/****************************** Module Header ******************************\
* Module Name: xlate.c
*
* Copyright (c) 1985-95, Microsoft Corporation
*
* History:
* 12-07-90 GregoryW      Created.
\***************************************************************************/

#include "precomp.h"
#pragma hdrstop


/*
 * "The great artist is the simplifier."
 * - Henri Frederic Amiel (1821-1881)
 * Ibid., November 25, 1861
 */

/*
 * Determine the state of all the Modifier Keys (a Modifier Key
 * is any key that may modify values produced by other keys: these are
 * commonly SHIFT, CTRL and/or ALT)
 * Build a bit-mask (wModBits) to encode which modifier keys are depressed.
 */
WORD GetModifierBits(
    PMODIFIERS pModifiers,
    LPBYTE afKeyState)
{
    PVK_TO_BIT pVkToBit = pModifiers->pVkToBit;
    WORD wModBits = 0;

    while (pVkToBit->Vk) {
        if (TestKeyDownBit(afKeyState, pVkToBit->Vk)) {
            wModBits |= pVkToBit->ModBits;
        }
        pVkToBit++;
    }
    return wModBits;
}

/*
 * Given modifier bits, return the modification number.
 */
WORD GetModificationNumber(
    PMODIFIERS pModifiers,
    WORD wModBits)
{
    if (wModBits > pModifiers->wMaxModBits) {
         return SHFT_INVALID;
    }

    return pModifiers->ModNumber[wModBits];
}

/*****************************************************************************\
* VKFromVSC
*
* This function is called from KeyEvent() after each call to VSCFromSC.  The
* keyboard input data passed in is translated to a virtual key code.
* This translation is dependent upon the currently depressed modifier keys.
*
* For instance, scan codes representing the number pad keys may be
* translated into VK_NUMPAD codes or cursor movement codes depending
* upon the state of NumLock and the modifier keys.
*
* History:
*
\*****************************************************************************/
BYTE VKFromVSC(
    PKE pke,
    BYTE bPrefix,
    LPBYTE afKeyState)
{
    USHORT usVKey = 0xFF;
    PVSC_VK pVscVk;
    PKBDTABLES pKbdTbl;
    static BOOL fVkPause;
#ifdef FE_IME // For Korea 103 keyboard
    extern USHORT gPrimaryLangID;
#endif

    DBG_UNREFERENCED_PARAMETER(afKeyState);

    if (pke->bScanCode == 0xFF) {
        /*
         * Kbd overrun (kbd hardware and/or keyboard driver) : Beep!
         * (some DELL keyboards send 0xFF if keys are hit hard enough,
         * presumably due to keybounce)
         */
        xxxMessageBeep(0);
        return 0;
    }

#ifdef FE_IME // For Korea 103 keyboard
    if (gPrimaryLangID == LANG_KOREAN && (pke->bScanCode==0x71 || pke->bScanCode==0x72)) {
        pke->bScanCode |= 0x80;
        bPrefix = 0xE0;
    }
    else
#endif
    pke->bScanCode &= 0x7F;

    if (gptiForeground == NULL) {
        RIPMSG0(RIP_VERBOSE, "VKFromVSC: NULL gptiForeground\n");
        pKbdTbl = gpKbdTbl;
    } else {
        if (gptiForeground->spklActive) {
            pKbdTbl = gptiForeground->spklActive->spkf->pKbdTbl;
        } else {
            RIPMSG0(RIP_VERBOSE, "VKFromVSC: NULL spklActive\n");
            pKbdTbl = gpKbdTbl;
        }
    }
    if (bPrefix == 0) {
        if (pke->bScanCode < pKbdTbl->bMaxVSCtoVK) {
            /*
             * direct index into non-prefix table
             */
            usVKey = pKbdTbl->pusVSCtoVK[pke->bScanCode];
            if (usVKey == 0) {
                return 0xFF;
            }
        } else {
            /*
             * unexpected scancode
             */
            RIPMSG2(RIP_VERBOSE, "unrecognized scancode 0x%x, prefix %x",
                    pke->bScanCode, bPrefix);
            return 0xFF;
        }
    } else {
        /*
         * Scan the E0 or E1 prefix table for a match
         */
        if (bPrefix == 0xE0) {
            /*
             * Ignore the SHIFT keystrokes generated by the hardware
             */
            if ((pke->bScanCode == SCANCODE_LSHIFT) ||
                    (pke->bScanCode == SCANCODE_RSHIFT)) {
                return 0;
            }
            pVscVk = pKbdTbl->pVSCtoVK_E0;
        } else if (bPrefix == 0xE1) {
            pVscVk = pKbdTbl->pVSCtoVK_E1;
        }
        while (pVscVk->Vk) {
            if (pVscVk->Vsc == pke->bScanCode) {
                usVKey = pVscVk->Vk;
                break;
            }
            pVscVk++;
        }
    }

    /*
     * Scancode set 1 returns PAUSE button as E1 1D 45 (E1 Ctrl NumLock)
     * so convert E1 Ctrl to VK_PAUSE, and remember to discard the NumLock
     */
    if (fVkPause) {
        /*
         * This is the "45" part of the Pause scancode sequence.
         * Discard this key event: it is a false NumLock
         */
        fVkPause = FALSE;
        return 0;
    }
    if (usVKey == VK_PAUSE) {
        /*
         * This is the "E1 1D" part of the Pause scancode sequence.
         * Alter the scancode to the value Windows expects for Pause,
         * and remember to discard the "45" scancode that will follow
         */
        pke->bScanCode = 0x45;
        fVkPause = TRUE;
    }

    /*
     * Convert to a different VK if some modifier keys are depressed.
     */
    if (usVKey & KBDMULTIVK) {
        WORD nMod;
        PULONG pul;

        nMod = GetModificationNumber(
                   &Modifiers_VK,
                   GetModifierBits(&Modifiers_VK, gafPhysKeyState));

        /*
         * Scan gapulCvt_VK[nMod] for matching VK.
         */
        if ((nMod != SHFT_INVALID) && ((pul = gapulCvt_VK[nMod]) != NULL)) {
            while (*pul != 0) {
                if (LOBYTE(*pul) == LOBYTE(usVKey)) {
                    pke->usFlaggedVk = (USHORT)HIWORD(*pul);
                    return (BYTE)pke->usFlaggedVk;
                }
                pul++;
            }
        }
    }

    pke->usFlaggedVk = usVKey;
    return (BYTE)usVKey;
}

/***************************************************************************\
* UINT InternalMapVirtualKeyEx(UINT wCode, UINT wType, PKBDTABLES pKbdTbl);
*
* History:
* IanJa 5/13/91  from Win3.1 \\pucus\win31ro!drivers\keyboard\getname.asm
* GregoryW 2/21/95  renamed from _MapVirtualKey and added third parameter.
\***************************************************************************/

UINT InternalMapVirtualKeyEx(
    UINT wCode,
    UINT wType,
    PKBDTABLES pKbdTbl)
{
    PVK_TO_WCHARS1 pVK;
    PVK_TO_WCHAR_TABLE pVKT;
    UINT VkRet = 0;
    USHORT usScanCode;
    PVSC_VK pVscVk;
    PBYTE pVkNumpad;

    switch (wType) {
    case 0:

        /*
         * Convert Virtual Key (wCode) to Scan Code
         */
        if ((wCode >= VK_SHIFT) && (wCode <= VK_MENU)) {

            /*
             * Convert ambiguous Shift/Control/Alt keys to left-hand keys
             */
            wCode = (UINT)((wCode - VK_SHIFT) * 2 + VK_LSHIFT);
        }

        /*
         * Scan through the table that maps Virtual Scancodes to Virtual Keys
         * for non-extended keys.
         */
        for (usScanCode = 0; usScanCode < pKbdTbl->bMaxVSCtoVK; usScanCode++) {
            if ((UINT)LOBYTE(pKbdTbl->pusVSCtoVK[usScanCode]) == wCode) {
                return usScanCode & 0xFF;
            }
        }

        /*
         * Scan through the table that maps Virtual Scancodes to Virtual Keys
         * for extended keys.
         */
        for (pVscVk = pKbdTbl->pVSCtoVK_E0; pVscVk->Vk; pVscVk++) {
            if ((UINT)LOBYTE(pVscVk->Vk) == wCode) {
                return (UINT)pVscVk->Vsc;
            }
        }

        /*
         * There was no match: maybe the Virtual Key can only be generated
         * with Numlock on. Scan through aVkNumpad[] to determine scancode.
         */
        for (pVkNumpad = aVkNumpad; *pVkNumpad != 0; pVkNumpad++) {
            if ((UINT)(*pVkNumpad) == wCode) {
                return pVkNumpad - aVkNumpad + SCANCODE_NUMPAD_FIRST;
            }
        }

        return 0;   // No match found!

    case 1:
    case 3:

        /*
         * Convert Scan Code (wCode) to Virtual Key, disregarding modifier keys
         * and NumLock key etc.  Returns 0 for no corresponding Virtual Key
         */
        if (wCode < (UINT)(pKbdTbl->bMaxVSCtoVK)) {
            VkRet = (UINT)LOBYTE(pKbdTbl->pusVSCtoVK[wCode]);
        } else {
            /*
             * Scan the E0 prefix table for a match
             */
            for (pVscVk = pKbdTbl->pVSCtoVK_E0; pVscVk->Vk; pVscVk++) {
                if ((UINT)pVscVk->Vsc == wCode) {
                    VkRet = (UINT)LOBYTE(pVscVk->Vk);
                    break;
                }
            }
        }

        if ((wType == 1) && (VkRet >= VK_LSHIFT) && (VkRet <= VK_RMENU)) {

            /*
             * Convert left/right Shift/Control/Alt keys to ambiguous keys
             * (neither left nor right)
             */
            VkRet = (UINT)((VkRet - VK_LSHIFT) / 2 + VK_SHIFT);
        }

        if (VkRet == 0xFF) {
            VkRet = 0;
        }
        return VkRet;

    case 2:

        /*
         * Bogus Win3.1 functionality: despite SDK documenation, return uppercase for
         * VK_A through VK_Z
         */
        if ((wCode >= (WORD)'A') && (wCode <= (WORD)'Z')) {
            return wCode;
        }

        /*
         * Convert Virtual Key (wCode) to ANSI.
         * Search each Shift-state table in turn, looking for the Virtual Key.
         */
        for (pVKT = pKbdTbl->pVkToWcharTable; pVKT->pVkToWchars != NULL; pVKT++) {
            pVK = pVKT->pVkToWchars;
            while (pVK->VirtualKey != 0) {
                if ((UINT)pVK->VirtualKey == wCode) {

                    /*
                     * Match found: return the unshifted character
                     */
                    if (pVK->wch[0] == WCH_DEAD) {

                        /*
                         * It is a dead character: the next entry contains its
                         * value.  Set the high bit to indicate dead key
                         * (undocumented behaviour)
                         */
                        pVK = (PVK_TO_WCHARS1)((PBYTE)pVK + pVKT->cbSize);
                        return pVK->wch[0] | (UINT)0x80000000;
                    } else if (pVK->wch[0] == WCH_NONE) {
                        return 0; // 9013
                    }
                    if (pVK->wch[0] == WCH_NONE) {
                        return 0;
                    }
                    return pVK->wch[0];
                }
                pVK = (PVK_TO_WCHARS1)((PBYTE)pVK + pVKT->cbSize);
            }
        }
    }

    /*
     * Can't find translation, or wType was invalid
     */
    return 0;
}

/***************************************************************************\
* _GetKeyNameText (API)
*
* int _GetKeyNameText(DWORD lParam, LPSTR lpStr, UINT size);
*
*   lParam: value from WM_KEYDOWN message, etc.
*
*       Byte 3 (bits 16..23) of lParam contains a scan code.
*
*       Bit 20 of lParam is the Extended bit (distingushes some keys on
*       Enhanced keyboard).
*
*       Bit 21 of lParam is a don't care bit (don't distingush between
*       left and right control, shift, Enter keys, between edit keys
*       in edit area and on numeric pad, etc).  The app calling this
*       function sets this bit in lParam, if it so desires.
*
*   lpStr:      Pointer to output string.
*
*   iSize:      Maximum length of output string, not including null byte.
*
* History:
* IanJa 4/11/91  from Win3.1 \\pucus\win31ro!drivers\keyboard\getname.asm
\***************************************************************************/

int APIENTRY _GetKeyNameText(
    LONG lParam,
    LPWSTR lpStr,
    int cchSize)
{
    BYTE Vsc = LOBYTE(HIWORD(lParam));
    PVSC_LPWSTR pKN;
    PTHREADINFO ptiT = PtiCurrentShared();
    PKBDTABLES pKbdTbl;
    UINT Vk;
    UINT Char;

    if (cchSize < 1)
        return 0;

    /*
     * If bit 25 set (don't care about the extended bit) then clear bit 24,
     * unless this is the Delete/Num-Del key (0x53), which is bass-ackward.
     */
    if (lParam & DONTCARE_BIT) {
        if (Vsc == 0x53) {
           lParam |= EXTENDED_BIT;
        } else {
           lParam &= ~EXTENDED_BIT;
        }
    }

    if (ptiT->spklActive == (PKL)NULL) {
        return 0;
    }
    pKbdTbl = ptiT->spklActive->spkf->pKbdTbl;

    /*
     * Scan pKbdTbl->pKeyNames[] or pKeyNamesExt[] for matching Virtual Scan Code
     */
    if (lParam & EXTENDED_BIT) {
        pKN = pKbdTbl->pKeyNamesExt;
    } else {
        pKN = pKbdTbl->pKeyNames;
    }

    if (pKN) {
        while (pKN->vsc != 0) {
            if (Vsc == pKN->vsc) {

                cchSize = wcsncpycch(lpStr, pKN->pwsz, cchSize);
                cchSize--;
                lpStr[cchSize] = L'\0';
                return cchSize;
            }
            pKN++;
        }
    }

    /*
     * The name of the key was not found in the table, so we
     * now attempt to construct the key name from the character produced by
     * the key.  Translate Scancode -> Virtual Key -> character.
     */

    /*
     * Translate Scancode to Virtual Key (ignoring modifier keys etc.)
     */
    Vk = InternalMapVirtualKeyEx((UINT)Vsc, 1, pKbdTbl);
    if (Vk == 0) {
        return 0;
    }

    /*
     * Now translate Virtual Key to character (ignoring modifier keys etc.)
     */
    Char = InternalMapVirtualKeyEx((UINT)Vk, 2, pKbdTbl);
    if (Char == 0) {
        return 0;
    }

    if (Char & 0x80000000) {
        LPWSTR *ppwsz;

        ppwsz = pKbdTbl->pKeyNamesDead;
        if (ppwsz) {
            while (*ppwsz != NULL) {
                if (*ppwsz[0] == (WCHAR)Char) {
                    cchSize = wcsncpycch(lpStr, (*ppwsz)+1, cchSize);
                    cchSize--;
                    lpStr[cchSize] = L'\0';
                    return cchSize;
                }
                ppwsz++;
            }
        }
    }

    /*
     * Construct a single character name (adding null-terminator if possible)
     */
    lpStr[0] = (WCHAR)Char;
    if (cchSize >= 2) {
        lpStr[1] = L'\0';
    }
    return 1;
}

/***************************************************************************\
* AltGr() - handle special case Right-hand ALT key (Locale dependent)
*
* Note:  gbAltGrDown reminds us to send the fake Ctrl key back up if we
* switched to a non-AltGr layout while ALtGr was down: otherwise the Ctrl key
* gets stuck down.  (For example: using AltGr with KBDSEL to switch from
* German to US layout).
\***************************************************************************/
BOOL gbAltGrDown = FALSE;

AltGr(
    PKE pKe)
{
    if (pKe == NULL) {
        /*
         * Clear state and deactivate this key processor
         */
        return FALSE;
    }

    if ((pKe->usFlaggedVk & 0xFF) != VK_RMENU) {
        return TRUE;
    }

    if (!(pKe->usFlaggedVk & KBDBREAK)) {
        /*
         * If neither CTRL key is down, then fake one going down so that
         * the right hand ALT key is converted to CTRL + ALT.
         */
        gbAltGrDown = TRUE;
        if (!TestKeyDownBit(gafPhysKeyState, VK_CONTROL)) {
            _KeyEvent(VK_LCONTROL, 0x1D | SCANCODE_SIMULATED, 0);
        }
    } else {
        /*
         * If the physical Left Ctrl key is not really down, fake the
         * Left Ctrl key coming back up (undo earlier faked Left Ctrl down)
         */
        gbAltGrDown = FALSE;
        if (!TestKeyDownBit(gafPhysKeyState, VK_LCONTROL)) {
            _KeyEvent(VK_LCONTROL | KBDBREAK, 0x1D | SCANCODE_SIMULATED, 0);
        }
    }
    return TRUE;
}

/*
 * Returning FALSE means the Key Event has been deleted by a special-case
 * KeyEvent processor.
 * Returning TRUE means the Key Event should be passed on (although it may
 * have been altered.
 */
BOOL KEOEMProcs(PKE pKe)
{
    int i;

    CheckCritIn();

    for (i = 0; aKEProcOEM[i] != NULL; i++) {
        if (!aKEProcOEM[i](pKe)) {
            /*
             * Eat the key event
             */
            return FALSE;
        }
    }

    /*
     * Pass the (possibly altered) key event on.
     */
    return TRUE;
}

/*
 * Returning FALSE means the Key Event has been deleted by a special-case
 * KeyEvent processor.
 * Returning TRUE means the Key Event should be passed on (although it may
 * have been altered.
 */
BOOL KELocaleProcs(PKE pKe)
{
    CheckCritIn();

    if ((gpKbdTbl->fLocaleFlags & KLLF_ALTGR) || gbAltGrDown) {
        if (!AltGr(pKe)) {
            return FALSE;
        }
    }

    /*
     * Other special Key Event processors
     */

    return TRUE;
}