ncurses 5.9 - patch 20130309
[ncurses.git] / form / frm_driver.c
1 /****************************************************************************
2  * Copyright (c) 1998-2012,2013 Free Software Foundation, Inc.              *
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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    *
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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
35 MODULE_ID("$Id: frm_driver.c,v 1.103 2013/03/09 22:48:47 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 /*
81 Some options that may effect compatibility in behavior to SVr4 forms,
82 but they are here to allow a more intuitive and user friendly behavior of
83 our form implementation. This doesn't affect the API, so we feel it is
84 uncritical.
85
86 The initial implementation tries to stay very close with the behavior
87 of the original SVr4 implementation, although in some areas it is quite
88 clear that this isn't the most appropriate way. As far as possible this
89 sources will allow you to build a forms lib that behaves quite similar
90 to SVr4, but now and in the future we will give you better options.
91 Perhaps 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   --------------------------------------------------------------------------*/
116 static int Inter_Field_Navigation(int (*const fct) (FORM *), FORM *form);
117 static int FN_Next_Field(FORM *form);
118 static int FN_Previous_Field(FORM *form);
119 static int FE_New_Line(FORM *);
120 static 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)((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   --------------------------------------------------------------------------*/
211 static FIELD_CELL myBLANK = BLANK;
212 static FIELD_CELL myZEROS;
213
214 #ifdef TRACE
215 static void
216 check_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 */
242 static int
243 wins_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  */
262 static int
263 fix_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  */
284 static int
285 cell_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  */
306 static int
307 cell_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  */
333 static void
334 delete_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 +--------------------------------------------------------------------------*/
361 NCURSES_INLINE static FIELD_CELL *
362 Get_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 +--------------------------------------------------------------------------*/
383 NCURSES_INLINE static FIELD_CELL *
384 After_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 +--------------------------------------------------------------------------*/
403 NCURSES_INLINE static FIELD_CELL *
404 Get_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 +--------------------------------------------------------------------------*/
425 NCURSES_INLINE static FIELD_CELL *
426 After_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 +--------------------------------------------------------------------------*/
454 NCURSES_INLINE static void
455 Adjust_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 +--------------------------------------------------------------------------*/
485 static void
486 Buffer_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 +--------------------------------------------------------------------------*/
527 NCURSES_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 +--------------------------------------------------------------------------*/
582 static void
583 Window_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 +--------------------------------------------------------------------------*/
599 NCURSES_INLINE static void
600 Synchronize_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 +--------------------------------------------------------------------------*/
625 static bool
626 Field_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 +--------------------------------------------------------------------------*/
776 static int
777 Field_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 +--------------------------------------------------------------------------*/
805 NCURSES_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 +--------------------------------------------------------------------------*/
846 NCURSES_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 +--------------------------------------------------------------------------*/
974 static void
975 Perform_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 +--------------------------------------------------------------------------*/
1018 static void
1019 Undo_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 +--------------------------------------------------------------------------*/
1049 static bool
1050 Check_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 +--------------------------------------------------------------------------*/
1097 static int
1098 Display_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 +--------------------------------------------------------------------------*/
1156 static int
1157 Synchronize_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 +--------------------------------------------------------------------------*/
1200 static int
1201 Synchronize_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 +--------------------------------------------------------------------------*/
1236 NCURSES_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 +--------------------------------------------------------------------------*/
1302 NCURSES_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 +--------------------------------------------------------------------------*/
1404 NCURSES_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 +--------------------------------------------------------------------------*/
1511 static int
1512 IFN_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 +--------------------------------------------------------------------------*/
1553 static int
1554 IFN_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 +--------------------------------------------------------------------------*/
1582 static int
1583 IFN_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 +--------------------------------------------------------------------------*/
1610 static int
1611 IFN_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 +--------------------------------------------------------------------------*/
1632 static int
1633 IFN_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 +--------------------------------------------------------------------------*/
1674 static int
1675 IFN_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 +--------------------------------------------------------------------------*/
1728 static int
1729 IFN_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 +--------------------------------------------------------------------------*/
1751 static int
1752 IFN_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 +--------------------------------------------------------------------------*/
1775 static int
1776 IFN_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 +--------------------------------------------------------------------------*/
1799 static int
1800 IFN_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 +--------------------------------------------------------------------------*/
1826 static int
1827 IFN_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 +--------------------------------------------------------------------------*/
1851 static int
1852 IFN_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 +--------------------------------------------------------------------------*/
1882 static int
1883 IFN_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 +--------------------------------------------------------------------------*/
1904 static int
1905 IFN_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 +--------------------------------------------------------------------------*/
1939 static int
1940 VSC_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 +--------------------------------------------------------------------------*/
1992 static int
1993 Vertical_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 +--------------------------------------------------------------------------*/
2015 static int
2016 VSC_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 +--------------------------------------------------------------------------*/
2031 static int
2032 VSC_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 +--------------------------------------------------------------------------*/
2047 static int
2048 VSC_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 +--------------------------------------------------------------------------*/
2063 static int
2064 VSC_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 +--------------------------------------------------------------------------*/
2079 static int
2080 VSC_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 +--------------------------------------------------------------------------*/
2095 static int
2096 VSC_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 +--------------------------------------------------------------------------*/
2119 static int
2120 HSC_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 +--------------------------------------------------------------------------*/
2171 static int
2172 Horizontal_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 +--------------------------------------------------------------------------*/
2189 static int
2190 HSC_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 +--------------------------------------------------------------------------*/
2205 static int
2206 HSC_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 +--------------------------------------------------------------------------*/
2221 static int
2222 HSC_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 +--------------------------------------------------------------------------*/
2237 static int
2238 HSC_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 +--------------------------------------------------------------------------*/
2253 static int
2254 HSC_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 +--------------------------------------------------------------------------*/
2269 static int
2270 HSC_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 +--------------------------------------------------------------------------*/
2294 NCURSES_INLINE static bool
2295 Is_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 +--------------------------------------------------------------------------*/
2316 NCURSES_INLINE static bool
2317 Is_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 +--------------------------------------------------------------------------*/
2351 static int
2352 Insert_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 +--------------------------------------------------------------------------*/
2426 static int
2427 Wrapping_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 +--------------------------------------------------------------------------*/
2504 static int
2505 Field_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 +--------------------------------------------------------------------------*/
2561 static int
2562 FE_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 +--------------------------------------------------------------------------*/
2645 static int
2646 FE_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 +--------------------------------------------------------------------------*/
2681 static int
2682 FE_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 +--------------------------------------------------------------------------*/
2718 static int
2719 FE_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 +--------------------------------------------------------------------------*/
2739 static int
2740 FE_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 +--------------------------------------------------------------------------*/
2809 static int
2810 FE_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 +--------------------------------------------------------------------------*/
2827 static int
2828 FE_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 +--------------------------------------------------------------------------*/
2867 static int
2868 FE_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 +--------------------------------------------------------------------------*/
2884 static int
2885 FE_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 +--------------------------------------------------------------------------*/
2901 static int
2902 FE_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 +--------------------------------------------------------------------------*/
2925 static int
2926 EM_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 +--------------------------------------------------------------------------*/
2941 static int
2942 EM_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 +--------------------------------------------------------------------------*/
2970 static bool
2971 Next_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 +--------------------------------------------------------------------------*/
3011 static bool
3012 Previous_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 +--------------------------------------------------------------------------*/
3055 static int
3056 CR_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 +--------------------------------------------------------------------------*/
3076 static int
3077 CR_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 +--------------------------------------------------------------------------*/
3109 static bool
3110 Check_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 +--------------------------------------------------------------------------*/
3162 NCURSES_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 +--------------------------------------------------------------------------*/
3198 static int
3199 FV_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 +--------------------------------------------------------------------------*/
3226 NCURSES_INLINE static FIELD *
3227 Next_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 +--------------------------------------------------------------------------*/
3256 NCURSES_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 +--------------------------------------------------------------------------*/
3309 NCURSES_INLINE static FIELD *
3310 Previous_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 +--------------------------------------------------------------------------*/
3339 NCURSES_INLINE static FIELD *
3340 Sorted_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 +--------------------------------------------------------------------------*/
3365 NCURSES_INLINE static FIELD *
3366 Sorted_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 +--------------------------------------------------------------------------*/
3390 NCURSES_INLINE static FIELD *
3391 Left_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 +--------------------------------------------------------------------------*/
3418 NCURSES_INLINE static FIELD *
3419 Right_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 +--------------------------------------------------------------------------*/
3446 static FIELD *
3447 Upper_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 +--------------------------------------------------------------------------*/
3496 static FIELD *
3497 Down_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 +--------------------------------------------------------------------------*/
3552 static int
3553 Inter_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 +--------------------------------------------------------------------------*/
3577 static int
3578 FN_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 +--------------------------------------------------------------------------*/
3595 static int
3596 FN_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 +--------------------------------------------------------------------------*/
3612 static int
3613 FN_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 +--------------------------------------------------------------------------*/
3629 static int
3630 FN_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 +--------------------------------------------------------------------------*/
3648 static int
3649 FN_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 +--------------------------------------------------------------------------*/
3666 static int
3667 FN_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 +--------------------------------------------------------------------------*/
3684 static int
3685 FN_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 |