imCallbk.c

/***********************************************************************
Copyright 1993 by Digital Equipment Corporation, Maynard, Massachusetts,
Copyright 1994 by FUJITSU LIMITED
Copyright 1994 by Sony Corporation

                        All Rights Reserved

Permission to use, copy, modify, and distribute this software and its
documentation for any purpose and without fee is hereby granted,
provided that the above copyright notice appear in all copies and that
both that copyright notice and this permission notice appear in
supporting documentation, and that the names of Digital, FUJITSU
LIMITED and Sony Corporation not be used in advertising or publicity
pertaining to distribution of the software without specific, written
prior permission.

DIGITAL, FUJITSU LIMITED AND SONY CORPORATION DISCLAIMS ALL WARRANTIES
WITH REGARD TO THIS SOFTWARE, INCLUDING ALL IMPLIED WARRANTIES OF
MERCHANTABILITY AND FITNESS, IN NO EVENT SHALL DIGITAL, FUJITSU LIMITED
AND SONY CORPORATION BE LIABLE FOR ANY SPECIAL, INDIRECT OR
CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF
USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR
OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR
PERFORMANCE OF THIS SOFTWARE.

  Author: Hiroyuki Miyamoto  Digital Equipment Corporation
                             miyamoto@jrd.dec.com
  Modifier: Takashi Fujiwara FUJITSU LIMITED
			     fujiwara@a80.tech.yk.fujitsu.co.jp
	    Makoto Wakamatsu Sony Corporation
		 	     makoto@sm.sony.co.jp

***********************************************************************/

#ifdef HAVE_CONFIG_H
#include <config.h>
#endif
#include "Xlibint.h"
#include "Xlcint.h"
#include "Ximint.h"
#include "XlcPubI.h"

#define sz_CARD8                 1
#define sz_INT8                  1
#define sz_CARD16                2
#define sz_INT16                 2
#define sz_BITMASK16             sz_CARD16
#define sz_CARD32                4
#define sz_INT32                 4
#define sz_BITMASK32             sz_CARD32
#define sz_XIMID                 sizeof(XIMID)
#define sz_XICID                 sizeof(XICID)
#define sz_XIMATTRID             sizeof(XIMATTRID)
#define sz_XICATTRID             sizeof(XICATTRID)
#define sz_ximPacketHeader       (XIM_HEADER_SIZE + sz_XIMID + sz_XICID)
#define sz_ximGeometry           0
#define sz_ximStrConversion      (sz_CARD32 + sz_CARD32 + sz_CARD32 + sz_CARD32)
#define sz_ximPreeditStart       0
#define sz_ximPreeditStartReply  sz_INT32
#define sz_ximPreeditCaret       (sz_INT32 + sz_CARD32 + sz_CARD32)
#define sz_ximPreeditCaretReply  sz_CARD32
#define sz_ximPreeditDone        0
#define sz_ximStatusStart        0
#define sz_ximStatusDone         0

typedef enum {
    XimCbSuccess,
    XimCbNoCallback,
    XimCbError,
    XimCbQueued,
    XimCbBadContextID,
    XimCbBadOpcode
} XimCbStatus;

typedef XimCbStatus (*XimCb)(
			     Xim, Xic, char*, int
			     );

#define PACKET_TO_MAJOROPCODE(p) (*(CARD8*)((CARD8*)(p)))
#define PACKET_TO_MINOROPCODE(p) (*(CARD8*)((CARD8*)(p) + sz_CARD8))
#define PACKET_TO_LENGTH(p) (*(CARD16*)((CARD8*)(p) + sz_CARD8 + sz_CARD8))
#define PACKET_TO_IMID(p) (*(XIMID*)((CARD8*)(p) + XIM_HEADER_SIZE))
#define PACKET_TO_ICID(p) (*(XICID*)((CARD8*)(p) + XIM_HEADER_SIZE + sz_XIMID))

#define _XimWriteData(im,len,data) \
    (im->private.proto.write((im),(len),(XPointer)(data)))
#define _XimReadData(im,buf,buf_len,len) \
    (im->private.proto.read((im),(XPointer)(buf),(buf_len),&(len)))
#define _XimFlushData(im) im->private.proto.flush((im))

static XimCbStatus _XimGeometryCallback(Xim, Xic, char*, int);
static XimCbStatus _XimStrConversionCallback(Xim, Xic, char*, int);
static XimCbStatus _XimPreeditStartCallback(Xim, Xic, char*, int);
static XimCbStatus _XimPreeditDoneCallback(Xim, Xic, char*, int);
static void _free_memory_for_text(XIMText*);
static XimCbStatus _XimPreeditDrawCallback(Xim, Xic, char*, int);
static XimCbStatus _XimPreeditCaretCallback(Xim, Xic, char*, int);
static XimCbStatus _XimStatusStartCallback(Xim, Xic, char*, int);
static XimCbStatus _XimStatusDoneCallback(Xim, Xic, char*, int);
static XimCbStatus _XimStatusDrawCallback(Xim, Xic, char*, int);
static XimCbStatus _XimPreeditStateNotifyCallback(Xim, Xic, char *, int);

#if defined(__STDC__) && ((defined(sun) && defined(SVR4)) || defined(WIN32))
#define RConst /**/
#else
#define RConst const
#endif

/* NOTE:
 * the table below depends on the protocol number
 * defined in the IM Protocol document.
 */
static RConst XimCb callback_table[] = {
    NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, /* #000-009 */
    NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, /* #010-019 */
    NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, /* #020-029 */
    NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, /* #030-039 */
    NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, /* #040-049 */
    NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, /* #050-059 */
    NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, /* #060-069 */
    _XimGeometryCallback,	/* #070 */
    _XimStrConversionCallback,	/* #071 */
    NULL,			/* #072 */
    _XimPreeditStartCallback,	/* #073 */
    NULL,			/* #074 */
    _XimPreeditDrawCallback,	/* #075 */
    _XimPreeditCaretCallback,	/* #076 */
    NULL,			/* #077 */
    _XimPreeditDoneCallback,	/* #078 */
    _XimStatusStartCallback,	/* #079 */
    _XimStatusDrawCallback,	/* #080 */
    _XimStatusDoneCallback,	/* #081 */
    _XimPreeditStateNotifyCallback	/* #082 */
    };


static Bool
_XimIsReadyForProcess(Xic ic)
{
    return(!ic->private.proto.waitCallback); /* check HM */
}

static void
_XimProcessPendingCallbacks(Xic ic)
{
    XimPendingCallback pcbq;

    while (((pcbq = ic->private.proto.pend_cb_que) != (XimPendingCallback)NULL)
	   && _XimIsReadyForProcess(ic)) {
	(void) (*callback_table[pcbq->major_opcode])(pcbq->im,
						     pcbq->ic,
						     pcbq->proto,
						     pcbq->proto_len);
	ic->private.proto.pend_cb_que = pcbq->next;
	Xfree(pcbq->proto);	/* free memory of XimPendingCallback */
	Xfree(pcbq);
    }
}

static void
_XimPutCbIntoQueue(Xic ic, XimPendingCallback call_data)
{
    XimPendingCallback pcbq = ic->private.proto.pend_cb_que;

    /* Queuing is FIFO
     */
    while (pcbq != (XimPendingCallback)NULL) {
	if (pcbq->next == (XimPendingCallback)NULL) {
	    break;
	}
	pcbq = pcbq->next;
    }
    if (pcbq == (XimPendingCallback)NULL) {
	ic->private.proto.pend_cb_que = call_data;
    }
    else {
	pcbq->next = call_data;
    }
}

Bool
_XimCbDispatch(Xim xim,
	       INT16 len,
	       XPointer data,
	       XPointer call_data)
{
    /* `data' points to the beginning of the packet defined in IM Protocol doc.
     */
    int major_opcode = PACKET_TO_MAJOROPCODE(data);
    XIMID imid = PACKET_TO_IMID(data);
    XICID icid = PACKET_TO_ICID(data);
    Xim im = (Xim)call_data;	/* check HM */
    Xic ic = _XimICOfXICID(im, icid);
    char* proto;
    int proto_len;

    /* check validity of im/ic
     */
    if ((imid != im->private.proto.imid) || !ic) {
	return False; /* status = XimCbBadContextID; */
    }

    /* process pending callbacks
     */
    _XimProcessPendingCallbacks(ic);

    /* check if the protocol should be processed here
     */
    if (major_opcode > 82) {
	return False; /* status = XimCbBadOpcode; */
    }
    if (!callback_table[major_opcode]) {
	return False; /* status = XimCbBadOpcode; */
    }

    /* move the pointer ahead by the IM Protocol packet header size
     */
    proto = (char*)data + sz_ximPacketHeader;
    proto_len = (int)len - sz_ximPacketHeader;

    /* check if it can be processed right away
     * and if no, queue the protocol, otherwise invoke a callback
     */
    if (!_XimIsReadyForProcess(ic)) {

	/* queue the protocol
	 */
	XimPendingCallback pcb;
	char *proto_buf = (proto_len > 0) ? Xmalloc(proto_len) : NULL;

	pcb = Xmalloc(sizeof(XimPendingCallbackRec));
	if (pcb && (proto_len <= 0 || proto_buf)) {
	    if (proto_len > 0)
		memcpy(proto_buf, proto, proto_len);

	    pcb->major_opcode = major_opcode;
	    pcb->im = im;
	    pcb->ic = ic;
	    pcb->proto = proto_buf;
	    pcb->proto_len = proto_len;
	    pcb->next = (XimPendingCallback)NULL; /* queue is FIFO */
	    _XimPutCbIntoQueue(ic, pcb);
	    /* status = XimCbQueued; */
	} else {
	    /* status = XimCbError; */
	    Xfree(pcb);
	    Xfree(proto_buf);
	}
    }
    else {
	/* invoke each callback according to the major opcode.
	 * `proto' points to the next address of IM-ID and IC-ID.
	 * `proto_len' specifies the packet length.
	 */
	(void) (*callback_table[major_opcode])(im, ic, proto, proto_len);
    }
    return True;
}

static XimCbStatus
_XimGeometryCallback(Xim im,
		     Xic ic,
		     char* proto,
		     int len)
{
    XICCallback* cb = &ic->core.geometry_callback;

    /* invoke the callack
     */
    if (cb && cb->callback) {
	(*cb->callback)((XIC)ic, cb->client_data, (XPointer)NULL);
    }
    else {

	/* no callback registered
	 */
	return XimCbNoCallback;
    }

    return XimCbSuccess;
}

static XimCbStatus
_XimStrConversionCallback(Xim im,
			  Xic ic,
			  char* proto,
			  int len)
{
    XICCallback* cb = &ic->core.string_conversion_callback; /* check HM */
    XIMStringConversionCallbackStruct cbrec;

    /* invoke the callback
     */
    if (cb && cb->callback) {
	int p = XIM_HEADER_SIZE;
	cbrec.position = (XIMStringConversionPosition)
	    *(CARD32*)&proto[p]; p += sz_CARD32;
	cbrec.direction = (XIMCaretDirection)
	    *(CARD32*)&proto[p]; p += sz_CARD32;
	cbrec.operation = (XIMStringConversionOperation)
	    *(CARD32*)&proto[p]; p += sz_CARD32;
	cbrec.factor = (unsigned short)
	    *(CARD32*)&proto[p];

	(*cb->callback)((XIC)ic, cb->client_data, (XPointer)&cbrec);
    }
    else {

	/* no callback registered
	 */
	_XimError(im, ic,
		  (CARD16)XIM_BadSomething,
		  (INT16)len,
		  (CARD16)XIM_STR_CONVERSION,
		  (char*)proto); /* send XIM_ERROR */
	return XimCbNoCallback;
    }

    /* send a reply
     */
    {
	CARD8	*buf;
	INT16	 buf_len;
	int	 p, length_in_bytes, i;

	/* Assumption:
	 * `cbrec.text->length' means the string length in characters
	 */
	{
	    length_in_bytes = (cbrec.text->encoding_is_wchar)?
		sizeof(wchar_t) * cbrec.text->length: /* wchar */
		strlen(cbrec.text->string.mbs);	/* mb */
	    buf_len = XIM_HEADER_SIZE +
		sz_CARD16 +
		2 + length_in_bytes +
		XIM_PAD(2 + length_in_bytes) +
		2 + 2 + sz_CARD32 * cbrec.text->length;
	    buf = Xmalloc(buf_len);
	}
	_XimSetHeader((XPointer)buf, XIM_STR_CONVERSION_REPLY, 0, &buf_len);
	buf_len -= XIM_HEADER_SIZE; /* added by _XimSetHeader (HACK) */
	p = XIM_HEADER_SIZE;
	*(CARD16*)&buf[p] = (CARD16)im->private.proto.imid; p += sz_CARD16;
	*(CARD16*)&buf[p] = (CARD16)ic->private.proto.icid; p += sz_CARD16;
	*(CARD16*)&buf[p] = (CARD16)cbrec.text->length; p += sz_CARD16;
	memcpy(&buf[p],&cbrec.text->string.mbs,length_in_bytes);
	p += length_in_bytes;
	*(CARD16*)&buf[p] = (CARD16)(sz_CARD32*cbrec.text->length);
	p += XIM_PAD(2);
	for (i = 0; i < (int)cbrec.text->length; i++) {
	    *(CARD32*)&buf[p] = (CARD32)cbrec.text->feedback[i];
	    p += sz_CARD32;
	}

	if (!(_XimWriteData(im, buf_len, buf))) {
	    return XimCbError;
	}
	_XimFlushData(im);

	Xfree(buf);
    }

    return XimCbSuccess;
}

static XimCbStatus
_XimPreeditStartCallback(Xim im,
			 Xic ic,
			 char* proto,
			 int len)
{
    XICCallback* cb = &ic->core.preedit_attr.start_callback;
    int ret;

    /* invoke the callback
     */
    if (cb && cb->callback){
	ret = (*(cb->callback))((XIC)ic, cb->client_data, (XPointer)NULL);
    }
    else {

	/* no callback registered
	 */
	_XimError(im, ic,
		  (CARD16)XIM_BadSomething,
		  (INT16)len,
		  (CARD16)XIM_PREEDIT_START,
		  (char*)proto); /* send XIM_ERROR */
	return XimCbNoCallback;
    }

    /* send a reply
     */
    {
	CARD32 buf32[(sz_ximPacketHeader + sz_ximPreeditStartReply) / 4];
	CARD8 *buf = (CARD8 *)buf32;
	INT16 buf_len = sz_XIMID + sz_XICID + sz_ximPreeditStartReply;
	int p;

	_XimSetHeader((XPointer)buf, XIM_PREEDIT_START_REPLY, 0, &buf_len);
	p = XIM_HEADER_SIZE;
	*(CARD16*)&buf[p] = (CARD16)im->private.proto.imid; p += sz_CARD16;
	*(CARD16*)&buf[p] = (CARD16)ic->private.proto.icid; p += sz_CARD16;
	*(INT32*)&buf[p]  = (INT32)ret;

	if (!(_XimWriteData(im, buf_len, buf))) {
	    return XimCbError;
	}
	_XimFlushData(im);
    }

    return XimCbSuccess;
}

static XimCbStatus
_XimPreeditDoneCallback(Xim im,
			Xic ic,
			char* proto,
			int len)
{
    XICCallback* cb = &ic->core.preedit_attr.done_callback;

    /* invoke the callback
     */
    if (cb && cb->callback) {
	(*cb->callback)((XIC)ic, cb->client_data, (XPointer)NULL);
    }
    else {

	/* no callback registered
	 */
	return XimCbNoCallback;
    }

    return XimCbSuccess;
}

static void
_read_text_from_packet(Xim im,
		       char* buf,
		       XIMText** text_ptr)
{
    int status;
    XIMText* text;
    int tmp_len;
    char* tmp_buf;
    Status s = 0;

    status = (int)*(BITMASK32*)buf; buf += sz_BITMASK32;

    /* string part
     */
    if (status & 0x00000001) /* "no string" bit on */ {
	buf += sz_CARD16;	/* skip "length of preedit string" */
	buf += 2;		/* pad */
	*text_ptr = (XIMText*)NULL;
	return;
    }

    *text_ptr = text = Xmalloc(sizeof(XIMText));
    if (text == (XIMText*)NULL) return;

	tmp_len = (int)*(CARD16*)buf;
	buf += sz_CARD16;
	if ((tmp_buf = Xmalloc(tmp_len + 1))) {
	    memcpy(tmp_buf, buf, tmp_len);
	    tmp_buf[tmp_len] = '\0';

	    text->encoding_is_wchar = False;
	    text->length = im->methods->ctstombs((XIM)im,
					tmp_buf, tmp_len,
					NULL, 0, &s); /* CT? HM */
	    if (s != XLookupNone) {
#ifndef NO_DEC_I18N_FIX
                /* Allow for NULL-terminated */
                if ((text->string.multi_byte = Xmalloc(text->length *
                      XLC_PUBLIC(im->core.lcd,mb_cur_max) + 1))) {
#else
		if (text->string.multi_byte = Xmalloc(text->length+1)) {
#endif
			int tmp;
#ifndef NO_DEC_I18N_FIX
                        char *char_tmp;
                        int char_len;
#endif
			tmp = im->methods->ctstombs((XIM)im,
					   tmp_buf, tmp_len,
#ifndef NO_DEC_I18N_FIX
                                           text->string.multi_byte,
                                           text->length * XLC_PUBLIC(im->core.lcd,mb_cur_max) + 1,
#else
					   text->string.multi_byte, text->length,
#endif
					   &s);
			text->string.multi_byte[tmp] = '\0';
#ifndef NO_DEC_I18N_FIX
                        text->length = 0;
                        char_tmp =  text->string.multi_byte;
                        while (*char_tmp != '\0') {
                              char_len = mblen(char_tmp, strlen(char_tmp));
                              char_tmp = char_tmp + char_len;
                              (text->length)++;
                        }
#endif
		}
	    }
	    else {
		text->length = 0;
		text->string.multi_byte = NULL;
	    }

	    Xfree(tmp_buf);
	}
	buf += tmp_len;

	buf += XIM_PAD(sz_CARD16 + tmp_len); /* pad */

    /* feedback part
     */
    if (status & 0x00000002) /* "no feedback" bit on */ {
	text->feedback = (XIMFeedback*)NULL;
    }
    else {
	int i, j;

	i = (int)*(CARD16*)buf; buf += sz_CARD16;
	buf += sz_CARD16; /* skip `unused' */
	text->feedback = Xmalloc(i*(sizeof(XIMFeedback)/sizeof(CARD32)));
	j = 0;
	while (i > 0) {
	    text->feedback[j] = (XIMFeedback)*(CARD32*)buf;
	    buf += sz_CARD32;
	    i -= sz_CARD32;
	    j++;
	}
	/*
	 * text->length tells how long both the status string and
	 * the feedback array are. If there's "no string" the
	 * text->length was set to zero previously. See above.
	 * But if there is feedback (i.e. not "no feedback") then
	 * we need to convey the length of the feedback array.
	 * It might have been better if the protocol sent two
	 * different values, one for the length of the status
	 * string and one for the length of the feedback array.
	 */
	if (status & 0x00000001) /* "no string" bit on */ {
	    text->length = j;
	}
    }
}

static void
_free_memory_for_text(XIMText* text)
{
    if (text) {
        Xfree(text->string.multi_byte);
        Xfree(text->feedback);
	Xfree(text);
    }
}

static XimCbStatus
_XimPreeditDrawCallback(Xim im,
			Xic ic,
			char* proto,
			int len)
{
    XICCallback* cb = &ic->core.preedit_attr.draw_callback;
    XIMPreeditDrawCallbackStruct cbs;

    /* invoke the callback
     */
    if (cb && cb->callback) {
	cbs.caret      = (int)*(INT32*)proto; proto += sz_INT32;
	cbs.chg_first  = (int)*(INT32*)proto; proto += sz_INT32;
	cbs.chg_length = (int)*(INT32*)proto; proto += sz_INT32;
	_read_text_from_packet(im, proto, &cbs.text);

	(*cb->callback)((XIC)ic, cb->client_data, (XPointer)&cbs);

	_free_memory_for_text((XIMText*)cbs.text);
    }
    else {

	/* no callback registered
	 */
	return XimCbNoCallback;
    }

    return XimCbSuccess;
}

static XimCbStatus
_XimPreeditCaretCallback(Xim im,
			 Xic ic,
			 char* proto,
			 int len)
{
    XICCallback* cb = &ic->core.preedit_attr.caret_callback;
    XIMPreeditCaretCallbackStruct cbs;

    /* invoke the callback
     */
    if (cb && cb->callback) {
	cbs.position  = (int)*(INT32*)proto; proto += sz_INT32;
	cbs.direction = (XIMCaretDirection)*(CARD32*)proto; proto += sz_CARD32;
	cbs.style     = (XIMCaretStyle)*(CARD32*)proto; proto += sz_CARD32;

	(*cb->callback)((XIC)ic, cb->client_data, (XPointer)&cbs);
    }
    else {

	/* no callback registered
	 */
	_XimError(im, ic,
		  (CARD16)XIM_BadSomething,
		  (INT16)len,
		  (CARD16)XIM_PREEDIT_CARET,
		  (char*)proto); /* send XIM_ERROR */
	return XimCbNoCallback;
    }

    /* Send a reply
     */
    {
	CARD8 buf[sz_ximPacketHeader + sz_ximPreeditCaretReply];
	INT16 len = sz_XIMID + sz_XICID + sz_ximPreeditCaretReply;
	int p;

	_XimSetHeader((XPointer)buf, XIM_PREEDIT_CARET_REPLY, 0, &len);
	p = XIM_HEADER_SIZE;
	*(CARD16*)&buf[p] = (CARD16)im->private.proto.imid; p += sz_CARD16;
	*(CARD16*)&buf[p] = (CARD16)ic->private.proto.icid; p += sz_CARD16;
	*(CARD32*)&buf[p] = (CARD32)cbs.position;

	if (!(_XimWriteData(im, len, buf))) {
	    return XimCbError;
	}
	_XimFlushData(im);
    }

    return XimCbSuccess;
}

static XimCbStatus
_XimStatusStartCallback(Xim im,
			Xic ic,
			char* proto,
			int len)
{
    XICCallback* cb = &ic->core.status_attr.start_callback;

    /* invoke the callback
     */
    if (cb && cb->callback) {
	(*cb->callback)((XIC)ic, cb->client_data, (XPointer)NULL);
    }
    else {

	/* no callback registered
	 */
	return XimCbNoCallback;
    }

    return XimCbSuccess;
}

static XimCbStatus
_XimStatusDoneCallback(Xim im,
		       Xic ic,
		       char* proto,
		       int len)
{
    XICCallback* cb = &ic->core.status_attr.done_callback;

    /* invoke the callback
     */
    if (cb && cb->callback) {
	(*cb->callback)((XIC)ic, cb->client_data, (XPointer)NULL);
    }
    else {

	/* no callback registered
	 */
	return XimCbNoCallback;
    }

    return XimCbSuccess;
}

static XimCbStatus
_XimStatusDrawCallback(Xim im,
		       Xic ic,
		       char* proto,
		       int len)
{
    XICCallback* cb = &ic->core.status_attr.draw_callback;
    XIMStatusDrawCallbackStruct cbs;

    /* invoke the callback
     */
    if (cb && cb->callback) {
	cbs.type = (XIMStatusDataType)*(CARD32*)proto; proto += sz_CARD32;
	if (cbs.type == XIMTextType) {
	    _read_text_from_packet(im, proto, &cbs.data.text);
	}
	else if (cbs.type == XIMBitmapType) {
	    cbs.data.bitmap = (Pixmap)*(CARD32*)proto;
	}

	(*cb->callback)((XIC)ic, cb->client_data, (XPointer)&cbs);

	if (cbs.type == XIMTextType)
	    _free_memory_for_text((XIMText *)cbs.data.text);
    }
    else {

	/* no callback registered
	 */
	return XimCbNoCallback;
    }

    return XimCbSuccess;
}

static XimCbStatus
_XimPreeditStateNotifyCallback( Xim im, Xic ic, char* proto, int len )
{
    XICCallback	*cb = &ic->core.preedit_attr.state_notify_callback;

    /* invoke the callack
     */
    if( cb  &&  cb->callback ) {
	XIMPreeditStateNotifyCallbackStruct cbrec;

	cbrec.state = *(BITMASK32 *)proto;
	(*cb->callback)( (XIC)ic, cb->client_data, (XPointer)&cbrec );
    }
    else {
	/* no callback registered
	 */
	return XimCbNoCallback;
    }

    return XimCbSuccess;
}