display more than a couple of items at a time, etc.

    The return value affects numerous screens, such as the partition menu,
    upgrade lists, etc.

Arguments:

    None.

Return Value:

    Boolean value indicating whether the implementation wants unnecessary
    spaces eliminated when text, menu, etc, are displayed.

--*/

*******************************************************************************

The functions listed below are exported from setupdd.sys for use by
language-specific drivers. Such drivers are free to use any NT API normally
available to NT device drivers in addition to the routines listed below.