1/****************************************************************************
2 * Copyright (c) 1998-2013,2014 Free Software Foundation, Inc.              *
3 *                                                                          *
4 * Permission is hereby granted, free of charge, to any person obtaining a  *
5 * copy of this software and associated documentation files (the            *
6 * "Software"), to deal in the Software without restriction, including      *
7 * without limitation the rights to use, copy, modify, merge, publish,      *
8 * distribute, distribute with modifications, sublicense, and/or sell       *
9 * copies of the Software, and to permit persons to whom the Software is    *
10 * furnished to do so, subject to the following conditions:                 *
11 *                                                                          *
12 * The above copyright notice and this permission notice shall be included  *
13 * in all copies or substantial portions of the Software.                   *
14 *                                                                          *
15 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS  *
16 * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF               *
17 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.   *
18 * IN NO EVENT SHALL THE ABOVE COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM,   *
19 * DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR    *
20 * OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR    *
21 * THE USE OR OTHER DEALINGS IN THE SOFTWARE.                               *
22 *                                                                          *
23 * Except as contained in this notice, the name(s) of the above copyright   *
24 * holders shall not be used in advertising or otherwise to promote the     *
25 * sale, use or other dealings in this Software without prior written       *
26 * authorization.                                                           *
27 ****************************************************************************/
28
29/****************************************************************************
30 *   Author:  Juergen Pfeifer, 1995,1997                                    *
31 ****************************************************************************/
32
33#include "form.priv.h"
34
35MODULE_ID("$Id: frm_driver.c,v 1.110 2014/02/10 00:42:48 tom Exp $")
36
37/*----------------------------------------------------------------------------
38  This is the core module of the form library. It contains the majority
39  of the driver routines as well as the form_driver function.
40
41  Essentially this module is nearly the whole library. This is because
42  all the functions in this module depends on some others in the module,
43  so it makes no sense to split them into separate files because they
44  will always be linked together. The only acceptable concern is turnaround
45  time for this module, but now we have all Pentiums or RISCs, so what!
46
47  The driver routines are grouped into nine generic categories:
48
49   a)   Page Navigation            ( all functions prefixed by PN_ )
50        The current page of the form is left and some new page is
51        entered.
52   b)   Inter-Field Navigation     ( all functions prefixed by FN_ )
53        The current field of the form is left and some new field is
54        entered.
55   c)   Intra-Field Navigation     ( all functions prefixed by IFN_ )
56        The current position in the current field is changed.
57   d)   Vertical Scrolling         ( all functions prefixed by VSC_ )
58        Essentially this is a specialization of Intra-Field navigation.
59        It has to check for a multi-line field.
60   e)   Horizontal Scrolling       ( all functions prefixed by HSC_ )
61        Essentially this is a specialization of Intra-Field navigation.
62        It has to check for a single-line field.
63   f)   Field Editing              ( all functions prefixed by FE_ )
64        The content of the current field is changed
65   g)   Edit Mode requests         ( all functions prefixed by EM_ )
66        Switching between insert and overlay mode
67   h)   Field-Validation requests  ( all functions prefixed by FV_ )
68        Perform verifications of the field.
69   i)   Choice requests            ( all functions prefixed by CR_ )
70        Requests to enumerate possible field values
71  --------------------------------------------------------------------------*/
72
73/*----------------------------------------------------------------------------
74  Some remarks on the placements of assert() macros :
75  I use them only on "strategic" places, i.e. top level entries where
76  I want to make sure that things are set correctly. Throughout subordinate
77  routines I omit them mostly.
78  --------------------------------------------------------------------------*/
79
80/*
81Some options that may effect compatibility in behavior to SVr4 forms,
82but they are here to allow a more intuitive and user friendly behavior of
83our form implementation. This doesn't affect the API, so we feel it is
84uncritical.
85
86The initial implementation tries to stay very close with the behavior
87of the original SVr4 implementation, although in some areas it is quite
88clear that this isn't the most appropriate way. As far as possible this
89sources will allow you to build a forms lib that behaves quite similar
90to SVr4, but now and in the future we will give you better options.
91Perhaps at some time we will make this configurable at runtime.
92*/
93
94/* Implement a more user-friendly previous/next word behavior */
95#define FRIENDLY_PREV_NEXT_WORD (1)
96/* Fix the wrong behavior for forms with all fields inactive */
97#define FIX_FORM_INACTIVE_BUG (1)
98/* Allow dynamic field growth also when navigating past the end */
99#define GROW_IF_NAVIGATE (1)
100
101#if USE_WIDEC_SUPPORT
102#define myADDNSTR(w, s, n) wadd_wchnstr(w, s, n)
103#define myINSNSTR(w, s, n) wins_wchnstr(w, s, n)
104#define myINNSTR(w, s, n)  fix_wchnstr(w, s, n)
105#define myWCWIDTH(w, y, x) cell_width(w, y, x)
106#else
107#define myADDNSTR(w, s, n) waddnstr(w, s, n)
108#define myINSNSTR(w, s, n) winsnstr(w, s, n)
109#define myINNSTR(w, s, n)  winnstr(w, s, n)
110#define myWCWIDTH(w, y, x) 1
111#endif
112
113/*----------------------------------------------------------------------------
114  Forward references to some internally used static functions
115  --------------------------------------------------------------------------*/
116static int Inter_Field_Navigation(int (*const fct) (FORM *), FORM *form);
117static int FN_Next_Field(FORM *form);
118static int FN_Previous_Field(FORM *form);
119static int FE_New_Line(FORM *);
120static int FE_Delete_Previous(FORM *);
121
122/*----------------------------------------------------------------------------
123  Macro Definitions.
124
125  Some Remarks on that: I use the convention to use UPPERCASE for constants
126  defined by Macros. If I provide a macro as a kind of inline routine to
127  provide some logic, I use my Upper_Lower case style.
128  --------------------------------------------------------------------------*/
129
130/* Calculate the position of a single row in a field buffer */
131#define Position_Of_Row_In_Buffer(field,row) ((row)*(field)->dcols)
132
133/* Calculate start address for the fields buffer# N */
134#define Address_Of_Nth_Buffer(field,N) \
135  ((field)->buf + (N)*(1+Buffer_Length(field)))
136
137/* Calculate the start address of the row in the fields specified buffer# N */
138#define Address_Of_Row_In_Nth_Buffer(field,N,row) \
139  (Address_Of_Nth_Buffer(field,N) + Position_Of_Row_In_Buffer(field,row))
140
141/* Calculate the start address of the row in the fields primary buffer */
142#define Address_Of_Row_In_Buffer(field,row) \
143  Address_Of_Row_In_Nth_Buffer(field,0,row)
144
145/* Calculate the start address of the row in the forms current field
146   buffer# N */
147#define Address_Of_Current_Row_In_Nth_Buffer(form,N) \
148   Address_Of_Row_In_Nth_Buffer((form)->current,N,(form)->currow)
149
150/* Calculate the start address of the row in the forms current field
151   primary buffer */
152#define Address_Of_Current_Row_In_Buffer(form) \
153   Address_Of_Current_Row_In_Nth_Buffer(form,0)
154
155/* Calculate the address of the cursor in the forms current field
156   primary buffer */
157#define Address_Of_Current_Position_In_Nth_Buffer(form,N) \
158   (Address_Of_Current_Row_In_Nth_Buffer(form,N) + (form)->curcol)
159
160/* Calculate the address of the cursor in the forms current field
161   buffer# N */
162#define Address_Of_Current_Position_In_Buffer(form) \
163  Address_Of_Current_Position_In_Nth_Buffer(form,0)
164
165/* Logic to decide whether or not a field is actually a field with
166   vertical or horizontal scrolling */
167#define Is_Scroll_Field(field)          \
168   (((field)->drows > (field)->rows) || \
169    ((field)->dcols > (field)->cols))
170
171/* Logic to decide whether or not a field needs to have an individual window
172   instead of a derived window because it contains invisible parts.
173   This is true for non-public fields and for scrollable fields. */
174#define Has_Invisible_Parts(field)     \
175  (!((unsigned)(field)->opts & O_PUBLIC) || \
176   Is_Scroll_Field(field))
177
178/* Logic to decide whether or not a field needs justification */
179#define Justification_Allowed(field)        \
180   (((field)->just != NO_JUSTIFICATION)  && \
181    (Single_Line_Field(field))           && \
182    (((field)->dcols == (field)->cols)   && \
183    ((unsigned)(field)->opts & O_STATIC)))
184
185/* Logic to determine whether or not a dynamic field may still grow */
186#define Growable(field) ((field)->status & _MAY_GROW)
187
188/* Macro to set the attributes for a fields window */
189#define Set_Field_Window_Attributes(field,win) \
190(  wbkgdset((win),(chtype)((chtype)((field)->pad) | (field)->back)), \
191   (void) wattrset((win), (int)(field)->fore) )
192
193/* Logic to decide whether or not a field really appears on the form */
194#define Field_Really_Appears(field)         \
195  ((field->form)                          &&\
196   (field->form->status & _POSTED)        &&\
197   ((unsigned)field->opts & O_VISIBLE)    &&\
198   (field->page == field->form->curpage))
199
200/* Logic to determine whether or not we are on the first position in the
201   current field */
202#define First_Position_In_Current_Field(form) \
203  (((form)->currow==0) && ((form)->curcol==0))
204
205#define Minimum(a,b) (((a)<=(b)) ? (a) : (b))
206#define Maximum(a,b) (((a)>=(b)) ? (a) : (b))
207
208/*----------------------------------------------------------------------------
209  Useful constants
210  --------------------------------------------------------------------------*/
211static FIELD_CELL myBLANK = BLANK;
212static FIELD_CELL myZEROS;
213
214#ifdef TRACE
215static void
216check_pos(FORM *form, int lineno)
217{
218  int y, x;
219
220  if (form && form->w)
221    {
222      getyx(form->w, y, x);
223      if (y != form->currow || x != form->curcol)
224	{
225	  T(("CHECKPOS %s@%d have position %d,%d vs want %d,%d",
226	     __FILE__, lineno,
227	     y, x,
228	     form->currow, form->curcol));
229	}
230    }
231}
232#define CHECKPOS(form) check_pos(form, __LINE__)
233#else
234#define CHECKPOS(form)		/* nothing */
235#endif
236
237/*----------------------------------------------------------------------------
238  Wide-character special functions
239  --------------------------------------------------------------------------*/
240#if USE_WIDEC_SUPPORT
241/* like winsnstr */
242static int
243wins_wchnstr(WINDOW *w, cchar_t *s, int n)
244{
245  int code = ERR;
246  int y, x;
247
248  while (n-- > 0)
249    {
250      getyx(w, y, x);
251      if ((code = wins_wch(w, s++)) != OK)
252	break;
253      if ((code = wmove(w, y, x + 1)) != OK)
254	break;
255    }
256  return code;
257}
258
259/* win_wchnstr is inconsistent with winnstr, since it returns OK rather than
260 * the number of items transferred.
261 */
262static int
263fix_wchnstr(WINDOW *w, cchar_t *s, int n)
264{
265  int x;
266
267  win_wchnstr(w, s, n);
268  /*
269   * This function is used to extract the text only from the window.
270   * Strip attributes and color from the string so they will not be added
271   * back when copying the string to the window.
272   */
273  for (x = 0; x < n; ++x)
274    {
275      RemAttr(s[x], A_ATTRIBUTES);
276      SetPair(s[x], 0);
277    }
278  return n;
279}
280
281/*
282 * Returns the column of the base of the given cell.
283 */
284static int
285cell_base(WINDOW *win, int y, int x)
286{
287  int result = x;
288
289  while (LEGALYX(win, y, x))
290    {
291      cchar_t *data = &(win->_line[y].text[x]);
292
293      if (isWidecBase(CHDEREF(data)) || !isWidecExt(CHDEREF(data)))
294	{
295	  result = x;
296	  break;
297	}
298      --x;
299    }
300  return result;
301}
302
303/*
304 * Returns the number of columns needed for the given cell in a window.
305 */
306static int
307cell_width(WINDOW *win, int y, int x)
308{
309  int result = 1;
310
311  if (LEGALYX(win, y, x))
312    {
313      cchar_t *data = &(win->_line[y].text[x]);
314
315      if (isWidecExt(CHDEREF(data)))
316	{
317	  /* recur, providing the number of columns to the next character */
318	  result = cell_width(win, y, x - 1);
319	}
320      else
321	{
322	  result = wcwidth(CharOf(CHDEREF(data)));
323	}
324    }
325  return result;
326}
327
328/*
329 * There is no wide-character function such as wdel_wch(), so we must find
330 * all of the cells that comprise a multi-column character and delete them
331 * one-by-one.
332 */
333static void
334delete_char(FORM *form)
335{
336  int cells = cell_width(form->w, form->currow, form->curcol);
337
338  form->curcol = cell_base(form->w, form->currow, form->curcol);
339  wmove(form->w, form->currow, form->curcol);
340  while (cells-- > 0)
341    {
342      wdelch(form->w);
343    }
344}
345#define DeleteChar(form) delete_char(form)
346#else
347#define DeleteChar(form) \
348	  wmove((form)->w, (form)->currow, (form)->curcol), \
349	  wdelch((form)->w)
350#endif
351
352/*---------------------------------------------------------------------------
353|   Facility      :  libnform
354|   Function      :  static char *Get_Start_Of_Data(char * buf, int blen)
355|
356|   Description   :  Return pointer to first non-blank position in buffer.
357|                    If buffer is empty return pointer to buffer itself.
358|
359|   Return Values :  Pointer to first non-blank position in buffer
360+--------------------------------------------------------------------------*/
361NCURSES_INLINE static FIELD_CELL *
362Get_Start_Of_Data(FIELD_CELL *buf, int blen)
363{
364  FIELD_CELL *p = buf;
365  FIELD_CELL *end = &buf[blen];
366
367  assert(buf && blen >= 0);
368  while ((p < end) && ISBLANK(*p))
369    p++;
370  return ((p == end) ? buf : p);
371}
372
373/*---------------------------------------------------------------------------
374|   Facility      :  libnform
375|   Function      :  static char *After_End_Of_Data(char * buf, int blen)
376|
377|   Description   :  Return pointer after last non-blank position in buffer.
378|                    If buffer is empty, return pointer to buffer itself.
379|
380|   Return Values :  Pointer to position after last non-blank position in
381|                    buffer.
382+--------------------------------------------------------------------------*/
383NCURSES_INLINE static FIELD_CELL *
384After_End_Of_Data(FIELD_CELL *buf, int blen)
385{
386  FIELD_CELL *p = &buf[blen];
387
388  assert(buf && blen >= 0);
389  while ((p > buf) && ISBLANK(p[-1]))
390    p--;
391  return (p);
392}
393
394/*---------------------------------------------------------------------------
395|   Facility      :  libnform
396|   Function      :  static char *Get_First_Whitespace_Character(
397|                                     char * buf, int   blen)
398|
399|   Description   :  Position to the first whitespace character.
400|
401|   Return Values :  Pointer to first whitespace character in buffer.
402+--------------------------------------------------------------------------*/
403NCURSES_INLINE static FIELD_CELL *
404Get_First_Whitespace_Character(FIELD_CELL *buf, int blen)
405{
406  FIELD_CELL *p = buf;
407  FIELD_CELL *end = &p[blen];
408
409  assert(buf && blen >= 0);
410  while ((p < end) && !ISBLANK(*p))
411    p++;
412  return ((p == end) ? buf : p);
413}
414
415/*---------------------------------------------------------------------------
416|   Facility      :  libnform
417|   Function      :  static char *After_Last_Whitespace_Character(
418|                                     char * buf, int blen)
419|
420|   Description   :  Get the position after the last whitespace character.
421|
422|   Return Values :  Pointer to position after last whitespace character in
423|                    buffer.
424+--------------------------------------------------------------------------*/
425NCURSES_INLINE static FIELD_CELL *
426After_Last_Whitespace_Character(FIELD_CELL *buf, int blen)
427{
428  FIELD_CELL *p = &buf[blen];
429
430  assert(buf && blen >= 0);
431  while ((p > buf) && !ISBLANK(p[-1]))
432    p--;
433  return (p);
434}
435
436/* Set this to 1 to use the div_t version. This is a good idea if your
437   compiler has an intrinsic div() support. Unfortunately GNU-C has it
438   not yet.
439   N.B.: This only works if form->curcol follows immediately form->currow
440         and both are of type int.
441*/
442#define USE_DIV_T (0)
443
444/*---------------------------------------------------------------------------
445|   Facility      :  libnform
446|   Function      :  static void Adjust_Cursor_Position(
447|                                       FORM * form, const char * pos)
448|
449|   Description   :  Set current row and column of the form to values
450|                    corresponding to the buffer position.
451|
452|   Return Values :  -
453+--------------------------------------------------------------------------*/
454NCURSES_INLINE static void
455Adjust_Cursor_Position(FORM *form, const FIELD_CELL *pos)
456{
457  FIELD *field;
458  int idx;
459
460  field = form->current;
461  assert(pos >= field->buf && field->dcols > 0);
462  idx = (int)(pos - field->buf);
463#if USE_DIV_T
464  *((div_t *) & (form->currow)) = div(idx, field->dcols);
465#else
466  form->currow = idx / field->dcols;
467  form->curcol = idx - field->cols * form->currow;
468#endif
469  if (field->drows < form->currow)
470    form->currow = 0;
471}
472
473/*---------------------------------------------------------------------------
474|   Facility      :  libnform
475|   Function      :  static void Buffer_To_Window(
476|                                      const FIELD  * field,
477|                                      WINDOW * win)
478|
479|   Description   :  Copy the buffer to the window. If it is a multi-line
480|                    field, the buffer is split to the lines of the
481|                    window without any editing.
482|
483|   Return Values :  -
484+--------------------------------------------------------------------------*/
485static void
486Buffer_To_Window(const FIELD *field, WINDOW *win)
487{
488  int width, height;
489  int y, x;
490  int len;
491  int row;
492  FIELD_CELL *pBuffer;
493
494  assert(win && field);
495
496  getyx(win, y, x);
497  width = getmaxx(win);
498  height = getmaxy(win);
499
500  for (row = 0, pBuffer = field->buf;
501       row < height;
502       row++, pBuffer += width)
503    {
504      if ((len = (int)(After_End_Of_Data(pBuffer, width) - pBuffer)) > 0)
505	{
506	  wmove(win, row, 0);
507	  myADDNSTR(win, pBuffer, len);
508	}
509    }
510  wmove(win, y, x);
511}
512
513/*---------------------------------------------------------------------------
514|   Facility      :  libnform
515|   Function      :  void _nc_get_fieldbuffer(
516|                                          WINDOW * win,
517|                                          FIELD  * field,
518|                                          FIELD_CELL * buf)
519|
520|   Description   :  Copy the content of the window into the buffer.
521|                    The multiple lines of a window are simply
522|                    concatenated into the buffer. Pad characters in
523|                    the window will be replaced by blanks in the buffer.
524|
525|   Return Values :  -
526+--------------------------------------------------------------------------*/
527NCURSES_EXPORT(void)
528_nc_get_fieldbuffer(FORM *form, FIELD *field, FIELD_CELL *buf)
529{
530  int pad;
531  int len = 0;
532  FIELD_CELL *p;
533  int row, height;
534  WINDOW *win;
535
536  assert(form && field && buf);
537
538  win = form->w;
539  assert(win);
540
541  pad = field->pad;
542  p = buf;
543  height = getmaxy(win);
544
545  for (row = 0; (row < height) && (row < field->drows); row++)
546    {
547      wmove(win, row, 0);
548      len += myINNSTR(win, p + len, field->dcols);
549    }
550  p[len] = myZEROS;
551
552  /* replace visual padding character by blanks in buffer */
553  if (pad != C_BLANK)
554    {
555      int i;
556
557      for (i = 0; i < len; i++, p++)
558	{
559	  if ((unsigned long)CharOf(*p) == ChCharOf(pad)
560#if USE_WIDEC_SUPPORT
561	      && p->chars[1] == 0
562#endif
563	    )
564	    *p = myBLANK;
565	}
566    }
567}
568
569/*---------------------------------------------------------------------------
570|   Facility      :  libnform
571|   Function      :  static void Window_To_Buffer(
572|                                          FORM   * form,
573|                                          FIELD  * field)
574|
575|   Description   :  Copy the content of the window into the buffer.
576|                    The multiple lines of a window are simply
577|                    concatenated into the buffer. Pad characters in
578|                    the window will be replaced by blanks in the buffer.
579|
580|   Return Values :  -
581+--------------------------------------------------------------------------*/
582static void
583Window_To_Buffer(FORM *form, FIELD *field)
584{
585  _nc_get_fieldbuffer(form, field, field->buf);
586}
587
588/*---------------------------------------------------------------------------
589|   Facility      :  libnform
590|   Function      :  static void Synchronize_Buffer(FORM * form)
591|
592|   Description   :  If there was a change, copy the content of the
593|                    window into the buffer, so the buffer is synchronized
594|                    with the windows content. We have to indicate that the
595|                    buffer needs validation due to the change.
596|
597|   Return Values :  -
598+--------------------------------------------------------------------------*/
599NCURSES_INLINE static void
600Synchronize_Buffer(FORM *form)
601{
602  if (form->status & _WINDOW_MODIFIED)
603    {
604      ClrStatus(form, _WINDOW_MODIFIED);
605      SetStatus(form, _FCHECK_REQUIRED);
606      Window_To_Buffer(form, form->current);
607      wmove(form->w, form->currow, form->curcol);
608    }
609}
610
611/*---------------------------------------------------------------------------
612|   Facility      :  libnform
613|   Function      :  static bool Field_Grown( FIELD *field, int amount)
614|
615|   Description   :  This function is called for growable dynamic fields
616|                    only. It has to increase the buffers and to allocate
617|                    a new window for this field.
618|                    This function has the side effect to set a new
619|                    field-buffer pointer, the dcols and drows values
620|                    as well as a new current Window for the field.
621|
622|   Return Values :  TRUE     - field successfully increased
623|                    FALSE    - there was some error
624+--------------------------------------------------------------------------*/
625static bool
626Field_Grown(FIELD *field, int amount)
627{
628  bool result = FALSE;
629
630  if (field && Growable(field))
631    {
632      bool single_line_field = Single_Line_Field(field);
633      int old_buflen = Buffer_Length(field);
634      int new_buflen;
635      int old_dcols = field->dcols;
636      int old_drows = field->drows;
637      FIELD_CELL *oldbuf = field->buf;
638      FIELD_CELL *newbuf;
639
640      int growth;
641      FORM *form = field->form;
642      bool need_visual_update = ((form != (FORM *)0) &&
643				 (form->status & _POSTED) &&
644				 (form->current == field));
645
646      if (need_visual_update)
647	Synchronize_Buffer(form);
648
649      if (single_line_field)
650	{
651	  growth = field->cols * amount;
652	  if (field->maxgrow)
653	    growth = Minimum(field->maxgrow - field->dcols, growth);
654	  field->dcols += growth;
655	  if (field->dcols == field->maxgrow)
656	    ClrStatus(field, _MAY_GROW);
657	}
658      else
659	{
660	  growth = (field->rows + field->nrow) * amount;
661	  if (field->maxgrow)
662	    growth = Minimum(field->maxgrow - field->drows, growth);
663	  field->drows += growth;
664	  if (field->drows == field->maxgrow)
665	    ClrStatus(field, _MAY_GROW);
666	}
667      /* drows, dcols changed, so we get really the new buffer length */
668      new_buflen = Buffer_Length(field);
669      newbuf = (FIELD_CELL *)malloc(Total_Buffer_Size(field));
670      if (!newbuf)
671	{
672	  /* restore to previous state */
673	  field->dcols = old_dcols;
674	  field->drows = old_drows;
675	  if ((single_line_field && (field->dcols != field->maxgrow)) ||
676	      (!single_line_field && (field->drows != field->maxgrow)))
677	    SetStatus(field, _MAY_GROW);
678	}
679      else
680	{
681	  /* Copy all the buffers.  This is the reason why we can't just use
682	   * realloc().
683	   */
684	  int i, j;
685	  FIELD_CELL *old_bp;
686	  FIELD_CELL *new_bp;
687
688	  result = TRUE;	/* allow sharing of recovery on failure */
689
690	  T((T_CREATE("fieldcell %p"), (void *)newbuf));
691	  field->buf = newbuf;
692	  for (i = 0; i <= field->nbuf; i++)
693	    {
694	      new_bp = Address_Of_Nth_Buffer(field, i);
695	      old_bp = oldbuf + i * (1 + old_buflen);
696	      for (j = 0; j < old_buflen; ++j)
697		new_bp[j] = old_bp[j];
698	      while (j < new_buflen)
699		new_bp[j++] = myBLANK;
700	      new_bp[new_buflen] = myZEROS;
701	    }
702
703#if USE_WIDEC_SUPPORT && NCURSES_EXT_FUNCS
704	  if (wresize(field->working, 1, Buffer_Length(field) + 1) == ERR)
705	    result = FALSE;
706#endif
707
708	  if (need_visual_update && result)
709	    {
710	      WINDOW *new_window = newpad(field->drows, field->dcols);
711
712	      if (new_window != 0)
713		{
714		  assert(form != (FORM *)0);
715		  if (form->w)
716		    delwin(form->w);
717		  form->w = new_window;
718		  Set_Field_Window_Attributes(field, form->w);
719		  werase(form->w);
720		  Buffer_To_Window(field, form->w);
721		  untouchwin(form->w);
722		  wmove(form->w, form->currow, form->curcol);
723		}
724	      else
725		result = FALSE;
726	    }
727
728	  if (result)
729	    {
730	      free(oldbuf);
731	      /* reflect changes in linked fields */
732	      if (field != field->link)
733		{
734		  FIELD *linked_field;
735
736		  for (linked_field = field->link;
737		       linked_field != field;
738		       linked_field = linked_field->link)
739		    {
740		      linked_field->buf = field->buf;
741		      linked_field->drows = field->drows;
742		      linked_field->dcols = field->dcols;
743		    }
744		}
745	    }
746	  else
747	    {
748	      /* restore old state */
749	      field->dcols = old_dcols;
750	      field->drows = old_drows;
751	      field->buf = oldbuf;
752	      if ((single_line_field &&
753		   (field->dcols != field->maxgrow)) ||
754		  (!single_line_field &&
755		   (field->drows != field->maxgrow)))
756		SetStatus(field, _MAY_GROW);
757	      free(newbuf);
758	    }
759	}
760    }
761  return (result);
762}
763
764#ifdef NCURSES_MOUSE_VERSION
765/*---------------------------------------------------------------------------
766|   Facility      :  libnform
767|   Function      :  int Field_encloses(FIELD *field, int ry, int rx)
768|
769|   Description   :  Check if the given coordinates lie within the given field.
770|
771|   Return Values :  E_OK              - success
772|                    E_BAD_ARGUMENT    - invalid form pointer
773|                    E_SYSTEM_ERROR    - form has no current field or
774|                                        field-window
775+--------------------------------------------------------------------------*/
776static int
777Field_encloses(FIELD *field, int ry, int rx)
778{
779  T((T_CALLED("Field_encloses(%p)"), (void *)field));
780  if (field != 0
781      && field->frow <= ry
782      && (field->frow + field->rows) > ry
783      && field->fcol <= rx
784      && (field->fcol + field->cols) > rx)
785    {
786      RETURN(E_OK);
787    }
788  RETURN(E_INVALID_FIELD);
789}
790#endif
791
792/*---------------------------------------------------------------------------
793|   Facility      :  libnform
794|   Function      :  int _nc_Position_Form_Cursor(FORM * form)
795|
796|   Description   :  Position the cursor in the window for the current
797|                    field to be in sync. with the currow and curcol
798|                    values.
799|
800|   Return Values :  E_OK              - success
801|                    E_BAD_ARGUMENT    - invalid form pointer
802|                    E_SYSTEM_ERROR    - form has no current field or
803|                                        field-window
804+--------------------------------------------------------------------------*/
805NCURSES_EXPORT(int)
806_nc_Position_Form_Cursor(FORM *form)
807{
808  FIELD *field;
809  WINDOW *formwin;
810
811  if (!form)
812    return (E_BAD_ARGUMENT);
813
814  if (!form->w || !form->current)
815    return (E_SYSTEM_ERROR);
816
817  field = form->current;
818  formwin = Get_Form_Window(form);
819
820  wmove(form->w, form->currow, form->curcol);
821  if (Has_Invisible_Parts(field))
822    {
823      /* in this case fieldwin isn't derived from formwin, so we have
824         to move the cursor in formwin by hand... */
825      wmove(formwin,
826	    field->frow + form->currow - form->toprow,
827	    field->fcol + form->curcol - form->begincol);
828      wcursyncup(formwin);
829    }
830  else
831    wcursyncup(form->w);
832  return (E_OK);
833}
834
835/*---------------------------------------------------------------------------
836|   Facility      :  libnform
837|   Function      :  int _nc_Refresh_Current_Field(FORM * form)
838|
839|   Description   :  Propagate the changes in the fields window to the
840|                    window of the form.
841|
842|   Return Values :  E_OK              - on success
843|                    E_BAD_ARGUMENT    - invalid form pointer
844|                    E_SYSTEM_ERROR    - general error
845+--------------------------------------------------------------------------*/
846NCURSES_EXPORT(int)
847_nc_Refresh_Current_Field(FORM *form)
848{
849  WINDOW *formwin;
850  FIELD *field;
851
852  T((T_CALLED("_nc_Refresh_Current_Field(%p)"), (void *)form));
853
854  if (!form)
855    RETURN(E_BAD_ARGUMENT);
856
857  if (!form->w || !form->current)
858    RETURN(E_SYSTEM_ERROR);
859
860  field = form->current;
861  formwin = Get_Form_Window(form);
862
863  if ((unsigned)field->opts & O_PUBLIC)
864    {
865      if (Is_Scroll_Field(field))
866	{
867	  /* Again, in this case the fieldwin isn't derived from formwin,
868	     so we have to perform a copy operation. */
869	  if (Single_Line_Field(field))
870	    {
871	      /* horizontal scrolling */
872	      if (form->curcol < form->begincol)
873		form->begincol = form->curcol;
874	      else
875		{
876		  if (form->curcol >= (form->begincol + field->cols))
877		    form->begincol = form->curcol - field->cols + 1;
878		}
879	      copywin(form->w,
880		      formwin,
881		      0,
882		      form->begincol,
883		      field->frow,
884		      field->fcol,
885		      field->frow,
886		      field->cols + field->fcol - 1,
887		      0);
888	    }
889	  else
890	    {
891	      /* A multi-line, i.e. vertical scrolling field */
892	      int row_after_bottom, first_modified_row, first_unmodified_row;
893
894	      if (field->drows > field->rows)
895		{
896		  row_after_bottom = form->toprow + field->rows;
897		  if (form->currow < form->toprow)
898		    {
899		      form->toprow = form->currow;
900		      SetStatus(field, _NEWTOP);
901		    }
902		  if (form->currow >= row_after_bottom)
903		    {
904		      form->toprow = form->currow - field->rows + 1;
905		      SetStatus(field, _NEWTOP);
906		    }
907		  if (field->status & _NEWTOP)
908		    {
909		      /* means we have to copy whole range */
910		      first_modified_row = form->toprow;
911		      first_unmodified_row = first_modified_row + field->rows;
912		      ClrStatus(field, _NEWTOP);
913		    }
914		  else
915		    {
916		      /* we try to optimize : finding the range of touched
917		         lines */
918		      first_modified_row = form->toprow;
919		      while (first_modified_row < row_after_bottom)
920			{
921			  if (is_linetouched(form->w, first_modified_row))
922			    break;
923			  first_modified_row++;
924			}
925		      first_unmodified_row = first_modified_row;
926		      while (first_unmodified_row < row_after_bottom)
927			{
928			  if (!is_linetouched(form->w, first_unmodified_row))
929			    break;
930			  first_unmodified_row++;
931			}
932		    }
933		}
934	      else
935		{
936		  first_modified_row = form->toprow;
937		  first_unmodified_row = first_modified_row + field->rows;
938		}
939	      if (first_unmodified_row != first_modified_row)
940		copywin(form->w,
941			formwin,
942			first_modified_row,
943			0,
944			field->frow + first_modified_row - form->toprow,
945			field->fcol,
946			field->frow + first_unmodified_row - form->toprow - 1,
947			field->cols + field->fcol - 1,
948			0);
949	    }
950	  wsyncup(formwin);
951	}
952      else
953	{
954	  /* if the field-window is simply a derived window, i.e. contains no
955	   * invisible parts, the whole thing is trivial
956	   */
957	  wsyncup(form->w);
958	}
959    }
960  untouchwin(form->w);
961  returnCode(_nc_Position_Form_Cursor(form));
962}
963
964/*---------------------------------------------------------------------------
965|   Facility      :  libnform
966|   Function      :  static void Perform_Justification(
967|                                        FIELD  * field,
968|                                        WINDOW * win)
969|
970|   Description   :  Output field with requested justification
971|
972|   Return Values :  -
973+--------------------------------------------------------------------------*/
974static void
975Perform_Justification(FIELD *field, WINDOW *win)
976{
977  FIELD_CELL *bp;
978  int len;
979  int col = 0;
980
981  bp = Get_Start_Of_Data(field->buf, Buffer_Length(field));
982  len = (int)(After_End_Of_Data(field->buf, Buffer_Length(field)) - bp);
983
984  if (len > 0)
985    {
986      assert(win && (field->drows == 1) && (field->dcols == field->cols));
987
988      switch (field->just)
989	{
990	case JUSTIFY_LEFT:
991	  break;
992	case JUSTIFY_CENTER:
993	  col = (field->cols - len) / 2;
994	  break;
995	case JUSTIFY_RIGHT:
996	  col = field->cols - len;
997	  break;
998	default:
999	  break;
1000	}
1001
1002      wmove(win, 0, col);
1003      myADDNSTR(win, bp, len);
1004    }
1005}
1006
1007/*---------------------------------------------------------------------------
1008|   Facility      :  libnform
1009|   Function      :  static void Undo_Justification(
1010|                                     FIELD  * field,
1011|                                     WINDOW * win)
1012|
1013|   Description   :  Display field without any justification, i.e.
1014|                    left justified
1015|
1016|   Return Values :  -
1017+--------------------------------------------------------------------------*/
1018static void
1019Undo_Justification(FIELD *field, WINDOW *win)
1020{
1021  FIELD_CELL *bp;
1022  int len;
1023
1024  bp = Get_Start_Of_Data(field->buf, Buffer_Length(field));
1025  len = (int)(After_End_Of_Data(field->buf, Buffer_Length(field)) - bp);
1026
1027  if (len > 0)
1028    {
1029      assert(win);
1030      wmove(win, 0, 0);
1031      myADDNSTR(win, bp, len);
1032    }
1033}
1034
1035/*---------------------------------------------------------------------------
1036|   Facility      :  libnform
1037|   Function      :  static bool Check_Char(FORM  *form,
1038|                                           FIELD *field,
1039|                                           FIELDTYPE * typ,
1040|                                           int ch,
1041|                                           TypeArgument *argp)
1042|
1043|   Description   :  Perform a single character check for character ch
1044|                    according to the fieldtype instance.
1045|
1046|   Return Values :  TRUE             - Character is valid
1047|                    FALSE            - Character is invalid
1048+--------------------------------------------------------------------------*/
1049static bool
1050Check_Char(FORM *form,
1051	   FIELD *field,
1052	   FIELDTYPE *typ,
1053	   int ch,
1054	   TypeArgument *argp)
1055{
1056  if (typ)
1057    {
1058      if (typ->status & _LINKED_TYPE)
1059	{
1060	  assert(argp);
1061	  return (
1062		   Check_Char(form, field, typ->left, ch, argp->left) ||
1063		   Check_Char(form, field, typ->right, ch, argp->right));
1064	}
1065      else
1066	{
1067#if NCURSES_INTEROP_FUNCS
1068	  if (typ->charcheck.occheck)
1069	    {
1070	      if (typ->status & _GENERIC)
1071		return typ->charcheck.gccheck(ch, form, field, (void *)argp);
1072	      else
1073		return typ->charcheck.occheck(ch, (void *)argp);
1074	    }
1075#else
1076	  if (typ->ccheck)
1077	    return typ->ccheck(ch, (void *)argp);
1078#endif
1079	}
1080    }
1081  return (!iscntrl(UChar(ch)) ? TRUE : FALSE);
1082}
1083
1084/*---------------------------------------------------------------------------
1085|   Facility      :  libnform
1086|   Function      :  static int Display_Or_Erase_Field(
1087|                                           FIELD * field,
1088|                                           bool bEraseFlag)
1089|
1090|   Description   :  Create a subwindow for the field and display the
1091|                    buffer contents (apply justification if required)
1092|                    or simply erase the field.
1093|
1094|   Return Values :  E_OK           - on success
1095|                    E_SYSTEM_ERROR - some error (typical no memory)
1096+--------------------------------------------------------------------------*/
1097static int
1098Display_Or_Erase_Field(FIELD *field, bool bEraseFlag)
1099{
1100  WINDOW *win;
1101  WINDOW *fwin;
1102
1103  if (!field)
1104    return E_SYSTEM_ERROR;
1105
1106  fwin = Get_Form_Window(field->form);
1107  win = derwin(fwin,
1108	       field->rows, field->cols, field->frow, field->fcol);
1109
1110  if (!win)
1111    return E_SYSTEM_ERROR;
1112  else
1113    {
1114      if ((unsigned)field->opts & O_VISIBLE)
1115	{
1116	  Set_Field_Window_Attributes(field, win);
1117	}
1118      else
1119	{
1120	  (void)wattrset(win, (int)WINDOW_ATTRS(fwin));
1121	}
1122      werase(win);
1123    }
1124
1125  if (!bEraseFlag)
1126    {
1127      if ((unsigned)field->opts & O_PUBLIC)
1128	{
1129	  if (Justification_Allowed(field))
1130	    Perform_Justification(field, win);
1131	  else
1132	    Buffer_To_Window(field, win);
1133	}
1134      ClrStatus(field, _NEWTOP);
1135    }
1136  wsyncup(win);
1137  delwin(win);
1138  return E_OK;
1139}
1140
1141/* Macros to preset the bEraseFlag */
1142#define Display_Field(field) Display_Or_Erase_Field(field,FALSE)
1143#define Erase_Field(field)   Display_Or_Erase_Field(field,TRUE)
1144
1145/*---------------------------------------------------------------------------
1146|   Facility      :  libnform
1147|   Function      :  static int Synchronize_Field(FIELD * field)
1148|
1149|   Description   :  Synchronize the windows content with the value in
1150|                    the buffer.
1151|
1152|   Return Values :  E_OK                - success
1153|                    E_BAD_ARGUMENT      - invalid field pointer
1154|                    E_SYSTEM_ERROR      - some severe basic error
1155+--------------------------------------------------------------------------*/
1156static int
1157Synchronize_Field(FIELD *field)
1158{
1159  FORM *form;
1160  int res = E_OK;
1161
1162  if (!field)
1163    return (E_BAD_ARGUMENT);
1164
1165  if (((form = field->form) != (FORM *)0)
1166      && Field_Really_Appears(field))
1167    {
1168      if (field == form->current)
1169	{
1170	  form->currow = form->curcol = form->toprow = form->begincol = 0;
1171	  werase(form->w);
1172
1173	  if (((unsigned)field->opts & O_PUBLIC) && Justification_Allowed(field))
1174	    Undo_Justification(field, form->w);
1175	  else
1176	    Buffer_To_Window(field, form->w);
1177
1178	  SetStatus(field, _NEWTOP);
1179	  res = _nc_Refresh_Current_Field(form);
1180	}
1181      else
1182	res = Display_Field(field);
1183    }
1184  SetStatus(field, _CHANGED);
1185  return (res);
1186}
1187
1188/*---------------------------------------------------------------------------
1189|   Facility      :  libnform
1190|   Function      :  static int Synchronize_Linked_Fields(FIELD * field)
1191|
1192|   Description   :  Propagate the Synchronize_Field function to all linked
1193|                    fields. The first error that occurs in the sequence
1194|                    of updates is the return value.
1195|
1196|   Return Values :  E_OK                - success
1197|                    E_BAD_ARGUMENT      - invalid field pointer
1198|                    E_SYSTEM_ERROR      - some severe basic error
1199+--------------------------------------------------------------------------*/
1200static int
1201Synchronize_Linked_Fields(FIELD *field)
1202{
1203  FIELD *linked_field;
1204  int res = E_OK;
1205  int syncres;
1206
1207  if (!field)
1208    return (E_BAD_ARGUMENT);
1209
1210  if (!field->link)
1211    return (E_SYSTEM_ERROR);
1212
1213  for (linked_field = field->link;
1214       (linked_field != field) && (linked_field != 0);
1215       linked_field = linked_field->link)
1216    {
1217      if (((syncres = Synchronize_Field(linked_field)) != E_OK) &&
1218	  (res == E_OK))
1219	res = syncres;
1220    }
1221  return (res);
1222}
1223
1224/*---------------------------------------------------------------------------
1225|   Facility      :  libnform
1226|   Function      :  int _nc_Synchronize_Attributes(FIELD * field)
1227|
1228|   Description   :  If a fields visual attributes have changed, this
1229|                    routine is called to propagate those changes to the
1230|                    screen.
1231|
1232|   Return Values :  E_OK             - success
1233|                    E_BAD_ARGUMENT   - invalid field pointer
1234|                    E_SYSTEM_ERROR   - some severe basic error
1235+--------------------------------------------------------------------------*/
1236NCURSES_EXPORT(int)
1237_nc_Synchronize_Attributes(FIELD *field)
1238{
1239  FORM *form;
1240  int res = E_OK;
1241  WINDOW *formwin;
1242
1243  T((T_CALLED("_nc_Synchronize_Attributes(%p)"), (void *)field));
1244
1245  if (!field)
1246    returnCode(E_BAD_ARGUMENT);
1247
1248  CHECKPOS(field->form);
1249  if (((form = field->form) != (FORM *)0)
1250      && Field_Really_Appears(field))
1251    {
1252      if (form->current == field)
1253	{
1254	  Synchronize_Buffer(form);
1255	  Set_Field_Window_Attributes(field, form->w);
1256	  werase(form->w);
1257	  wmove(form->w, form->currow, form->curcol);
1258
1259	  if ((unsigned)field->opts & O_PUBLIC)
1260	    {
1261	      if (Justification_Allowed(field))
1262		Undo_Justification(field, form->w);
1263	      else
1264		Buffer_To_Window(field, form->w);
1265	    }
1266	  else
1267	    {
1268	      formwin = Get_Form_Window(form);
1269	      copywin(form->w, formwin,
1270		      0, 0,
1271		      field->frow, field->fcol,
1272		      field->rows - 1, field->cols - 1, 0);
1273	      wsyncup(formwin);
1274	      Buffer_To_Window(field, form->w);
1275	      SetStatus(field, _NEWTOP);	/* fake refresh to paint all */
1276	      _nc_Refresh_Current_Field(form);
1277	    }
1278	}
1279      else
1280	{
1281	  res = Display_Field(field);
1282	}
1283    }
1284  CHECKPOS(form);
1285  returnCode(res);
1286}
1287
1288/*---------------------------------------------------------------------------
1289|   Facility      :  libnform
1290|   Function      :  int _nc_Synchronize_Options(FIELD * field,
1291|                                                Field_Options newopts)
1292|
1293|   Description   :  If a fields options have changed, this routine is
1294|                    called to propagate these changes to the screen and
1295|                    to really change the behavior of the field.
1296|
1297|   Return Values :  E_OK                - success
1298|                    E_BAD_ARGUMENT      - invalid field pointer
1299|                    E_CURRENT           - field is the current one
1300|                    E_SYSTEM_ERROR      - some severe basic error
1301+--------------------------------------------------------------------------*/
1302NCURSES_EXPORT(int)
1303_nc_Synchronize_Options(FIELD *field, Field_Options newopts)
1304{
1305  Field_Options oldopts;
1306  Field_Options changed_opts;
1307  FORM *form;
1308  int res = E_OK;
1309
1310  T((T_CALLED("_nc_Synchronize_Options(%p,%#x)"), (void *)field, newopts));
1311
1312  if (!field)
1313    returnCode(E_BAD_ARGUMENT);
1314
1315  oldopts = field->opts;
1316  changed_opts = oldopts ^ newopts;
1317  field->opts = newopts;
1318  form = field->form;
1319
1320  if (form)
1321    {
1322      if (form->status & _POSTED)
1323	{
1324	  if (form->current == field)
1325	    {
1326	      field->opts = oldopts;
1327	      returnCode(E_CURRENT);
1328	    }
1329	  if (form->curpage == field->page)
1330	    {
1331	      if ((unsigned)changed_opts & O_VISIBLE)
1332		{
1333		  if ((unsigned)newopts & O_VISIBLE)
1334		    res = Display_Field(field);
1335		  else
1336		    res = Erase_Field(field);
1337		}
1338	      else
1339		{
1340		  if (((unsigned)changed_opts & O_PUBLIC) &&
1341		      ((unsigned)newopts & O_VISIBLE))
1342		    res = Display_Field(field);
1343		}
1344	    }
1345	}
1346    }
1347
1348  if ((unsigned)changed_opts & O_STATIC)
1349    {
1350      bool single_line_field = Single_Line_Field(field);
1351      int res2 = E_OK;
1352
1353      if ((unsigned)newopts & O_STATIC)
1354	{
1355	  /* the field becomes now static */
1356	  ClrStatus(field, _MAY_GROW);
1357	  /* if actually we have no hidden columns, justification may
1358	     occur again */
1359	  if (single_line_field &&
1360	      (field->cols == field->dcols) &&
1361	      (field->just != NO_JUSTIFICATION) &&
1362	      Field_Really_Appears(field))
1363	    {
1364	      res2 = Display_Field(field);
1365	    }
1366	}
1367      else
1368	{
1369	  /* field is no longer static */
1370	  if ((field->maxgrow == 0) ||
1371	      (single_line_field && (field->dcols < field->maxgrow)) ||
1372	      (!single_line_field && (field->drows < field->maxgrow)))
1373	    {
1374	      SetStatus(field, _MAY_GROW);
1375	      /* a field with justification now changes its behavior,
1376	         so we must redisplay it */
1377	      if (single_line_field &&
1378		  (field->just != NO_JUSTIFICATION) &&
1379		  Field_Really_Appears(field))
1380		{
1381		  res2 = Display_Field(field);
1382		}
1383	    }
1384	}
1385      if (res2 != E_OK)
1386	res = res2;
1387    }
1388
1389  returnCode(res);
1390}
1391
1392/*---------------------------------------------------------------------------
1393|   Facility      :  libnform
1394|   Function      :  int _nc_Set_Current_Field(FORM  * form,
1395|                                              FIELD * newfield)
1396|
1397|   Description   :  Make the newfield the new current field.
1398|
1399|   Return Values :  E_OK              - success
1400|                    E_BAD_ARGUMENT    - invalid form or field pointer
1401|                    E_SYSTEM_ERROR    - some severe basic error
1402|                    E_NOT_CONNECTED   - no fields are connected to the form
1403+--------------------------------------------------------------------------*/
1404NCURSES_EXPORT(int)
1405_nc_Set_Current_Field(FORM *form, FIELD *newfield)
1406{
1407  FIELD *field;
1408  WINDOW *new_window;
1409
1410  T((T_CALLED("_nc_Set_Current_Field(%p,%p)"), (void *)form, (void *)newfield));
1411
1412  if (!form || !newfield || !form->current || (newfield->form != form))
1413    returnCode(E_BAD_ARGUMENT);
1414
1415  if ((form->status & _IN_DRIVER))
1416    returnCode(E_BAD_STATE);
1417
1418  if (!(form->field))
1419    returnCode(E_NOT_CONNECTED);
1420
1421  field = form->current;
1422
1423  if ((field != newfield) ||
1424      !(form->status & _POSTED))
1425    {
1426      if ((form->w) &&
1427	  ((unsigned)field->opts & O_VISIBLE) &&
1428	  (field->form->curpage == field->page))
1429	{
1430	  _nc_Refresh_Current_Field(form);
1431	  if ((unsigned)field->opts & O_PUBLIC)
1432	    {
1433	      if (field->drows > field->rows)
1434		{
1435		  if (form->toprow == 0)
1436		    ClrStatus(field, _NEWTOP);
1437		  else
1438		    SetStatus(field, _NEWTOP);
1439		}
1440	      else
1441		{
1442		  if (Justification_Allowed(field))
1443		    {
1444		      Window_To_Buffer(form, field);
1445		      werase(form->w);
1446		      Perform_Justification(field, form->w);
1447		      wsyncup(form->w);
1448		    }
1449		}
1450	    }
1451	  delwin(form->w);
1452	  form->w = (WINDOW *)0;
1453	}
1454
1455      field = newfield;
1456
1457      if (Has_Invisible_Parts(field))
1458	new_window = newpad(field->drows, field->dcols);
1459      else
1460	new_window = derwin(Get_Form_Window(form),
1461			    field->rows, field->cols, field->frow, field->fcol);
1462
1463      if (!new_window)
1464	returnCode(E_SYSTEM_ERROR);
1465
1466      form->current = field;
1467
1468      if (form->w)
1469	delwin(form->w);
1470      form->w = new_window;
1471
1472      ClrStatus(form, _WINDOW_MODIFIED);
1473      Set_Field_Window_Attributes(field, form->w);
1474
1475      if (Has_Invisible_Parts(field))
1476	{
1477	  werase(form->w);
1478	  Buffer_To_Window(field, form->w);
1479	}
1480      else
1481	{
1482	  if (Justification_Allowed(field))
1483	    {
1484	      werase(form->w);
1485	      Undo_Justification(field, form->w);
1486	      wsyncup(form->w);
1487	    }
1488	}
1489
1490      untouchwin(form->w);
1491    }
1492
1493  form->currow = form->curcol = form->toprow = form->begincol = 0;
1494  returnCode(E_OK);
1495}
1496
1497/*----------------------------------------------------------------------------
1498  Intra-Field Navigation routines
1499  --------------------------------------------------------------------------*/
1500
1501/*---------------------------------------------------------------------------
1502|   Facility      :  libnform
1503|   Function      :  static int IFN_Next_Character(FORM * form)
1504|
1505|   Description   :  Move to the next character in the field. In a multi-line
1506|                    field this wraps at the end of the line.
1507|
1508|   Return Values :  E_OK                - success
1509|                    E_REQUEST_DENIED    - at the rightmost position
1510+--------------------------------------------------------------------------*/
1511static int
1512IFN_Next_Character(FORM *form)
1513{
1514  FIELD *field = form->current;
1515  int step = myWCWIDTH(form->w, form->currow, form->curcol);
1516
1517  T((T_CALLED("IFN_Next_Character(%p)"), (void *)form));
1518  if ((form->curcol += step) == field->dcols)
1519    {
1520      if ((++(form->currow)) == field->drows)
1521	{
1522#if GROW_IF_NAVIGATE
1523	  if (!Single_Line_Field(field) && Field_Grown(field, 1))
1524	    {
1525	      form->curcol = 0;
1526	      returnCode(E_OK);
1527	    }
1528#endif
1529	  form->currow--;
1530#if GROW_IF_NAVIGATE
1531	  if (Single_Line_Field(field) && Field_Grown(field, 1))
1532	    returnCode(E_OK);
1533#endif
1534	  form->curcol -= step;
1535	  returnCode(E_REQUEST_DENIED);
1536	}
1537      form->curcol = 0;
1538    }
1539  returnCode(E_OK);
1540}
1541
1542/*---------------------------------------------------------------------------
1543|   Facility      :  libnform
1544|   Function      :  static int IFN_Previous_Character(FORM * form)
1545|
1546|   Description   :  Move to the previous character in the field. In a
1547|                    multi-line field this wraps and the beginning of the
1548|                    line.
1549|
1550|   Return Values :  E_OK                - success
1551|                    E_REQUEST_DENIED    - at the leftmost position
1552+--------------------------------------------------------------------------*/
1553static int
1554IFN_Previous_Character(FORM *form)
1555{
1556  int amount = myWCWIDTH(form->w, form->currow, form->curcol - 1);
1557  int oldcol = form->curcol;
1558
1559  T((T_CALLED("IFN_Previous_Character(%p)"), (void *)form));
1560  if ((form->curcol -= amount) < 0)
1561    {
1562      if ((--(form->currow)) < 0)
1563	{
1564	  form->currow++;
1565	  form->curcol = oldcol;
1566	  returnCode(E_REQUEST_DENIED);
1567	}
1568      form->curcol = form->current->dcols - 1;
1569    }
1570  returnCode(E_OK);
1571}
1572
1573/*---------------------------------------------------------------------------
1574|   Facility      :  libnform
1575|   Function      :  static int IFN_Next_Line(FORM * form)
1576|
1577|   Description   :  Move to the beginning of the next line in the field
1578|
1579|   Return Values :  E_OK                - success
1580|                    E_REQUEST_DENIED    - at the last line
1581+--------------------------------------------------------------------------*/
1582static int
1583IFN_Next_Line(FORM *form)
1584{
1585  FIELD *field = form->current;
1586
1587  T((T_CALLED("IFN_Next_Line(%p)"), (void *)form));
1588  if ((++(form->currow)) == field->drows)
1589    {
1590#if GROW_IF_NAVIGATE
1591      if (!Single_Line_Field(field) && Field_Grown(field, 1))
1592	returnCode(E_OK);
1593#endif
1594      form->currow--;
1595      returnCode(E_REQUEST_DENIED);
1596    }
1597  form->curcol = 0;
1598  returnCode(E_OK);
1599}
1600
1601/*---------------------------------------------------------------------------
1602|   Facility      :  libnform
1603|   Function      :  static int IFN_Previous_Line(FORM * form)
1604|
1605|   Description   :  Move to the beginning of the previous line in the field
1606|
1607|   Return Values :  E_OK                - success
1608|                    E_REQUEST_DENIED    - at the first line
1609+--------------------------------------------------------------------------*/
1610static int
1611IFN_Previous_Line(FORM *form)
1612{
1613  T((T_CALLED("IFN_Previous_Line(%p)"), (void *)form));
1614  if ((--(form->currow)) < 0)
1615    {
1616      form->currow++;
1617      returnCode(E_REQUEST_DENIED);
1618    }
1619  form->curcol = 0;
1620  returnCode(E_OK);
1621}
1622
1623/*---------------------------------------------------------------------------
1624|   Facility      :  libnform
1625|   Function      :  static int IFN_Next_Word(FORM * form)
1626|
1627|   Description   :  Move to the beginning of the next word in the field.
1628|
1629|   Return Values :  E_OK             - success
1630|                    E_REQUEST_DENIED - there is no next word
1631+--------------------------------------------------------------------------*/
1632static int
1633IFN_Next_Word(FORM *form)
1634{
1635  FIELD *field = form->current;
1636  FIELD_CELL *bp = Address_Of_Current_Position_In_Buffer(form);
1637  FIELD_CELL *s;
1638  FIELD_CELL *t;
1639
1640  T((T_CALLED("IFN_Next_Word(%p)"), (void *)form));
1641
1642  /* We really need access to the data, so we have to synchronize */
1643  Synchronize_Buffer(form);
1644
1645  /* Go to the first whitespace after the current position (including
1646     current position). This is then the starting point to look for the
1647     next non-blank data */
1648  s = Get_First_Whitespace_Character(bp, Buffer_Length(field) -
1649				     (int)(bp - field->buf));
1650
1651  /* Find the start of the next word */
1652  t = Get_Start_Of_Data(s, Buffer_Length(field) -
1653			(int)(s - field->buf));
1654#if !FRIENDLY_PREV_NEXT_WORD
1655  if (s == t)
1656    returnCode(E_REQUEST_DENIED);
1657  else
1658#endif
1659    {
1660      Adjust_Cursor_Position(form, t);
1661      returnCode(E_OK);
1662    }
1663}
1664
1665/*---------------------------------------------------------------------------
1666|   Facility      :  libnform
1667|   Function      :  static int IFN_Previous_Word(FORM * form)
1668|
1669|   Description   :  Move to the beginning of the previous word in the field.
1670|
1671|   Return Values :  E_OK             - success
1672|                    E_REQUEST_DENIED - there is no previous word
1673+--------------------------------------------------------------------------*/
1674static int
1675IFN_Previous_Word(FORM *form)
1676{
1677  FIELD *field = form->current;
1678  FIELD_CELL *bp = Address_Of_Current_Position_In_Buffer(form);
1679  FIELD_CELL *s;
1680  FIELD_CELL *t;
1681  bool again = FALSE;
1682
1683  T((T_CALLED("IFN_Previous_Word(%p)"), (void *)form));
1684
1685  /* We really need access to the data, so we have to synchronize */
1686  Synchronize_Buffer(form);
1687
1688  s = After_End_Of_Data(field->buf, (int)(bp - field->buf));
1689  /* s points now right after the last non-blank in the buffer before bp.
1690     If bp was in a word, s equals bp. In this case we must find the last
1691     whitespace in the buffer before bp and repeat the game to really find
1692     the previous word! */
1693  if (s == bp)
1694    again = TRUE;
1695
1696  /* And next call now goes backward to look for the last whitespace
1697     before that, pointing right after this, so it points to the begin
1698     of the previous word.
1699   */
1700  t = After_Last_Whitespace_Character(field->buf, (int)(s - field->buf));
1701#if !FRIENDLY_PREV_NEXT_WORD
1702  if (s == t)
1703    returnCode(E_REQUEST_DENIED);
1704#endif
1705  if (again)
1706    {
1707      /* and do it again, replacing bp by t */
1708      s = After_End_Of_Data(field->buf, (int)(t - field->buf));
1709      t = After_Last_Whitespace_Character(field->buf, (int)(s - field->buf));
1710#if !FRIENDLY_PREV_NEXT_WORD
1711      if (s == t)
1712	returnCode(E_REQUEST_DENIED);
1713#endif
1714    }
1715  Adjust_Cursor_Position(form, t);
1716  returnCode(E_OK);
1717}
1718
1719/*---------------------------------------------------------------------------
1720|   Facility      :  libnform
1721|   Function      :  static int IFN_Beginning_Of_Field(FORM * form)
1722|
1723|   Description   :  Place the cursor at the first non-pad character in
1724|                    the field.
1725|
1726|   Return Values :  E_OK             - success
1727+--------------------------------------------------------------------------*/
1728static int
1729IFN_Beginning_Of_Field(FORM *form)
1730{
1731  FIELD *field = form->current;
1732
1733  T((T_CALLED("IFN_Beginning_Of_Field(%p)"), (void *)form));
1734  Synchronize_Buffer(form);
1735  Adjust_Cursor_Position(form,
1736			 Get_Start_Of_Data(field->buf, Buffer_Length(field)));
1737  returnCode(E_OK);
1738}
1739
1740/*---------------------------------------------------------------------------
1741|   Facility      :  libnform
1742|   Function      :  static int IFN_End_Of_Field(FORM * form)
1743|
1744|   Description   :  Place the cursor after the last non-pad character in
1745|                    the field. If the field occupies the last position in
1746|                    the buffer, the cursor is positioned on the last
1747|                    character.
1748|
1749|   Return Values :  E_OK              - success
1750+--------------------------------------------------------------------------*/
1751static int
1752IFN_End_Of_Field(FORM *form)
1753{
1754  FIELD *field = form->current;
1755  FIELD_CELL *pos;
1756
1757  T((T_CALLED("IFN_End_Of_Field(%p)"), (void *)form));
1758  Synchronize_Buffer(form);
1759  pos = After_End_Of_Data(field->buf, Buffer_Length(field));
1760  if (pos == (field->buf + Buffer_Length(field)))
1761    pos--;
1762  Adjust_Cursor_Position(form, pos);
1763  returnCode(E_OK);
1764}
1765
1766/*---------------------------------------------------------------------------
1767|   Facility      :  libnform
1768|   Function      :  static int IFN_Beginning_Of_Line(FORM * form)
1769|
1770|   Description   :  Place the cursor on the first non-pad character in
1771|                    the current line of the field.
1772|
1773|   Return Values :  E_OK         - success
1774+--------------------------------------------------------------------------*/
1775static int
1776IFN_Beginning_Of_Line(FORM *form)
1777{
1778  FIELD *field = form->current;
1779
1780  T((T_CALLED("IFN_Beginning_Of_Line(%p)"), (void *)form));
1781  Synchronize_Buffer(form);
1782  Adjust_Cursor_Position(form,
1783			 Get_Start_Of_Data(Address_Of_Current_Row_In_Buffer(form),
1784					   field->dcols));
1785  returnCode(E_OK);
1786}
1787
1788/*---------------------------------------------------------------------------
1789|   Facility      :  libnform
1790|   Function      :  static int IFN_End_Of_Line(FORM * form)
1791|
1792|   Description   :  Place the cursor after the last non-pad character in the
1793|                    current line of the field. If the field occupies the
1794|                    last column in the line, the cursor is positioned on the
1795|                    last character of the line.
1796|
1797|   Return Values :  E_OK        - success
1798+--------------------------------------------------------------------------*/
1799static int
1800IFN_End_Of_Line(FORM *form)
1801{
1802  FIELD *field = form->current;
1803  FIELD_CELL *pos;
1804  FIELD_CELL *bp;
1805
1806  T((T_CALLED("IFN_End_Of_Line(%p)"), (void *)form));
1807  Synchronize_Buffer(form);
1808  bp = Address_Of_Current_Row_In_Buffer(form);
1809  pos = After_End_Of_Data(bp, field->dcols);
1810  if (pos == (bp + field->dcols))
1811    pos--;
1812  Adjust_Cursor_Position(form, pos);
1813  returnCode(E_OK);
1814}
1815
1816/*---------------------------------------------------------------------------
1817|   Facility      :  libnform
1818|   Function      :  static int IFN_Left_Character(FORM * form)
1819|
1820|   Description   :  Move one character to the left in the current line.
1821|                    This doesn't cycle.
1822|
1823|   Return Values :  E_OK             - success
1824|                    E_REQUEST_DENIED - already in first column
1825+--------------------------------------------------------------------------*/
1826static int
1827IFN_Left_Character(FORM *form)
1828{
1829  int amount = myWCWIDTH(form->w, form->currow, form->curcol - 1);
1830  int oldcol = form->curcol;
1831
1832  T((T_CALLED("IFN_Left_Character(%p)"), (void *)form));
1833  if ((form->curcol -= amount) < 0)
1834    {
1835      form->curcol = oldcol;
1836      returnCode(E_REQUEST_DENIED);
1837    }
1838  returnCode(E_OK);
1839}
1840
1841/*---------------------------------------------------------------------------
1842|   Facility      :  libnform
1843|   Function      :  static int IFN_Right_Character(FORM * form)
1844|
1845|   Description   :  Move one character to the right in the current line.
1846|                    This doesn't cycle.
1847|
1848|   Return Values :  E_OK              - success
1849|                    E_REQUEST_DENIED  - already in last column
1850+--------------------------------------------------------------------------*/
1851static int
1852IFN_Right_Character(FORM *form)
1853{
1854  int amount = myWCWIDTH(form->w, form->currow, form->curcol);
1855  int oldcol = form->curcol;
1856
1857  T((T_CALLED("IFN_Right_Character(%p)"), (void *)form));
1858  if ((form->curcol += amount) >= form->current->dcols)
1859    {
1860#if GROW_IF_NAVIGATE
1861      FIELD *field = form->current;
1862
1863      if (Single_Line_Field(field) && Field_Grown(field, 1))
1864	returnCode(E_OK);
1865#endif
1866      form->curcol = oldcol;
1867      returnCode(E_REQUEST_DENIED);
1868    }
1869  returnCode(E_OK);
1870}
1871
1872/*---------------------------------------------------------------------------
1873|   Facility      :  libnform
1874|   Function      :  static int IFN_Up_Character(FORM * form)
1875|
1876|   Description   :  Move one line up. This doesn't cycle through the lines
1877|                    of the field.
1878|
1879|   Return Values :  E_OK              - success
1880|                    E_REQUEST_DENIED  - already in last column
1881+--------------------------------------------------------------------------*/
1882static int
1883IFN_Up_Character(FORM *form)
1884{
1885  T((T_CALLED("IFN_Up_Character(%p)"), (void *)form));
1886  if ((--(form->currow)) < 0)
1887    {
1888      form->currow++;
1889      returnCode(E_REQUEST_DENIED);
1890    }
1891  returnCode(E_OK);
1892}
1893
1894/*---------------------------------------------------------------------------
1895|   Facility      :  libnform
1896|   Function      :  static int IFN_Down_Character(FORM * form)
1897|
1898|   Description   :  Move one line down. This doesn't cycle through the
1899|                    lines of the field.
1900|
1901|   Return Values :  E_OK              - success
1902|                    E_REQUEST_DENIED  - already in last column
1903+--------------------------------------------------------------------------*/
1904static int
1905IFN_Down_Character(FORM *form)
1906{
1907  FIELD *field = form->current;
1908
1909  T((T_CALLED("IFN_Down_Character(%p)"), (void *)form));
1910  if ((++(form->currow)) == field->drows)
1911    {
1912#if GROW_IF_NAVIGATE
1913      if (!Single_Line_Field(field) && Field_Grown(field, 1))
1914	returnCode(E_OK);
1915#endif
1916      --(form->currow);
1917      returnCode(E_REQUEST_DENIED);
1918    }
1919  returnCode(E_OK);
1920}
1921/*----------------------------------------------------------------------------
1922  END of Intra-Field Navigation routines
1923  --------------------------------------------------------------------------*/
1924
1925/*----------------------------------------------------------------------------
1926  Vertical scrolling helper routines
1927  --------------------------------------------------------------------------*/
1928
1929/*---------------------------------------------------------------------------
1930|   Facility      :  libnform
1931|   Function      :  static int VSC_Generic(FORM *form, int nlines)
1932|
1933|   Description   :  Scroll multi-line field forward (nlines>0) or
1934|                    backward (nlines<0) this many lines.
1935|
1936|   Return Values :  E_OK              - success
1937|                    E_REQUEST_DENIED  - can't scroll
1938+--------------------------------------------------------------------------*/
1939static int
1940VSC_Generic(FORM *form, int nlines)
1941{
1942  FIELD *field = form->current;
1943  int res = E_REQUEST_DENIED;
1944  int rows_to_go = (nlines > 0 ? nlines : -nlines);
1945
1946  if (nlines > 0)
1947    {
1948      if ((rows_to_go + form->toprow) > (field->drows - field->rows))
1949	rows_to_go = (field->drows - field->rows - form->toprow);
1950
1951      if (rows_to_go > 0)
1952	{
1953	  form->currow += rows_to_go;
1954	  form->toprow += rows_to_go;
1955	  res = E_OK;
1956	}
1957    }
1958  else
1959    {
1960      if (rows_to_go > form->toprow)
1961	rows_to_go = form->toprow;
1962
1963      if (rows_to_go > 0)
1964	{
1965	  form->currow -= rows_to_go;
1966	  form->toprow -= rows_to_go;
1967	  res = E_OK;
1968	}
1969    }
1970  return (res);
1971}
1972/*----------------------------------------------------------------------------
1973  End of Vertical scrolling helper routines
1974  --------------------------------------------------------------------------*/
1975
1976/*----------------------------------------------------------------------------
1977  Vertical scrolling routines
1978  --------------------------------------------------------------------------*/
1979
1980/*---------------------------------------------------------------------------
1981|   Facility      :  libnform
1982|   Function      :  static int Vertical_Scrolling(
1983|                                           int (* const fct) (FORM *),
1984|                                           FORM * form)
1985|
1986|   Description   :  Performs the generic vertical scrolling routines.
1987|                    This has to check for a multi-line field and to set
1988|                    the _NEWTOP flag if scrolling really occurred.
1989|
1990|   Return Values :  Propagated error code from low-level driver calls
1991+--------------------------------------------------------------------------*/
1992static int
1993Vertical_Scrolling(int (*const fct) (FORM *), FORM *form)
1994{
1995  int res = E_REQUEST_DENIED;
1996
1997  if (!Single_Line_Field(form->current))
1998    {
1999      res = fct(form);
2000      if (res == E_OK)
2001	SetStatus(form, _NEWTOP);
2002    }
2003  return (res);
2004}
2005
2006/*---------------------------------------------------------------------------
2007|   Facility      :  libnform
2008|   Function      :  static int VSC_Scroll_Line_Forward(FORM * form)
2009|
2010|   Description   :  Scroll multi-line field forward a line
2011|
2012|   Return Values :  E_OK                - success
2013|                    E_REQUEST_DENIED    - no data ahead
2014+--------------------------------------------------------------------------*/
2015static int
2016VSC_Scroll_Line_Forward(FORM *form)
2017{
2018  T((T_CALLED("VSC_Scroll_Line_Forward(%p)"), (void *)form));
2019  returnCode(VSC_Generic(form, 1));
2020}
2021
2022/*---------------------------------------------------------------------------
2023|   Facility      :  libnform
2024|   Function      :  static int VSC_Scroll_Line_Backward(FORM * form)
2025|
2026|   Description   :  Scroll multi-line field backward a line
2027|
2028|   Return Values :  E_OK                - success
2029|                    E_REQUEST_DENIED    - no data behind
2030+--------------------------------------------------------------------------*/
2031static int
2032VSC_Scroll_Line_Backward(FORM *form)
2033{
2034  T((T_CALLED("VSC_Scroll_Line_Backward(%p)"), (void *)form));
2035  returnCode(VSC_Generic(form, -1));
2036}
2037
2038/*---------------------------------------------------------------------------
2039|   Facility      :  libnform
2040|   Function      :  static int VSC_Scroll_Page_Forward(FORM * form)
2041|
2042|   Description   :  Scroll a multi-line field forward a page
2043|
2044|   Return Values :  E_OK              - success
2045|                    E_REQUEST_DENIED  - no data ahead
2046+--------------------------------------------------------------------------*/
2047static int
2048VSC_Scroll_Page_Forward(FORM *form)
2049{
2050  T((T_CALLED("VSC_Scroll_Page_Forward(%p)"), (void *)form));
2051  returnCode(VSC_Generic(form, form->current->rows));
2052}
2053
2054/*---------------------------------------------------------------------------
2055|   Facility      :  libnform
2056|   Function      :  static int VSC_Scroll_Half_Page_Forward(FORM * form)
2057|
2058|   Description   :  Scroll a multi-line field forward half a page
2059|
2060|   Return Values :  E_OK              - success
2061|                    E_REQUEST_DENIED  - no data ahead
2062+--------------------------------------------------------------------------*/
2063static int
2064VSC_Scroll_Half_Page_Forward(FORM *form)
2065{
2066  T((T_CALLED("VSC_Scroll_Half_Page_Forward(%p)"), (void *)form));
2067  returnCode(VSC_Generic(form, (form->current->rows + 1) / 2));
2068}
2069
2070/*---------------------------------------------------------------------------
2071|   Facility      :  libnform
2072|   Function      :  static int VSC_Scroll_Page_Backward(FORM * form)
2073|
2074|   Description   :  Scroll a multi-line field backward a page
2075|
2076|   Return Values :  E_OK              - success
2077|                    E_REQUEST_DENIED  - no data behind
2078+--------------------------------------------------------------------------*/
2079static int
2080VSC_Scroll_Page_Backward(FORM *form)
2081{
2082  T((T_CALLED("VSC_Scroll_Page_Backward(%p)"), (void *)form));
2083  returnCode(VSC_Generic(form, -(form->current->rows)));
2084}
2085
2086/*---------------------------------------------------------------------------
2087|   Facility      :  libnform
2088|   Function      :  static int VSC_Scroll_Half_Page_Backward(FORM * form)
2089|
2090|   Description   :  Scroll a multi-line field backward half a page
2091|
2092|   Return Values :  E_OK              - success
2093|                    E_REQUEST_DENIED  - no data behind
2094+--------------------------------------------------------------------------*/
2095static int
2096VSC_Scroll_Half_Page_Backward(FORM *form)
2097{
2098  T((T_CALLED("VSC_Scroll_Half_Page_Backward(%p)"), (void *)form));
2099  returnCode(VSC_Generic(form, -((form->current->rows + 1) / 2)));
2100}
2101/*----------------------------------------------------------------------------
2102  End of Vertical scrolling routines
2103  --------------------------------------------------------------------------*/
2104
2105/*----------------------------------------------------------------------------
2106  Horizontal scrolling helper routines
2107  --------------------------------------------------------------------------*/
2108
2109/*---------------------------------------------------------------------------
2110|   Facility      :  libnform
2111|   Function      :  static int HSC_Generic(FORM *form, int ncolumns)
2112|
2113|   Description   :  Scroll single-line field forward (ncolumns>0) or
2114|                    backward (ncolumns<0) this many columns.
2115|
2116|   Return Values :  E_OK              - success
2117|                    E_REQUEST_DENIED  - can't scroll
2118+--------------------------------------------------------------------------*/
2119static int
2120HSC_Generic(FORM *form, int ncolumns)
2121{
2122  FIELD *field = form->current;
2123  int res = E_REQUEST_DENIED;
2124  int cols_to_go = (ncolumns > 0 ? ncolumns : -ncolumns);
2125
2126  if (ncolumns > 0)
2127    {
2128      if ((cols_to_go + form->begincol) > (field->dcols - field->cols))
2129	cols_to_go = field->dcols - field->cols - form->begincol;
2130
2131      if (cols_to_go > 0)
2132	{
2133	  form->curcol += cols_to_go;
2134	  form->begincol += cols_to_go;
2135	  res = E_OK;
2136	}
2137    }
2138  else
2139    {
2140      if (cols_to_go > form->begincol)
2141	cols_to_go = form->begincol;
2142
2143      if (cols_to_go > 0)
2144	{
2145	  form->curcol -= cols_to_go;
2146	  form->begincol -= cols_to_go;
2147	  res = E_OK;
2148	}
2149    }
2150  return (res);
2151}
2152/*----------------------------------------------------------------------------
2153  End of Horizontal scrolling helper routines
2154  --------------------------------------------------------------------------*/
2155
2156/*----------------------------------------------------------------------------
2157  Horizontal scrolling routines
2158  --------------------------------------------------------------------------*/
2159
2160/*---------------------------------------------------------------------------
2161|   Facility      :  libnform
2162|   Function      :  static int Horizontal_Scrolling(
2163|                                          int (* const fct) (FORM *),
2164|                                          FORM * form)
2165|
2166|   Description   :  Performs the generic horizontal scrolling routines.
2167|                    This has to check for a single-line field.
2168|
2169|   Return Values :  Propagated error code from low-level driver calls
2170+--------------------------------------------------------------------------*/
2171static int
2172Horizontal_Scrolling(int (*const fct) (FORM *), FORM *form)
2173{
2174  if (Single_Line_Field(form->current))
2175    return fct(form);
2176  else
2177    return (E_REQUEST_DENIED);
2178}
2179
2180/*---------------------------------------------------------------------------
2181|   Facility      :  libnform
2182|   Function      :  static int HSC_Scroll_Char_Forward(FORM * form)
2183|
2184|   Description   :  Scroll single-line field forward a character
2185|
2186|   Return Values :  E_OK                - success
2187|                    E_REQUEST_DENIED    - no data ahead
2188+--------------------------------------------------------------------------*/
2189static int
2190HSC_Scroll_Char_Forward(FORM *form)
2191{
2192  T((T_CALLED("HSC_Scroll_Char_Forward(%p)"), (void *)form));
2193  returnCode(HSC_Generic(form, 1));
2194}
2195
2196/*---------------------------------------------------------------------------
2197|   Facility      :  libnform
2198|   Function      :  static int HSC_Scroll_Char_Backward(FORM * form)
2199|
2200|   Description   :  Scroll single-line field backward a character
2201|
2202|   Return Values :  E_OK                - success
2203|                    E_REQUEST_DENIED    - no data behind
2204+--------------------------------------------------------------------------*/
2205static int
2206HSC_Scroll_Char_Backward(FORM *form)
2207{
2208  T((T_CALLED("HSC_Scroll_Char_Backward(%p)"), (void *)form));
2209  returnCode(HSC_Generic(form, -1));
2210}
2211
2212/*---------------------------------------------------------------------------
2213|   Facility      :  libnform
2214|   Function      :  static int HSC_Horizontal_Line_Forward(FORM* form)
2215|
2216|   Description   :  Scroll single-line field forward a line
2217|
2218|   Return Values :  E_OK                - success
2219|                    E_REQUEST_DENIED    - no data ahead
2220+--------------------------------------------------------------------------*/
2221static int
2222HSC_Horizontal_Line_Forward(FORM *form)
2223{
2224  T((T_CALLED("HSC_Horizontal_Line_Forward(%p)"), (void *)form));
2225  returnCode(HSC_Generic(form, form->current->cols));
2226}
2227
2228/*---------------------------------------------------------------------------
2229|   Facility      :  libnform
2230|   Function      :  static int HSC_Horizontal_Half_Line_Forward(FORM* form)
2231|
2232|   Description   :  Scroll single-line field forward half a line
2233|
2234|   Return Values :  E_OK               - success
2235|                    E_REQUEST_DENIED   - no data ahead
2236+--------------------------------------------------------------------------*/
2237static int
2238HSC_Horizontal_Half_Line_Forward(FORM *form)
2239{
2240  T((T_CALLED("HSC_Horizontal_Half_Line_Forward(%p)"), (void *)form));
2241  returnCode(HSC_Generic(form, (form->current->cols + 1) / 2));
2242}
2243
2244/*---------------------------------------------------------------------------
2245|   Facility      :  libnform
2246|   Function      :  static int HSC_Horizontal_Line_Backward(FORM* form)
2247|
2248|   Description   :  Scroll single-line field backward a line
2249|
2250|   Return Values :  E_OK                - success
2251|                    E_REQUEST_DENIED    - no data behind
2252+--------------------------------------------------------------------------*/
2253static int
2254HSC_Horizontal_Line_Backward(FORM *form)
2255{
2256  T((T_CALLED("HSC_Horizontal_Line_Backward(%p)"), (void *)form));
2257  returnCode(HSC_Generic(form, -(form->current->cols)));
2258}
2259
2260/*---------------------------------------------------------------------------
2261|   Facility      :  libnform
2262|   Function      :  static int HSC_Horizontal_Half_Line_Backward(FORM* form)
2263|
2264|   Description   :  Scroll single-line field backward half a line
2265|
2266|   Return Values :  E_OK                - success
2267|                    E_REQUEST_DENIED    - no data behind
2268+--------------------------------------------------------------------------*/
2269static int
2270HSC_Horizontal_Half_Line_Backward(FORM *form)
2271{
2272  T((T_CALLED("HSC_Horizontal_Half_Line_Backward(%p)"), (void *)form));
2273  returnCode(HSC_Generic(form, -((form->current->cols + 1) / 2)));
2274}
2275
2276/*----------------------------------------------------------------------------
2277  End of Horizontal scrolling routines
2278  --------------------------------------------------------------------------*/
2279
2280/*----------------------------------------------------------------------------
2281  Helper routines for Field Editing
2282  --------------------------------------------------------------------------*/
2283
2284/*---------------------------------------------------------------------------
2285|   Facility      :  libnform
2286|   Function      :  static bool Is_There_Room_For_A_Line(FORM * form)
2287|
2288|   Description   :  Check whether or not there is enough room in the
2289|                    buffer to enter a whole line.
2290|
2291|   Return Values :  TRUE   - there is enough space
2292|                    FALSE  - there is not enough space
2293+--------------------------------------------------------------------------*/
2294NCURSES_INLINE static bool
2295Is_There_Room_For_A_Line(FORM *form)
2296{
2297  FIELD *field = form->current;
2298  FIELD_CELL *begin_of_last_line, *s;
2299
2300  Synchronize_Buffer(form);
2301  begin_of_last_line = Address_Of_Row_In_Buffer(field, (field->drows - 1));
2302  s = After_End_Of_Data(begin_of_last_line, field->dcols);
2303  return ((s == begin_of_last_line) ? TRUE : FALSE);
2304}
2305
2306/*---------------------------------------------------------------------------
2307|   Facility      :  libnform
2308|   Function      :  static bool Is_There_Room_For_A_Char_In_Line(FORM * form)
2309|
2310|   Description   :  Checks whether or not there is room for a new character
2311|                    in the current line.
2312|
2313|   Return Values :  TRUE    - there is room
2314|                    FALSE   - there is not enough room (line full)
2315+--------------------------------------------------------------------------*/
2316NCURSES_INLINE static bool
2317Is_There_Room_For_A_Char_In_Line(FORM *form)
2318{
2319  int last_char_in_line;
2320
2321  wmove(form->w, form->currow, form->current->dcols - 1);
2322  last_char_in_line = (int)(winch(form->w) & A_CHARTEXT);
2323  wmove(form->w, form->currow, form->curcol);
2324  return (((last_char_in_line == form->current->pad) ||
2325	   is_blank(last_char_in_line)) ? TRUE : FALSE);
2326}
2327
2328#define There_Is_No_Room_For_A_Char_In_Line(f) \
2329  !Is_There_Room_For_A_Char_In_Line(f)
2330
2331/*---------------------------------------------------------------------------
2332|   Facility      :  libnform
2333|   Function      :  static int Insert_String(
2334|                                             FORM * form,
2335|                                             int row,
2336|                                             char *txt,
2337|                                             int  len )
2338|
2339|   Description   :  Insert the 'len' characters beginning at pointer 'txt'
2340|                    into the 'row' of the 'form'. The insertion occurs
2341|                    on the beginning of the row, all other characters are
2342|                    moved to the right. After the text a pad character will
2343|                    be inserted to separate the text from the rest. If
2344|                    necessary the insertion moves characters on the next
2345|                    line to make place for the requested insertion string.
2346|
2347|   Return Values :  E_OK              - success
2348|                    E_REQUEST_DENIED  -
2349|                    E_SYSTEM_ERROR    - system error
2350+--------------------------------------------------------------------------*/
2351static int
2352Insert_String(FORM *form, int row, FIELD_CELL *txt, int len)
2353{
2354  FIELD *field = form->current;
2355  FIELD_CELL *bp = Address_Of_Row_In_Buffer(field, row);
2356  int datalen = (int)(After_End_Of_Data(bp, field->dcols) - bp);
2357  int freelen = field->dcols - datalen;
2358  int requiredlen = len + 1;
2359  FIELD_CELL *split;
2360  int result = E_REQUEST_DENIED;
2361
2362  if (freelen >= requiredlen)
2363    {
2364      wmove(form->w, row, 0);
2365      myINSNSTR(form->w, txt, len);
2366      wmove(form->w, row, len);
2367      myINSNSTR(form->w, &myBLANK, 1);
2368      return E_OK;
2369    }
2370  else
2371    {
2372      /* we have to move characters on the next line. If we are on the
2373         last line this may work, if the field is growable */
2374      if ((row == (field->drows - 1)) && Growable(field))
2375	{
2376	  if (!Field_Grown(field, 1))
2377	    return (E_SYSTEM_ERROR);
2378	  /* !!!Side-Effect : might be changed due to growth!!! */
2379	  bp = Address_Of_Row_In_Buffer(field, row);
2380	}
2381
2382      if (row < (field->drows - 1))
2383	{
2384	  split =
2385	    After_Last_Whitespace_Character(bp,
2386					    (int)(Get_Start_Of_Data(bp
2387								    + field->dcols
2388								    - requiredlen,
2389								    requiredlen)
2390						  - bp));
2391	  /* split points now to the first character of the portion of the
2392	     line that must be moved to the next line */
2393	  datalen = (int)(split - bp);	/* + freelen has to stay on this line   */
2394	  freelen = field->dcols - (datalen + freelen);		/* for the next line */
2395
2396	  if ((result = Insert_String(form, row + 1, split, freelen)) == E_OK)
2397	    {
2398	      wmove(form->w, row, datalen);
2399	      wclrtoeol(form->w);
2400	      wmove(form->w, row, 0);
2401	      myINSNSTR(form->w, txt, len);
2402	      wmove(form->w, row, len);
2403	      myINSNSTR(form->w, &myBLANK, 1);
2404	      return E_OK;
2405	    }
2406	}
2407      return (result);
2408    }
2409}
2410
2411/*---------------------------------------------------------------------------
2412|   Facility      :  libnform
2413|   Function      :  static int Wrapping_Not_Necessary_Or_Wrapping_Ok(
2414|                                             FORM * form)
2415|
2416|   Description   :  If a character has been entered into a field, it may
2417|                    be that wrapping has to occur. This routine checks
2418|                    whether or not wrapping is required and if so, performs
2419|                    the wrapping.
2420|
2421|   Return Values :  E_OK              - no wrapping required or wrapping
2422|                                        was successful
2423|                    E_REQUEST_DENIED  -
2424|                    E_SYSTEM_ERROR    - some system error
2425+--------------------------------------------------------------------------*/
2426static int
2427Wrapping_Not_Necessary_Or_Wrapping_Ok(FORM *form)
2428{
2429  FIELD *field = form->current;
2430  int result = E_REQUEST_DENIED;
2431  bool Last_Row = ((field->drows - 1) == form->currow);
2432
2433  if (((unsigned)field->opts & O_WRAP) &&	/* wrapping wanted     */
2434      (!Single_Line_Field(field)) &&	/* must be multi-line  */
2435      (There_Is_No_Room_For_A_Char_In_Line(form)) &&	/* line is full        */
2436      (!Last_Row || Growable(field)))	/* there are more lines */
2437    {
2438      FIELD_CELL *bp;
2439      FIELD_CELL *split;
2440      int chars_to_be_wrapped;
2441      int chars_to_remain_on_line;
2442
2443      if (Last_Row)
2444	{
2445	  /* the above logic already ensures, that in this case the field
2446	     is growable */
2447	  if (!Field_Grown(field, 1))
2448	    return E_SYSTEM_ERROR;
2449	}
2450      bp = Address_Of_Current_Row_In_Buffer(form);
2451      Window_To_Buffer(form, field);
2452      split = After_Last_Whitespace_Character(bp, field->dcols);
2453      /* split points to the first character of the sequence to be brought
2454         on the next line */
2455      chars_to_remain_on_line = (int)(split - bp);
2456      chars_to_be_wrapped = field->dcols - chars_to_remain_on_line;
2457      if (chars_to_remain_on_line > 0)
2458	{
2459	  if ((result = Insert_String(form, form->currow + 1, split,
2460				      chars_to_be_wrapped)) == E_OK)
2461	    {
2462	      wmove(form->w, form->currow, chars_to_remain_on_line);
2463	      wclrtoeol(form->w);
2464	      if (form->curcol >= chars_to_remain_on_line)
2465		{
2466		  form->currow++;
2467		  form->curcol -= chars_to_remain_on_line;
2468		}
2469	      return E_OK;
2470	    }
2471	}
2472      else
2473	return E_OK;
2474      if (result != E_OK)
2475	{
2476	  DeleteChar(form);
2477	  Window_To_Buffer(form, field);
2478	  result = E_REQUEST_DENIED;
2479	}
2480    }
2481  else
2482    result = E_OK;		/* wrapping was not necessary */
2483  return (result);
2484}
2485
2486/*----------------------------------------------------------------------------
2487  Field Editing routines
2488  --------------------------------------------------------------------------*/
2489
2490/*---------------------------------------------------------------------------
2491|   Facility      :  libnform
2492|   Function      :  static int Field_Editing(
2493|                                    int (* const fct) (FORM *),
2494|                                    FORM * form)
2495|
2496|   Description   :  Generic routine for field editing requests. The driver
2497|                    routines are only called for editable fields, the
2498|                    _WINDOW_MODIFIED flag is set if editing occurred.
2499|                    This is somewhat special due to the overload semantics
2500|                    of the NEW_LINE and DEL_PREV requests.
2501|
2502|   Return Values :  Error code from low level drivers.
2503+--------------------------------------------------------------------------*/
2504static int
2505Field_Editing(int (*const fct) (FORM *), FORM *form)
2506{
2507  int res = E_REQUEST_DENIED;
2508
2509  /* We have to deal here with the specific case of the overloaded
2510     behavior of New_Line and Delete_Previous requests.
2511     They may end up in navigational requests if we are on the first
2512     character in a field. But navigation is also allowed on non-
2513     editable fields.
2514   */
2515  if ((fct == FE_Delete_Previous) &&
2516      ((unsigned)form->opts & O_BS_OVERLOAD) &&
2517      First_Position_In_Current_Field(form))
2518    {
2519      res = Inter_Field_Navigation(FN_Previous_Field, form);
2520    }
2521  else
2522    {
2523      if (fct == FE_New_Line)
2524	{
2525	  if (((unsigned)form->opts & O_NL_OVERLOAD) &&
2526	      First_Position_In_Current_Field(form))
2527	    {
2528	      res = Inter_Field_Navigation(FN_Next_Field, form);
2529	    }
2530	  else
2531	    /* FE_New_Line deals itself with the _WINDOW_MODIFIED flag */
2532	    res = fct(form);
2533	}
2534      else
2535	{
2536	  /* From now on, everything must be editable */
2537	  if ((unsigned)form->current->opts & O_EDIT)
2538	    {
2539	      res = fct(form);
2540	      if (res == E_OK)
2541		SetStatus(form, _WINDOW_MODIFIED);
2542	    }
2543	}
2544    }
2545  return res;
2546}
2547
2548/*---------------------------------------------------------------------------
2549|   Facility      :  libnform
2550|   Function      :  static int FE_New_Line(FORM * form)
2551|
2552|   Description   :  Perform a new line request. This is rather complex
2553|                    compared to other routines in this code due to the
2554|                    rather difficult to understand description in the
2555|                    manuals.
2556|
2557|   Return Values :  E_OK               - success
2558|                    E_REQUEST_DENIED   - new line not allowed
2559|                    E_SYSTEM_ERROR     - system error
2560+--------------------------------------------------------------------------*/
2561static int
2562FE_New_Line(FORM *form)
2563{
2564  FIELD *field = form->current;
2565  FIELD_CELL *bp, *t;
2566  bool Last_Row = ((field->drows - 1) == form->currow);
2567
2568  T((T_CALLED("FE_New_Line(%p)"), (void *)form));
2569  if (form->status & _OVLMODE)
2570    {
2571      if (Last_Row &&
2572	  (!(Growable(field) && !Single_Line_Field(field))))
2573	{
2574	  if (!((unsigned)form->opts & O_NL_OVERLOAD))
2575	    returnCode(E_REQUEST_DENIED);
2576	  wmove(form->w, form->currow, form->curcol);
2577	  wclrtoeol(form->w);
2578	  /* we have to set this here, although it is also
2579	     handled in the generic routine. The reason is,
2580	     that FN_Next_Field may fail, but the form is
2581	     definitively changed */
2582	  SetStatus(form, _WINDOW_MODIFIED);
2583	  returnCode(Inter_Field_Navigation(FN_Next_Field, form));
2584	}
2585      else
2586	{
2587	  if (Last_Row && !Field_Grown(field, 1))
2588	    {
2589	      /* N.B.: due to the logic in the 'if', LastRow==TRUE
2590	         means here that the field is growable and not
2591	         a single-line field */
2592	      returnCode(E_SYSTEM_ERROR);
2593	    }
2594	  wmove(form->w, form->currow, form->curcol);
2595	  wclrtoeol(form->w);
2596	  form->currow++;
2597	  form->curcol = 0;
2598	  SetStatus(form, _WINDOW_MODIFIED);
2599	  returnCode(E_OK);
2600	}
2601    }
2602  else
2603    {
2604      /* Insert Mode */
2605      if (Last_Row &&
2606	  !(Growable(field) && !Single_Line_Field(field)))
2607	{
2608	  if (!((unsigned)form->opts & O_NL_OVERLOAD))
2609	    returnCode(E_REQUEST_DENIED);
2610	  returnCode(Inter_Field_Navigation(FN_Next_Field, form));
2611	}
2612      else
2613	{
2614	  bool May_Do_It = !Last_Row && Is_There_Room_For_A_Line(form);
2615
2616	  if (!(May_Do_It || Growable(field)))
2617	    returnCode(E_REQUEST_DENIED);
2618	  if (!May_Do_It && !Field_Grown(field, 1))
2619	    returnCode(E_SYSTEM_ERROR);
2620
2621	  bp = Address_Of_Current_Position_In_Buffer(form);
2622	  t = After_End_Of_Data(bp, field->dcols - form->curcol);
2623	  wmove(form->w, form->currow, form->curcol);
2624	  wclrtoeol(form->w);
2625	  form->currow++;
2626	  form->curcol = 0;
2627	  wmove(form->w, form->currow, form->curcol);
2628	  winsertln(form->w);
2629	  myADDNSTR(form->w, bp, (int)(t - bp));
2630	  SetStatus(form, _WINDOW_MODIFIED);
2631	  returnCode(E_OK);
2632	}
2633    }
2634}
2635
2636/*---------------------------------------------------------------------------
2637|   Facility      :  libnform
2638|   Function      :  static int FE_Insert_Character(FORM * form)
2639|
2640|   Description   :  Insert blank character at the cursor position
2641|
2642|   Return Values :  E_OK
2643|                    E_REQUEST_DENIED
2644+--------------------------------------------------------------------------*/
2645static int
2646FE_Insert_Character(FORM *form)
2647{
2648  FIELD *field = form->current;
2649  int result = E_REQUEST_DENIED;
2650
2651  T((T_CALLED("FE_Insert_Character(%p)"), (void *)form));
2652  if (Check_Char(form, field, field->type, (int)C_BLANK,
2653		 (TypeArgument *)(field->arg)))
2654    {
2655      bool There_Is_Room = Is_There_Room_For_A_Char_In_Line(form);
2656
2657      if (There_Is_Room ||
2658	  ((Single_Line_Field(field) && Growable(field))))
2659	{
2660	  if (!There_Is_Room && !Field_Grown(field, 1))
2661	    result = E_SYSTEM_ERROR;
2662	  else
2663	    {
2664	      winsch(form->w, (chtype)C_BLANK);
2665	      result = Wrapping_Not_Necessary_Or_Wrapping_Ok(form);
2666	    }
2667	}
2668    }
2669  returnCode(result);
2670}
2671
2672/*---------------------------------------------------------------------------
2673|   Facility      :  libnform
2674|   Function      :  static int FE_Insert_Line(FORM * form)
2675|
2676|   Description   :  Insert a blank line at the cursor position
2677|
2678|   Return Values :  E_OK               - success
2679|                    E_REQUEST_DENIED   - line can not be inserted
2680+--------------------------------------------------------------------------*/
2681static int
2682FE_Insert_Line(FORM *form)
2683{
2684  FIELD *field = form->current;
2685  int result = E_REQUEST_DENIED;
2686
2687  T((T_CALLED("FE_Insert_Line(%p)"), (void *)form));
2688  if (Check_Char(form, field,
2689		 field->type, (int)C_BLANK, (TypeArgument *)(field->arg)))
2690    {
2691      bool Maybe_Done = (form->currow != (field->drows - 1)) &&
2692      Is_There_Room_For_A_Line(form);
2693
2694      if (!Single_Line_Field(field) &&
2695	  (Maybe_Done || Growable(field)))
2696	{
2697	  if (!Maybe_Done && !Field_Grown(field, 1))
2698	    result = E_SYSTEM_ERROR;
2699	  else
2700	    {
2701	      form->curcol = 0;
2702	      winsertln(form->w);
2703	      result = E_OK;
2704	    }
2705	}
2706    }
2707  returnCode(result);
2708}
2709
2710/*---------------------------------------------------------------------------
2711|   Facility      :  libnform
2712|   Function      :  static int FE_Delete_Character(FORM * form)
2713|
2714|   Description   :  Delete character at the cursor position
2715|
2716|   Return Values :  E_OK    - success
2717+--------------------------------------------------------------------------*/
2718static int
2719FE_Delete_Character(FORM *form)
2720{
2721  T((T_CALLED("FE_Delete_Character(%p)"), (void *)form));
2722  DeleteChar(form);
2723  returnCode(E_OK);
2724}
2725
2726/*---------------------------------------------------------------------------
2727|   Facility      :  libnform
2728|   Function      :  static int FE_Delete_Previous(FORM * form)
2729|
2730|   Description   :  Delete character before cursor. Again this is a rather
2731|                    difficult piece compared to others due to the overloading
2732|                    semantics of backspace.
2733|                    N.B.: The case of overloaded BS on first field position
2734|                          is already handled in the generic routine.
2735|
2736|   Return Values :  E_OK                - success
2737|                    E_REQUEST_DENIED    - Character can't be deleted
2738+--------------------------------------------------------------------------*/
2739static int
2740FE_Delete_Previous(FORM *form)
2741{
2742  FIELD *field = form->current;
2743
2744  T((T_CALLED("FE_Delete_Previous(%p)"), (void *)form));
2745  if (First_Position_In_Current_Field(form))
2746    returnCode(E_REQUEST_DENIED);
2747
2748  if ((--(form->curcol)) < 0)
2749    {
2750      FIELD_CELL *this_line, *prev_line, *prev_end, *this_end;
2751      int this_row = form->currow;
2752
2753      form->curcol++;
2754      if (form->status & _OVLMODE)
2755	returnCode(E_REQUEST_DENIED);
2756
2757      prev_line = Address_Of_Row_In_Buffer(field, (form->currow - 1));
2758      this_line = Address_Of_Row_In_Buffer(field, (form->currow));
2759      Synchronize_Buffer(form);
2760      prev_end = After_End_Of_Data(prev_line, field->dcols);
2761      this_end = After_End_Of_Data(this_line, field->dcols);
2762      if ((int)(this_end - this_line) >
2763	  (field->cols - (int)(prev_end - prev_line)))
2764	returnCode(E_REQUEST_DENIED);
2765      wmove(form->w, form->currow, form->curcol);
2766      wdeleteln(form->w);
2767      Adjust_Cursor_Position(form, prev_end);
2768      /*
2769       * If we did not really move to the previous line, help the user a
2770       * little.  It is however a little inconsistent.  Normally, when
2771       * backspacing around the point where text wraps to a new line in a
2772       * multi-line form, we absorb one keystroke for the wrapping point.  That
2773       * is consistent with SVr4 forms.  However, SVr4 does not allow typing
2774       * into the last column of the field, and requires the user to enter a
2775       * newline to move to the next line.  Therefore it can consistently eat
2776       * that keystroke.  Since ncurses allows the last column, it wraps
2777       * automatically (given the proper options).  But we cannot eat the
2778       * keystroke to back over the wrapping point, since that would put the
2779       * cursor past the end of the form field.  In this case, just delete the
2780       * character at the end of the field.
2781       */
2782      if (form->currow == this_row && this_row > 0)
2783	{
2784	  form->currow -= 1;
2785	  form->curcol = field->dcols - 1;
2786	  DeleteChar(form);
2787	}
2788      else
2789	{
2790	  wmove(form->w, form->currow, form->curcol);
2791	  myADDNSTR(form->w, this_line, (int)(this_end - this_line));
2792	}
2793    }
2794  else
2795    {
2796      DeleteChar(form);
2797    }
2798  returnCode(E_OK);
2799}
2800
2801/*---------------------------------------------------------------------------
2802|   Facility      :  libnform
2803|   Function      :  static int FE_Delete_Line(FORM * form)
2804|
2805|   Description   :  Delete line at cursor position.
2806|
2807|   Return Values :  E_OK  - success
2808+--------------------------------------------------------------------------*/
2809static int
2810FE_Delete_Line(FORM *form)
2811{
2812  T((T_CALLED("FE_Delete_Line(%p)"), (void *)form));
2813  form->curcol = 0;
2814  wdeleteln(form->w);
2815  returnCode(E_OK);
2816}
2817
2818/*---------------------------------------------------------------------------
2819|   Facility      :  libnform
2820|   Function      :  static int FE_Delete_Word(FORM * form)
2821|
2822|   Description   :  Delete word at cursor position
2823|
2824|   Return Values :  E_OK               - success
2825|                    E_REQUEST_DENIED   - failure
2826+--------------------------------------------------------------------------*/
2827static int
2828FE_Delete_Word(FORM *form)
2829{
2830  FIELD *field = form->current;
2831  FIELD_CELL *bp = Address_Of_Current_Row_In_Buffer(form);
2832  FIELD_CELL *ep = bp + field->dcols;
2833  FIELD_CELL *cp = bp + form->curcol;
2834  FIELD_CELL *s;
2835
2836  T((T_CALLED("FE_Delete_Word(%p)"), (void *)form));
2837  Synchronize_Buffer(form);
2838  if (ISBLANK(*cp))
2839    returnCode(E_REQUEST_DENIED);	/* not in word */
2840
2841  /* move cursor to begin of word and erase to end of screen-line */
2842  Adjust_Cursor_Position(form,
2843			 After_Last_Whitespace_Character(bp, form->curcol));
2844  wmove(form->w, form->currow, form->curcol);
2845  wclrtoeol(form->w);
2846
2847  /* skip over word in buffer */
2848  s = Get_First_Whitespace_Character(cp, (int)(ep - cp));
2849  /* to begin of next word    */
2850  s = Get_Start_Of_Data(s, (int)(ep - s));
2851  if ((s != cp) && !ISBLANK(*s))
2852    {
2853      /* copy remaining line to window */
2854      myADDNSTR(form->w, s, (int)(s - After_End_Of_Data(s, (int)(ep - s))));
2855    }
2856  returnCode(E_OK);
2857}
2858
2859/*---------------------------------------------------------------------------
2860|   Facility      :  libnform
2861|   Function      :  static int FE_Clear_To_End_Of_Line(FORM * form)
2862|
2863|   Description   :  Clear to end of current line.
2864|
2865|   Return Values :  E_OK   - success
2866+--------------------------------------------------------------------------*/
2867static int
2868FE_Clear_To_End_Of_Line(FORM *form)
2869{
2870  T((T_CALLED("FE_Clear_To_End_Of_Line(%p)"), (void *)form));
2871  wmove(form->w, form->currow, form->curcol);
2872  wclrtoeol(form->w);
2873  returnCode(E_OK);
2874}
2875
2876/*---------------------------------------------------------------------------
2877|   Facility      :  libnform
2878|   Function      :  static int FE_Clear_To_End_Of_Field(FORM * form)
2879|
2880|   Description   :  Clear to end of field.
2881|
2882|   Return Values :  E_OK   - success
2883+--------------------------------------------------------------------------*/
2884static int
2885FE_Clear_To_End_Of_Field(FORM *form)
2886{
2887  T((T_CALLED("FE_Clear_To_End_Of_Field(%p)"), (void *)form));
2888  wmove(form->w, form->currow, form->curcol);
2889  wclrtobot(form->w);
2890  returnCode(E_OK);
2891}
2892
2893/*---------------------------------------------------------------------------
2894|   Facility      :  libnform
2895|   Function      :  static int FE_Clear_Field(FORM * form)
2896|
2897|   Description   :  Clear entire field.
2898|
2899|   Return Values :  E_OK   - success
2900+--------------------------------------------------------------------------*/
2901static int
2902FE_Clear_Field(FORM *form)
2903{
2904  T((T_CALLED("FE_Clear_Field(%p)"), (void *)form));
2905  form->currow = form->curcol = 0;
2906  werase(form->w);
2907  returnCode(E_OK);
2908}
2909/*----------------------------------------------------------------------------
2910  END of Field Editing routines
2911  --------------------------------------------------------------------------*/
2912
2913/*----------------------------------------------------------------------------
2914  Edit Mode routines
2915  --------------------------------------------------------------------------*/
2916
2917/*---------------------------------------------------------------------------
2918|   Facility      :  libnform
2919|   Function      :  static int EM_Overlay_Mode(FORM * form)
2920|
2921|   Description   :  Switch to overlay mode.
2922|
2923|   Return Values :  E_OK   - success
2924+--------------------------------------------------------------------------*/
2925static int
2926EM_Overlay_Mode(FORM *form)
2927{
2928  T((T_CALLED("EM_Overlay_Mode(%p)"), (void *)form));
2929  SetStatus(form, _OVLMODE);
2930  returnCode(E_OK);
2931}
2932
2933/*---------------------------------------------------------------------------
2934|   Facility      :  libnform
2935|   Function      :  static int EM_Insert_Mode(FORM * form)
2936|
2937|   Description   :  Switch to insert mode
2938|
2939|   Return Values :  E_OK   - success
2940+--------------------------------------------------------------------------*/
2941static int
2942EM_Insert_Mode(FORM *form)
2943{
2944  T((T_CALLED("EM_Insert_Mode(%p)"), (void *)form));
2945  ClrStatus(form, _OVLMODE);
2946  returnCode(E_OK);
2947}
2948
2949/*----------------------------------------------------------------------------
2950  END of Edit Mode routines
2951  --------------------------------------------------------------------------*/
2952
2953/*----------------------------------------------------------------------------
2954  Helper routines for Choice Requests
2955  --------------------------------------------------------------------------*/
2956
2957/*---------------------------------------------------------------------------
2958|   Facility      :  libnform
2959|   Function      :  static bool Next_Choice(FORM * form,
2960|                                            FIELDTYPE * typ,
2961|                                            FIELD * field,
2962|                                            TypeArgument *argp)
2963|
2964|   Description   :  Get the next field choice. For linked types this is
2965|                    done recursively.
2966|
2967|   Return Values :  TRUE    - next choice successfully retrieved
2968|                    FALSE   - couldn't retrieve next choice
2969+--------------------------------------------------------------------------*/
2970static bool
2971Next_Choice(FORM *form, FIELDTYPE *typ, FIELD *field, TypeArgument *argp)
2972{
2973  if (!typ || !(typ->status & _HAS_CHOICE))
2974    return FALSE;
2975
2976  if (typ->status & _LINKED_TYPE)
2977    {
2978      assert(argp);
2979      return (
2980	       Next_Choice(form, typ->left, field, argp->left) ||
2981	       Next_Choice(form, typ->right, field, argp->right));
2982    }
2983  else
2984    {
2985#if NCURSES_INTEROP_FUNCS
2986      assert(typ->enum_next.onext);
2987      if (typ->status & _GENERIC)
2988	return typ->enum_next.gnext(form, field, (void *)argp);
2989      else
2990	return typ->enum_next.onext(field, (void *)argp);
2991#else
2992      assert(typ->next);
2993      return typ->next(field, (void *)argp);
2994#endif
2995    }
2996}
2997
2998/*---------------------------------------------------------------------------
2999|   Facility      :  libnform
3000|   Function      :  static bool Previous_Choice(FORM * form,
3001|                                                FIELDTYPE * typ,
3002|                                                FIELD * field,
3003|                                                TypeArgument *argp)
3004|
3005|   Description   :  Get the previous field choice. For linked types this
3006|                    is done recursively.
3007|
3008|   Return Values :  TRUE    - previous choice successfully retrieved
3009|                    FALSE   - couldn't retrieve previous choice
3010+--------------------------------------------------------------------------*/
3011static bool
3012Previous_Choice(FORM *form, FIELDTYPE *typ, FIELD *field, TypeArgument *argp)
3013{
3014  if (!typ || !(typ->status & _HAS_CHOICE))
3015    return FALSE;
3016
3017  if (typ->status & _LINKED_TYPE)
3018    {
3019      assert(argp);
3020      return (
3021	       Previous_Choice(form, typ->left, field, argp->left) ||
3022	       Previous_Choice(form, typ->right, field, argp->right));
3023    }
3024  else
3025    {
3026#if NCURSES_INTEROP_FUNCS
3027      assert(typ->enum_prev.oprev);
3028      if (typ->status & _GENERIC)
3029	return typ->enum_prev.gprev(form, field, (void *)argp);
3030      else
3031	return typ->enum_prev.oprev(field, (void *)argp);
3032#else
3033      assert(typ->prev);
3034      return typ->prev(field, (void *)argp);
3035#endif
3036    }
3037}
3038/*----------------------------------------------------------------------------
3039  End of Helper routines for Choice Requests
3040  --------------------------------------------------------------------------*/
3041
3042/*----------------------------------------------------------------------------
3043  Routines for Choice Requests
3044  --------------------------------------------------------------------------*/
3045
3046/*---------------------------------------------------------------------------
3047|   Facility      :  libnform
3048|   Function      :  static int CR_Next_Choice(FORM * form)
3049|
3050|   Description   :  Get the next field choice.
3051|
3052|   Return Values :  E_OK              - success
3053|                    E_REQUEST_DENIED  - next choice couldn't be retrieved
3054+--------------------------------------------------------------------------*/
3055static int
3056CR_Next_Choice(FORM *form)
3057{
3058  FIELD *field = form->current;
3059
3060  T((T_CALLED("CR_Next_Choice(%p)"), (void *)form));
3061  Synchronize_Buffer(form);
3062  returnCode((Next_Choice(form, field->type, field, (TypeArgument *)(field->arg)))
3063	     ? E_OK
3064	     : E_REQUEST_DENIED);
3065}
3066
3067/*---------------------------------------------------------------------------
3068|   Facility      :  libnform
3069|   Function      :  static int CR_Previous_Choice(FORM * form)
3070|
3071|   Description   :  Get the previous field choice.
3072|
3073|   Return Values :  E_OK              - success
3074|                    E_REQUEST_DENIED  - prev. choice couldn't be retrieved
3075+--------------------------------------------------------------------------*/
3076static int
3077CR_Previous_Choice(FORM *form)
3078{
3079  FIELD *field = form->current;
3080
3081  T((T_CALLED("CR_Previous_Choice(%p)"), (void *)form));
3082  Synchronize_Buffer(form);
3083  returnCode((Previous_Choice(form, field->type, field, (TypeArgument *)(field->arg)))
3084	     ? E_OK
3085	     : E_REQUEST_DENIED);
3086}
3087/*----------------------------------------------------------------------------
3088  End of Routines for Choice Requests
3089  --------------------------------------------------------------------------*/
3090
3091/*----------------------------------------------------------------------------
3092  Helper routines for Field Validations.
3093  --------------------------------------------------------------------------*/
3094
3095/*---------------------------------------------------------------------------
3096|   Facility      :  libnform
3097|   Function      :  static bool Check_Field(FORM* form,
3098|                                            FIELDTYPE * typ,
3099|                                            FIELD * field,
3100|                                            TypeArgument * argp)
3101|
3102|   Description   :  Check the field according to its fieldtype and its
3103|                    actual arguments. For linked fieldtypes this is done
3104|                    recursively.
3105|
3106|   Return Values :  TRUE       - field is valid
3107|                    FALSE      - field is invalid.
3108+--------------------------------------------------------------------------*/
3109static bool
3110Check_Field(FORM *form, FIELDTYPE *typ, FIELD *field, TypeArgument *argp)
3111{
3112  if (typ)
3113    {
3114      if ((unsigned)field->opts & O_NULLOK)
3115	{
3116	  FIELD_CELL *bp = field->buf;
3117
3118	  assert(bp);
3119	  while (ISBLANK(*bp))
3120	    {
3121	      bp++;
3122	    }
3123	  if (CharOf(*bp) == 0)
3124	    return TRUE;
3125	}
3126
3127      if (typ->status & _LINKED_TYPE)
3128	{
3129	  assert(argp);
3130	  return (
3131		   Check_Field(form, typ->left, field, argp->left) ||
3132		   Check_Field(form, typ->right, field, argp->right));
3133	}
3134      else
3135	{
3136#if NCURSES_INTEROP_FUNCS
3137	  if (typ->fieldcheck.ofcheck)
3138	    {
3139	      if (typ->status & _GENERIC)
3140		return typ->fieldcheck.gfcheck(form, field, (void *)argp);
3141	      else
3142		return typ->fieldcheck.ofcheck(field, (void *)argp);
3143	    }
3144#else
3145	  if (typ->fcheck)
3146	    return typ->fcheck(field, (void *)argp);
3147#endif
3148	}
3149    }
3150  return TRUE;
3151}
3152
3153/*---------------------------------------------------------------------------
3154|   Facility      :  libnform
3155|   Function      :  bool _nc_Internal_Validation(FORM * form )
3156|
3157|   Description   :  Validate the current field of the form.
3158|
3159|   Return Values :  TRUE  - field is valid
3160|                    FALSE - field is invalid
3161+--------------------------------------------------------------------------*/
3162NCURSES_EXPORT(bool)
3163_nc_Internal_Validation(FORM *form)
3164{
3165  FIELD *field;
3166
3167  field = form->current;
3168
3169  Synchronize_Buffer(form);
3170  if ((form->status & _FCHECK_REQUIRED) ||
3171      (!((unsigned)field->opts & O_PASSOK)))
3172    {
3173      if (!Check_Field(form, field->type, field, (TypeArgument *)(field->arg)))
3174	return FALSE;
3175      ClrStatus(form, _FCHECK_REQUIRED);
3176      SetStatus(field, _CHANGED);
3177      Synchronize_Linked_Fields(field);
3178    }
3179  return TRUE;
3180}
3181/*----------------------------------------------------------------------------
3182  End of Helper routines for Field Validations.
3183  --------------------------------------------------------------------------*/
3184
3185/*----------------------------------------------------------------------------
3186  Routines for Field Validation.
3187  --------------------------------------------------------------------------*/
3188
3189/*---------------------------------------------------------------------------
3190|   Facility      :  libnform
3191|   Function      :  static int FV_Validation(FORM * form)
3192|
3193|   Description   :  Validate the current field of the form.
3194|
3195|   Return Values :  E_OK             - field valid
3196|                    E_INVALID_FIELD  - field not valid
3197+--------------------------------------------------------------------------*/
3198static int
3199FV_Validation(FORM *form)
3200{
3201  T((T_CALLED("FV_Validation(%p)"), (void *)form));
3202  if (_nc_Internal_Validation(form))
3203    returnCode(E_OK);
3204  else
3205    returnCode(E_INVALID_FIELD);
3206}
3207/*----------------------------------------------------------------------------
3208  End of routines for Field Validation.
3209  --------------------------------------------------------------------------*/
3210
3211/*----------------------------------------------------------------------------
3212  Helper routines for Inter-Field Navigation
3213  --------------------------------------------------------------------------*/
3214
3215/*---------------------------------------------------------------------------
3216|   Facility      :  libnform
3217|   Function      :  static FIELD *Next_Field_On_Page(FIELD * field)
3218|
3219|   Description   :  Get the next field after the given field on the current
3220|                    page. The order of fields is the one defined by the
3221|                    fields array. Only visible and active fields are
3222|                    counted.
3223|
3224|   Return Values :  Pointer to the next field.
3225+--------------------------------------------------------------------------*/
3226NCURSES_INLINE static FIELD *
3227Next_Field_On_Page(FIELD *field)
3228{
3229  FORM *form = field->form;
3230  FIELD **field_on_page = &form->field[field->index];
3231  FIELD **first_on_page = &form->field[form->page[form->curpage].pmin];
3232  FIELD **last_on_page = &form->field[form->page[form->curpage].pmax];
3233
3234  do
3235    {
3236      field_on_page =
3237	(field_on_page == last_on_page) ? first_on_page : field_on_page + 1;
3238      if (Field_Is_Selectable(*field_on_page))
3239	break;
3240    }
3241  while (field != (*field_on_page));
3242  return (*field_on_page);
3243}
3244
3245/*---------------------------------------------------------------------------
3246|   Facility      :  libnform
3247|   Function      :  FIELD* _nc_First_Active_Field(FORM * form)
3248|
3249|   Description   :  Get the first active field on the current page,
3250|                    if there are such. If there are none, get the first
3251|                    visible field on the page. If there are also none,
3252|                    we return the first field on page and hope the best.
3253|
3254|   Return Values :  Pointer to calculated field.
3255+--------------------------------------------------------------------------*/
3256NCURSES_EXPORT(FIELD *)
3257_nc_First_Active_Field(FORM *form)
3258{
3259  FIELD **last_on_page = &form->field[form->page[form->curpage].pmax];
3260  FIELD *proposed = Next_Field_On_Page(*last_on_page);
3261
3262  if (proposed == *last_on_page)
3263    {
3264      /* there might be the special situation, where there is no
3265         active and visible field on the current page. We then select
3266         the first visible field on this readonly page
3267       */
3268      if (Field_Is_Not_Selectable(proposed))
3269	{
3270	  FIELD **field = &form->field[proposed->index];
3271	  FIELD **first = &form->field[form->page[form->curpage].pmin];
3272
3273	  do
3274	    {
3275	      field = (field == last_on_page) ? first : field + 1;
3276	      if (((unsigned)(*field)->opts & O_VISIBLE))
3277		break;
3278	    }
3279	  while (proposed != (*field));
3280
3281	  proposed = *field;
3282
3283	  if ((proposed == *last_on_page) &&
3284	      !((unsigned)proposed->opts & O_VISIBLE))
3285	    {
3286	      /* This means, there is also no visible field on the page.
3287	         So we propose the first one and hope the very best...
3288	         Some very clever user has designed a readonly and invisible
3289	         page on this form.
3290	       */
3291	      proposed = *first;
3292	    }
3293	}
3294    }
3295  return (proposed);
3296}
3297
3298/*---------------------------------------------------------------------------
3299|   Facility      :  libnform
3300|   Function      :  static FIELD *Previous_Field_On_Page(FIELD * field)
3301|
3302|   Description   :  Get the previous field before the given field on the
3303|                    current page. The order of fields is the one defined by
3304|                    the fields array. Only visible and active fields are
3305|                    counted.
3306|
3307|   Return Values :  Pointer to the previous field.
3308+--------------------------------------------------------------------------*/
3309NCURSES_INLINE static FIELD *
3310Previous_Field_On_Page(FIELD *field)
3311{
3312  FORM *form = field->form;
3313  FIELD **field_on_page = &form->field[field->index];
3314  FIELD **first_on_page = &form->field[form->page[form->curpage].pmin];
3315  FIELD **last_on_page = &form->field[form->page[form->curpage].pmax];
3316
3317  do
3318    {
3319      field_on_page =
3320	(field_on_page == first_on_page) ? last_on_page : field_on_page - 1;
3321      if (Field_Is_Selectable(*field_on_page))
3322	break;
3323    }
3324  while (field != (*field_on_page));
3325
3326  return (*field_on_page);
3327}
3328
3329/*---------------------------------------------------------------------------
3330|   Facility      :  libnform
3331|   Function      :  static FIELD *Sorted_Next_Field(FIELD * field)
3332|
3333|   Description   :  Get the next field after the given field on the current
3334|                    page. The order of fields is the one defined by the
3335|                    (row,column) geometry, rows are major.
3336|
3337|   Return Values :  Pointer to the next field.
3338+--------------------------------------------------------------------------*/
3339NCURSES_INLINE static FIELD *
3340Sorted_Next_Field(FIELD *field)
3341{
3342  FIELD *field_on_page = field;
3343
3344  do
3345    {
3346      field_on_page = field_on_page->snext;
3347      if (Field_Is_Selectable(field_on_page))
3348	break;
3349    }
3350  while (field_on_page != field);
3351
3352  return (field_on_page);
3353}
3354
3355/*---------------------------------------------------------------------------
3356|   Facility      :  libnform
3357|   Function      :  static FIELD *Sorted_Previous_Field(FIELD * field)
3358|
3359|   Description   :  Get the previous field before the given field on the
3360|                    current page. The order of fields is the one defined
3361|                    by the (row,column) geometry, rows are major.
3362|
3363|   Return Values :  Pointer to the previous field.
3364+--------------------------------------------------------------------------*/
3365NCURSES_INLINE static FIELD *
3366Sorted_Previous_Field(FIELD *field)
3367{
3368  FIELD *field_on_page = field;
3369
3370  do
3371    {
3372      field_on_page = field_on_page->sprev;
3373      if (Field_Is_Selectable(field_on_page))
3374	break;
3375    }
3376  while (field_on_page != field);
3377
3378  return (field_on_page);
3379}
3380
3381/*---------------------------------------------------------------------------
3382|   Facility      :  libnform
3383|   Function      :  static FIELD *Left_Neighbor_Field(FIELD * field)
3384|
3385|   Description   :  Get the left neighbor of the field on the same line
3386|                    and the same page. Cycles through the line.
3387|
3388|   Return Values :  Pointer to left neighbor field.
3389+--------------------------------------------------------------------------*/
3390NCURSES_INLINE static FIELD *
3391Left_Neighbor_Field(FIELD *field)
3392{
3393  FIELD *field_on_page = field;
3394
3395  /* For a field that has really a left neighbor, the while clause
3396     immediately fails and the loop is left, positioned at the right
3397     neighbor. Otherwise we cycle backwards through the sorted field list
3398     until we enter the same line (from the right end).
3399   */
3400  do
3401    {
3402      field_on_page = Sorted_Previous_Field(field_on_page);
3403    }
3404  while (field_on_page->frow != field->frow);
3405
3406  return (field_on_page);
3407}
3408
3409/*---------------------------------------------------------------------------
3410|   Facility      :  libnform
3411|   Function      :  static FIELD *Right_Neighbor_Field(FIELD * field)
3412|
3413|   Description   :  Get the right neighbor of the field on the same line
3414|                    and the same page.
3415|
3416|   Return Values :  Pointer to right neighbor field.
3417+--------------------------------------------------------------------------*/
3418NCURSES_INLINE static FIELD *
3419Right_Neighbor_Field(FIELD *field)
3420{
3421  FIELD *field_on_page = field;
3422
3423  /* See the comments on Left_Neighbor_Field to understand how it works */
3424  do
3425    {
3426      field_on_page = Sorted_Next_Field(field_on_page);
3427    }
3428  while (field_on_page->frow != field->frow);
3429
3430  return (field_on_page);
3431}
3432
3433/*---------------------------------------------------------------------------
3434|   Facility      :  libnform
3435|   Function      :  static FIELD *Upper_Neighbor_Field(FIELD * field)
3436|
3437|   Description   :  Because of the row-major nature of sorting the fields,
3438|                    it is more difficult to define whats the upper neighbor
3439|                    field really means. We define that it must be on a
3440|                    'previous' line (cyclic order!) and is the rightmost
3441|                    field laying on the left side of the given field. If
3442|                    this set is empty, we take the first field on the line.
3443|
3444|   Return Values :  Pointer to the upper neighbor field.
3445+--------------------------------------------------------------------------*/
3446static FIELD *
3447Upper_Neighbor_Field(FIELD *field)
3448{
3449  FIELD *field_on_page = field;
3450  int frow = field->frow;
3451  int fcol = field->fcol;
3452
3453  /* Walk back to the 'previous' line. The second term in the while clause
3454     just guarantees that we stop if we cycled through the line because
3455     there might be no 'previous' line if the page has just one line.
3456   */
3457  do
3458    {
3459      field_on_page = Sorted_Previous_Field(field_on_page);
3460    }
3461  while (field_on_page->frow == frow && field_on_page->fcol != fcol);
3462
3463  if (field_on_page->frow != frow)
3464    {
3465      /* We really found a 'previous' line. We are positioned at the
3466         rightmost field on this line */
3467      frow = field_on_page->frow;
3468
3469      /* We walk to the left as long as we are really right of the
3470         field. */
3471      while (field_on_page->frow == frow && field_on_page->fcol > fcol)
3472	field_on_page = Sorted_Previous_Field(field_on_page);
3473
3474      /* If we wrapped, just go to the right which is the first field on
3475         the row */
3476      if (field_on_page->frow != frow)
3477	field_on_page = Sorted_Next_Field(field_on_page);
3478    }
3479
3480  return (field_on_page);
3481}
3482
3483/*---------------------------------------------------------------------------
3484|   Facility      :  libnform
3485|   Function      :  static FIELD *Down_Neighbor_Field(FIELD * field)
3486|
3487|   Description   :  Because of the row-major nature of sorting the fields,
3488|                    its more difficult to define whats the down neighbor
3489|                    field really means. We define that it must be on a
3490|                    'next' line (cyclic order!) and is the leftmost
3491|                    field laying on the right side of the given field. If
3492|                    this set is empty, we take the last field on the line.
3493|
3494|   Return Values :  Pointer to the upper neighbor field.
3495+--------------------------------------------------------------------------*/
3496static FIELD *
3497Down_Neighbor_Field(FIELD *field)
3498{
3499  FIELD *field_on_page = field;
3500  int frow = field->frow;
3501  int fcol = field->fcol;
3502
3503  /* Walk forward to the 'next' line. The second term in the while clause
3504     just guarantees that we stop if we cycled through the line because
3505     there might be no 'next' line if the page has just one line.
3506   */
3507  do
3508    {
3509      field_on_page = Sorted_Next_Field(field_on_page);
3510    }
3511  while (field_on_page->frow == frow && field_on_page->fcol != fcol);
3512
3513  if (field_on_page->frow != frow)
3514    {
3515      /* We really found a 'next' line. We are positioned at the rightmost
3516         field on this line */
3517      frow = field_on_page->frow;
3518
3519      /* We walk to the right as long as we are really left of the
3520         field. */
3521      while (field_on_page->frow == frow && field_on_page->fcol < fcol)
3522	field_on_page = Sorted_Next_Field(field_on_page);
3523
3524      /* If we wrapped, just go to the left which is the last field on
3525         the row */
3526      if (field_on_page->frow != frow)
3527	field_on_page = Sorted_Previous_Field(field_on_page);
3528    }
3529
3530  return (field_on_page);
3531}
3532
3533/*----------------------------------------------------------------------------
3534  Inter-Field Navigation routines
3535  --------------------------------------------------------------------------*/
3536
3537/*---------------------------------------------------------------------------
3538|   Facility      :  libnform
3539|   Function      :  static int Inter_Field_Navigation(
3540|                                           int (* const fct) (FORM *),
3541|                                           FORM * form)
3542|
3543|   Description   :  Generic behavior for changing the current field, the
3544|                    field is left and a new field is entered. So the field
3545|                    must be validated and the field init/term hooks must
3546|                    be called.
3547|
3548|   Return Values :  E_OK                - success
3549|                    E_INVALID_FIELD     - field is invalid
3550|                    some other          - error from subordinate call
3551+--------------------------------------------------------------------------*/
3552static int
3553Inter_Field_Navigation(int (*const fct) (FORM *), FORM *form)
3554{
3555  int res;
3556
3557  if (!_nc_Internal_Validation(form))
3558    res = E_INVALID_FIELD;
3559  else
3560    {
3561      Call_Hook(form, fieldterm);
3562      res = fct(form);
3563      Call_Hook(form, fieldinit);
3564    }
3565  return res;
3566}
3567
3568/*---------------------------------------------------------------------------
3569|   Facility      :  libnform
3570|   Function      :  static int FN_Next_Field(FORM * form)
3571|
3572|   Description   :  Move to the next field on the current page of the form
3573|
3574|   Return Values :  E_OK                 - success
3575|                    != E_OK              - error from subordinate call
3576+--------------------------------------------------------------------------*/
3577static int
3578FN_Next_Field(FORM *form)
3579{
3580  T((T_CALLED("FN_Next_Field(%p)"), (void *)form));
3581  returnCode(_nc_Set_Current_Field(form,
3582				   Next_Field_On_Page(form->current)));
3583}
3584
3585/*---------------------------------------------------------------------------
3586|   Facility      :  libnform
3587|   Function      :  static int FN_Previous_Field(FORM * form)
3588|
3589|   Description   :  Move to the previous field on the current page of the
3590|                    form
3591|
3592|   Return Values :  E_OK                 - success
3593|                    != E_OK              - error from subordinate call
3594+--------------------------------------------------------------------------*/
3595static int
3596FN_Previous_Field(FORM *form)
3597{
3598  T((T_CALLED("FN_Previous_Field(%p)"), (void *)form));
3599  returnCode(_nc_Set_Current_Field(form,
3600				   Previous_Field_On_Page(form->current)));
3601}
3602
3603/*---------------------------------------------------------------------------
3604|   Facility      :  libnform
3605|   Function      :  static int FN_First_Field(FORM * form)
3606|
3607|   Description   :  Move to the first field on the current page of the form
3608|
3609|   Return Values :  E_OK                 - success
3610|                    != E_OK              - error from subordinate call
3611+--------------------------------------------------------------------------*/
3612static int
3613FN_First_Field(FORM *form)
3614{
3615  T((T_CALLED("FN_First_Field(%p)"), (void *)form));
3616  returnCode(_nc_Set_Current_Field(form,
3617				   Next_Field_On_Page(form->field[form->page[form->curpage].pmax])));
3618}
3619
3620/*---------------------------------------------------------------------------
3621|   Facility      :  libnform
3622|   Function      :  static int FN_Last_Field(FORM * form)
3623|
3624|   Description   :  Move to the last field on the current page of the form
3625|
3626|   Return Values :  E_OK                 - success
3627|                    != E_OK              - error from subordinate call
3628+--------------------------------------------------------------------------*/
3629static int
3630FN_Last_Field(FORM *form)
3631{
3632  T((T_CALLED("FN_Last_Field(%p)"), (void *)form));
3633  returnCode(
3634	      _nc_Set_Current_Field(form,
3635				    Previous_Field_On_Page(form->field[form->page[form->curpage].pmin])));
3636}
3637
3638/*---------------------------------------------------------------------------
3639|   Facility      :  libnform
3640|   Function      :  static int FN_Sorted_Next_Field(FORM * form)
3641|
3642|   Description   :  Move to the sorted next field on the current page
3643|                    of the form.
3644|
3645|   Return Values :  E_OK            - success
3646|                    != E_OK         - error from subordinate call
3647+--------------------------------------------------------------------------*/
3648static int
3649FN_Sorted_Next_Field(FORM *form)
3650{
3651  T((T_CALLED("FN_Sorted_Next_Field(%p)"), (void *)form));
3652  returnCode(_nc_Set_Current_Field(form,
3653				   Sorted_Next_Field(form->current)));
3654}
3655
3656/*---------------------------------------------------------------------------
3657|   Facility      :  libnform
3658|   Function      :  static int FN_Sorted_Previous_Field(FORM * form)
3659|
3660|   Description   :  Move to the sorted previous field on the current page
3661|                    of the form.
3662|
3663|   Return Values :  E_OK            - success
3664|                    != E_OK         - error from subordinate call
3665+--------------------------------------------------------------------------*/
3666static int
3667FN_Sorted_Previous_Field(FORM *form)
3668{
3669  T((T_CALLED("FN_Sorted_Previous_Field(%p)"), (void *)form));
3670  returnCode(_nc_Set_Current_Field(form,
3671				   Sorted_Previous_Field(form->current)));
3672}
3673
3674/*---------------------------------------------------------------------------
3675|   Facility      :  libnform
3676|   Function      :  static int FN_Sorted_First_Field(FORM * form)
3677|
3678|   Description   :  Move to the sorted first field on the current page
3679|                    of the form.
3680|
3681|   Return Values :  E_OK            - success
3682|                    != E_OK         - error from subordinate call
3683+--------------------------------------------------------------------------*/
3684static int
3685FN_Sorted_First_Field(FORM *form)
3686{
3687  T((T_CALLED("FN_Sorted_First_Field(%p)"), (void *)form));
3688  returnCode(_nc_Set_Current_Field(form,
3689				   Sorted_Next_Field(form->field[form->page[form->curpage].smax])));
3690}
3691
3692/*---------------------------------------------------------------------------
3693|   Facility      :  libnform
3694|   Function      :  static int FN_Sorted_Last_Field(FORM * form)
3695|
3696|   Description   :  Move to the sorted last field on the current page
3697|                    of the form.
3698|
3699|   Return Values :  E_OK            - success
3700|                    != E_OK         - error from subordinate call
3701+--------------------------------------------------------------------------*/
3702static int
3703FN_Sorted_Last_Field(FORM *form)
3704{
3705  T((T_CALLED("FN_Sorted_Last_Field(%p)"), (void *)form));
3706  returnCode(_nc_Set_Current_Field(form,
3707				   Sorted_Previous_Field(form->field[form->page[form->curpage].smin])));
3708}
3709
3710/*---------------------------------------------------------------------------
3711|   Facility      :  libnform
3712|   Function      :  static int FN_Left_Field(FORM * form)
3713|
3714|   Description   :  Get the field on the left of the current field on the
3715|                    same line and the same page. Cycles through the line.
3716|
3717|   Return Values :  E_OK            - success
3718|                    != E_OK         - error from subordinate call
3719+--------------------------------------------------------------------------*/
3720static int
3721FN_Left_Field(FORM *form)
3722{
3723  T((T_CALLED("FN_Left_Field(%p)"), (void *)form));
3724  returnCode(_nc_Set_Current_Field(form,
3725				   Left_Neighbor_Field(form->current)));
3726}
3727
3728/*---------------------------------------------------------------------------
3729|   Facility      :  libnform
3730|   Function      :  static int FN_Right_Field(FORM * form)
3731|
3732|   Description   :  Get the field on the right of the current field on the
3733|                    same line and the same page. Cycles through the line.
3734|
3735|   Return Values :  E_OK            - success
3736|                    != E_OK         - error from subordinate call
3737+--------------------------------------------------------------------------*/
3738static int
3739FN_Right_Field(FORM *form)
3740{
3741  T((T_CALLED("FN_Right_Field(%p)"), (void *)form));
3742  returnCode(_nc_Set_Current_Field(form,
3743				   Right_Neighbor_Field(form->current)));
3744}
3745
3746/*---------------------------------------------------------------------------
3747|   Facility      :  libnform
3748|   Function      :  static int FN_Up_Field(FORM * form)
3749|
3750|   Description   :  Get the upper neighbor of the current field. This
3751|                    cycles through the page. See the comments of the
3752|                    Upper_Neighbor_Field function to understand how
3753|                    'upper' is defined.
3754|
3755|   Return Values :  E_OK            - success
3756|                    != E_OK         - error from subordinate call
3757+--------------------------------------------------------------------------*/
3758static int
3759FN_Up_Field(FORM *form)
3760{
3761  T((T_CALLED("FN_Up_Field(%p)"), (void *)form));
3762  returnCode(_nc_Set_Current_Field(form,
3763				   Upper_Neighbor_Field(form->current)));
3764}
3765
3766/*---------------------------------------------------------------------------
3767|   Facility      :  libnform
3768|   Function      :  static int FN_Down_Field(FORM * form)
3769|
3770|   Description   :  Get the down neighbor of the current field. This
3771|                    cycles through the page. See the comments of the
3772|                    Down_Neighbor_Field function to understand how
3773|                    'down' is defined.
3774|
3775|   Return Values :  E_OK            - success
3776|                    != E_OK         - error from subordinate call
3777+--------------------------------------------------------------------------*/
3778static int
3779FN_Down_Field(FORM *form)
3780{
3781  T((T_CALLED("FN_Down_Field(%p)"), (void *)form));
3782  returnCode(_nc_Set_Current_Field(form,
3783				   Down_Neighbor_Field(form->current)));
3784}
3785/*----------------------------------------------------------------------------
3786  END of Field Navigation routines
3787  --------------------------------------------------------------------------*/
3788
3789/*----------------------------------------------------------------------------
3790  Helper routines for Page Navigation
3791  --------------------------------------------------------------------------*/
3792
3793/*---------------------------------------------------------------------------
3794|   Facility      :  libnform
3795|   Function      :  int _nc_Set_Form_Page(FORM * form,
3796|                                          int page,
3797|                                          FIELD * field)
3798|
3799|   Description   :  Make the given page number the current page and make
3800|                    the given field the current field on the page. If
3801|                    for the field NULL is given, make the first field on
3802|                    the page the current field. The routine acts only
3803|                    if the requested page is not the current page.
3804|
3805|   Return Values :  E_OK                - success
3806|                    != E_OK             - error from subordinate call
3807|                    E_BAD_ARGUMENT      - invalid field pointer
3808|                    E_SYSTEM_ERROR      - some severe basic error
3809+--------------------------------------------------------------------------*/
3810NCURSES_EXPORT(int)
3811_nc_Set_Form_Page(FORM *form, int page, FIELD *field)
3812{
3813  int res = E_OK;
3814
3815  if ((form->curpage != page))
3816    {
3817      FIELD *last_field, *field_on_page;
3818
3819      werase(Get_Form_Window(form));
3820      form->curpage = (short)page;
3821      last_field = field_on_page = form->field[form->page[page].smin];
3822      do
3823	{
3824	  if ((unsigned)field_on_page->opts & O_VISIBLE)
3825	    if ((res = Display_Field(field_on_page)) != E_OK)
3826	      return (res);
3827	  field_on_page = field_on_page->snext;
3828	}
3829      while (field_on_page != last_field);
3830
3831      if (field)
3832	res = _nc_Set_Current_Field(form, field);
3833      else
3834	/* N.B.: we don't encapsulate this by Inter_Field_Navigation(),
3835	   because this is already executed in a page navigation
3836	   context that contains field navigation
3837	 */
3838	res = FN_First_Field(form);
3839    }
3840  return (res);
3841}
3842
3843/*---------------------------------------------------------------------------
3844|   Facility      :  libnform
3845|   Function      :  static int Next_Page_Number(const FORM * form)
3846|
3847|   Description   :  Calculate the page number following the current page
3848|                    number. This cycles if the highest page number is
3849|                    reached.
3850|
3851|   Return Values :  The next page number
3852+--------------------------------------------------------------------------*/
3853NCURSES_INLINE static int
3854Next_Page_Number(const FORM *form)
3855{
3856  return (form->curpage + 1) % form->maxpage;
3857}
3858
3859/*---------------------------------------------------------------------------
3860|   Facility      :  libnform
3861|   Function      :  static int Previous_Page_Number(const FORM * form)
3862|
3863|   Description   :  Calculate the page number before the current page
3864|                    number. This cycles if the first page number is
3865|                    reached.
3866|
3867|   Return Values :  The previous page number
3868+--------------------------------------------------------------------------*/
3869NCURSES_INLINE static int
3870Previous_Page_Number(const FORM *form)
3871{
3872  return (form->curpage != 0 ? form->curpage - 1 : form->maxpage - 1);
3873}
3874
3875/*----------------------------------------------------------------------------
3876  Page Navigation routines
3877  --------------------------------------------------------------------------*/
3878
3879/*---------------------------------------------------------------------------
3880|   Facility      :  libnform
3881|   Function      :  static int Page_Navigation(
3882|                                               int (* const fct) (FORM *),
3883|                                               FORM * form)
3884|
3885|   Description   :  Generic behavior for changing a page. This means
3886|                    that the field is left and a new field is entered.
3887|                    So the field must be validated and the field init/term
3888|                    hooks must be called. Because also the page is changed,
3889|                    the forms init/term hooks must be called also.
3890|
3891|   Return Values :  E_OK                - success
3892|                    E_INVALID_FIELD     - field is invalid
3893|                    some other          - error from subordinate call
3894+--------------------------------------------------------------------------*/
3895static int
3896Page_Navigation(int (*const fct) (FORM *), FORM *form)
3897{
3898  int res;
3899
3900  if (!_nc_Internal_Validation(form))
3901    res = E_INVALID_FIELD;
3902  else
3903    {
3904      Call_Hook(form, fieldterm);
3905      Call_Hook(form, formterm);
3906      res = fct(form);
3907      Call_Hook(form, forminit);
3908      Call_Hook(form, fieldinit);
3909    }
3910  return res;
3911}
3912
3913/*---------------------------------------------------------------------------
3914|   Facility      :  libnform
3915|   Function      :  static int PN_Next_Page(FORM * form)
3916|
3917|   Description   :  Move to the next page of the form
3918|
3919|   Return Values :  E_OK                - success
3920|                    != E_OK             - error from subordinate call
3921+--------------------------------------------------------------------------*/
3922static int
3923PN_Next_Page(FORM *form)
3924{
3925  T((T_CALLED("PN_Next_Page(%p)"), (void *)form));
3926  returnCode(_nc_Set_Form_Page(form, Next_Page_Number(form), (FIELD *)0));
3927}
3928
3929/*---------------------------------------------------------------------------
3930|   Facility      :  libnform
3931|   Function      :  static int PN_Previous_Page(FORM * form)
3932|
3933|   Description   :  Move to the previous page of the form
3934|
3935|   Return Values :  E_OK              - success
3936|                    != E_OK           - error from subordinate call
3937+--------------------------------------------------------------------------*/
3938static int
3939PN_Previous_Page(FORM *form)
3940{
3941  T((T_CALLED("PN_Previous_Page(%p)"), (void *)form));
3942  returnCode(_nc_Set_Form_Page(form, Previous_Page_Number(form), (FIELD *)0));
3943}
3944
3945/*---------------------------------------------------------------------------
3946|   Facility      :  libnform
3947|   Function      :  static int PN_First_Page(FORM * form)
3948|
3949|   Description   :  Move to the first page of the form
3950|
3951|   Return Values :  E_OK              - success
3952|                    != E_OK           - error from subordinate call
3953+--------------------------------------------------------------------------*/
3954static int
3955PN_First_Page(FORM *form)
3956{
3957  T((T_CALLED("PN_First_Page(%p)"), (void *)form));
3958  returnCode(_nc_Set_Form_Page(form, 0, (FIELD *)0));
3959}
3960
3961/*---------------------------------------------------------------------------
3962|   Facility      :  libnform
3963|   Function      :  static int PN_Last_Page(FORM * form)
3964|
3965|   Description   :  Move to the last page of the form
3966|
3967|   Return Values :  E_OK              - success
3968|                    != E_OK           - error from subordinate call
3969+--------------------------------------------------------------------------*/
3970static int
3971PN_Last_Page(FORM *form)
3972{
3973  T((T_CALLED("PN_Last_Page(%p)"), (void *)form));
3974  returnCode(_nc_Set_Form_Page(form, form->maxpage - 1, (FIELD *)0));
3975}
3976
3977/*----------------------------------------------------------------------------
3978  END of Field Navigation routines
3979  --------------------------------------------------------------------------*/
3980
3981/*----------------------------------------------------------------------------
3982  Helper routines for the core form driver.
3983  --------------------------------------------------------------------------*/
3984
3985# if USE_WIDEC_SUPPORT
3986/*---------------------------------------------------------------------------
3987|   Facility      :  libnform
3988|   Function      :  static int Data_Entry_w(FORM * form, wchar_t c)
3989|
3990|   Description   :  Enter the wide character c into at the current
3991|                    position of the current field of the form.
3992|
3993|   Return Values :  E_OK              - success
3994|                    E_REQUEST_DENIED  - driver could not process the request
3995|                    E_SYSTEM_ERROR    -
3996+--------------------------------------------------------------------------*/
3997static int
3998Data_Entry_w(FORM *form, wchar_t c)
3999{
4000  FIELD *field = form->current;
4001  int result = E_REQUEST_DENIED;
4002
4003  T((T_CALLED("Data_Entry(%p,%s)"), (void *)form, _tracechtype((chtype)c)));
4004  if (((unsigned)field->opts & O_EDIT)
4005#if FIX_FORM_INACTIVE_BUG
4006      && ((unsigned)field->opts & O_ACTIVE)
4007#endif
4008    )
4009    {
4010      wchar_t given[2];
4011      cchar_t temp_ch;
4012
4013      given[0] = c;
4014      given[1] = 1;
4015      setcchar(&temp_ch, given, 0, 0, (void *)0);
4016      if (((unsigned)field->opts & O_BLANK) &&
4017	  First_Position_In_Current_Field(form) &&
4018	  !(form->status & _FCHECK_REQUIRED) &&
4019	  !(form->status & _WINDOW_MODIFIED))
4020	werase(form->w);
4021
4022      if (form->status & _OVLMODE)
4023	{
4024	  wadd_wch(form->w, &temp_ch);
4025	}
4026      else
4027	/* no _OVLMODE */
4028	{
4029	  bool There_Is_Room = Is_There_Room_For_A_Char_In_Line(form);
4030
4031	  if (!(There_Is_Room ||
4032		((Single_Line_Field(field) && Growable(field)))))
4033	    RETURN(E_REQUEST_DENIED);
4034
4035	  if (!There_Is_Room && !Field_Grown(field, 1))
4036	    RETURN(E_SYSTEM_ERROR);
4037
4038	  wins_wch(form->w, &temp_ch);
4039	}
4040
4041      if ((result = Wrapping_Not_Necessary_Or_Wrapping_Ok(form)) == E_OK)
4042	{
4043	  bool End_Of_Field = (((field->drows - 1) == form->currow) &&
4044			       ((field->dcols - 1) == form->curcol));
4045
4046	  form->status |= _WINDOW_MODIFIED;
4047	  if (End_Of_Field && !Growable(field) && ((unsigned)field->opts & O_AUTOSKIP))
4048	    result = Inter_Field_Navigation(FN_Next_Field, form);
4049	  else
4050	    {
4051	      if (End_Of_Field && Growable(field) && !Field_Grown(field, 1))
4052		result = E_SYSTEM_ERROR;
4053	      else
4054		{
4055		  /*
4056		   * We have just added a byte to the form field.  It may have
4057		   * been part of a multibyte character.  If it was, the
4058		   * addch_used field is nonzero and we should not try to move
4059		   * to a new column.
4060		   */
4061		  if (WINDOW_EXT(form->w, addch_used) == 0)
4062		    IFN_Next_Character(form);
4063
4064		  result = E_OK;
4065		}
4066	    }
4067	}
4068    }
4069  RETURN(result);
4070}
4071# endif
4072
4073/*---------------------------------------------------------------------------
4074|   Facility      :  libnform
4075|   Function      :  static int Data_Entry(FORM * form,int c)
4076|
4077|   Description   :  Enter character c into at the current position of the
4078|                    current field of the form.
4079|
4080|   Return Values :  E_OK              - success
4081|                    E_REQUEST_DENIED  - driver could not process the request
4082|                    E_SYSTEM_ERROR    -
4083+--------------------------------------------------------------------------*/
4084static int
4085Data_Entry(FORM *form, int c)
4086{
4087  FIELD *field = form->current;
4088  int result = E_REQUEST_DENIED;
4089
4090  T((T_CALLED("Data_Entry(%p,%s)"), (void *)form, _tracechtype((chtype)c)));
4091  if (((unsigned)field->opts & O_EDIT)
4092#if FIX_FORM_INACTIVE_BUG
4093      && ((unsigned)field->opts & O_ACTIVE)
4094#endif
4095    )
4096    {
4097      if (((unsigned)field->opts & O_BLANK) &&
4098	  First_Position_In_Current_Field(form) &&
4099	  !(form->status & _FCHECK_REQUIRED) &&
4100	  !(form->status & _WINDOW_MODIFIED))
4101	werase(form->w);
4102
4103      if (form->status & _OVLMODE)
4104	{
4105	  waddch(form->w, (chtype)c);
4106	}
4107      else
4108	/* no _OVLMODE */
4109	{
4110	  bool There_Is_Room = Is_There_Room_For_A_Char_In_Line(form);
4111
4112	  if (!(There_Is_Room ||
4113		((Single_Line_Field(field) && Growable(field)))))
4114	    RETURN(E_REQUEST_DENIED);
4115
4116	  if (!There_Is_Room && !Field_Grown(field, 1))
4117	    RETURN(E_SYSTEM_ERROR);
4118
4119	  winsch(form->w, (chtype)c);
4120	}
4121
4122      if ((result = Wrapping_Not_Necessary_Or_Wrapping_Ok(form)) == E_OK)
4123	{
4124	  bool End_Of_Field = (((field->drows - 1) == form->currow) &&
4125			       ((field->dcols - 1) == form->curcol));
4126
4127	  SetStatus(form, _WINDOW_MODIFIED);
4128	  if (End_Of_Field && !Growable(field) && ((unsigned)field->opts & O_AUTOSKIP))
4129	    result = Inter_Field_Navigation(FN_Next_Field, form);
4130	  else
4131	    {
4132	      if (End_Of_Field && Growable(field) && !Field_Grown(field, 1))
4133		result = E_SYSTEM_ERROR;
4134	      else
4135		{
4136#if USE_WIDEC_SUPPORT
4137		  /*
4138		   * We have just added a byte to the form field.  It may have
4139		   * been part of a multibyte character.  If it was, the
4140		   * addch_used field is nonzero and we should not try to move
4141		   * to a new column.
4142		   */
4143		  if (WINDOW_EXT(form->w, addch_used) == 0)
4144		    IFN_Next_Character(form);
4145#else
4146		  IFN_Next_Character(form);
4147#endif
4148		  result = E_OK;
4149		}
4150	    }
4151	}
4152    }
4153  RETURN(result);
4154}
4155
4156/* Structure to describe the binding of a request code to a function.
4157   The member keycode codes the request value as well as the generic
4158   routine to use for the request. The code for the generic routine
4159   is coded in the upper 16 Bits while the request code is coded in
4160   the lower 16 bits.
4161
4162   In terms of C++ you might think of a request as a class with a
4163   virtual method "perform". The different types of request are
4164   derived from this base class and overload (or not) the base class
4165   implementation of perform.
4166*/
4167typedef struct
4168{
4169  int keycode;			/* must be at least 32 bit: hi:mode, lo: key */
4170  int (*cmd) (FORM *);		/* low level driver routine for this key     */
4171}
4172Binding_Info;
4173
4174/* You may see this is the class-id of the request type class */
4175#define ID_PN    (0x00000000)	/* Page navigation           */
4176#define ID_FN    (0x00010000)	/* Inter-Field navigation    */
4177#define ID_IFN   (0x00020000)	/* Intra-Field navigation    */
4178#define ID_VSC   (0x00030000)	/* Vertical Scrolling        */
4179#define ID_HSC   (0x00040000)	/* Horizontal Scrolling      */
4180#define ID_FE    (0x00050000)	/* Field Editing             */
4181#define ID_EM    (0x00060000)	/* Edit Mode                 */
4182#define ID_FV    (0x00070000)	/* Field Validation          */
4183#define ID_CH    (0x00080000)	/* Choice                    */
4184#define ID_Mask  (0xffff0000)
4185#define Key_Mask (0x0000ffff)
4186#define ID_Shft  (16)
4187
4188/* This array holds all the Binding Infos */
4189/* *INDENT-OFF* */
4190static const Binding_Info bindings[MAX_FORM_COMMAND - MIN_FORM_COMMAND + 1] =
4191{
4192  { REQ_NEXT_PAGE    |ID_PN  ,PN_Next_Page},
4193  { REQ_PREV_PAGE    |ID_PN  ,PN_Previous_Page},
4194  { REQ_FIRST_PAGE   |ID_PN  ,PN_First_Page},
4195  { REQ_LAST_PAGE    |ID_PN  ,PN_Last_Page},
4196
4197  { REQ_NEXT_FIELD   |ID_FN  ,FN_Next_Field},
4198  { REQ_PREV_FIELD   |ID_FN  ,FN_Previous_Field},
4199  { REQ_FIRST_FIELD  |ID_FN  ,FN_First_Field},
4200  { REQ_LAST_FIELD   |ID_FN  ,FN_Last_Field},
4201  { REQ_SNEXT_FIELD  |ID_FN  ,FN_Sorted_Next_Field},
4202  { REQ_SPREV_FIELD  |ID_FN  ,FN_Sorted_Previous_Field},
4203  { REQ_SFIRST_FIELD |ID_FN  ,FN_Sorted_First_Field},
4204  { REQ_SLAST_FIELD  |ID_FN  ,FN_Sorted_Last_Field},
4205  { REQ_LEFT_FIELD   |ID_FN  ,FN_Left_Field},
4206  { REQ_RIGHT_FIELD  |ID_FN  ,FN_Right_Field},
4207  { REQ_UP_FIELD     |ID_FN  ,FN_Up_Field},
4208  { REQ_DOWN_FIELD   |ID_FN  ,FN_Down_Field},
4209
4210  { REQ_NEXT_CHAR    |ID_IFN ,IFN_Next_Character},
4211  { REQ_PREV_CHAR    |ID_IFN ,IFN_Previous_Character},
4212  { REQ_NEXT_LINE    |ID_IFN ,IFN_Next_Line},
4213  { REQ_PREV_LINE    |ID_IFN ,IFN_Previous_Line},
4214  { REQ_NEXT_WORD    |ID_IFN ,IFN_Next_Word},
4215  { REQ_PREV_WORD    |ID_IFN ,IFN_Previous_Word},
4216  { REQ_BEG_FIELD    |ID_IFN ,IFN_Beginning_Of_Field},
4217  { REQ_END_FIELD    |ID_IFN ,IFN_End_Of_Field},
4218  { REQ_BEG_LINE     |ID_IFN ,IFN_Beginning_Of_Line},
4219  { REQ_END_LINE     |ID_IFN ,IFN_End_Of_Line},
4220  { REQ_LEFT_CHAR    |ID_IFN ,IFN_Left_Character},
4221  { REQ_RIGHT_CHAR   |ID_IFN ,IFN_Right_Character},
4222  { REQ_UP_CHAR      |ID_IFN ,IFN_Up_Character},
4223  { REQ_DOWN_CHAR    |ID_IFN ,IFN_Down_Character},
4224
4225  { REQ_NEW_LINE     |ID_FE  ,FE_New_Line},
4226  { REQ_INS_CHAR     |ID_FE  ,FE_Insert_Character},
4227  { REQ_INS_LINE     |ID_FE  ,FE_Insert_Line},
4228  { REQ_DEL_CHAR     |ID_FE  ,FE_Delete_Character},
4229  { REQ_DEL_PREV     |ID_FE  ,FE_Delete_Previous},
4230  { REQ_DEL_LINE     |ID_FE  ,FE_Delete_Line},
4231  { REQ_DEL_WORD     |ID_FE  ,FE_Delete_Word},
4232  { REQ_CLR_EOL      |ID_FE  ,FE_Clear_To_End_Of_Line},
4233  { REQ_CLR_EOF      |ID_FE  ,FE_Clear_To_End_Of_Field},
4234  { REQ_CLR_FIELD    |ID_FE  ,FE_Clear_Field},
4235
4236  { REQ_OVL_MODE     |ID_EM  ,EM_Overlay_Mode},
4237  { REQ_INS_MODE     |ID_EM  ,EM_Insert_Mode},
4238
4239  { REQ_SCR_FLINE    |ID_VSC ,VSC_Scroll_Line_Forward},
4240  { REQ_SCR_BLINE    |ID_VSC ,VSC_Scroll_Line_Backward},
4241  { REQ_SCR_FPAGE    |ID_VSC ,VSC_Scroll_Page_Forward},
4242  { REQ_SCR_BPAGE    |ID_VSC ,VSC_Scroll_Page_Backward},
4243  { REQ_SCR_FHPAGE   |ID_VSC ,VSC_Scroll_Half_Page_Forward},
4244  { REQ_SCR_BHPAGE   |ID_VSC ,VSC_Scroll_Half_Page_Backward},
4245
4246  { REQ_SCR_FCHAR    |ID_HSC ,HSC_Scroll_Char_Forward},
4247  { REQ_SCR_BCHAR    |ID_HSC ,HSC_Scroll_Char_Backward},
4248  { REQ_SCR_HFLINE   |ID_HSC ,HSC_Horizontal_Line_Forward},
4249  { REQ_SCR_HBLINE   |ID_HSC ,HSC_Horizontal_Line_Backward},
4250  { REQ_SCR_HFHALF   |ID_HSC ,HSC_Horizontal_Half_Line_Forward},
4251  { REQ_SCR_HBHALF   |ID_HSC ,HSC_Horizontal_Half_Line_Backward},
4252
4253  { REQ_VALIDATION   |ID_FV  ,FV_Validation},
4254
4255  { REQ_NEXT_CHOICE  |ID_CH  ,CR_Next_Choice},
4256  { REQ_PREV_CHOICE  |ID_CH  ,CR_Previous_Choice}
4257};
4258/* *INDENT-ON* */
4259
4260/*---------------------------------------------------------------------------
4261|   Facility      :  libnform
4262|   Function      :  int form_driver(FORM * form,int  c)
4263|
4264|   Description   :  This is the workhorse of the forms system. It checks
4265|                    to determine whether the character c is a request or
4266|                    data. If it is a request, the form driver executes
4267|                    the request and returns the result. If it is data
4268|                    (printable character), it enters the data into the
4269|                    current position in the current field. If it is not
4270|                    recognized, the form driver assumes it is an application
4271|                    defined command and returns E_UNKNOWN_COMMAND.
4272|                    Application defined command should be defined relative
4273|                    to MAX_FORM_COMMAND, the maximum value of a request.
4274|
4275|   Return Values :  E_OK              - success
4276|                    E_SYSTEM_ERROR    - system error
4277|                    E_BAD_ARGUMENT    - an argument is incorrect
4278|                    E_NOT_POSTED      - form is not posted
4279|                    E_INVALID_FIELD   - field contents are invalid
4280|                    E_BAD_STATE       - called from inside a hook routine
4281|                    E_REQUEST_DENIED  - request failed
4282|                    E_NOT_CONNECTED   - no fields are connected to the form
4283|                    E_UNKNOWN_COMMAND - command not known
4284+--------------------------------------------------------------------------*/
4285NCURSES_EXPORT(int)
4286form_driver(FORM *form, int c)
4287{
4288  const Binding_Info *BI = (Binding_Info *) 0;
4289  int res = E_UNKNOWN_COMMAND;
4290
4291  T((T_CALLED("form_driver(%p,%d)"), (void *)form, c));
4292
4293  if (!form)
4294    RETURN(E_BAD_ARGUMENT);
4295
4296  if (!(form->field))
4297    RETURN(E_NOT_CONNECTED);
4298
4299  assert(form->page);
4300
4301  if (c == FIRST_ACTIVE_MAGIC)
4302    {
4303      form->current = _nc_First_Active_Field(form);
4304      RETURN(E_OK);
4305    }
4306
4307  assert(form->current &&
4308	 form->current->buf &&
4309	 (form->current->form == form)
4310    );
4311
4312  if (form->status & _IN_DRIVER)
4313    RETURN(E_BAD_STATE);
4314
4315  if (!(form->status & _POSTED))
4316    RETURN(E_NOT_POSTED);
4317
4318  if ((c >= MIN_FORM_COMMAND && c <= MAX_FORM_COMMAND) &&
4319      ((bindings[c - MIN_FORM_COMMAND].keycode & Key_Mask) == c))
4320    {
4321      TR(TRACE_CALLS, ("form_request %s", form_request_name(c)));
4322      BI = &(bindings[c - MIN_FORM_COMMAND]);
4323    }
4324
4325  if (BI)
4326    {
4327      typedef int (*Generic_Method) (int (*const) (FORM *), FORM *);
4328      static const Generic_Method Generic_Methods[] =
4329      {
4330	Page_Navigation,	/* overloaded to call field&form hooks */
4331	Inter_Field_Navigation,	/* overloaded to call field hooks      */
4332	NULL,			/* Intra-Field is generic              */
4333	Vertical_Scrolling,	/* Overloaded to check multi-line      */
4334	Horizontal_Scrolling,	/* Overloaded to check single-line     */
4335	Field_Editing,		/* Overloaded to mark modification     */
4336	NULL,			/* Edit Mode is generic                */
4337	NULL,			/* Field Validation is generic         */
4338	NULL			/* Choice Request is generic           */
4339      };
4340      size_t nMethods = (sizeof(Generic_Methods) / sizeof(Generic_Methods[0]));
4341      size_t method = (size_t) ((BI->keycode >> ID_Shft) & 0xffff);	/* see ID_Mask */
4342
4343      if ((method >= nMethods) || !(BI->cmd))
4344	res = E_SYSTEM_ERROR;
4345      else
4346	{
4347	  Generic_Method fct = Generic_Methods[method];
4348
4349	  if (fct)
4350	    {
4351	      res = fct(BI->cmd, form);
4352	    }
4353	  else
4354	    {
4355	      res = (BI->cmd) (form);
4356	    }
4357	}
4358    }
4359#ifdef NCURSES_MOUSE_VERSION
4360  else if (KEY_MOUSE == c)
4361    {
4362      MEVENT event;
4363      WINDOW *win = form->win ? form->win : StdScreen(Get_Form_Screen(form));
4364      WINDOW *sub = form->sub ? form->sub : win;
4365
4366      getmouse(&event);
4367      if ((event.bstate & (BUTTON1_CLICKED |
4368			   BUTTON1_DOUBLE_CLICKED |
4369			   BUTTON1_TRIPLE_CLICKED))
4370	  && wenclose(win, event.y, event.x))
4371	{			/* we react only if the click was in the userwin, that means
4372				 * inside the form display area or at the decoration window.
4373				 */
4374	  int ry = event.y, rx = event.x;	/* screen coordinates */
4375
4376	  res = E_REQUEST_DENIED;
4377	  if (mouse_trafo(&ry, &rx, FALSE))
4378	    {			/* rx, ry are now "curses" coordinates */
4379	      if (ry < sub->_begy)
4380		{		/* we clicked above the display region; this is
4381				 * interpreted as "scroll up" request
4382				 */
4383		  if (event.bstate & BUTTON1_CLICKED)
4384		    res = form_driver(form, REQ_PREV_FIELD);
4385		  else if (event.bstate & BUTTON1_DOUBLE_CLICKED)
4386		    res = form_driver(form, REQ_PREV_PAGE);
4387		  else if (event.bstate & BUTTON1_TRIPLE_CLICKED)
4388		    res = form_driver(form, REQ_FIRST_FIELD);
4389		}
4390	      else if (ry > sub->_begy + sub->_maxy)
4391		{		/* we clicked below the display region; this is
4392				 * interpreted as "scroll down" request
4393				 */
4394		  if (event.bstate & BUTTON1_CLICKED)
4395		    res = form_driver(form, REQ_NEXT_FIELD);
4396		  else if (event.bstate & BUTTON1_DOUBLE_CLICKED)
4397		    res = form_driver(form, REQ_NEXT_PAGE);
4398		  else if (event.bstate & BUTTON1_TRIPLE_CLICKED)
4399		    res = form_driver(form, REQ_LAST_FIELD);
4400		}
4401	      else if (wenclose(sub, event.y, event.x))
4402		{		/* Inside the area we try to find the hit item */
4403		  int i;
4404
4405		  ry = event.y;
4406		  rx = event.x;
4407		  if (wmouse_trafo(sub, &ry, &rx, FALSE))
4408		    {
4409		      int min_field = form->page[form->curpage].pmin;
4410		      int max_field = form->page[form->curpage].pmax;
4411
4412		      for (i = min_field; i <= max_field; ++i)
4413			{
4414			  FIELD *field = form->field[i];
4415
4416			  if (Field_Is_Selectable(field)
4417			      && Field_encloses(field, ry, rx) == E_OK)
4418			    {
4419			      res = _nc_Set_Current_Field(form, field);
4420			      if (res == E_OK)
4421				res = _nc_Position_Form_Cursor(form);
4422			      if (res == E_OK
4423				  && (event.bstate & BUTTON1_DOUBLE_CLICKED))
4424				res = E_UNKNOWN_COMMAND;
4425			      break;
4426			    }
4427			}
4428		    }
4429		}
4430	    }
4431	}
4432      else
4433	res = E_REQUEST_DENIED;
4434    }
4435#endif /* NCURSES_MOUSE_VERSION */
4436  else if (!(c & (~(int)MAX_REGULAR_CHARACTER)))
4437    {
4438      /*
4439       * If we're using 8-bit characters, iscntrl+isprint cover the whole set.
4440       * But with multibyte characters, there is a third possibility, i.e.,
4441       * parts of characters that build up into printable characters which are
4442       * not considered printable.
4443       *
4444       * FIXME: the wide-character branch should also use Check_Char().
4445       */
4446#if USE_WIDEC_SUPPORT
4447      if (!iscntrl(UChar(c)))
4448#else
4449      if (isprint(UChar(c)) &&
4450	  Check_Char(form, form->current, form->current->type, c,
4451		     (TypeArgument *)(form->current->arg)))
4452#endif
4453	res = Data_Entry(form, c);
4454    }
4455  _nc_Refresh_Current_Field(form);
4456  RETURN(res);
4457}
4458
4459# if USE_WIDEC_SUPPORT
4460/*---------------------------------------------------------------------------
4461|   Facility      :  libnform
4462|   Function      :  int form_driver_w(FORM * form,int type,wchar_t  c)
4463|
4464|   Description   :  This is the workhorse of the forms system.
4465|
4466|                    Input is either a key code (request) or a wide char
4467|                    returned by e.g. get_wch (). The type must be passed
4468|                    as well,so that we are able to determine whether the char
4469|                    is a multibyte char or a request.
4470
4471|                    If it is a request, the form driver executes
4472|                    the request and returns the result. If it is data
4473|                    (printable character), it enters the data into the
4474|                    current position in the current field. If it is not
4475|                    recognized, the form driver assumes it is an application
4476|                    defined command and returns E_UNKNOWN_COMMAND.
4477|                    Application defined command should be defined relative
4478|                    to MAX_FORM_COMMAND, the maximum value of a request.
4479|
4480|   Return Values :  E_OK              - success
4481|                    E_SYSTEM_ERROR    - system error
4482|                    E_BAD_ARGUMENT    - an argument is incorrect
4483|                    E_NOT_POSTED      - form is not posted
4484|                    E_INVALID_FIELD   - field contents are invalid
4485|                    E_BAD_STATE       - called from inside a hook routine
4486|                    E_REQUEST_DENIED  - request failed
4487|                    E_NOT_CONNECTED   - no fields are connected to the form
4488|                    E_UNKNOWN_COMMAND - command not known
4489+--------------------------------------------------------------------------*/
4490NCURSES_EXPORT(int)
4491form_driver_w(FORM *form, int type, wchar_t c)
4492{
4493  const Binding_Info *BI = (Binding_Info *) 0;
4494  int res = E_UNKNOWN_COMMAND;
4495
4496  T((T_CALLED("form_driver(%p,%d)"), (void *)form, (int) c));
4497
4498  if (!form)
4499    RETURN(E_BAD_ARGUMENT);
4500
4501  if (!(form->field))
4502    RETURN(E_NOT_CONNECTED);
4503
4504  assert(form->page);
4505
4506  if (c == (wchar_t)FIRST_ACTIVE_MAGIC)
4507    {
4508      form->current = _nc_First_Active_Field(form);
4509      RETURN(E_OK);
4510    }
4511
4512  assert(form->current &&
4513	 form->current->buf &&
4514	 (form->current->form == form)
4515    );
4516
4517  if (form->status & _IN_DRIVER)
4518    RETURN(E_BAD_STATE);
4519
4520  if (!(form->status & _POSTED))
4521    RETURN(E_NOT_POSTED);
4522
4523  /* check if this is a keycode or a (wide) char */
4524  if (type == KEY_CODE_YES)
4525    {
4526      if ((c >= MIN_FORM_COMMAND && c <= MAX_FORM_COMMAND) &&
4527	  ((bindings[c - MIN_FORM_COMMAND].keycode & Key_Mask) == c))
4528	BI = &(bindings[c - MIN_FORM_COMMAND]);
4529    }
4530
4531  if (BI)
4532    {
4533      typedef int (*Generic_Method) (int (*const) (FORM *), FORM *);
4534      static const Generic_Method Generic_Methods[] =
4535      {
4536	Page_Navigation,	/* overloaded to call field&form hooks */
4537	Inter_Field_Navigation,	/* overloaded to call field hooks      */
4538	NULL,			/* Intra-Field is generic              */
4539	Vertical_Scrolling,	/* Overloaded to check multi-line      */
4540	Horizontal_Scrolling,	/* Overloaded to check single-line     */
4541	Field_Editing,		/* Overloaded to mark modification     */
4542	NULL,			/* Edit Mode is generic                */
4543	NULL,			/* Field Validation is generic         */
4544	NULL			/* Choice Request is generic           */
4545      };
4546      size_t nMethods = (sizeof(Generic_Methods) / sizeof(Generic_Methods[0]));
4547      size_t method = (size_t) (BI->keycode >> ID_Shft) & 0xffff;	/* see ID_Mask */
4548
4549      if ((method >= nMethods) || !(BI->cmd))
4550	res = E_SYSTEM_ERROR;
4551      else
4552	{
4553	  Generic_Method fct = Generic_Methods[method];
4554
4555	  if (fct)
4556	    res = fct(BI->cmd, form);
4557	  else
4558	    res = (BI->cmd) (form);
4559	}
4560    }
4561#ifdef NCURSES_MOUSE_VERSION
4562  else if (KEY_MOUSE == c)
4563    {
4564      MEVENT event;
4565      WINDOW *win = form->win ? form->win : StdScreen(Get_Form_Screen(form));
4566      WINDOW *sub = form->sub ? form->sub : win;
4567
4568      getmouse(&event);
4569      if ((event.bstate & (BUTTON1_CLICKED |
4570			   BUTTON1_DOUBLE_CLICKED |
4571			   BUTTON1_TRIPLE_CLICKED))
4572	  && wenclose(win, event.y, event.x))
4573	{			/* we react only if the click was in the userwin, that means
4574				   * inside the form display area or at the decoration window.
4575				 */
4576	  int ry = event.y, rx = event.x;	/* screen coordinates */
4577
4578	  res = E_REQUEST_DENIED;
4579	  if (mouse_trafo(&ry, &rx, FALSE))
4580	    {			/* rx, ry are now "curses" coordinates */
4581	      if (ry < sub->_begy)
4582		{		/* we clicked above the display region; this is
4583				   * interpreted as "scroll up" request
4584				 */
4585		  if (event.bstate & BUTTON1_CLICKED)
4586		    res = form_driver(form, REQ_PREV_FIELD);
4587		  else if (event.bstate & BUTTON1_DOUBLE_CLICKED)
4588		    res = form_driver(form, REQ_PREV_PAGE);
4589		  else if (event.bstate & BUTTON1_TRIPLE_CLICKED)
4590		    res = form_driver(form, REQ_FIRST_FIELD);
4591		}
4592	      else if (ry > sub->_begy + sub->_maxy)
4593		{		/* we clicked below the display region; this is
4594				   * interpreted as "scroll down" request
4595				 */
4596		  if (event.bstate & BUTTON1_CLICKED)
4597		    res = form_driver(form, REQ_NEXT_FIELD);
4598		  else if (event.bstate & BUTTON1_DOUBLE_CLICKED)
4599		    res = form_driver(form, REQ_NEXT_PAGE);
4600		  else if (event.bstate & BUTTON1_TRIPLE_CLICKED)
4601		    res = form_driver(form, REQ_LAST_FIELD);
4602		}
4603	      else if (wenclose(sub, event.y, event.x))
4604		{		/* Inside the area we try to find the hit item */
4605		  int i;
4606
4607		  ry = event.y;
4608		  rx = event.x;
4609		  if (wmouse_trafo(sub, &ry, &rx, FALSE))
4610		    {
4611		      int min_field = form->page[form->curpage].pmin;
4612		      int max_field = form->page[form->curpage].pmax;
4613
4614		      for (i = min_field; i <= max_field; ++i)
4615			{
4616			  FIELD *field = form->field[i];
4617
4618			  if (Field_Is_Selectable(field)
4619			      && Field_encloses(field, ry, rx) == E_OK)
4620			    {
4621			      res = _nc_Set_Current_Field(form, field);
4622			      if (res == E_OK)
4623				res = _nc_Position_Form_Cursor(form);
4624			      if (res == E_OK
4625				  && (event.bstate & BUTTON1_DOUBLE_CLICKED))
4626				res = E_UNKNOWN_COMMAND;
4627			      break;
4628			    }
4629			}
4630		    }
4631		}
4632	    }
4633	}
4634      else
4635	res = E_REQUEST_DENIED;
4636    }
4637#endif /* NCURSES_MOUSE_VERSION */
4638  else if (type == OK)
4639    {
4640      res = Data_Entry_w(form, c);
4641    }
4642
4643  _nc_Refresh_Current_Field(form);
4644  RETURN(res);
4645}
4646# endif	/* USE_WIDEC_SUPPORT */
4647
4648/*----------------------------------------------------------------------------
4649  Field-Buffer manipulation routines.
4650  The effects of setting a buffer are tightly coupled to the core of the form
4651  driver logic. This is especially true in the case of growable fields.
4652  So I don't separate this into a separate module.
4653  --------------------------------------------------------------------------*/
4654
4655/*---------------------------------------------------------------------------
4656|   Facility      :  libnform
4657|   Function      :  int set_field_buffer(FIELD *field,
4658|                                         int buffer, char *value)
4659|
4660|   Description   :  Set the given buffer of the field to the given value.
4661|                    Buffer 0 stores the displayed content of the field.
4662|                    For dynamic fields this may grow the fieldbuffers if
4663|                    the length of the value exceeds the current buffer
4664|                    length. For buffer 0 only printable values are allowed.
4665|                    For static fields, the value needs not to be zero ter-
4666|                    minated. It is copied up to the length of the buffer.
4667|
4668|   Return Values :  E_OK            - success
4669|                    E_BAD_ARGUMENT  - invalid argument
4670|                    E_SYSTEM_ERROR  - system error
4671+--------------------------------------------------------------------------*/
4672NCURSES_EXPORT(int)
4673set_field_buffer(FIELD *field, int buffer, const char *value)
4674{
4675  FIELD_CELL *p;
4676  int res = E_OK;
4677  int i;
4678  int len;
4679
4680#if USE_WIDEC_SUPPORT
4681  FIELD_CELL *widevalue = 0;
4682#endif
4683
4684  T((T_CALLED("set_field_buffer(%p,%d,%s)"), (void *)field, buffer, _nc_visbuf(value)));
4685
4686  if (!field || !value || ((buffer < 0) || (buffer > field->nbuf)))
4687    RETURN(E_BAD_ARGUMENT);
4688
4689  len = Buffer_Length(field);
4690
4691  if (Growable(field))
4692    {
4693      /* for a growable field we must assume zero terminated strings, because
4694         somehow we have to detect the length of what should be copied.
4695       */
4696      int vlen = (int)strlen(value);
4697
4698      if (vlen > len)
4699	{
4700	  if (!Field_Grown(field,
4701			   (int)(1 + (vlen - len) / ((field->rows + field->nrow)
4702						     * field->cols))))
4703	    RETURN(E_SYSTEM_ERROR);
4704
4705#if !USE_WIDEC_SUPPORT
4706	  len = vlen;
4707#endif
4708	}
4709    }
4710
4711  p = Address_Of_Nth_Buffer(field, buffer);
4712
4713#if USE_WIDEC_SUPPORT
4714  /*
4715   * Use addstr's logic for converting a string to an array of cchar_t's.
4716   * There should be a better way, but this handles nonspacing characters
4717   * and other special cases that we really do not want to handle here.
4718   */
4719#if NCURSES_EXT_FUNCS
4720  if (wresize(field->working, 1, Buffer_Length(field) + 1) == ERR)
4721#endif
4722    {
4723      delwin(field->working);
4724      field->working = newpad(1, Buffer_Length(field) + 1);
4725    }
4726  len = Buffer_Length(field);
4727  wclear(field->working);
4728  (void)mvwaddstr(field->working, 0, 0, value);
4729
4730  if ((widevalue = typeCalloc(FIELD_CELL, len + 1)) == 0)
4731    {
4732      RETURN(E_SYSTEM_ERROR);
4733    }
4734  else
4735    {
4736      for (i = 0; i < field->drows; ++i)
4737	{
4738	  (void)mvwin_wchnstr(field->working, 0, (int)i * field->dcols,
4739			      widevalue + ((int)i * field->dcols),
4740			      field->dcols);
4741	}
4742      for (i = 0; i < len; ++i)
4743	{
4744	  if (CharEq(myZEROS, widevalue[i]))
4745	    {
4746	      while (i < len)
4747		p[i++] = myBLANK;
4748	      break;
4749	    }
4750	  p[i] = widevalue[i];
4751	}
4752      free(widevalue);
4753    }
4754#else
4755  for (i = 0; i < len; ++i)
4756    {
4757      if (value[i] == '\0')
4758	{
4759	  while (i < len)
4760	    p[i++] = myBLANK;
4761	  break;
4762	}
4763      p[i] = value[i];
4764    }
4765#endif
4766
4767  if (buffer == 0)
4768    {
4769      int syncres;
4770
4771      if (((syncres = Synchronize_Field(field)) != E_OK) &&
4772	  (res == E_OK))
4773	res = syncres;
4774      if (((syncres = Synchronize_Linked_Fields(field)) != E_OK) &&
4775	  (res == E_OK))
4776	res = syncres;
4777    }
4778  RETURN(res);
4779}
4780
4781/*---------------------------------------------------------------------------
4782|   Facility      :  libnform
4783|   Function      :  char *field_buffer(const FIELD *field,int buffer)
4784|
4785|   Description   :  Return the address of the buffer for the field.
4786|
4787|   Return Values :  Pointer to buffer or NULL if arguments were invalid.
4788+--------------------------------------------------------------------------*/
4789NCURSES_EXPORT(char *)
4790field_buffer(const FIELD *field, int buffer)
4791{
4792  char *result = 0;
4793
4794  T((T_CALLED("field_buffer(%p,%d)"), (const void *)field, buffer));
4795
4796  if (field && (buffer >= 0) && (buffer <= field->nbuf))
4797    {
4798#if USE_WIDEC_SUPPORT
4799      FIELD_CELL *data = Address_Of_Nth_Buffer(field, buffer);
4800      size_t need = 0;
4801      int size = Buffer_Length(field);
4802      int n;
4803
4804      /* determine the number of bytes needed to store the expanded string */
4805      for (n = 0; n < size; ++n)
4806	{
4807	  if (!isWidecExt(data[n]) && data[n].chars[0] != L'\0')
4808	    {
4809	      mbstate_t state;
4810	      size_t next;
4811
4812	      init_mb(state);
4813	      next = _nc_wcrtomb(0, data[n].chars[0], &state);
4814	      if (next > 0)
4815		need += next;
4816	    }
4817	}
4818
4819      /* allocate a place to store the expanded string */
4820      if (field->expanded[buffer] != 0)
4821	free(field->expanded[buffer]);
4822      field->expanded[buffer] = typeMalloc(char, need + 1);
4823
4824      /*
4825       * Expand the multibyte data.
4826       *
4827       * It may also be multi-column data.  In that case, the data for a row
4828       * may be null-padded to align to the dcols/drows layout (or it may
4829       * contain embedded wide-character extensions).  Change the null-padding
4830       * to blanks as needed.
4831       */
4832      if ((result = field->expanded[buffer]) != 0)
4833	{
4834	  wclear(field->working);
4835	  wmove(field->working, 0, 0);
4836	  for (n = 0; n < size; ++n)
4837	    {
4838	      if (!isWidecExt(data[n]) && data[n].chars[0] != L'\0')
4839		wadd_wch(field->working, &data[n]);
4840	    }
4841	  wmove(field->working, 0, 0);
4842	  winnstr(field->working, result, (int)need);
4843	}
4844#else
4845      result = Address_Of_Nth_Buffer(field, buffer);
4846#endif
4847    }
4848  returnPtr(result);
4849}
4850
4851#if USE_WIDEC_SUPPORT
4852
4853/*---------------------------------------------------------------------------
4854| Convert a multibyte string to a wide-character string.  The result must be
4855| freed by the caller.
4856+--------------------------------------------------------------------------*/
4857NCURSES_EXPORT(wchar_t *)
4858_nc_Widen_String(char *source, int *lengthp)
4859{
4860  wchar_t *result = 0;
4861  wchar_t wch;
4862  size_t given = strlen(source);
4863  size_t tries;
4864  int pass;
4865  int status;
4866
4867#ifndef state_unused
4868  mbstate_t state;
4869#endif
4870
4871  for (pass = 0; pass < 2; ++pass)
4872    {
4873      unsigned need = 0;
4874      size_t passed = 0;
4875
4876      while (passed < given)
4877	{
4878	  bool found = FALSE;
4879
4880	  for (tries = 1, status = 0; tries <= (given - passed); ++tries)
4881	    {
4882	      int save = source[passed + tries];
4883
4884	      source[passed + tries] = 0;
4885	      reset_mbytes(state);
4886	      status = check_mbytes(wch, source + passed, tries, state);
4887	      source[passed + tries] = (char)save;
4888
4889	      if (status > 0)
4890		{
4891		  found = TRUE;
4892		  break;
4893		}
4894	    }
4895	  if (found)
4896	    {
4897	      if (pass)
4898		{
4899		  result[need] = wch;
4900		}
4901	      passed += (size_t) status;
4902	      ++need;
4903	    }
4904	  else
4905	    {
4906	      if (pass)
4907		{
4908		  result[need] = source[passed];
4909		}
4910	      ++need;
4911	      ++passed;
4912	    }
4913	}
4914
4915      if (!pass)
4916	{
4917	  if (!need)
4918	    break;
4919	  result = typeCalloc(wchar_t, need);
4920
4921	  *lengthp = (int)need;
4922	  if (result == 0)
4923	    break;
4924	}
4925    }
4926
4927  return result;
4928}
4929#endif
4930
4931/* frm_driver.c ends here */
4932