/* 
 * tkUnixKey.c --
 *
 *	This file contains routines for dealing with international keyboard
 *	input.
 *
 * Copyright (c) 1997 by Sun Microsystems, Inc.
 *
 * See the file "license.terms" for information on usage and redistribution
 * of this file, and for a DISCLAIMER OF ALL WARRANTIES.
 *
 * RCS: @(#) $Id: tkUnixKey.c,v 1.5 2000/04/10 22:43:13 ericm Exp $
 */

#include "tkInt.h"

/*
 * Prototypes for local procedures defined in this file:
 */



/*
 *----------------------------------------------------------------------
 *
 * TkpGetString --
 *
 *	Retrieve the UTF string associated with a keyboard event.
 *
 * Results:
 *	Returns the UTF string.
 *
 * Side effects:
 *	Stores the input string in the specified Tcl_DString.  Modifies
 *	the internal input state.  This routine can only be called
 *	once for a given event.
 *
 *----------------------------------------------------------------------
 */

char *
TkpGetString(winPtr, eventPtr, dsPtr)
    TkWindow *winPtr;		/* Window where event occurred:  needed to
				 * get input context. */
    XEvent *eventPtr;		/* X keyboard event. */
    Tcl_DString *dsPtr;		/* Uninitialized or empty string to hold
				 * result. */
{
    int len;
    Tcl_DString buf;
    Status status;

    /*
     * Overallocate the dstring to the maximum stack amount.
     */

    Tcl_DStringInit(&buf);
    Tcl_DStringSetLength(&buf, TCL_DSTRING_STATIC_SIZE-1);
    
#ifdef TK_USE_INPUT_METHODS
    if (winPtr->dispPtr->useInputMethods
	    && (winPtr->inputContext != NULL)
	    && (eventPtr->type == KeyPress)) {
	len = XmbLookupString(winPtr->inputContext, &eventPtr->xkey,
		Tcl_DStringValue(&buf), Tcl_DStringLength(&buf),
		(KeySym *) NULL, &status);
	/*
	 * If the buffer wasn't big enough, grow the buffer and try again.
	 */

	if (status == XBufferOverflow) {
	    Tcl_DStringSetLength(&buf, len);
	    len = XmbLookupString(winPtr->inputContext, &eventPtr->xkey,
		    Tcl_DStringValue(&buf), len, (KeySym *) NULL, &status);
	}
	if ((status != XLookupChars) && (status != XLookupBoth)) {
	    len = 0;
	}
    } else {
	len = XLookupString(&eventPtr->xkey, Tcl_DStringValue(&buf),
		Tcl_DStringLength(&buf), (KeySym *) NULL,
		(XComposeStatus *) NULL);
    }
#else /* TK_USE_INPUT_METHODS */
    len = XLookupString(&eventPtr->xkey, Tcl_DStringValue(&buf),
	    Tcl_DStringLength(&buf), (KeySym *) NULL,
	    (XComposeStatus *) NULL);
#endif /* TK_USE_INPUT_METHODS */
    Tcl_DStringSetLength(&buf, len);

    Tcl_ExternalToUtfDString(NULL, Tcl_DStringValue(&buf), len, dsPtr);
    Tcl_DStringFree(&buf);

    return Tcl_DStringValue(dsPtr);
}

/*
 * When mapping from a keysym to a keycode, need
 * information about the modifier state that should be used
 * so that when they call XKeycodeToKeysym taking into
 * account the xkey.state, they will get back the original
 * keysym.
 */

void
TkpSetKeycodeAndState(tkwin, keySym, eventPtr)
    Tk_Window tkwin;
    KeySym keySym;
    XEvent *eventPtr;
{
    Display *display;
    int state;
    KeyCode keycode;
    
    display = Tk_Display(tkwin);
    
    if (keySym == NoSymbol) {
	keycode = 0;
    } else {
	keycode = XKeysymToKeycode(display, keySym);
    }
    if (keycode != 0) {
	for (state = 0; state < 4; state++) {
	    if (XKeycodeToKeysym(display, keycode, state) == keySym) {
		if (state & 1) {
		    eventPtr->xkey.state |= ShiftMask;
		}
		if (state & 2) {
		    TkDisplay *dispPtr;

		    dispPtr = ((TkWindow *) tkwin)->dispPtr; 
		    eventPtr->xkey.state |= dispPtr->modeModMask;
		}
		break;
	    }
	}
    }
    eventPtr->xkey.keycode = keycode;
}

/*
 *----------------------------------------------------------------------
 *
 * TkpGetKeySym --
 *
 *	Given an X KeyPress or KeyRelease event, map the
 *	keycode in the event into a KeySym.
 *
 * Results:
 *	The return value is the KeySym corresponding to
 *	eventPtr, or NoSymbol if no matching Keysym could be
 *	found.
 *
 * Side effects:
 *	In the first call for a given display, keycode-to-
 *	KeySym maps get loaded.
 *
 *----------------------------------------------------------------------
 */

KeySym
TkpGetKeySym(dispPtr, eventPtr)
    TkDisplay *dispPtr;	/* Display in which to
					 * map keycode. */
    XEvent *eventPtr;		/* Description of X event. */
{
    KeySym sym;
    int index;

    /*
     * Refresh the mapping information if it's stale
     */

    if (dispPtr->bindInfoStale) {
	TkpInitKeymapInfo(dispPtr);
    }

    /*
     * Figure out which of the four slots in the keymap vector to
     * use for this key.  Refer to Xlib documentation for more info
     * on how this computation works.
     */

    index = 0;
    if (eventPtr->xkey.state & dispPtr->modeModMask) {
	index = 2;
    }
    if ((eventPtr->xkey.state & ShiftMask)
	    || ((dispPtr->lockUsage != LU_IGNORE)
	    && (eventPtr->xkey.state & LockMask))) {
	index += 1;
    }
    sym = XKeycodeToKeysym(dispPtr->display, eventPtr->xkey.keycode, index);

    /*
     * Special handling:  if the key was shifted because of Lock, but
     * lock is only caps lock, not shift lock, and the shifted keysym
     * isn't upper-case alphabetic, then switch back to the unshifted
     * keysym.
     */

    if ((index & 1) && !(eventPtr->xkey.state & ShiftMask)
	    && (dispPtr->lockUsage == LU_CAPS)) {
	if (!(((sym >= XK_A) && (sym <= XK_Z))
		|| ((sym >= XK_Agrave) && (sym <= XK_Odiaeresis))
		|| ((sym >= XK_Ooblique) && (sym <= XK_Thorn)))) {
	    index &= ~1;
	    sym = XKeycodeToKeysym(dispPtr->display, eventPtr->xkey.keycode,
		    index);
	}
    }

    /*
     * Another bit of special handling:  if this is a shifted key and there
     * is no keysym defined, then use the keysym for the unshifted key.
     */

    if ((index & 1) && (sym == NoSymbol)) {
	sym = XKeycodeToKeysym(dispPtr->display, eventPtr->xkey.keycode,
		index & ~1);
    }
    return sym;
}

/*
 *--------------------------------------------------------------
 *
 * TkpInitKeymapInfo --
 *
 *	This procedure is invoked to scan keymap information
 *	to recompute stuff that's important for binding, such
 *	as the modifier key (if any) that corresponds to "mode
 *	switch".
 *
 * Results:
 *	None.
 *
 * Side effects:
 *	Keymap-related information in dispPtr is updated.
 *
 *--------------------------------------------------------------
 */

void
TkpInitKeymapInfo(dispPtr)
    TkDisplay *dispPtr;		/* Display for which to recompute keymap
				 * information. */
{
    XModifierKeymap *modMapPtr;
    KeyCode *codePtr;
    KeySym keysym;
    int count, i, j, max, arraySize;
#define KEYCODE_ARRAY_SIZE 20

    dispPtr->bindInfoStale = 0;
    modMapPtr = XGetModifierMapping(dispPtr->display);

    /*
     * Check the keycodes associated with the Lock modifier.  If
     * any of them is associated with the XK_Shift_Lock modifier,
     * then Lock has to be interpreted as Shift Lock, not Caps Lock.
     */

    dispPtr->lockUsage = LU_IGNORE;
    codePtr = modMapPtr->modifiermap + modMapPtr->max_keypermod*LockMapIndex;
    for (count = modMapPtr->max_keypermod; count > 0; count--, codePtr++) {
	if (*codePtr == 0) {
	    continue;
	}
	keysym = XKeycodeToKeysym(dispPtr->display, *codePtr, 0);
	if (keysym == XK_Shift_Lock) {
	    dispPtr->lockUsage = LU_SHIFT;
	    break;
	}
	if (keysym == XK_Caps_Lock) {
	    dispPtr->lockUsage = LU_CAPS;
	    break;
	}
    }

    /*
     * Look through the keycodes associated with modifiers to see if
     * the the "mode switch", "meta", or "alt" keysyms are associated
     * with any modifiers.  If so, remember their modifier mask bits.
     */

    dispPtr->modeModMask = 0;
    dispPtr->metaModMask = 0;
    dispPtr->altModMask = 0;
    codePtr = modMapPtr->modifiermap;
    max = 8*modMapPtr->max_keypermod;
    for (i = 0; i < max; i++, codePtr++) {
	if (*codePtr == 0) {
	    continue;
	}
	keysym = XKeycodeToKeysym(dispPtr->display, *codePtr, 0);
	if (keysym == XK_Mode_switch) {
	    dispPtr->modeModMask |= ShiftMask << (i/modMapPtr->max_keypermod);
	}
	if ((keysym == XK_Meta_L) || (keysym == XK_Meta_R)) {
	    dispPtr->metaModMask |= ShiftMask << (i/modMapPtr->max_keypermod);
	}
	if ((keysym == XK_Alt_L) || (keysym == XK_Alt_R)) {
	    dispPtr->altModMask |= ShiftMask << (i/modMapPtr->max_keypermod);
	}
    }

    /*
     * Create an array of the keycodes for all modifier keys.
     */

    if (dispPtr->modKeyCodes != NULL) {
	ckfree((char *) dispPtr->modKeyCodes);
    }
    dispPtr->numModKeyCodes = 0;
    arraySize = KEYCODE_ARRAY_SIZE;
    dispPtr->modKeyCodes = (KeyCode *) ckalloc((unsigned)
	    (KEYCODE_ARRAY_SIZE * sizeof(KeyCode)));
    for (i = 0, codePtr = modMapPtr->modifiermap; i < max; i++, codePtr++) {
	if (*codePtr == 0) {
	    continue;
	}

	/*
	 * Make sure that the keycode isn't already in the array.
	 */

	for (j = 0; j < dispPtr->numModKeyCodes; j++) {
	    if (dispPtr->modKeyCodes[j] == *codePtr) {
		goto nextModCode;
	    }
	}
	if (dispPtr->numModKeyCodes >= arraySize) {
	    KeyCode *new;

	    /*
	     * Ran out of space in the array;  grow it.
	     */

	    arraySize *= 2;
	    new = (KeyCode *) ckalloc((unsigned)
		    (arraySize * sizeof(KeyCode)));
	    memcpy((VOID *) new, (VOID *) dispPtr->modKeyCodes,
		    (dispPtr->numModKeyCodes * sizeof(KeyCode)));
	    ckfree((char *) dispPtr->modKeyCodes);
	    dispPtr->modKeyCodes = new;
	}
	dispPtr->modKeyCodes[dispPtr->numModKeyCodes] = *codePtr;
	dispPtr->numModKeyCodes++;
	nextModCode: continue;
    }
    XFreeModifiermap(modMapPtr);
}
