ncurses 5.0
[ncurses.git] / form / frm_driver.c
1 /****************************************************************************
2  * Copyright (c) 1998 Free Software Foundation, Inc.                        *
3  *                                                                          *
4  * Permission is hereby granted, free of charge, to any person obtaining a  *
5  * copy of this software and associated documentation files (the            *
6  * "Software"), to deal in the Software without restriction, including      *
7  * without limitation the rights to use, copy, modify, merge, publish,      *
8  * distribute, distribute with modifications, sublicense, and/or sell       *
9  * copies of the Software, and to permit persons to whom the Software is    *
10  * furnished to do so, subject to the following conditions:                 *
11  *                                                                          *
12  * The above copyright notice and this permission notice shall be included  *
13  * in all copies or substantial portions of the Software.                   *
14  *                                                                          *
15  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS  *
16  * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF               *
17  * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.   *
18  * IN NO EVENT SHALL THE ABOVE COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM,   *
19  * DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR    *
20  * OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR    *
21  * THE USE OR OTHER DEALINGS IN THE SOFTWARE.                               *
22  *                                                                          *
23  * Except as contained in this notice, the name(s) of the above copyright   *
24  * holders shall not be used in advertising or otherwise to promote the     *
25  * sale, use or other dealings in this Software without prior written       *
26  * authorization.                                                           *
27  ****************************************************************************/
28
29 /****************************************************************************
30  *   Author: Juergen Pfeifer <juergen.pfeifer@gmx.net> 1995,1997            *
31  ****************************************************************************/
32 #include "form.priv.h"
33
34 MODULE_ID("$Id: frm_driver.c,v 1.35 1999/05/16 17:20:52 juergen Exp $")
35
36 /*----------------------------------------------------------------------------
37   This is the core module of the form library. It contains the majority
38   of the driver routines as well as the form_driver function. 
39
40   Essentially this module is nearly the whole library. This is because
41   all the functions in this module depends on some others in the module,
42   so it makes no sense to split them into separate files because they
43   will always be linked together. The only acceptable concern is turnaround
44   time for this module, but now we have all Pentiums or Riscs, so what!
45
46   The driver routines are grouped into nine generic categories:
47
48    a)   Page Navigation            ( all functions prefixed by PN_ )
49         The current page of the form is left and some new page is
50         entered.
51    b)   Inter-Field Navigation     ( all functions prefixed by FN_ )
52         The current field of the form is left and some new field is
53         entered.
54    c)   Intra-Field Navigation     ( all functions prefixed by IFN_ )
55         The current position in the current field is changed. 
56    d)   Vertical Scrolling         ( all functions prefixed by VSC_ )
57         Esseantially this is a specialization of Intra-Field navigation.
58         It has to check for a multi-line field.
59    e)   Horizontal Scrolling       ( all functions prefixed by HSC_ )
60         Esseantially this is a specialization of Intra-Field navigation.
61         It has to check for a single-line field.
62    f)   Field Editing              ( all functions prefixed by FE_ )
63         The content of the current field is changed
64    g)   Edit Mode requests         ( all functions prefixed by EM_ )
65         Switching between insert and overlay mode
66    h)   Field-Validation requests  ( all functions prefixed by FV_ )
67         Perform verifications of the field.
68    i)   Choice requests            ( all functions prefixed by CR_ )
69         Requests to enumerate possible field values
70   --------------------------------------------------------------------------*/
71
72 /*----------------------------------------------------------------------------
73   Some remarks on the placements of assert() macros :
74   I use them only on "strategic" places, i.e. top level entries where
75   I want to make sure that things are set correctly. Throughout subordinate
76   routines I omit them mostly.
77   --------------------------------------------------------------------------*/
78
79 /*
80 Some options that may effect compatibility in behavior to SVr4 forms,
81 but they are here to allow a more intuitive and user friendly behaviour of
82 our form implementation. This doesn't affect the API, so we feel it is
83 uncritical.
84
85 The initial implementation tries to stay very close with the behaviour
86 of the original SVr4 implementation, although in some areas it is quite
87 clear that this isn't the most appropriate way. As far as possible this
88 sources will allow you to build a forms lib that behaves quite similar
89 to SVr4, but now and in the future we will give you better options. 
90 Perhaps at some time we will make this configurable at runtime.
91 */
92
93 /* Implement a more user-friendly previous/next word behaviour */
94 #define FRIENDLY_PREV_NEXT_WORD (1)
95 /* Fix the wrong behaviour for forms with all fields inactive */
96 #define FIX_FORM_INACTIVE_BUG (1)
97 /* Allow dynamic field growth also when navigating past the end */
98 #define GROW_IF_NAVIGATE (1)
99
100 /*----------------------------------------------------------------------------
101   Forward references to some internally used static functions
102   --------------------------------------------------------------------------*/
103 static int Inter_Field_Navigation ( int (* const fct) (FORM *), FORM * form );
104 static int FN_Next_Field (FORM * form);
105 static int FN_Previous_Field (FORM * form);
106 static int FE_New_Line(FORM *);
107 static int FE_Delete_Previous(FORM *);
108 \f
109 /*----------------------------------------------------------------------------
110   Macro Definitions.
111
112   Some Remarks on that: I use the convention to use UPPERCASE for constants
113   defined by Macros. If I provide a macro as a kind of inline routine to
114   provide some logic, I use my Upper_Lower case style.
115   --------------------------------------------------------------------------*/
116
117 /* Calculate the position of a single row in a field buffer */
118 #define Position_Of_Row_In_Buffer(field,row) ((row)*(field)->dcols)
119
120 /* Calculate start address for the fields buffer# N */
121 #define Address_Of_Nth_Buffer(field,N) \
122   ((field)->buf + (N)*(1+Buffer_Length(field)))
123
124 /* Calculate the start address of the row in the fields specified buffer# N */
125 #define Address_Of_Row_In_Nth_Buffer(field,N,row) \
126   (Address_Of_Nth_Buffer(field,N) + Position_Of_Row_In_Buffer(field,row))
127
128 /* Calculate the start address of the row in the fields primary buffer */
129 #define Address_Of_Row_In_Buffer(field,row) \
130   Address_Of_Row_In_Nth_Buffer(field,0,row)
131
132 /* Calculate the start address of the row in the forms current field
133    buffer# N */
134 #define Address_Of_Current_Row_In_Nth_Buffer(form,N) \
135    Address_Of_Row_In_Nth_Buffer((form)->current,N,(form)->currow)
136
137 /* Calculate the start address of the row in the forms current field
138    primary buffer */
139 #define Address_Of_Current_Row_In_Buffer(form) \
140    Address_Of_Current_Row_In_Nth_Buffer(form,0)
141
142 /* Calculate the address of the cursor in the forms current field
143    primary buffer */
144 #define Address_Of_Current_Position_In_Nth_Buffer(form,N) \
145    (Address_Of_Current_Row_In_Nth_Buffer(form,N) + (form)->curcol)
146
147 /* Calculate the address of the cursor in the forms current field
148    buffer# N */
149 #define Address_Of_Current_Position_In_Buffer(form) \
150   Address_Of_Current_Position_In_Nth_Buffer(form,0)
151
152 /* Logic to decide wether or not a field is actually a field with
153    vertical or horizontal scrolling */
154 #define Is_Scroll_Field(field)          \
155    (((field)->drows > (field)->rows) || \
156     ((field)->dcols > (field)->cols))
157
158 /* Logic to decide whether or not a field needs to have an individual window
159    instead of a derived window because it contains invisible parts.
160    This is true for non-public fields and for scrollable fields. */
161 #define Has_Invisible_Parts(field)     \
162   (!((field)->opts & O_PUBLIC)      || \
163    Is_Scroll_Field(field))
164
165 /* Logic to decide whether or not a field needs justification */
166 #define Justification_Allowed(field)        \
167    (((field)->just != NO_JUSTIFICATION)  && \
168     (Single_Line_Field(field))           && \
169     (((field)->dcols == (field)->cols)   && \
170     ((field)->opts & O_STATIC))             )
171
172 /* Logic to determine whether or not a dynamic field may still grow */
173 #define Growable(field) ((field)->status & _MAY_GROW)
174
175 /* Macro to set the attributes for a fields window */
176 #define Set_Field_Window_Attributes(field,win) \
177 (  wbkgdset((win),(chtype)((field)->pad | (field)->back)), \
178    wattrset((win),(field)->fore) )
179
180 /* Logic to decide whether or not a field really appears on the form */
181 #define Field_Really_Appears(field)         \
182   ((field->form)                          &&\
183    (field->form->status & _POSTED)        &&\
184    (field->opts & O_VISIBLE)              &&\
185    (field->page == field->form->curpage))
186
187 /* Logic to determine whether or not we are on the first position in the
188    current field */
189 #define First_Position_In_Current_Field(form) \
190   (((form)->currow==0) && ((form)->curcol==0))
191
192
193 #define Minimum(a,b) (((a)<=(b)) ? (a) : (b))
194 #define Maximum(a,b) (((a)>=(b)) ? (a) : (b))
195 \f
196 /*---------------------------------------------------------------------------
197 |   Facility      :  libnform  
198 |   Function      :  static char *Get_Start_Of_Data(char * buf, int blen)
199 |   
200 |   Description   :  Return pointer to first non-blank position in buffer.
201 |                    If buffer is empty return pointer to buffer itself.
202 |
203 |   Return Values :  Pointer to first non-blank position in buffer
204 +--------------------------------------------------------------------------*/
205 INLINE static char *Get_Start_Of_Data(char * buf, int blen)
206 {
207   char *p   = buf;
208   char *end = &buf[blen];
209
210   assert(buf && blen>=0);
211   while( (p < end) && is_blank(*p) ) 
212     p++;
213   return( (p==end) ? buf : p );
214 }
215
216 /*---------------------------------------------------------------------------
217 |   Facility      :  libnform  
218 |   Function      :  static char *After_End_Of_Data(char * buf, int blen)
219 |   
220 |   Description   :  Return pointer after last non-blank position in buffer.
221 |                    If buffer is empty, return pointer to buffer itself.
222 |
223 |   Return Values :  Pointer to position after last non-blank position in 
224 |                    buffer.
225 +--------------------------------------------------------------------------*/
226 INLINE static char *After_End_Of_Data(char * buf,int blen)
227 {
228   char *p   = &buf[blen];
229   
230   assert(buf && blen>=0);
231   while( (p>buf) && is_blank(p[-1]) ) 
232     p--;
233   return( p );
234 }
235
236 /*---------------------------------------------------------------------------
237 |   Facility      :  libnform  
238 |   Function      :  static char *Get_First_Whitespace_Character(
239 |                                     char * buf, int   blen)
240 |   
241 |   Description   :  Position to the first whitespace character.
242 |
243 |   Return Values :  Pointer to first whitespace character in buffer.
244 +--------------------------------------------------------------------------*/
245 INLINE static char *Get_First_Whitespace_Character(char * buf, int blen)
246 {
247   char *p   = buf;
248   char *end = &p[blen];
249   
250   assert(buf && blen>=0);
251   while( (p < end) && !is_blank(*p)) 
252     p++;
253   return( (p==end) ? buf : p );
254 }
255
256 /*---------------------------------------------------------------------------
257 |   Facility      :  libnform  
258 |   Function      :  static char *After_Last_Whitespace_Character(
259 |                                     char * buf, int blen)
260 |   
261 |   Description   :  Get the position after the last whitespace character.
262 |
263 |   Return Values :  Pointer to position after last whitespace character in 
264 |                    buffer.
265 +--------------------------------------------------------------------------*/
266 INLINE static char *After_Last_Whitespace_Character(char * buf, int blen)
267 {
268   char *p   = &buf[blen];
269   
270   assert(buf && blen>=0);
271   while( (p>buf) && !is_blank(p[-1]) ) 
272     p--;
273   return( p );
274 }
275
276 /* Set this to 1 to use the div_t version. This is a good idea if your
277    compiler has an intrinsic div() support. Unfortunately GNU-C has it
278    not yet. 
279    N.B.: This only works if form->curcol follows immediately form->currow
280          and both are of type int. 
281 */
282 #define USE_DIV_T (0)
283
284 /*---------------------------------------------------------------------------
285 |   Facility      :  libnform  
286 |   Function      :  static void Adjust_Cursor_Position(
287 |                                       FORM * form, const char * pos)
288 |   
289 |   Description   :  Set current row and column of the form to values 
290 |                    corresponding to the buffer position.
291 |
292 |   Return Values :  -
293 +--------------------------------------------------------------------------*/
294 INLINE static void Adjust_Cursor_Position(FORM * form, const char * pos)
295 {
296   FIELD *field;
297   int idx;
298
299   field = form->current;
300   assert( pos >= field->buf && field->dcols > 0);
301   idx = (int)( pos - field->buf );
302 #if USE_DIV_T
303   *((div_t *)&(form->currow)) = div(idx,field->dcols);
304 #else
305   form->currow = idx / field->dcols;
306   form->curcol = idx - field->cols * form->currow;
307 #endif  
308   if ( field->drows < form->currow )
309     form->currow = 0;
310 }
311
312 /*---------------------------------------------------------------------------
313 |   Facility      :  libnform  
314 |   Function      :  static void Buffer_To_Window(
315 |                                      const FIELD  * field,
316 |                                      WINDOW * win)
317 |   
318 |   Description   :  Copy the buffer to the window. If its a multiline
319 |                    field, the buffer is split to the lines of the
320 |                    window without any editing.
321 |
322 |   Return Values :  -
323 +--------------------------------------------------------------------------*/
324 static void Buffer_To_Window(const FIELD  * field, WINDOW * win)
325 {
326   int width, height;
327   int len;
328   int row;
329   char *pBuffer;
330
331   assert(win && field);
332
333   width  = getmaxx(win);
334   height = getmaxy(win);
335
336   for(row=0, pBuffer=field->buf; 
337       row < height; 
338       row++, pBuffer += width )
339     {
340       if ((len = (int)( After_End_Of_Data( pBuffer, width ) - pBuffer )) > 0)
341         {
342           wmove( win, row, 0 );
343           waddnstr( win, pBuffer, len );
344         }
345     }   
346 }
347
348 /*---------------------------------------------------------------------------
349 |   Facility      :  libnform  
350 |   Function      :  static void Window_To_Buffer(
351 |                                          WINDOW * win,
352 |                                          FIELD  * field)
353 |   
354 |   Description   :  Copy the content of the window into the buffer.
355 |                    The multiple lines of a window are simply
356 |                    concatenated into the buffer. Pad characters in
357 |                    the window will be replaced by blanks in the buffer.
358 |
359 |   Return Values :  -
360 +--------------------------------------------------------------------------*/
361 static void Window_To_Buffer(WINDOW * win, FIELD  * field)
362 {
363   int pad;
364   int len = 0;
365   char *p;
366   int row, height;
367   
368   assert(win && field && field->buf );
369
370   pad = field->pad;
371   p = field->buf;
372   height = getmaxy(win);
373
374   for(row=0; (row < height) && (row < field->drows); row++ )
375     {
376       wmove( win, row, 0 );
377       len += winnstr( win, p+len, field->dcols );
378     }
379   p[len] = '\0';
380
381   /* replace visual padding character by blanks in buffer */
382   if (pad != C_BLANK)
383     {
384       int i;
385       for(i=0; i<len; i++, p++)
386         {
387           if (*p==pad) 
388             *p = C_BLANK;
389         }
390     }
391 }
392
393 /*---------------------------------------------------------------------------
394 |   Facility      :  libnform  
395 |   Function      :  static void Synchronize_Buffer(FORM * form)
396 |   
397 |   Description   :  If there was a change, copy the content of the
398 |                    window into the buffer, so the buffer is synchronized
399 |                    with the windows content. We have to indicate that the
400 |                    buffer needs validation due to the change.
401 |
402 |   Return Values :  -
403 +--------------------------------------------------------------------------*/
404 INLINE static void Synchronize_Buffer(FORM * form)
405 {
406   if (form->status & _WINDOW_MODIFIED)
407     {
408       form->status &= ~_WINDOW_MODIFIED;
409       form->status |=  _FCHECK_REQUIRED;
410       Window_To_Buffer(form->w,form->current);
411       wmove(form->w,form->currow,form->curcol);
412     }
413 }
414
415 /*---------------------------------------------------------------------------
416 |   Facility      :  libnform  
417 |   Function      :  static bool Field_Grown( FIELD *field, int amount)
418 |   
419 |   Description   :  This function is called for growable dynamic fields
420 |                    only. It has to increase the buffers and to allocate
421 |                    a new window for this field.
422 |                    This function has the side effect to set a new
423 |                    field-buffer pointer, the dcols and drows values
424 |                    as well as a new current Window for the field.
425 |
426 |   Return Values :  TRUE     - field successfully increased
427 |                    FALSE    - there was some error
428 +--------------------------------------------------------------------------*/
429 static bool Field_Grown(FIELD * field, int amount)
430 {
431   bool result = FALSE;
432
433   if (field && Growable(field))
434     {
435       bool single_line_field = Single_Line_Field(field);
436       int old_buflen = Buffer_Length(field);
437       int new_buflen;
438       int old_dcols = field->dcols;
439       int old_drows = field->drows;
440       char *oldbuf  = field->buf;
441       char *newbuf;
442
443       int growth;
444       FORM *form = field->form;
445       bool need_visual_update = ((form != (FORM *)0)      &&
446                                  (form->status & _POSTED) &&
447                                  (form->current==field));
448       
449       if (need_visual_update)
450         Synchronize_Buffer(form);
451       
452       if (single_line_field)
453         {
454           growth = field->cols * amount;
455           if (field->maxgrow)
456             growth = Minimum(field->maxgrow - field->dcols,growth);
457           field->dcols += growth;
458           if (field->dcols == field->maxgrow)
459             field->status &= ~_MAY_GROW;
460         }
461       else
462         {
463           growth = (field->rows + field->nrow) * amount;
464           if (field->maxgrow)
465             growth = Minimum(field->maxgrow - field->drows,growth);
466           field->drows += growth;
467           if (field->drows == field->maxgrow)
468             field->status &= ~_MAY_GROW;
469         }
470       /* drows, dcols changed, so we get really the new buffer length */
471       new_buflen = Buffer_Length(field);
472       newbuf=(char *)malloc((size_t)Total_Buffer_Size(field));
473       if (!newbuf)
474         { /* restore to previous state */
475           field->dcols = old_dcols;
476           field->drows = old_drows;
477           if (( single_line_field && (field->dcols!=field->maxgrow)) ||
478               (!single_line_field && (field->drows!=field->maxgrow)))
479             field->status |= _MAY_GROW;
480           return FALSE;
481         }
482       else
483         { /* Copy all the buffers. This is the reason why we can't
484              just use realloc().
485              */
486           int i;
487           char *old_bp;
488           char *new_bp;
489           
490           field->buf = newbuf;
491           for(i=0;i<=field->nbuf;i++)
492             {
493               new_bp = Address_Of_Nth_Buffer(field,i);
494               old_bp = oldbuf + i*(1+old_buflen);
495               memcpy(new_bp,old_bp,(size_t)old_buflen);
496               if (new_buflen > old_buflen)
497                 memset(new_bp + old_buflen,C_BLANK,
498                        (size_t)(new_buflen - old_buflen));
499               *(new_bp + new_buflen) = '\0';
500             }
501
502           if (need_visual_update)
503             {         
504               WINDOW *new_window = newpad(field->drows,field->dcols);
505               if (!new_window)
506                 { /* restore old state */
507                   field->dcols = old_dcols;
508                   field->drows = old_drows;
509                   field->buf   = oldbuf;
510                   if (( single_line_field              && 
511                         (field->dcols!=field->maxgrow)) ||
512                       (!single_line_field              && 
513                        (field->drows!=field->maxgrow)))
514                     field->status |= _MAY_GROW;
515                   free( newbuf );
516                   return FALSE;
517                 }
518               assert(form!=(FORM *)0);
519               delwin(form->w);
520               form->w = new_window;
521               Set_Field_Window_Attributes(field,form->w);
522               werase(form->w);
523               Buffer_To_Window(field,form->w);
524               untouchwin(form->w);
525               wmove(form->w,form->currow,form->curcol);
526             }
527
528           free(oldbuf);
529           /* reflect changes in linked fields */
530           if (field != field->link)
531             {
532               FIELD *linked_field;
533               for(linked_field = field->link;
534                   linked_field!= field;
535                   linked_field = linked_field->link)
536                 {
537                   linked_field->buf   = field->buf;
538                   linked_field->drows = field->drows;
539                   linked_field->dcols = field->dcols;
540                 }
541             }
542           result = TRUE;
543         }       
544     }
545   return(result);
546 }
547
548 /*---------------------------------------------------------------------------
549 |   Facility      :  libnform  
550 |   Function      :  int _nc_Position_Form_Cursor(FORM * form)
551 |   
552 |   Description   :  Position the cursor in the window for the current
553 |                    field to be in sync. with the currow and curcol 
554 |                    values.
555 |
556 |   Return Values :  E_OK              - success
557 |                    E_BAD_ARGUMENT    - invalid form pointer
558 |                    E_SYSTEM_ERROR    - form has no current field or
559 |                                        field-window
560 +--------------------------------------------------------------------------*/
561 int
562 _nc_Position_Form_Cursor(FORM * form)
563 {
564   FIELD  *field;
565   WINDOW *formwin;
566   
567   if (!form)
568     return(E_BAD_ARGUMENT);
569
570   if (!form->w || !form->current) 
571     return(E_SYSTEM_ERROR);
572
573   field    = form->current;
574   formwin  = Get_Form_Window(form);
575
576   wmove( form->w, form->currow, form->curcol );
577   if ( Has_Invisible_Parts(field) )
578     {
579       /* in this case fieldwin isn't derived from formwin, so we have
580          to move the cursor in formwin by hand... */
581       wmove(formwin,
582             field->frow + form->currow - form->toprow,
583             field->fcol + form->curcol - form->begincol);
584       wcursyncup(formwin);
585     }
586   else 
587     wcursyncup(form->w);
588   return(E_OK);
589 }
590
591 /*---------------------------------------------------------------------------
592 |   Facility      :  libnform  
593 |   Function      :  int _nc_Refresh_Current_Field(FORM * form)
594 |   
595 |   Description   :  Propagate the changes in the fields window to the
596 |                    window of the form.
597 |
598 |   Return Values :  E_OK              - on success
599 |                    E_BAD_ARGUMENT    - invalid form pointer
600 |                    E_SYSTEM_ERROR    - general error
601 +--------------------------------------------------------------------------*/
602 int
603 _nc_Refresh_Current_Field(FORM * form)
604 {
605   WINDOW *formwin;
606   FIELD  *field;
607
608   if (!form)
609     RETURN(E_BAD_ARGUMENT);
610
611   if (!form->w || !form->current) 
612     RETURN(E_SYSTEM_ERROR);
613
614   field    = form->current;
615   formwin  = Get_Form_Window(form);
616
617   if (field->opts & O_PUBLIC)
618     {
619       if (Is_Scroll_Field(field))
620         {
621           /* Again, in this case the fieldwin isn't derived from formwin,
622              so we have to perform a copy operation. */
623           if (Single_Line_Field(field))
624             { /* horizontal scrolling */
625               if (form->curcol < form->begincol)
626                   form->begincol = form->curcol;
627               else
628                 {
629                   if (form->curcol >= (form->begincol + field->cols))
630                       form->begincol = form->curcol - field->cols + 1;
631                 }
632               copywin(form->w,
633                       formwin,
634                       0,
635                       form->begincol,
636                       field->frow,
637                       field->fcol,
638                       field->frow,
639                       field->cols + field->fcol - 1,
640                       0);
641             }
642           else
643             { /* A multiline, i.e. vertical scrolling field */
644               int row_after_bottom,first_modified_row,first_unmodified_row;
645
646               if (field->drows > field->rows)
647                 {
648                   row_after_bottom = form->toprow + field->rows;
649                   if (form->currow < form->toprow)
650                     {
651                       form->toprow = form->currow;
652                       field->status |= _NEWTOP;
653                     }
654                   if (form->currow >= row_after_bottom)
655                     {
656                       form->toprow = form->currow - field->rows + 1;
657                       field->status |= _NEWTOP;
658                     }
659                   if (field->status & _NEWTOP)
660                     { /* means we have to copy whole range */
661                       first_modified_row = form->toprow;
662                       first_unmodified_row = first_modified_row + field->rows;
663                       field->status &= ~_NEWTOP;
664                     }
665                   else 
666                     { /* we try to optimize : finding the range of touched
667                          lines */
668                       first_modified_row = form->toprow;
669                       while(first_modified_row < row_after_bottom)
670                         {
671                           if (is_linetouched(form->w,first_modified_row)) 
672                             break;
673                           first_modified_row++;
674                         }
675                       first_unmodified_row = first_modified_row;
676                       while(first_unmodified_row < row_after_bottom)
677                         {
678                           if (!is_linetouched(form->w,first_unmodified_row)) 
679                             break;
680                           first_unmodified_row++;
681                         }
682                     }
683                 }
684               else
685                 {
686                   first_modified_row   = form->toprow;
687                   first_unmodified_row = first_modified_row + field->rows;
688                 }
689               if (first_unmodified_row != first_modified_row)
690                 copywin(form->w,
691                         formwin,
692                         first_modified_row,
693                         0,
694                         field->frow + first_modified_row - form->toprow,
695                         field->fcol,
696                         field->frow + first_unmodified_row - form->toprow - 1,
697                         field->cols + field->fcol - 1,
698                         0);
699             }
700           wsyncup(formwin);
701         }
702       else
703         { /* if the field-window is simply a derived window, i.e. contains
704              no invisible parts, the whole thing is trivial 
705           */
706           wsyncup(form->w);
707         }
708     }
709   untouchwin(form->w);
710   return _nc_Position_Form_Cursor(form);
711 }
712         
713 /*---------------------------------------------------------------------------
714 |   Facility      :  libnform  
715 |   Function      :  static void Perform_Justification(
716 |                                        FIELD  * field,
717 |                                        WINDOW * win)
718 |   
719 |   Description   :  Output field with requested justification 
720 |
721 |   Return Values :  -
722 +--------------------------------------------------------------------------*/
723 static void Perform_Justification(FIELD  * field, WINDOW * win)
724 {
725   char *bp;
726   int len;
727   int col  = 0;
728
729   bp  = Get_Start_Of_Data(field->buf,Buffer_Length(field));
730   len = (int)(After_End_Of_Data(field->buf,Buffer_Length(field)) - bp);
731
732   if (len>0)
733     {
734       assert(win && (field->drows == 1) && (field->dcols == field->cols));
735
736       switch(field->just)
737         {
738         case JUSTIFY_LEFT:
739           break;
740         case JUSTIFY_CENTER:
741           col = (field->cols - len)/2;
742           break;
743         case JUSTIFY_RIGHT:
744           col = field->cols - len;
745           break;
746         default:
747           break;
748         }
749
750       wmove(win,0,col);
751       waddnstr(win,bp,len);
752     }
753 }
754
755 /*---------------------------------------------------------------------------
756 |   Facility      :  libnform  
757 |   Function      :  static void Undo_Justification(
758 |                                     FIELD  * field,
759 |                                     WINDOW * win)
760 |   
761 |   Description   :  Display field without any justification, i.e.
762 |                    left justified
763 |
764 |   Return Values :  -
765 +--------------------------------------------------------------------------*/
766 static void Undo_Justification(FIELD  * field, WINDOW * win)
767 {
768   char *bp;
769   int len;
770
771   bp  = Get_Start_Of_Data(field->buf,Buffer_Length(field));
772   len = (int)(After_End_Of_Data(field->buf,Buffer_Length(field))-bp);
773
774   if (len>0)
775     {
776       assert(win);
777       wmove(win,0,0);
778       waddnstr(win,bp,len);
779     }
780 }
781
782 /*---------------------------------------------------------------------------
783 |   Facility      :  libnform  
784 |   Function      :  static bool Check_Char(
785 |                                           FIELDTYPE * typ,
786 |                                           int ch,
787 |                                           TypeArgument *argp)
788 |   
789 |   Description   :  Perform a single character check for character ch
790 |                    according to the fieldtype instance.  
791 |
792 |   Return Values :  TRUE             - Character is valid
793 |                    FALSE            - Character is invalid
794 +--------------------------------------------------------------------------*/
795 static bool Check_Char(FIELDTYPE * typ, int ch, TypeArgument *argp)
796 {
797   if (typ) 
798     {
799       if (typ->status & _LINKED_TYPE)
800         {
801           assert(argp);
802           return(
803             Check_Char(typ->left ,ch,argp->left ) ||
804             Check_Char(typ->right,ch,argp->right) );
805         } 
806       else 
807         {
808           if (typ->ccheck)
809             return typ->ccheck(ch,(void *)argp);
810         }
811     }
812   return (isprint((unsigned char)ch) ? TRUE : FALSE);
813 }
814
815 /*---------------------------------------------------------------------------
816 |   Facility      :  libnform  
817 |   Function      :  static int Display_Or_Erase_Field(
818 |                                           FIELD * field,
819 |                                           bool bEraseFlag)
820 |   
821 |   Description   :  Create a subwindow for the field and display the
822 |                    buffer contents (apply justification if required)
823 |                    or simply erase the field.
824 |
825 |   Return Values :  E_OK           - on success
826 |                    E_SYSTEM_ERROR - some error (typical no memory)
827 +--------------------------------------------------------------------------*/
828 static int Display_Or_Erase_Field(FIELD * field, bool bEraseFlag)
829 {
830   WINDOW *win;
831   WINDOW *fwin;
832
833   if (!field)
834     return E_SYSTEM_ERROR;
835
836   fwin = Get_Form_Window(field->form);
837   win  = derwin(fwin,
838                 field->rows,field->cols,field->frow,field->fcol);
839
840   if (!win) 
841     return E_SYSTEM_ERROR;
842   else
843     {
844       if (field->opts & O_VISIBLE)
845         Set_Field_Window_Attributes(field,win);
846       else
847         wattrset(win,getattrs(fwin));
848       werase(win);
849     }
850
851   if (!bEraseFlag)
852     {
853       if (field->opts & O_PUBLIC)
854         {
855           if (Justification_Allowed(field))
856             Perform_Justification(field,win);
857           else
858             Buffer_To_Window(field,win);
859         }
860       field->status &= ~_NEWTOP;
861     }
862   wsyncup(win);
863   delwin(win);
864   return E_OK;
865 }
866
867 /* Macros to preset the bEraseFlag */
868 #define Display_Field(field) Display_Or_Erase_Field(field,FALSE)
869 #define Erase_Field(field)   Display_Or_Erase_Field(field,TRUE)
870
871 /*---------------------------------------------------------------------------
872 |   Facility      :  libnform  
873 |   Function      :  static int Synchronize_Field(FIELD * field)
874 |   
875 |   Description   :  Synchronize the windows content with the value in
876 |                    the buffer.
877 |
878 |   Return Values :  E_OK                - success
879 |                    E_BAD_ARGUMENT      - invalid field pointer 
880 |                    E_SYSTEM_ERROR      - some severe basic error
881 +--------------------------------------------------------------------------*/
882 static int Synchronize_Field(FIELD * field)
883 {
884   FORM *form;
885   int res = E_OK;
886
887   if (!field)
888     return(E_BAD_ARGUMENT);
889
890   if (((form=field->form) != (FORM *)0)
891       && Field_Really_Appears(field))
892     {
893       if (field == form->current)
894         { 
895           form->currow  = form->curcol = form->toprow = form->begincol = 0;
896           werase(form->w);
897       
898           if ( (field->opts & O_PUBLIC) && Justification_Allowed(field) )
899             Undo_Justification( field, form->w );
900           else
901             Buffer_To_Window( field, form->w );
902           
903           field->status |= _NEWTOP;
904           res = _nc_Refresh_Current_Field( form );
905         }
906       else
907         res = Display_Field( field );
908     }
909   field->status |= _CHANGED;
910   return(res);
911 }
912
913 /*---------------------------------------------------------------------------
914 |   Facility      :  libnform  
915 |   Function      :  static int Synchronize_Linked_Fields(FIELD * field)
916 |   
917 |   Description   :  Propagate the Synchronize_Field function to all linked
918 |                    fields. The first error that occurs in the sequence
919 |                    of updates is the returnvalue.
920 |
921 |   Return Values :  E_OK                - success
922 |                    E_BAD_ARGUMENT      - invalid field pointer 
923 |                    E_SYSTEM_ERROR      - some severe basic error
924 +--------------------------------------------------------------------------*/
925 static int Synchronize_Linked_Fields(FIELD * field)
926 {
927   FIELD *linked_field;
928   int res = E_OK;
929   int syncres;
930
931   if (!field)
932     return(E_BAD_ARGUMENT);
933
934   if (!field->link)
935     return(E_SYSTEM_ERROR);
936
937   for(linked_field = field->link; 
938       linked_field!= field;
939       linked_field = linked_field->link )
940     {
941       if (((syncres=Synchronize_Field(linked_field)) != E_OK) &&
942           (res==E_OK))
943         res = syncres;
944     }
945   return(res);
946 }
947
948 /*---------------------------------------------------------------------------
949 |   Facility      :  libnform  
950 |   Function      :  int _nc_Synchronize_Attributes(FIELD * field)
951 |   
952 |   Description   :  If a fields visual attributes have changed, this
953 |                    routine is called to propagate those changes to the
954 |                    screen.  
955 |
956 |   Return Values :  E_OK             - success
957 |                    E_BAD_ARGUMENT   - invalid field pointer
958 |                    E_SYSTEM_ERROR   - some severe basic error
959 +--------------------------------------------------------------------------*/
960 int _nc_Synchronize_Attributes(FIELD * field)
961 {
962   FORM *form;
963   int res = E_OK;
964   WINDOW *formwin;
965
966   if (!field)
967     return(E_BAD_ARGUMENT);
968
969   if (((form=field->form) != (FORM *)0)
970       && Field_Really_Appears(field))
971     {    
972       if (form->current==field)
973         {
974           Synchronize_Buffer(form);
975           Set_Field_Window_Attributes(field,form->w);
976           werase(form->w);
977           if (field->opts & O_PUBLIC)
978             {
979               if (Justification_Allowed(field))
980                 Undo_Justification(field,form->w);
981               else 
982                 Buffer_To_Window(field,form->w);
983             }
984           else 
985             {
986               formwin = Get_Form_Window(form); 
987               copywin(form->w,formwin,
988                       0,0,
989                       field->frow,field->fcol,
990                       field->rows-1,field->cols-1,0);
991               wsyncup(formwin);
992               Buffer_To_Window(field,form->w);
993               field->status |= _NEWTOP; /* fake refresh to paint all */
994               _nc_Refresh_Current_Field(form);
995             }
996         }
997       else 
998         {
999           res = Display_Field(field);
1000         }
1001     }
1002   return(res);
1003 }
1004
1005 /*---------------------------------------------------------------------------
1006 |   Facility      :  libnform  
1007 |   Function      :  int _nc_Synchronize_Options(FIELD * field,
1008 |                                                Field_Options newopts)
1009 |   
1010 |   Description   :  If a fields options have changed, this routine is
1011 |                    called to propagate these changes to the screen and
1012 |                    to really change the behaviour of the field.
1013 |
1014 |   Return Values :  E_OK                - success
1015 |                    E_BAD_ARGUMENT      - invalid field pointer 
1016 |                    E_SYSTEM_ERROR      - some severe basic error
1017 +--------------------------------------------------------------------------*/
1018 int
1019 _nc_Synchronize_Options(FIELD *field, Field_Options newopts)
1020 {
1021   Field_Options oldopts;
1022   Field_Options changed_opts;
1023   FORM *form;
1024   int res = E_OK;
1025
1026   if (!field)
1027     return(E_BAD_ARGUMENT);
1028
1029   oldopts      = field->opts;
1030   changed_opts = oldopts ^ newopts;
1031   field->opts  = newopts;
1032   form         = field->form;
1033
1034   if (form)
1035     {
1036       if (form->current == field)
1037         {
1038           field->opts = oldopts;
1039           return(E_CURRENT);
1040         }
1041
1042       if (form->status & _POSTED)
1043         {
1044           if ((form->curpage == field->page))
1045             {
1046               if (changed_opts & O_VISIBLE)
1047                 {
1048                   if (newopts & O_VISIBLE)
1049                     res = Display_Field(field);
1050                   else
1051                     res = Erase_Field(field);
1052                 }
1053               else
1054                 {
1055                   if ((changed_opts & O_PUBLIC) &&
1056                       (newopts & O_VISIBLE))
1057                     res = Display_Field(field);
1058                 }
1059             }
1060         }
1061     }
1062
1063   if (changed_opts & O_STATIC)
1064     {
1065       bool single_line_field = Single_Line_Field(field);
1066       int res2 = E_OK;
1067
1068       if (newopts & O_STATIC)
1069         { /* the field becomes now static */
1070           field->status &= ~_MAY_GROW;
1071           /* if actually we have no hidden columns, justification may
1072              occur again */
1073           if (single_line_field                 &&
1074               (field->cols == field->dcols)     &&
1075               (field->just != NO_JUSTIFICATION) &&
1076               Field_Really_Appears(field))
1077             {
1078               res2 = Display_Field(field);
1079             }
1080         }
1081       else
1082         { /* field is no longer static */
1083           if ((field->maxgrow==0) ||
1084               ( single_line_field && (field->dcols < field->maxgrow)) ||
1085               (!single_line_field && (field->drows < field->maxgrow)))
1086             {
1087               field->status |= _MAY_GROW;
1088               /* a field with justification now changes its behaviour,
1089                  so we must redisplay it */
1090               if (single_line_field                 &&
1091                   (field->just != NO_JUSTIFICATION) &&
1092                   Field_Really_Appears(field))
1093                 {
1094                   res2 = Display_Field(field);
1095                 }        
1096             }     
1097         }
1098       if (res2 != E_OK)
1099         res = res2;
1100     }
1101
1102   return(res);
1103 }
1104
1105 /*---------------------------------------------------------------------------
1106 |   Facility      :  libnform  
1107 |   Function      :  int _nc_Set_Current_Field(FORM  * form,
1108 |                                              FIELD * newfield)
1109 |   
1110 |   Description   :  Make the newfield the new current field.
1111 |
1112 |   Return Values :  E_OK                - success
1113 |                    E_BAD_ARGUMENT      - invalid form or field pointer 
1114 |                    E_SYSTEM_ERROR      - some severe basic error
1115 +--------------------------------------------------------------------------*/
1116 int
1117 _nc_Set_Current_Field(FORM  *form, FIELD *newfield)
1118 {
1119   FIELD  *field;
1120   WINDOW *new_window;
1121
1122   if (!form || !newfield || !form->current || (newfield->form!=form))
1123     return(E_BAD_ARGUMENT);
1124
1125   if ( (form->status & _IN_DRIVER) )
1126     return(E_BAD_STATE);
1127
1128   if (!(form->field))
1129     return(E_NOT_CONNECTED);
1130
1131   field = form->current;
1132  
1133   if ((field!=newfield) || 
1134       !(form->status & _POSTED))
1135     {
1136       if ((form->w) && 
1137           (field->opts & O_VISIBLE) &&
1138           (field->form->curpage == field->page))
1139         {
1140           _nc_Refresh_Current_Field(form);
1141           if (field->opts & O_PUBLIC)
1142             {
1143               if (field->drows > field->rows)
1144                 {
1145                   if (form->toprow==0)
1146                     field->status &= ~_NEWTOP;
1147                   else 
1148                     field->status |= _NEWTOP;
1149                 } 
1150               else 
1151                 {
1152                   if (Justification_Allowed(field))
1153                     {
1154                       Window_To_Buffer(form->w,field);
1155                       werase(form->w);
1156                       Perform_Justification(field,form->w);
1157                       wsyncup(form->w);
1158                     }
1159                 }
1160             }
1161           delwin(form->w);
1162         }
1163       
1164       field = newfield;
1165
1166       if (Has_Invisible_Parts(field))
1167         new_window = newpad(field->drows,field->dcols);
1168       else 
1169         new_window = derwin(Get_Form_Window(form),
1170                             field->rows,field->cols,field->frow,field->fcol);
1171
1172       if (!new_window) 
1173         return(E_SYSTEM_ERROR);
1174
1175       form->current = field;
1176       form->w       = new_window;
1177       form->status &= ~_WINDOW_MODIFIED;
1178       Set_Field_Window_Attributes(field,form->w);
1179
1180       if (Has_Invisible_Parts(field))
1181         {
1182           werase(form->w);
1183           Buffer_To_Window(field,form->w);
1184         } 
1185       else 
1186         {
1187           if (Justification_Allowed(field))
1188             {
1189               werase(form->w);
1190               Undo_Justification(field,form->w);
1191               wsyncup(form->w);
1192             }
1193         }
1194
1195       untouchwin(form->w);
1196     }
1197
1198   form->currow = form->curcol = form->toprow = form->begincol = 0;
1199   return(E_OK);
1200 }
1201 \f
1202 /*----------------------------------------------------------------------------
1203   Intra-Field Navigation routines
1204   --------------------------------------------------------------------------*/
1205
1206 /*---------------------------------------------------------------------------
1207 |   Facility      :  libnform  
1208 |   Function      :  static int IFN_Next_Character(FORM * form)
1209 |   
1210 |   Description   :  Move to the next character in the field. In a multiline
1211 |                    field this wraps at the end of the line.
1212 |
1213 |   Return Values :  E_OK                - success
1214 |                    E_REQUEST_DENIED    - at the rightmost position
1215 +--------------------------------------------------------------------------*/
1216 static int IFN_Next_Character(FORM * form)
1217 {
1218   FIELD *field = form->current;
1219   
1220   if ((++(form->curcol))==field->dcols)
1221     {
1222       if ((++(form->currow))==field->drows)
1223         {
1224 #if GROW_IF_NAVIGATE
1225           if (!Single_Line_Field(field) && Field_Grown(field,1)) {
1226             form->curcol = 0;
1227             return(E_OK);
1228           }
1229 #endif
1230           form->currow--;
1231 #if GROW_IF_NAVIGATE
1232           if (Single_Line_Field(field) && Field_Grown(field,1))
1233             return(E_OK);
1234 #endif
1235           form->curcol--;
1236           return(E_REQUEST_DENIED);
1237         }
1238       form->curcol = 0;
1239     }
1240   return(E_OK);
1241 }
1242
1243 /*---------------------------------------------------------------------------
1244 |   Facility      :  libnform  
1245 |   Function      :  static int IFN_Previous_Character(FORM * form)
1246 |   
1247 |   Description   :  Move to the previous character in the field. In a 
1248 |                    multiline field this wraps and the beginning of the 
1249 |                    line.
1250 |
1251 |   Return Values :  E_OK                - success
1252 |                    E_REQUEST_DENIED    - at the leftmost position
1253 +--------------------------------------------------------------------------*/
1254 static int IFN_Previous_Character(FORM * form)
1255 {
1256   if ((--(form->curcol))<0)
1257     {
1258       if ((--(form->currow))<0)
1259         {
1260           form->currow++;
1261           form->curcol++;
1262           return(E_REQUEST_DENIED);
1263         }
1264       form->curcol = form->current->dcols - 1;
1265     }
1266   return(E_OK);
1267 }
1268
1269 /*---------------------------------------------------------------------------
1270 |   Facility      :  libnform  
1271 |   Function      :  static int IFN_Next_Line(FORM * form)
1272 |   
1273 |   Description   :  Move to the beginning of the next line in the field
1274 |
1275 |   Return Values :  E_OK                - success
1276 |                    E_REQUEST_DENIED    - at the last line
1277 +--------------------------------------------------------------------------*/
1278 static int IFN_Next_Line(FORM * form)
1279 {
1280   FIELD *field = form->current;
1281
1282   if ((++(form->currow))==field->drows)
1283     {
1284 #if GROW_IF_NAVIGATE
1285       if (!Single_Line_Field(field) && Field_Grown(field,1))
1286         return(E_OK);
1287 #endif
1288       form->currow--;
1289       return(E_REQUEST_DENIED);
1290     }
1291   form->curcol = 0;
1292   return(E_OK);
1293 }
1294
1295 /*---------------------------------------------------------------------------
1296 |   Facility      :  libnform  
1297 |   Function      :  static int IFN_Previous_Line(FORM * form)
1298 |   
1299 |   Description   :  Move to the beginning of the previous line in the field
1300 |
1301 |   Return Values :  E_OK                - success
1302 |                    E_REQUEST_DENIED    - at the first line
1303 +--------------------------------------------------------------------------*/
1304 static int IFN_Previous_Line(FORM * form)
1305 {
1306   if ( (--(form->currow)) < 0 )
1307     {
1308       form->currow++;
1309       return(E_REQUEST_DENIED);
1310     }
1311   form->curcol = 0;
1312   return(E_OK);
1313 }
1314
1315 /*---------------------------------------------------------------------------
1316 |   Facility      :  libnform  
1317 |   Function      :  static int IFN_Next_Word(FORM * form)
1318 |   
1319 |   Description   :  Move to the beginning of the next word in the field.
1320 |
1321 |   Return Values :  E_OK             - success
1322 |                    E_REQUEST_DENIED - there is no next word
1323 +--------------------------------------------------------------------------*/
1324 static int IFN_Next_Word(FORM * form)
1325 {
1326   FIELD *field = form->current;
1327   char  *bp    = Address_Of_Current_Position_In_Buffer(form);
1328   char  *s;
1329   char  *t;
1330
1331   /* We really need access to the data, so we have to synchronize */
1332   Synchronize_Buffer(form);
1333
1334   /* Go to the first whitespace after the current position (including
1335      current position). This is then the startpoint to look for the
1336     next non-blank data */
1337   s = Get_First_Whitespace_Character(bp,Buffer_Length(field) -
1338                                      (int)(bp - field->buf));
1339
1340   /* Find the start of the next word */
1341   t = Get_Start_Of_Data(s,Buffer_Length(field) -
1342                         (int)(s - field->buf));
1343 #if !FRIENDLY_PREV_NEXT_WORD
1344   if (s==t) 
1345     return(E_REQUEST_DENIED);
1346   else
1347 #endif
1348     {
1349       Adjust_Cursor_Position(form,t);
1350       return(E_OK);
1351     }
1352 }
1353
1354 /*---------------------------------------------------------------------------
1355 |   Facility      :  libnform  
1356 |   Function      :  static int IFN_Previous_Word(FORM * form)
1357 |   
1358 |   Description   :  Move to the beginning of the previous word in the field.
1359 |
1360 |   Return Values :  E_OK             - success
1361 |                    E_REQUEST_DENIED - there is no previous word
1362 +--------------------------------------------------------------------------*/
1363 static int IFN_Previous_Word(FORM * form)
1364 {
1365   FIELD *field = form->current;
1366   char  *bp    = Address_Of_Current_Position_In_Buffer(form);
1367   char  *s;
1368   char  *t;
1369   bool  again = FALSE;
1370
1371   /* We really need access to the data, so we have to synchronize */
1372   Synchronize_Buffer(form);
1373
1374   s = After_End_Of_Data(field->buf,(int)(bp-field->buf));
1375   /* s points now right after the last non-blank in the buffer before bp.
1376      If bp was in a word, s equals bp. In this case we must find the last
1377      whitespace in the buffer before bp and repeat the game to really find
1378      the previous word! */
1379   if (s==bp)
1380     again = TRUE;
1381   
1382   /* And next call now goes backward to look for the last whitespace
1383      before that, pointing right after this, so it points to the begin
1384      of the previous word. 
1385   */
1386   t = After_Last_Whitespace_Character(field->buf,(int)(s - field->buf));
1387 #if !FRIENDLY_PREV_NEXT_WORD
1388   if (s==t) 
1389     return(E_REQUEST_DENIED);
1390 #endif
1391   if (again)
1392     { /* and do it again, replacing bp by t */
1393       s = After_End_Of_Data(field->buf,(int)(t - field->buf));
1394       t = After_Last_Whitespace_Character(field->buf,(int)(s - field->buf));
1395 #if !FRIENDLY_PREV_NEXT_WORD
1396       if (s==t) 
1397         return(E_REQUEST_DENIED);
1398 #endif
1399     }
1400   Adjust_Cursor_Position(form,t);
1401   return(E_OK);
1402 }
1403
1404 /*---------------------------------------------------------------------------
1405 |   Facility      :  libnform  
1406 |   Function      :  static int IFN_Beginning_Of_Field(FORM * form)
1407 |   
1408 |   Description   :  Place the cursor at the first non-pad character in
1409 |                    the field. 
1410 |
1411 |   Return Values :  E_OK             - success            
1412 +--------------------------------------------------------------------------*/
1413 static int IFN_Beginning_Of_Field(FORM * form)
1414 {
1415   FIELD *field = form->current;
1416
1417   Synchronize_Buffer(form);
1418   Adjust_Cursor_Position(form,
1419                  Get_Start_Of_Data(field->buf,Buffer_Length(field)));
1420   return(E_OK);
1421 }
1422
1423 /*---------------------------------------------------------------------------
1424 |   Facility      :  libnform  
1425 |   Function      :  static int IFN_End_Of_Field(FORM * form)
1426 |   
1427 |   Description   :  Place the cursor after the last non-pad character in
1428 |                    the field. If the field occupies the last position in
1429 |                    the buffer, the cursos is positioned on the last 
1430 |                    character.
1431 |
1432 |   Return Values :  E_OK              - success
1433 +--------------------------------------------------------------------------*/
1434 static int IFN_End_Of_Field(FORM * form)
1435 {
1436   FIELD *field = form->current;
1437   char *pos;
1438
1439   Synchronize_Buffer(form);
1440   pos = After_End_Of_Data(field->buf,Buffer_Length(field));
1441   if (pos==(field->buf + Buffer_Length(field)))
1442     pos--;
1443   Adjust_Cursor_Position(form,pos);
1444   return(E_OK);
1445 }
1446
1447 /*---------------------------------------------------------------------------
1448 |   Facility      :  libnform  
1449 |   Function      :  static int IFN_Beginning_Of_Line(FORM * form)
1450 |   
1451 |   Description   :  Place the cursor on the first non-pad character in
1452 |                    the current line of the field.
1453 |
1454 |   Return Values :  E_OK         - success
1455 +--------------------------------------------------------------------------*/
1456 static int IFN_Beginning_Of_Line(FORM * form)
1457 {
1458   FIELD *field = form->current;
1459
1460   Synchronize_Buffer(form);
1461   Adjust_Cursor_Position(form,
1462                  Get_Start_Of_Data(Address_Of_Current_Row_In_Buffer(form),
1463                                    field->dcols));
1464   return(E_OK);
1465 }
1466
1467 /*---------------------------------------------------------------------------
1468 |   Facility      :  libnform  
1469 |   Function      :  static int IFN_End_Of_Line(FORM * form)
1470 |   
1471 |   Description   :  Place the cursor after the last non-pad character in the
1472 |                    current line of the field. If the field occupies the 
1473 |                    last column in the line, the cursor is positioned on the
1474 |                    last character of the line.
1475 |
1476 |   Return Values :  E_OK        - success
1477 +--------------------------------------------------------------------------*/
1478 static int IFN_End_Of_Line(FORM * form)
1479 {
1480   FIELD *field = form->current;
1481   char *pos;
1482   char *bp;
1483
1484   Synchronize_Buffer(form);
1485   bp  = Address_Of_Current_Row_In_Buffer(form); 
1486   pos = After_End_Of_Data(bp,field->dcols);
1487   if (pos == (bp + field->dcols))
1488     pos--;
1489   Adjust_Cursor_Position(form,pos);
1490   return(E_OK);
1491 }
1492
1493 /*---------------------------------------------------------------------------
1494 |   Facility      :  libnform  
1495 |   Function      :  static int IFN_Left_Character(FORM * form)
1496 |   
1497 |   Description   :  Move one character to the left in the current line.
1498 |                    This doesn't cycle.  
1499 |
1500 |   Return Values :  E_OK             - success
1501 |                    E_REQUEST_DENIED - already in first column
1502 +--------------------------------------------------------------------------*/
1503 static int IFN_Left_Character(FORM * form)
1504 {
1505   if ( (--(form->curcol)) < 0 )
1506     {
1507       form->curcol++;
1508       return(E_REQUEST_DENIED);
1509     }
1510   return(E_OK);
1511 }
1512
1513 /*---------------------------------------------------------------------------
1514 |   Facility      :  libnform  
1515 |   Function      :  static int IFN_Right_Character(FORM * form)
1516 |   
1517 |   Description   :  Move one character to the right in the current line.
1518 |                    This doesn't cycle.
1519 |
1520 |   Return Values :  E_OK              - success
1521 |                    E_REQUEST_DENIED  - already in last column
1522 +--------------------------------------------------------------------------*/
1523 static int IFN_Right_Character(FORM * form)
1524 {
1525   if ( (++(form->curcol)) == form->current->dcols )
1526     {
1527 #if GROW_IF_NAVIGATE
1528       FIELD *field = form->current;
1529       if (Single_Line_Field(field) && Field_Grown(field,1))
1530         return(E_OK);
1531 #endif
1532       --(form->curcol);
1533       return(E_REQUEST_DENIED);
1534     }
1535   return(E_OK);
1536 }
1537
1538 /*---------------------------------------------------------------------------
1539 |   Facility      :  libnform  
1540 |   Function      :  static int IFN_Up_Character(FORM * form)
1541 |   
1542 |   Description   :  Move one line up. This doesn't cycle through the lines
1543 |                    of the field.
1544 |
1545 |   Return Values :  E_OK              - success
1546 |                    E_REQUEST_DENIED  - already in last column
1547 +--------------------------------------------------------------------------*/
1548 static int IFN_Up_Character(FORM * form)
1549 {
1550   if ( (--(form->currow)) < 0 )
1551     {
1552       form->currow++;
1553       return(E_REQUEST_DENIED);
1554     }
1555   return(E_OK);
1556 }
1557
1558 /*---------------------------------------------------------------------------
1559 |   Facility      :  libnform  
1560 |   Function      :  static int IFN_Down_Character(FORM * form)
1561 |   
1562 |   Description   :  Move one line down. This doesn't cycle through the
1563 |                    lines of the field.
1564 |
1565 |   Return Values :  E_OK              - success
1566 |                    E_REQUEST_DENIED  - already in last column
1567 +--------------------------------------------------------------------------*/
1568 static int IFN_Down_Character(FORM * form)
1569 {
1570   FIELD *field = form->current;
1571
1572   if ( (++(form->currow)) == field->drows )
1573     {
1574 #if GROW_IF_NAVIGATE
1575       if (!Single_Line_Field(field) && Field_Grown(field,1))
1576         return(E_OK);
1577 #endif
1578       --(form->currow);
1579       return(E_REQUEST_DENIED);
1580     }
1581   return(E_OK);
1582 }
1583 /*----------------------------------------------------------------------------
1584   END of Intra-Field Navigation routines 
1585   --------------------------------------------------------------------------*/
1586 \f
1587 /*----------------------------------------------------------------------------
1588   Vertical scrolling helper routines
1589   --------------------------------------------------------------------------*/
1590
1591 /*---------------------------------------------------------------------------
1592 |   Facility      :  libnform  
1593 |   Function      :  static int VSC_Generic(FORM *form, int lines)
1594 |
1595 |   Description   :  Scroll multi-line field forward (lines>0) or
1596 |                    backward (lines<0) this many lines.
1597 |
1598 |   Return Values :  E_OK              - success 
1599 |                    E_REQUEST_DENIED  - can't scroll
1600 +--------------------------------------------------------------------------*/
1601 static int VSC_Generic(FORM *form, int lines)
1602 {
1603   FIELD *field = form->current;
1604   int res = E_REQUEST_DENIED;
1605   int rows_to_go = (lines > 0 ? lines : -lines);
1606
1607   if (lines > 0)
1608     {
1609       if ( (rows_to_go + form->toprow) > (field->drows - field->rows) )
1610         rows_to_go = (field->drows - field->rows - form->toprow);
1611
1612       if (rows_to_go > 0)
1613         {
1614           form->currow += rows_to_go;
1615           form->toprow += rows_to_go;
1616           res = E_OK;
1617         }
1618     }
1619   else
1620     {
1621       if (rows_to_go > form->toprow)
1622         rows_to_go = form->toprow;
1623       
1624       if (rows_to_go > 0)
1625         {
1626           form->currow -= rows_to_go;
1627           form->toprow -= rows_to_go;
1628           res = E_OK;
1629         }
1630     }
1631   return(res);
1632 }
1633 /*----------------------------------------------------------------------------
1634   End of Vertical scrolling helper routines
1635   --------------------------------------------------------------------------*/
1636 \f
1637 /*----------------------------------------------------------------------------
1638   Vertical scrolling routines
1639   --------------------------------------------------------------------------*/
1640
1641 /*---------------------------------------------------------------------------
1642 |   Facility      :  libnform  
1643 |   Function      :  static int Vertical_Scrolling(
1644 |                                           int (* const fct) (FORM *),
1645 |                                           FORM * form)
1646 |   
1647 |   Description   :  Performs the generic vertical scrolling routines. 
1648 |                    This has to check for a multi-line field and to set
1649 |                    the _NEWTOP flag if scrolling really occured.
1650 |
1651 |   Return Values :  Propagated error code from low-level driver calls
1652 +--------------------------------------------------------------------------*/
1653 static int Vertical_Scrolling(int (* const fct) (FORM *), FORM * form)
1654 {
1655   int res = E_REQUEST_DENIED;
1656
1657   if (!Single_Line_Field(form->current))
1658     {
1659       res = fct(form);
1660       if (res == E_OK)
1661         form->current->status |= _NEWTOP;
1662     }
1663   return(res);
1664 }
1665
1666 /*---------------------------------------------------------------------------
1667 |   Facility      :  libnform  
1668 |   Function      :  static int VSC_Scroll_Line_Forward(FORM * form)
1669 |   
1670 |   Description   :  Scroll multi-line field forward a line
1671 |
1672 |   Return Values :  E_OK                - success
1673 |                    E_REQUEST_DENIED    - no data ahead
1674 +--------------------------------------------------------------------------*/
1675 static int VSC_Scroll_Line_Forward(FORM * form)
1676 {
1677   return VSC_Generic(form,1);
1678 }
1679
1680 /*---------------------------------------------------------------------------
1681 |   Facility      :  libnform  
1682 |   Function      :  static int VSC_Scroll_Line_Backward(FORM * form)
1683 |   
1684 |   Description   :  Scroll multi-line field backward a line
1685 |
1686 |   Return Values :  E_OK                - success
1687 |                    E_REQUEST_DENIED    - no data behind
1688 +--------------------------------------------------------------------------*/
1689 static int VSC_Scroll_Line_Backward(FORM * form)
1690 {
1691   return VSC_Generic(form,-1);
1692 }
1693
1694 /*---------------------------------------------------------------------------
1695 |   Facility      :  libnform  
1696 |   Function      :  static int VSC_Scroll_Page_Forward(FORM * form)
1697 |   
1698 |   Description   :  Scroll a multi-line field forward a page
1699 |
1700 |   Return Values :  E_OK              - success
1701 |                    E_REQUEST_DENIED  - no data ahead
1702 +--------------------------------------------------------------------------*/
1703 static int VSC_Scroll_Page_Forward(FORM * form)
1704 {
1705   return VSC_Generic(form,form->current->rows);
1706 }
1707
1708 /*---------------------------------------------------------------------------
1709 |   Facility      :  libnform  
1710 |   Function      :  static int VSC_Scroll_Half_Page_Forward(FORM * form)
1711 |   
1712 |   Description   :  Scroll a multi-line field forward half a page
1713 |
1714 |   Return Values :  E_OK              - success
1715 |                    E_REQUEST_DENIED  - no data ahead
1716 +--------------------------------------------------------------------------*/
1717 static int VSC_Scroll_Half_Page_Forward(FORM * form)
1718 {
1719   return VSC_Generic(form,(form->current->rows + 1)/2);
1720 }
1721
1722 /*---------------------------------------------------------------------------
1723 |   Facility      :  libnform  
1724 |   Function      :  static int VSC_Scroll_Page_Backward(FORM * form)
1725 |   
1726 |   Description   :  Scroll a multi-line field backward a page
1727 |
1728 |   Return Values :  E_OK              - success
1729 |                    E_REQUEST_DENIED  - no data behind
1730 +--------------------------------------------------------------------------*/
1731 static int VSC_Scroll_Page_Backward(FORM * form)
1732 {
1733   return VSC_Generic(form, -(form->current->rows));
1734 }
1735
1736 /*---------------------------------------------------------------------------
1737 |   Facility      :  libnform  
1738 |   Function      :  static int VSC_Scroll_Half_Page_Backward(FORM * form)
1739 |   
1740 |   Description   :  Scroll a multi-line field backward half a page
1741 |
1742 |   Return Values :  E_OK              - success
1743 |                    E_REQUEST_DENIED  - no data behind
1744 +--------------------------------------------------------------------------*/
1745 static int VSC_Scroll_Half_Page_Backward(FORM * form)
1746 {
1747   return VSC_Generic(form, -((form->current->rows + 1)/2));
1748 }
1749 /*----------------------------------------------------------------------------
1750   End of Vertical scrolling routines
1751   --------------------------------------------------------------------------*/
1752 \f
1753 /*----------------------------------------------------------------------------
1754   Horizontal scrolling helper routines
1755   --------------------------------------------------------------------------*/
1756
1757 /*---------------------------------------------------------------------------
1758 |   Facility      :  libnform  
1759 |   Function      :  static int HSC_Generic(FORM *form, int columns)
1760 |
1761 |   Description   :  Scroll single-line field forward (columns>0) or
1762 |                    backward (columns<0) this many columns.
1763 |
1764 |   Return Values :  E_OK              - success 
1765 |                    E_REQUEST_DENIED  - can't scroll
1766 +--------------------------------------------------------------------------*/
1767 static int HSC_Generic(FORM *form, int columns)
1768 {
1769   FIELD *field = form->current;
1770   int res = E_REQUEST_DENIED;
1771   int cols_to_go = (columns > 0 ? columns : -columns);
1772
1773   if (columns > 0)
1774     {
1775       if ((cols_to_go + form->begincol) > (field->dcols - field->cols))
1776         cols_to_go = field->dcols - field->cols - form->begincol;
1777       
1778       if (cols_to_go > 0)
1779         {
1780           form->curcol   += cols_to_go;
1781           form->begincol += cols_to_go;
1782           res = E_OK;
1783         }
1784     }
1785   else
1786     {
1787       if ( cols_to_go > form->begincol )
1788         cols_to_go = form->begincol;
1789
1790       if (cols_to_go > 0)
1791         {
1792           form->curcol   -= cols_to_go;
1793           form->begincol -= cols_to_go;
1794           res = E_OK;
1795         }
1796     }
1797   return(res);
1798 }
1799 /*----------------------------------------------------------------------------
1800   End of Horizontal scrolling helper routines
1801   --------------------------------------------------------------------------*/
1802 \f
1803 /*----------------------------------------------------------------------------
1804   Horizontal scrolling routines
1805   --------------------------------------------------------------------------*/
1806
1807 /*---------------------------------------------------------------------------
1808 |   Facility      :  libnform  
1809 |   Function      :  static int Horizontal_Scrolling(
1810 |                                          int (* const fct) (FORM *),
1811 |                                          FORM * form)
1812 |   
1813 |   Description   :  Performs the generic horizontal scrolling routines. 
1814 |                    This has to check for a single-line field.
1815 |
1816 |   Return Values :  Propagated error code from low-level driver calls
1817 +--------------------------------------------------------------------------*/
1818 static int Horizontal_Scrolling(int (* const fct) (FORM *), FORM * form)
1819 {
1820   if (Single_Line_Field(form->current))
1821     return fct(form);
1822   else
1823     return(E_REQUEST_DENIED);
1824 }
1825
1826 /*---------------------------------------------------------------------------
1827 |   Facility      :  libnform  
1828 |   Function      :  static int HSC_Scroll_Char_Forward(FORM * form)
1829 |   
1830 |   Description   :  Scroll single-line field forward a character
1831 |
1832 |   Return Values :  E_OK                - success
1833 |                    E_REQUEST_DENIED    - no data ahead
1834 +--------------------------------------------------------------------------*/
1835 static int HSC_Scroll_Char_Forward(FORM *form)
1836 {
1837   return HSC_Generic(form,1);
1838 }
1839
1840 /*---------------------------------------------------------------------------
1841 |   Facility      :  libnform  
1842 |   Function      :  static int HSC_Scroll_Char_Backward(FORM * form)
1843 |   
1844 |   Description   :  Scroll single-line field backward a character
1845 |
1846 |   Return Values :  E_OK                - success
1847 |                    E_REQUEST_DENIED    - no data behind
1848 +--------------------------------------------------------------------------*/
1849 static int HSC_Scroll_Char_Backward(FORM *form)
1850 {
1851   return HSC_Generic(form,-1);
1852 }
1853
1854 /*---------------------------------------------------------------------------
1855 |   Facility      :  libnform  
1856 |   Function      :  static int HSC_Horizontal_Line_Forward(FORM* form)
1857 |   
1858 |   Description   :  Scroll single-line field forward a line
1859 |
1860 |   Return Values :  E_OK                - success
1861 |                    E_REQUEST_DENIED    - no data ahead
1862 +--------------------------------------------------------------------------*/
1863 static int HSC_Horizontal_Line_Forward(FORM * form)
1864 {
1865   return HSC_Generic(form,form->current->cols);
1866 }
1867
1868 /*---------------------------------------------------------------------------
1869 |   Facility      :  libnform  
1870 |   Function      :  static int HSC_Horizontal_Half_Line_Forward(FORM* form)
1871 |   
1872 |   Description   :  Scroll single-line field forward half a line
1873 |
1874 |   Return Values :  E_OK               - success
1875 |                    E_REQUEST_DENIED   - no data ahead
1876 +--------------------------------------------------------------------------*/
1877 static int HSC_Horizontal_Half_Line_Forward(FORM * form)
1878 {
1879   return HSC_Generic(form,(form->current->cols + 1)/2);
1880 }
1881
1882 /*---------------------------------------------------------------------------
1883 |   Facility      :  libnform  
1884 |   Function      :  static int HSC_Horizontal_Line_Backward(FORM* form)
1885 |   
1886 |   Description   :  Scroll single-line field backward a line
1887 |
1888 |   Return Values :  E_OK                - success
1889 |                    E_REQUEST_DENIED    - no data behind
1890 +--------------------------------------------------------------------------*/
1891 static int HSC_Horizontal_Line_Backward(FORM * form)
1892 {
1893   return HSC_Generic(form,-(form->current->cols));
1894 }
1895
1896 /*---------------------------------------------------------------------------
1897 |   Facility      :  libnform  
1898 |   Function      :  static int HSC_Horizontal_Half_Line_Backward(FORM* form)
1899 |   
1900 |   Description   :  Scroll single-line field backward half a line
1901 |
1902 |   Return Values :  E_OK                - success
1903 |                    E_REQUEST_DENIED    - no data behind
1904 +--------------------------------------------------------------------------*/
1905 static int HSC_Horizontal_Half_Line_Backward(FORM * form)
1906 {
1907   return HSC_Generic(form,-((form->current->cols + 1)/2));
1908 }
1909
1910 /*----------------------------------------------------------------------------
1911   End of Horizontal scrolling routines
1912   --------------------------------------------------------------------------*/
1913 \f
1914 /*----------------------------------------------------------------------------
1915   Helper routines for Field Editing
1916   --------------------------------------------------------------------------*/
1917
1918 /*---------------------------------------------------------------------------
1919 |   Facility      :  libnform  
1920 |   Function      :  static bool Is_There_Room_For_A_Line(FORM * form)
1921 |   
1922 |   Description   :  Check whether or not there is enough room in the
1923 |                    buffer to enter a whole line.
1924 |
1925 |   Return Values :  TRUE   - there is enough space
1926 |                    FALSE  - there is not enough space
1927 +--------------------------------------------------------------------------*/
1928 INLINE static bool Is_There_Room_For_A_Line(FORM * form)
1929 {
1930   FIELD *field = form->current;
1931   char *begin_of_last_line, *s;
1932   
1933   Synchronize_Buffer(form);
1934   begin_of_last_line = Address_Of_Row_In_Buffer(field,(field->drows-1));
1935   s  = After_End_Of_Data(begin_of_last_line,field->dcols);
1936   return ((s==begin_of_last_line) ? TRUE : FALSE);
1937 }
1938
1939 /*---------------------------------------------------------------------------
1940 |   Facility      :  libnform  
1941 |   Function      :  static bool Is_There_Room_For_A_Char_In_Line(FORM * form)
1942 |   
1943 |   Description   :  Checks whether or not there is room for a new character
1944 |                    in the current line.
1945 |
1946 |   Return Values :  TRUE    - there is room
1947 |                    FALSE   - there is not enough room (line full)
1948 +--------------------------------------------------------------------------*/
1949 INLINE static bool Is_There_Room_For_A_Char_In_Line(FORM * form)
1950 {
1951   int last_char_in_line;
1952
1953   wmove(form->w,form->currow,form->current->dcols-1);
1954   last_char_in_line  = (int)(winch(form->w) & A_CHARTEXT);
1955   wmove(form->w,form->currow,form->curcol);
1956   return (((last_char_in_line == form->current->pad) ||
1957            is_blank(last_char_in_line)) ? TRUE : FALSE);
1958 }
1959
1960 #define There_Is_No_Room_For_A_Char_In_Line(f) \
1961   !Is_There_Room_For_A_Char_In_Line(f)
1962
1963 /*---------------------------------------------------------------------------
1964 |   Facility      :  libnform  
1965 |   Function      :  static int Insert_String(
1966 |                                             FORM * form,
1967 |                                             int row,
1968 |                                             char *txt,
1969 |                                             int  len )
1970 |   
1971 |   Description   :  Insert the 'len' characters beginning at pointer 'txt'
1972 |                    into the 'row' of the 'form'. The insertion occurs
1973 |                    on the beginning of the row, all other characters are
1974 |                    moved to the right. After the text a pad character will 
1975 |                    be inserted to separate the text from the rest. If
1976 |                    necessary the insertion moves characters on the next
1977 |                    line to make place for the requested insertion string.
1978 |
1979 |   Return Values :  E_OK              - success 
1980 |                    E_REQUEST_DENIED  -
1981 |                    E_SYSTEM_ERROR    - system error
1982 +--------------------------------------------------------------------------*/
1983 static int Insert_String(FORM *form, int row, char *txt, int len)
1984
1985   FIELD  *field    = form->current;
1986   char *bp         = Address_Of_Row_In_Buffer(field,row);
1987   int datalen      = (int)(After_End_Of_Data(bp,field->dcols) - bp);
1988   int freelen      = field->dcols - datalen;
1989   int requiredlen  = len+1;
1990   char *split;
1991   int result = E_REQUEST_DENIED;
1992   const char *Space = " ";
1993
1994   if (freelen >= requiredlen)
1995     {
1996       wmove(form->w,row,0);
1997       winsnstr(form->w,txt,len);
1998       wmove(form->w,row,len);
1999       winsnstr(form->w,Space,1);
2000       return E_OK;
2001     }
2002   else
2003     { /* we have to move characters on the next line. If we are on the
2004          last line this may work, if the field is growable */
2005       if ((row == (field->drows - 1)) && Growable(field))
2006         {
2007           if (!Field_Grown(field,1))
2008             return(E_SYSTEM_ERROR);
2009           /* !!!Side-Effect : might be changed due to growth!!! */
2010           bp = Address_Of_Row_In_Buffer(field,row); 
2011         }
2012
2013       if (row < (field->drows - 1)) 
2014         { 
2015           split = After_Last_Whitespace_Character(bp,
2016                     (int)(Get_Start_Of_Data(bp + field->dcols - requiredlen ,
2017                                             requiredlen) - bp));
2018           /* split points now to the first character of the portion of the
2019              line that must be moved to the next line */
2020           datalen = (int)(split-bp); /* + freelen has to stay on this line   */
2021           freelen = field->dcols - (datalen + freelen); /* for the next line */
2022
2023           if ((result=Insert_String(form,row+1,split,freelen))==E_OK) 
2024             {
2025               wmove(form->w,row,datalen);
2026               wclrtoeol(form->w);
2027               wmove(form->w,row,0);
2028               winsnstr(form->w,txt,len);
2029               wmove(form->w,row,len);
2030               winsnstr(form->w,Space,1);
2031               return E_OK;
2032             }
2033         }
2034       return(result);
2035     }
2036 }
2037
2038 /*---------------------------------------------------------------------------
2039 |   Facility      :  libnform  
2040 |   Function      :  static int Wrapping_Not_Necessary_Or_Wrapping_Ok(
2041 |                                             FORM * form)
2042 |   
2043 |   Description   :  If a character has been entered into a field, it may
2044 |                    be that wrapping has to occur. This routine checks
2045 |                    whether or not wrapping is required and if so, performs
2046 |                    the wrapping.
2047 |
2048 |   Return Values :  E_OK              - no wrapping required or wrapping
2049 |                                        was successfull
2050 |                    E_REQUEST_DENIED  -
2051 |                    E_SYSTEM_ERROR    - some system error
2052 +--------------------------------------------------------------------------*/
2053 static int Wrapping_Not_Necessary_Or_Wrapping_Ok(FORM * form)
2054 {
2055   FIELD  *field = form->current;
2056   int result = E_REQUEST_DENIED;
2057   bool Last_Row = ((field->drows - 1) == form->currow);
2058
2059   if ( (field->opts & O_WRAP)                     &&  /* wrapping wanted     */
2060       (!Single_Line_Field(field))                 &&  /* must be multi-line  */
2061       (There_Is_No_Room_For_A_Char_In_Line(form)) &&  /* line is full        */
2062       (!Last_Row || Growable(field))               )  /* there are more lines*/
2063     {
2064       char *bp;
2065       char *split;
2066       int chars_to_be_wrapped;
2067       int chars_to_remain_on_line;
2068       if (Last_Row)
2069         { /* the above logic already ensures, that in this case the field
2070              is growable */
2071           if (!Field_Grown(field,1))
2072             return E_SYSTEM_ERROR;
2073         }
2074       bp = Address_Of_Current_Row_In_Buffer(form);
2075       Window_To_Buffer(form->w,field);
2076       split = After_Last_Whitespace_Character(bp,field->dcols);
2077       /* split points to the first character of the sequence to be brought
2078          on the next line */
2079       chars_to_remain_on_line = (int)(split - bp);
2080       chars_to_be_wrapped     = field->dcols - chars_to_remain_on_line;
2081       if (chars_to_remain_on_line > 0)
2082         {
2083           if ((result=Insert_String(form,form->currow+1,split,
2084                                     chars_to_be_wrapped)) == E_OK)
2085             {
2086               wmove(form->w,form->currow,chars_to_remain_on_line);
2087               wclrtoeol(form->w);
2088               if (form->curcol >= chars_to_remain_on_line)
2089                 {
2090                   form->currow++;
2091                   form->curcol -= chars_to_remain_on_line;
2092                 }
2093               return E_OK;
2094             }
2095         }
2096       else
2097         return E_OK;
2098       if (result!=E_OK)
2099         {
2100           wmove(form->w,form->currow,form->curcol);
2101           wdelch(form->w);
2102           Window_To_Buffer(form->w,field);
2103           result = E_REQUEST_DENIED;
2104         }
2105     }
2106   else
2107     result = E_OK; /* wrapping was not necessary */
2108   return(result);
2109 }
2110 \f
2111 /*----------------------------------------------------------------------------
2112   Field Editing routines
2113   --------------------------------------------------------------------------*/
2114
2115 /*---------------------------------------------------------------------------
2116 |   Facility      :  libnform  
2117 |   Function      :  static int Field_Editing(
2118 |                                    int (* const fct) (FORM *),
2119 |                                    FORM * form)
2120 |   
2121 |   Description   :  Generic routine for field editing requests. The driver
2122 |                    routines are only called for editable fields, the
2123 |                    _WINDOW_MODIFIED flag is set if editing occured.
2124 |                    This is somewhat special due to the overload semantics
2125 |                    of the NEW_LINE and DEL_PREV requests.
2126 |
2127 |   Return Values :  Error code from low level drivers.
2128 +--------------------------------------------------------------------------*/
2129 static int Field_Editing(int (* const fct) (FORM *), FORM * form)
2130 {
2131   int res = E_REQUEST_DENIED;
2132
2133   /* We have to deal here with the specific case of the overloaded 
2134      behaviour of New_Line and Delete_Previous requests.
2135      They may end up in navigational requests if we are on the first
2136      character in a field. But navigation is also allowed on non-
2137      editable fields.
2138   */ 
2139   if ((fct==FE_Delete_Previous)            && 
2140       (form->opts & O_BS_OVERLOAD)         &&
2141       First_Position_In_Current_Field(form) )
2142     {
2143       res = Inter_Field_Navigation(FN_Previous_Field,form);
2144     }
2145   else
2146     {
2147       if (fct==FE_New_Line)
2148         {
2149           if ((form->opts & O_NL_OVERLOAD)         &&
2150               First_Position_In_Current_Field(form))
2151             {
2152               res = Inter_Field_Navigation(FN_Next_Field,form);
2153             }
2154           else
2155             /* FE_New_Line deals itself with the _WINDOW_MODIFIED flag */
2156             res = fct(form);
2157         }
2158       else
2159         {
2160           /* From now on, everything must be editable */
2161           if (form->current->opts & O_EDIT)
2162             {
2163               res = fct(form);
2164               if (res==E_OK)
2165                 form->status |= _WINDOW_MODIFIED;
2166             }
2167         }
2168     }
2169   return res;
2170 }
2171
2172 /*---------------------------------------------------------------------------
2173 |   Facility      :  libnform  
2174 |   Function      :  static int FE_New_Line(FORM * form)
2175 |   
2176 |   Description   :  Perform a new line request. This is rather complex
2177 |                    compared to other routines in this code due to the 
2178 |                    rather difficult to understand description in the
2179 |                    manuals.
2180 |
2181 |   Return Values :  E_OK               - success
2182 |                    E_REQUEST_DENIED   - new line not allowed
2183 |                    E_SYSTEM_ERROR     - system error
2184 +--------------------------------------------------------------------------*/
2185 static int FE_New_Line(FORM * form)
2186 {
2187   FIELD  *field = form->current;
2188   char *bp, *t;
2189   bool Last_Row = ((field->drows - 1)==form->currow);
2190   
2191   if (form->status & _OVLMODE) 
2192     {
2193       if (Last_Row && 
2194           (!(Growable(field) && !Single_Line_Field(field))))
2195         {
2196           if (!(form->opts & O_NL_OVERLOAD))
2197             return(E_REQUEST_DENIED);
2198           wclrtoeol(form->w);
2199           /* we have to set this here, although it is also
2200              handled in the generic routine. The reason is,
2201              that FN_Next_Field may fail, but the form is
2202              definitively changed */
2203           form->status |= _WINDOW_MODIFIED;
2204           return Inter_Field_Navigation(FN_Next_Field,form);
2205         }
2206       else 
2207         {
2208           if (Last_Row && !Field_Grown(field,1))
2209             { /* N.B.: due to the logic in the 'if', LastRow==TRUE
2210                  means here that the field is growable and not
2211                  a single-line field */
2212               return(E_SYSTEM_ERROR);
2213             }
2214           wclrtoeol(form->w);
2215           form->currow++;
2216           form->curcol = 0;
2217           form->status |= _WINDOW_MODIFIED;
2218           return(E_OK);
2219         }
2220     }
2221   else 
2222     { /* Insert Mode */
2223       if (Last_Row &&
2224           !(Growable(field) && !Single_Line_Field(field)))
2225         {
2226           if (!(form->opts & O_NL_OVERLOAD))
2227             return(E_REQUEST_DENIED);
2228           return Inter_Field_Navigation(FN_Next_Field,form);
2229         }
2230       else 
2231         {
2232           bool May_Do_It = !Last_Row && Is_There_Room_For_A_Line(form);
2233           
2234           if (!(May_Do_It || Growable(field)))
2235             return(E_REQUEST_DENIED);
2236           if (!May_Do_It && !Field_Grown(field,1))
2237             return(E_SYSTEM_ERROR);
2238           
2239           bp= Address_Of_Current_Position_In_Buffer(form);
2240           t = After_End_Of_Data(bp,field->dcols - form->curcol);
2241           wclrtoeol(form->w);
2242           form->currow++;
2243           form->curcol=0;
2244           wmove(form->w,form->currow,form->curcol);
2245           winsertln(form->w);
2246           waddnstr(form->w,bp,(int)(t-bp));
2247           form->status |= _WINDOW_MODIFIED;
2248           return E_OK;
2249         }
2250     }
2251 }
2252
2253 /*---------------------------------------------------------------------------
2254 |   Facility      :  libnform  
2255 |   Function      :  static int FE_Insert_Character(FORM * form)
2256 |   
2257 |   Description   :  Insert blank character at the cursor position
2258 |
2259 |   Return Values :  E_OK
2260 |                    E_REQUEST_DENIED
2261 +--------------------------------------------------------------------------*/
2262 static int FE_Insert_Character(FORM * form)
2263 {
2264   FIELD *field = form->current;
2265   int result = E_REQUEST_DENIED;
2266
2267   if (Check_Char(field->type,(int)C_BLANK,(TypeArgument *)(field->arg)))
2268     {
2269       bool There_Is_Room = Is_There_Room_For_A_Char_In_Line(form);
2270
2271       if (There_Is_Room ||
2272           ((Single_Line_Field(field) && Growable(field))))
2273         {
2274           if (!There_Is_Room && !Field_Grown(field,1))
2275             result =  E_SYSTEM_ERROR;
2276           else
2277             {
2278               winsch(form->w,(chtype)C_BLANK);
2279               result = Wrapping_Not_Necessary_Or_Wrapping_Ok(form);
2280             }
2281         }
2282     }
2283   return result;
2284 }
2285
2286 /*---------------------------------------------------------------------------
2287 |   Facility      :  libnform  
2288 |   Function      :  static int FE_Insert_Line(FORM * form)
2289 |   
2290 |   Description   :  Insert a blank line at the cursor position
2291 |
2292 |   Return Values :  E_OK               - success
2293 |                    E_REQUEST_DENIED   - line can not be inserted
2294 +--------------------------------------------------------------------------*/
2295 static int FE_Insert_Line(FORM * form)
2296 {
2297   FIELD *field = form->current;
2298   int result = E_REQUEST_DENIED;
2299
2300   if (Check_Char(field->type,(int)C_BLANK,(TypeArgument *)(field->arg)))
2301     {
2302       bool Maybe_Done = (form->currow!=(field->drows-1)) && 
2303                         Is_There_Room_For_A_Line(form);
2304
2305       if (!Single_Line_Field(field) &&
2306           (Maybe_Done || Growable(field)))
2307         {
2308           if (!Maybe_Done && !Field_Grown(field,1))
2309             result = E_SYSTEM_ERROR;
2310           else
2311             {
2312               form->curcol = 0;
2313               winsertln(form->w);
2314               result = E_OK;
2315             }
2316         }
2317     }
2318   return result;
2319 }
2320
2321 /*---------------------------------------------------------------------------
2322 |   Facility      :  libnform  
2323 |   Function      :  static int FE_Delete_Character(FORM * form)
2324 |   
2325 |   Description   :  Delete character at the cursor position
2326 |
2327 |   Return Values :  E_OK    - success
2328 +--------------------------------------------------------------------------*/
2329 static int FE_Delete_Character(FORM * form)
2330 {
2331   wdelch(form->w);
2332   return E_OK;
2333 }
2334
2335 /*---------------------------------------------------------------------------
2336 |   Facility      :  libnform  
2337 |   Function      :  static int FE_Delete_Previous(FORM * form)
2338 |   
2339 |   Description   :  Delete character before cursor. Again this is a rather
2340 |                    difficult piece compared to others due to the overloading
2341 |                    semantics of backspace.
2342 |                    N.B.: The case of overloaded BS on first field position
2343 |                          is already handled in the generic routine.
2344 |
2345 |   Return Values :  E_OK                - success
2346 |                    E_REQUEST_DENIED    - Character can't be deleted
2347 +--------------------------------------------------------------------------*/
2348 static int FE_Delete_Previous(FORM * form)
2349 {
2350   FIELD  *field = form->current;
2351   
2352   if (First_Position_In_Current_Field(form))
2353     return E_REQUEST_DENIED;
2354
2355   if ( (--(form->curcol))<0 )
2356     {
2357       char *this_line, *prev_line, *prev_end, *this_end;
2358       
2359       form->curcol++;
2360       if (form->status & _OVLMODE) 
2361         return E_REQUEST_DENIED;
2362       
2363       prev_line = Address_Of_Row_In_Buffer(field,(form->currow-1));
2364       this_line = Address_Of_Row_In_Buffer(field,(form->currow));
2365       Synchronize_Buffer(form);
2366       prev_end = After_End_Of_Data(prev_line,field->dcols);
2367       this_end = After_End_Of_Data(this_line,field->dcols);
2368       if ((int)(this_end-this_line) > 
2369           (field->cols-(int)(prev_end-prev_line))) 
2370         return E_REQUEST_DENIED;
2371       wdeleteln(form->w);
2372       Adjust_Cursor_Position(form,prev_end);
2373       wmove(form->w,form->currow,form->curcol);
2374       waddnstr(form->w,this_line,(int)(this_end-this_line));
2375     } 
2376   else 
2377     {
2378       wmove(form->w,form->currow,form->curcol);
2379       wdelch(form->w);
2380     }
2381   return E_OK;
2382 }
2383
2384 /*---------------------------------------------------------------------------
2385 |   Facility      :  libnform  
2386 |   Function      :  static int FE_Delete_Line(FORM * form)
2387 |   
2388 |   Description   :  Delete line at cursor position.
2389 |
2390 |   Return Values :  E_OK  - success
2391 +--------------------------------------------------------------------------*/
2392 static int FE_Delete_Line(FORM * form)
2393 {
2394   form->curcol = 0;
2395   wdeleteln(form->w);
2396   return E_OK;
2397 }
2398
2399 /*---------------------------------------------------------------------------
2400 |   Facility      :  libnform  
2401 |   Function      :  static int FE_Delete_Word(FORM * form)
2402 |   
2403 |   Description   :  Delete word at cursor position
2404 |
2405 |   Return Values :  E_OK               - success
2406 |                    E_REQUEST_DENIED   - failure
2407 +--------------------------------------------------------------------------*/
2408 static int FE_Delete_Word(FORM * form)
2409 {
2410   FIELD  *field = form->current;
2411   char   *bp = Address_Of_Current_Row_In_Buffer(form);
2412   char   *ep = bp + field->dcols;
2413   char   *cp = bp + form->curcol;
2414   char *s;
2415   
2416   Synchronize_Buffer(form);
2417   if (is_blank(*cp)) 
2418     return E_REQUEST_DENIED; /* not in word */
2419
2420   /* move cursor to begin of word and erase to end of screen-line */
2421   Adjust_Cursor_Position(form,
2422                          After_Last_Whitespace_Character(bp,form->curcol)); 
2423   wmove(form->w,form->currow,form->curcol);
2424   wclrtoeol(form->w);
2425
2426   /* skip over word in buffer */
2427   s = Get_First_Whitespace_Character(cp,(int)(ep-cp)); 
2428   /* to begin of next word    */
2429   s = Get_Start_Of_Data(s,(int)(ep - s));
2430   if ( (s!=cp) && !is_blank(*s))
2431     {
2432       /* copy remaining line to window */
2433       waddnstr(form->w,s,(int)(s - After_End_Of_Data(s,(int)(ep - s))));
2434     }
2435   return E_OK;
2436 }
2437
2438 /*---------------------------------------------------------------------------
2439 |   Facility      :  libnform  
2440 |   Function      :  static int FE_Clear_To_End_Of_Line(FORM * form)
2441 |   
2442 |   Description   :  Clear to end of current line.
2443 |
2444 |   Return Values :  E_OK   - success
2445 +--------------------------------------------------------------------------*/
2446 static int FE_Clear_To_End_Of_Line(FORM * form)
2447 {
2448   wclrtoeol(form->w);
2449   return E_OK;
2450 }
2451
2452 /*---------------------------------------------------------------------------
2453 |   Facility      :  libnform  
2454 |   Function      :  static int FE_Clear_To_End_Of_Form(FORM * form)
2455 |   
2456 |   Description   :  Clear to end of form.
2457 |
2458 |   Return Values :  E_OK   - success
2459 +--------------------------------------------------------------------------*/
2460 static int FE_Clear_To_End_Of_Form(FORM * form)
2461 {
2462   wclrtobot(form->w);
2463   return E_OK;
2464 }
2465
2466 /*---------------------------------------------------------------------------
2467 |   Facility      :  libnform  
2468 |   Function      :  static int FE_Clear_Field(FORM * form)
2469 |   
2470 |   Description   :  Clear entire field.
2471 |
2472 |   Return Values :  E_OK   - success
2473 +--------------------------------------------------------------------------*/
2474 static int FE_Clear_Field(FORM * form)
2475 {
2476   form->currow = form->curcol = 0;
2477   werase(form->w);
2478   return E_OK;
2479 }
2480 /*----------------------------------------------------------------------------
2481   END of Field Editing routines 
2482   --------------------------------------------------------------------------*/
2483 \f
2484 /*----------------------------------------------------------------------------
2485   Edit Mode routines
2486   --------------------------------------------------------------------------*/
2487
2488 /*---------------------------------------------------------------------------
2489 |   Facility      :  libnform  
2490 |   Function      :  static int EM_Overlay_Mode(FORM * form)
2491 |   
2492 |   Description   :  Switch to overlay mode.
2493 |
2494 |   Return Values :  E_OK   - success
2495 +--------------------------------------------------------------------------*/
2496 static int EM_Overlay_Mode(FORM * form)
2497 {
2498   form->status |= _OVLMODE;
2499   return E_OK;
2500 }
2501
2502 /*---------------------------------------------------------------------------
2503 |   Facility      :  libnform  
2504 |   Function      :  static int EM_Insert_Mode(FORM * form)
2505 |   
2506 |   Description   :  Switch to insert mode
2507 |
2508 |   Return Values :  E_OK   - success
2509 +--------------------------------------------------------------------------*/
2510 static int EM_Insert_Mode(FORM * form)
2511 {
2512   form->status &= ~_OVLMODE;
2513   return E_OK;
2514 }
2515
2516 /*----------------------------------------------------------------------------
2517   END of Edit Mode routines 
2518   --------------------------------------------------------------------------*/
2519 \f
2520 /*----------------------------------------------------------------------------
2521   Helper routines for Choice Requests
2522   --------------------------------------------------------------------------*/
2523
2524 /*---------------------------------------------------------------------------
2525 |   Facility      :  libnform  
2526 |   Function      :  static bool Next_Choice(
2527 |                                            FIELDTYPE * typ,
2528 |                                            FIELD * field,
2529 |                                            TypeArgument *argp)
2530 |   
2531 |   Description   :  Get the next field choice. For linked types this is
2532 |                    done recursively.
2533 |
2534 |   Return Values :  TRUE    - next choice successfully retrieved
2535 |                    FALSE   - couldn't retrieve next choice
2536 +--------------------------------------------------------------------------*/
2537 static bool Next_Choice(FIELDTYPE * typ, FIELD *field, TypeArgument *argp)
2538 {
2539   if (!typ || !(typ->status & _HAS_CHOICE)) 
2540     return FALSE;
2541
2542   if (typ->status & _LINKED_TYPE)
2543     {
2544       assert(argp);
2545       return(
2546              Next_Choice(typ->left ,field,argp->left) ||
2547              Next_Choice(typ->right,field,argp->right) );
2548     } 
2549   else
2550     {
2551       assert(typ->next);
2552       return typ->next(field,(void *)argp);
2553     }
2554 }
2555
2556 /*---------------------------------------------------------------------------
2557 |   Facility      :  libnform  
2558 |   Function      :  static bool Previous_Choice(
2559 |                                                FIELDTYPE * typ,
2560 |                                                FIELD * field,
2561 |                                                TypeArgument *argp)
2562 |   
2563 |   Description   :  Get the previous field choice. For linked types this
2564 |                    is done recursively.
2565 |
2566 |   Return Values :  TRUE    - previous choice successfully retrieved
2567 |                    FALSE   - couldn't retrieve previous choice
2568 +--------------------------------------------------------------------------*/
2569 static bool Previous_Choice(FIELDTYPE *typ, FIELD *field, TypeArgument *argp)
2570 {
2571   if (!typ || !(typ->status & _HAS_CHOICE)) 
2572     return FALSE;
2573
2574   if (typ->status & _LINKED_TYPE)
2575     {
2576       assert(argp);
2577       return(
2578              Previous_Choice(typ->left ,field,argp->left) ||
2579              Previous_Choice(typ->right,field,argp->right));
2580     } 
2581   else 
2582     {
2583       assert(typ->prev);
2584       return typ->prev(field,(void *)argp);
2585     }
2586 }
2587 /*----------------------------------------------------------------------------
2588   End of Helper routines for Choice Requests
2589   --------------------------------------------------------------------------*/
2590 \f
2591 /*----------------------------------------------------------------------------
2592   Routines for Choice Requests
2593   --------------------------------------------------------------------------*/
2594
2595 /*---------------------------------------------------------------------------
2596 |   Facility      :  libnform  
2597 |   Function      :  static int CR_Next_Choice(FORM * form)
2598 |   
2599 |   Description   :  Get the next field choice.
2600 |
2601 |   Return Values :  E_OK              - success
2602 |                    E_REQUEST_DENIED  - next choice couldn't be retrieved
2603 +--------------------------------------------------------------------------*/
2604 static int CR_Next_Choice(FORM * form)
2605 {
2606   FIELD *field = form->current;
2607   Synchronize_Buffer(form);
2608   return ((Next_Choice(field->type,field,(TypeArgument *)(field->arg))) ? 
2609           E_OK : E_REQUEST_DENIED);
2610 }
2611
2612 /*---------------------------------------------------------------------------
2613 |   Facility      :  libnform  
2614 |   Function      :  static int CR_Previous_Choice(FORM * form)
2615 |   
2616 |   Description   :  Get the previous field choice.
2617 |
2618 |   Return Values :  E_OK              - success
2619 |                    E_REQUEST_DENIED  - prev. choice couldn't be retrieved
2620 +--------------------------------------------------------------------------*/
2621 static int CR_Previous_Choice(FORM * form)
2622 {
2623   FIELD *field = form->current;
2624   Synchronize_Buffer(form);
2625   return ((Previous_Choice(field->type,field,(TypeArgument *)(field->arg))) ? 
2626           E_OK : E_REQUEST_DENIED);
2627 }
2628 /*----------------------------------------------------------------------------
2629   End of Routines for Choice Requests
2630   --------------------------------------------------------------------------*/
2631 \f
2632 /*----------------------------------------------------------------------------
2633   Helper routines for Field Validations.
2634   --------------------------------------------------------------------------*/
2635
2636 /*---------------------------------------------------------------------------
2637 |   Facility      :  libnform  
2638 |   Function      :  static bool Check_Field(
2639 |                                            FIELDTYPE * typ,
2640 |                                            FIELD * field,
2641 |                                            TypeArgument * argp)
2642 |   
2643 |   Description   :  Check the field according to its fieldtype and its
2644 |                    actual arguments. For linked fieldtypes this is done
2645 |                    recursively.
2646 |
2647 |   Return Values :  TRUE       - field is valid
2648 |                    FALSE      - field is invalid.
2649 +--------------------------------------------------------------------------*/
2650 static bool Check_Field(FIELDTYPE *typ, FIELD *field, TypeArgument *argp)
2651 {
2652   if (typ)
2653     {
2654       if (field->opts & O_NULLOK)
2655         {
2656           char *bp = field->buf;
2657           assert(bp);
2658           while(is_blank(*bp))
2659             { bp++; }
2660           if (*bp == '\0') 
2661             return TRUE;
2662         }
2663
2664       if (typ->status & _LINKED_TYPE)
2665         {
2666           assert(argp);
2667           return( 
2668                  Check_Field(typ->left ,field,argp->left ) ||
2669                  Check_Field(typ->right,field,argp->right) );
2670         }
2671       else 
2672         {
2673           if (typ->fcheck)
2674             return typ->fcheck(field,(void *)argp);
2675         }
2676     }
2677   return TRUE;
2678 }
2679
2680 /*---------------------------------------------------------------------------
2681 |   Facility      :  libnform  
2682 |   Function      :  bool _nc_Internal_Validation(FORM * form )
2683 |   
2684 |   Description   :  Validate the current field of the form.  
2685 |
2686 |   Return Values :  TRUE  - field is valid
2687 |                    FALSE - field is invalid
2688 +--------------------------------------------------------------------------*/
2689 bool
2690 _nc_Internal_Validation(FORM *form)
2691 {
2692   FIELD *field;
2693
2694   field = form->current; 
2695   
2696   Synchronize_Buffer(form);
2697   if ((form->status & _FCHECK_REQUIRED) ||
2698       (!(field->opts & O_PASSOK)))
2699     {
2700       if (!Check_Field(field->type,field,(TypeArgument *)(field->arg)))
2701         return FALSE;
2702       form->status  &= ~_FCHECK_REQUIRED;
2703       field->status |= _CHANGED;
2704       Synchronize_Linked_Fields(field);
2705     }
2706   return TRUE;
2707 }
2708 /*----------------------------------------------------------------------------
2709   End of Helper routines for Field Validations.
2710   --------------------------------------------------------------------------*/
2711 \f
2712 /*----------------------------------------------------------------------------
2713   Routines for Field Validation.
2714   --------------------------------------------------------------------------*/
2715
2716 /*---------------------------------------------------------------------------
2717 |   Facility      :  libnform  
2718 |   Function      :  static int FV_Validation(FORM * form)
2719 |   
2720 |   Description   :  Validate the current field of the form.
2721 |
2722 |   Return Values :  E_OK             - field valid
2723 |                    E_INVALID_FIELD  - field not valid
2724 +--------------------------------------------------------------------------*/
2725 static int FV_Validation(FORM * form)
2726 {
2727   if (_nc_Internal_Validation(form))
2728     return E_OK;
2729   else
2730     return E_INVALID_FIELD;
2731 }
2732 /*----------------------------------------------------------------------------
2733   End of routines for Field Validation.
2734   --------------------------------------------------------------------------*/
2735 \f
2736 /*----------------------------------------------------------------------------
2737   Helper routines for Inter-Field Navigation
2738   --------------------------------------------------------------------------*/
2739
2740 /*---------------------------------------------------------------------------
2741 |   Facility      :  libnform  
2742 |   Function      :  static FIELD *Next_Field_On_Page(FIELD * field)
2743 |   
2744 |   Description   :  Get the next field after the given field on the current 
2745 |                    page. The order of fields is the one defined by the
2746 |                    fields array. Only visible and active fields are
2747 |                    counted.
2748 |
2749 |   Return Values :  Pointer to the next field.
2750 +--------------------------------------------------------------------------*/
2751 INLINE static FIELD *Next_Field_On_Page(FIELD * field)
2752 {
2753   FORM  *form = field->form;
2754   FIELD **field_on_page = &form->field[field->index];
2755   FIELD **first_on_page = &form->field[form->page[form->curpage].pmin];
2756   FIELD **last_on_page  = &form->field[form->page[form->curpage].pmax];
2757
2758   do
2759     {
2760       field_on_page = 
2761         (field_on_page==last_on_page) ? first_on_page : field_on_page + 1;
2762       if (Field_Is_Selectable(*field_on_page))
2763         break;
2764     } while(field!=(*field_on_page));  
2765   return(*field_on_page);
2766 }
2767
2768 /*---------------------------------------------------------------------------
2769 |   Facility      :  libnform  
2770 |   Function      :  FIELD* _nc_First_Active_Field(FORM * form)
2771 |   
2772 |   Description   :  Get the first active field on the current page,
2773 |                    if there are such. If there are none, get the first
2774 |                    visible field on the page. If there are also none,
2775 |                    we return the first field on page and hope the best.
2776 |
2777 |   Return Values :  Pointer to calculated field.
2778 +--------------------------------------------------------------------------*/
2779 FIELD*
2780 _nc_First_Active_Field(FORM * form)
2781 {
2782   FIELD **last_on_page = &form->field[form->page[form->curpage].pmax];
2783   FIELD *proposed = Next_Field_On_Page(*last_on_page);
2784
2785   if (proposed == *last_on_page)
2786     { /* there might be the special situation, where there is no 
2787          active and visible field on the current page. We then select
2788          the first visible field on this readonly page
2789       */
2790       if (Field_Is_Not_Selectable(proposed))
2791         {
2792           FIELD **field = &form->field[proposed->index];
2793           FIELD **first = &form->field[form->page[form->curpage].pmin];
2794
2795           do
2796             {
2797               field = (field==last_on_page) ? first : field + 1;
2798               if (((*field)->opts & O_VISIBLE))
2799                 break;
2800             } while(proposed!=(*field));
2801           
2802           proposed = *field;
2803
2804           if ((proposed == *last_on_page) && !(proposed->opts&O_VISIBLE))
2805             { /* This means, there is also no visible field on the page.
2806                  So we propose the first one and hope the very best... 
2807                  Some very clever user has designed a readonly and invisible
2808                  page on this form.
2809                */
2810               proposed = *first;
2811             }
2812         }
2813     }
2814   return(proposed);
2815 }
2816
2817 /*---------------------------------------------------------------------------
2818 |   Facility      :  libnform  
2819 |   Function      :  static FIELD *Previous_Field_On_Page(FIELD * field)
2820 |   
2821 |   Description   :  Get the previous field before the given field on the 
2822 |                    current page. The order of fields is the one defined by 
2823 |                    the fields array. Only visible and active fields are
2824 |                    counted.
2825 |
2826 |   Return Values :  Pointer to the previous field.
2827 +--------------------------------------------------------------------------*/
2828 INLINE static FIELD *Previous_Field_On_Page(FIELD * field)
2829 {
2830   FORM  *form   = field->form;
2831   FIELD **field_on_page = &form->field[field->index];
2832   FIELD **first_on_page = &form->field[form->page[form->curpage].pmin];
2833   FIELD **last_on_page  = &form->field[form->page[form->curpage].pmax];
2834   
2835   do
2836     {
2837       field_on_page = 
2838         (field_on_page==first_on_page) ? last_on_page : field_on_page - 1;
2839       if (Field_Is_Selectable(*field_on_page))
2840         break;
2841     } while(field!=(*field_on_page));
2842   
2843   return (*field_on_page);
2844 }
2845
2846 /*---------------------------------------------------------------------------
2847 |   Facility      :  libnform  
2848 |   Function      :  static FIELD *Sorted_Next_Field(FIELD * field)
2849 |   
2850 |   Description   :  Get the next field after the given field on the current 
2851 |                    page. The order of fields is the one defined by the
2852 |                    (row,column) geometry, rows are major.
2853 |
2854 |   Return Values :  Pointer to the next field.
2855 +--------------------------------------------------------------------------*/
2856 INLINE static FIELD *Sorted_Next_Field(FIELD * field)
2857 {
2858   FIELD *field_on_page = field;
2859
2860   do
2861     {
2862       field_on_page = field_on_page->snext;
2863       if (Field_Is_Selectable(field_on_page))
2864         break;
2865     } while(field_on_page!=field);
2866   
2867   return (field_on_page);
2868 }
2869
2870 /*---------------------------------------------------------------------------
2871 |   Facility      :  libnform  
2872 |   Function      :  static FIELD *Sorted_Previous_Field(FIELD * field)
2873 |   
2874 |   Description   :  Get the previous field before the given field on the 
2875 |                    current page. The order of fields is the one defined 
2876 |                    by the (row,column) geometry, rows are major.
2877 |
2878 |   Return Values :  Pointer to the previous field.
2879 +--------------------------------------------------------------------------*/
2880 INLINE static FIELD *Sorted_Previous_Field(FIELD * field)
2881 {
2882   FIELD *field_on_page = field;
2883
2884   do
2885     {
2886       field_on_page = field_on_page->sprev;
2887       if (Field_Is_Selectable(field_on_page))
2888         break;
2889     } while(field_on_page!=field);
2890   
2891   return (field_on_page);
2892 }
2893
2894 /*---------------------------------------------------------------------------
2895 |   Facility      :  libnform  
2896 |   Function      :  static FIELD *Left_Neighbour_Field(FIELD * field)
2897 |   
2898 |   Description   :  Get the left neighbour of the field on the same line
2899 |                    and the same page. Cycles through the line.
2900 |
2901 |   Return Values :  Pointer to left neighbour field.
2902 +--------------------------------------------------------------------------*/
2903 INLINE static FIELD *Left_Neighbour_Field(FIELD * field)
2904 {
2905   FIELD *field_on_page = field;
2906
2907   /* For a field that has really a left neighbour, the while clause
2908      immediately fails and the loop is left, positioned at the right
2909      neighbour. Otherwise we cycle backwards through the sorted fieldlist
2910      until we enter the same line (from the right end).
2911   */
2912   do
2913     {
2914       field_on_page = Sorted_Previous_Field(field_on_page);
2915     } while(field_on_page->frow != field->frow);
2916   
2917   return (field_on_page);
2918 }
2919
2920 /*---------------------------------------------------------------------------
2921 |   Facility      :  libnform  
2922 |   Function      :  static FIELD *Right_Neighbour_Field(FIELD * field)
2923 |   
2924 |   Description   :  Get the right neighbour of the field on the same line
2925 |                    and the same page.
2926 |
2927 |   Return Values :  Pointer to right neighbour field.
2928 +--------------------------------------------------------------------------*/
2929 INLINE static FIELD *Right_Neighbour_Field(FIELD * field)
2930 {
2931   FIELD *field_on_page = field;
2932
2933   /* See the comments on Left_Neighbour_Field to understand how it works */
2934   do
2935     {
2936       field_on_page = Sorted_Next_Field(field_on_page);
2937     } while(field_on_page->frow != field->frow);
2938   
2939   return (field_on_page);
2940 }
2941
2942 /*---------------------------------------------------------------------------
2943 |   Facility      :  libnform  
2944 |   Function      :  static FIELD *Upper_Neighbour_Field(FIELD * field)
2945 |   
2946 |   Description   :  Because of the row-major nature of sorting the fields,
2947 |                    its more difficult to define whats the upper neighbour
2948 |                    field really means. We define that it must be on a
2949 |                    'previous' line (cyclic order!) and is the rightmost
2950 |                    field laying on the left side of the given field. If
2951 |                    this set is empty, we take the first field on the line.
2952 |
2953 |   Return Values :  Pointer to the upper neighbour field.
2954 +--------------------------------------------------------------------------*/
2955 static FIELD *Upper_Neighbour_Field(FIELD * field)
2956 {
2957   FIELD *field_on_page = field;
2958   int frow = field->frow;
2959   int fcol = field->fcol;
2960
2961   /* Walk back to the 'previous' line. The second term in the while clause
2962      just guarantees that we stop if we cycled through the line because
2963      there might be no 'previous' line if the page has just one line.
2964   */
2965   do
2966     {
2967       field_on_page = Sorted_Previous_Field(field_on_page);
2968     } while(field_on_page->frow==frow && field_on_page->fcol!=fcol);
2969   
2970   if (field_on_page->frow!=frow)
2971     { /* We really found a 'previous' line. We are positioned at the
2972          rightmost field on this line */
2973       frow = field_on_page->frow; 
2974
2975       /* We walk to the left as long as we are really right of the 
2976          field. */
2977       while(field_on_page->frow==frow && field_on_page->fcol>fcol)
2978         field_on_page = Sorted_Previous_Field(field_on_page);
2979
2980       /* If we wrapped, just go to the right which is the first field on 
2981          the row */
2982       if (field_on_page->frow!=frow)
2983         field_on_page = Sorted_Next_Field(field_on_page);
2984     }
2985   
2986   return (field_on_page);
2987 }
2988
2989 /*---------------------------------------------------------------------------
2990 |   Facility      :  libnform  
2991 |   Function      :  static FIELD *Down_Neighbour_Field(FIELD * field)
2992 |   
2993 |   Description   :  Because of the row-major nature of sorting the fields,
2994 |                    its more difficult to define whats the down neighbour
2995 |                    field really means. We define that it must be on a
2996 |                    'next' line (cyclic order!) and is the leftmost
2997 |                    field laying on the right side of the given field. If
2998 |                    this set is empty, we take the last field on the line.
2999 |
3000 |   Return Values :  Pointer to the upper neighbour field.
3001 +--------------------------------------------------------------------------*/
3002 static FIELD *Down_Neighbour_Field(FIELD * field)
3003 {
3004   FIELD *field_on_page = field;
3005   int frow = field->frow;
3006   int fcol = field->fcol;
3007
3008   /* Walk forward to the 'next' line. The second term in the while clause
3009      just guarantees that we stop if we cycled through the line because
3010      there might be no 'next' line if the page has just one line.
3011   */
3012   do
3013     {
3014       field_on_page = Sorted_Next_Field(field_on_page);
3015     } while(field_on_page->frow==frow && field_on_page->fcol!=fcol);
3016
3017   if (field_on_page->frow!=frow)
3018     { /* We really found a 'next' line. We are positioned at the rightmost
3019          field on this line */
3020       frow = field_on_page->frow;
3021
3022       /* We walk to the right as long as we are really left of the 
3023          field. */
3024       while(field_on_page->frow==frow && field_on_page->fcol<fcol)
3025         field_on_page = Sorted_Next_Field(field_on_page);
3026
3027       /* If we wrapped, just go to the left which is the last field on 
3028          the row */
3029       if (field_on_page->frow!=frow)
3030         field_on_page = Sorted_Previous_Field(field_on_page);
3031     }
3032   
3033   return(field_on_page);
3034 }
3035 \f
3036 /*----------------------------------------------------------------------------
3037   Inter-Field Navigation routines
3038   --------------------------------------------------------------------------*/
3039
3040 /*---------------------------------------------------------------------------
3041 |   Facility      :  libnform  
3042 |   Function      :  static int Inter_Field_Navigation(
3043 |                                           int (* const fct) (FORM *),
3044 |                                           FORM * form)
3045 |   
3046 |   Description   :  Generic behaviour for changing the current field, the
3047 |                    field is left and a new field is entered. So the field
3048 |                    must be validated and the field init/term hooks must
3049 |                    be called.
3050 |
3051 |   Return Values :  E_OK                - success
3052 |                    E_INVALID_FIELD     - field is invalid
3053 |                    some other          - error from subordinate call
3054 +--------------------------------------------------------------------------*/
3055 static int Inter_Field_Navigation(int (* const fct) (FORM *),FORM *form)
3056 {
3057   int res;
3058
3059   if (!_nc_Internal_Validation(form)) 
3060     res = E_INVALID_FIELD;
3061   else
3062     {
3063       Call_Hook(form,fieldterm);
3064       res = fct(form);
3065       Call_Hook(form,fieldinit);
3066     }
3067   return res;
3068 }
3069
3070 /*---------------------------------------------------------------------------
3071 |   Facility      :  libnform  
3072 |   Function      :  static int FN_Next_Field(FORM * form)
3073 |   
3074 |   Description   :  Move to the next field on the current page of the form
3075 |
3076 |   Return Values :  E_OK                 - success
3077 |                    != E_OK              - error from subordinate call
3078 +--------------------------------------------------------------------------*/
3079 static int FN_Next_Field(FORM * form)
3080 {
3081   return _nc_Set_Current_Field(form,
3082                                Next_Field_On_Page(form->current));
3083 }
3084
3085 /*---------------------------------------------------------------------------
3086 |   Facility      :  libnform  
3087 |   Function      :  static int FN_Previous_Field(FORM * form)
3088 |   
3089 |   Description   :  Move to the previous field on the current page of the 
3090 |                    form
3091 |
3092 |   Return Values :  E_OK                 - success
3093 |                    != E_OK              - error from subordinate call
3094 +--------------------------------------------------------------------------*/
3095 static int FN_Previous_Field(FORM * form)
3096 {
3097   return _nc_Set_Current_Field(form,
3098                                Previous_Field_On_Page(form->current));
3099 }
3100
3101 /*---------------------------------------------------------------------------
3102 |   Facility      :  libnform  
3103 |   Function      :  static int FN_First_Field(FORM * form)
3104 |   
3105 |   Description   :  Move to the first field on the current page of the form
3106 |
3107 |   Return Values :  E_OK                 - success
3108 |                    != E_OK              - error from subordinate call
3109 +--------------------------------------------------------------------------*/
3110 static int FN_First_Field(FORM * form)
3111 {
3112   return _nc_Set_Current_Field(form,
3113       Next_Field_On_Page(form->field[form->page[form->curpage].pmax]));
3114 }
3115
3116 /*---------------------------------------------------------------------------
3117 |   Facility      :  libnform  
3118 |   Function      :  static int FN_Last_Field(FORM * form)
3119 |   
3120 |   Description   :  Move to the last field on the current page of the form
3121 |
3122 |   Return Values :  E_OK                 - success
3123 |                    != E_OK              - error from subordinate call
3124 +--------------------------------------------------------------------------*/
3125 static int FN_Last_Field(FORM * form)
3126 {
3127   return 
3128     _nc_Set_Current_Field(form,
3129        Previous_Field_On_Page(form->field[form->page[form->curpage].pmin]));
3130 }
3131
3132 /*---------------------------------------------------------------------------
3133 |   Facility      :  libnform  
3134 |   Function      :  static int FN_Sorted_Next_Field(FORM * form)
3135 |   
3136 |   Description   :  Move to the sorted next field on the current page
3137 |                    of the form.
3138 |
3139 |   Return Values :  E_OK            - success
3140 |                    != E_OK         - error from subordinate call
3141 +--------------------------------------------------------------------------*/
3142 static int FN_Sorted_Next_Field(FORM * form)
3143 {
3144   return _nc_Set_Current_Field(form,
3145                                Sorted_Next_Field(form->current));
3146 }
3147
3148 /*---------------------------------------------------------------------------
3149 |   Facility      :  libnform  
3150 |   Function      :  static int FN_Sorted_Previous_Field(FORM * form)
3151 |   
3152 |   Description   :  Move to the sorted previous field on the current page
3153 |                    of the form.
3154 |
3155 |   Return Values :  E_OK            - success
3156 |                    != E_OK         - error from subordinate call
3157 +--------------------------------------------------------------------------*/
3158 static int FN_Sorted_Previous_Field(FORM * form)
3159 {
3160   return _nc_Set_Current_Field(form,
3161                                Sorted_Previous_Field(form->current));
3162 }
3163
3164 /*---------------------------------------------------------------------------
3165 |   Facility      :  libnform  
3166 |   Function      :  static int FN_Sorted_First_Field(FORM * form)
3167 |   
3168 |   Description   :  Move to the sorted first field on the current page
3169 |                    of the form.
3170 |
3171 |   Return Values :  E_OK            - success
3172 |                    != E_OK         - error from subordinate call
3173 +--------------------------------------------------------------------------*/
3174 static int FN_Sorted_First_Field(FORM * form)
3175 {
3176   return _nc_Set_Current_Field(form,
3177               Sorted_Next_Field(form->field[form->page[form->curpage].smax]));
3178 }
3179
3180 /*---------------------------------------------------------------------------
3181 |   Facility      :  libnform  
3182 |   Function      :  static int FN_Sorted_Last_Field(FORM * form)
3183 |   
3184 |   Description   :  Move to the sorted last field on the current page
3185 |                    of the form.
3186 |
3187 |   Return Values :  E_OK            - success
3188 |                    != E_OK         - error from subordinate call
3189 +--------------------------------------------------------------------------*/
3190 static int FN_Sorted_Last_Field(FORM * form)
3191 {
3192   return _nc_Set_Current_Field(form,
3193            Sorted_Previous_Field(form->field[form->page[form->curpage].smin]));
3194 }
3195
3196 /*---------------------------------------------------------------------------
3197 |   Facility      :  libnform  
3198 |   Function      :  static int FN_Left_Field(FORM * form)
3199 |   
3200 |   Description   :  Get the field on the left of the current field on the
3201 |                    same line and the same page. Cycles through the line.
3202 |
3203 |   Return Values :  E_OK            - success
3204 |                    != E_OK         - error from subordinate call
3205 +--------------------------------------------------------------------------*/
3206 static int FN_Left_Field(FORM * form)
3207 {
3208   return _nc_Set_Current_Field(form,
3209                                Left_Neighbour_Field(form->current));
3210 }
3211
3212 /*---------------------------------------------------------------------------
3213 |   Facility      :  libnform  
3214 |   Function      :  static int FN_Right_Field(FORM * form)
3215 |   
3216 |   Description   :  Get the field on the right of the current field on the
3217 |                    same line and the same page. Cycles through the line.
3218 |
3219 |   Return Values :  E_OK            - success
3220 |                    != E_OK         - error from subordinate call
3221 +--------------------------------------------------------------------------*/
3222 static int FN_Right_Field(FORM * form)
3223 {
3224   return _nc_Set_Current_Field(form,
3225                                Right_Neighbour_Field(form->current));
3226 }
3227
3228 /*---------------------------------------------------------------------------
3229 |   Facility      :  libnform  
3230 |   Function      :  static int FN_Up_Field(FORM * form)
3231 |   
3232 |   Description   :  Get the upper neighbour of the current field. This
3233 |                    cycles through the page. See the comments of the
3234 |                    Upper_Neighbour_Field function to understand how
3235 |                    'upper' is defined. 
3236 |
3237 |   Return Values :  E_OK            - success
3238 |                    != E_OK         - error from subordinate call
3239 +--------------------------------------------------------------------------*/
3240 static int FN_Up_Field(FORM * form)
3241 {
3242   return _nc_Set_Current_Field(form,
3243                                Upper_Neighbour_Field(form->current));
3244 }
3245
3246 /*---------------------------------------------------------------------------
3247 |   Facility      :  libnform  
3248 |   Function      :  static int FN_Down_Field(FORM * form)
3249 |   
3250 |   Description   :  Get the down neighbour of the current field. This
3251 |                    cycles through the page. See the comments of the
3252 |                    Down_Neighbour_Field function to understand how
3253 |                    'down' is defined. 
3254 |
3255 |   Return Values :  E_OK            - success
3256 |                    != E_OK         - error from subordinate call
3257 +--------------------------------------------------------------------------*/
3258 static int FN_Down_Field(FORM * form)
3259 {
3260   return _nc_Set_Current_Field(form,
3261                                Down_Neighbour_Field(form->current));
3262 }
3263 /*----------------------------------------------------------------------------
3264   END of Field Navigation routines 
3265   --------------------------------------------------------------------------*/
3266 \f
3267 /*----------------------------------------------------------------------------
3268   Helper routines for Page Navigation
3269   --------------------------------------------------------------------------*/
3270
3271 /*---------------------------------------------------------------------------
3272 |   Facility      :  libnform  
3273 |   Function      :  int _nc_Set_Form_Page(FORM * form,
3274 |                                          int page,
3275 |                                          FIELD * field)
3276 |   
3277 |   Description   :  Make the given page nr. the current page and make
3278 |                    the given field the current field on the page. If
3279 |                    for the field NULL is given, make the first field on
3280 |                    the page the current field. The routine acts only
3281 |                    if the requested page is not the current page.
3282 |
3283 |   Return Values :  E_OK                - success
3284 |                    != E_OK             - error from subordinate call
3285 +--------------------------------------------------------------------------*/
3286 int
3287 _nc_Set_Form_Page(FORM * form, int page, FIELD * field)
3288 {
3289   int res = E_OK;
3290
3291   if ((form->curpage!=page))
3292     {
3293       FIELD *last_field, *field_on_page;
3294
3295       werase(Get_Form_Window(form));
3296       form->curpage = page;
3297       last_field = field_on_page = form->field[form->page[page].smin];
3298       do
3299         {
3300           if (field_on_page->opts & O_VISIBLE)
3301             if ((res=Display_Field(field_on_page))!=E_OK) 
3302               return(res);
3303           field_on_page = field_on_page->snext;
3304         } while(field_on_page != last_field);
3305
3306       if (field)
3307         res = _nc_Set_Current_Field(form,field);
3308       else
3309         /* N.B.: we don't encapsulate this by Inter_Field_Navigation(),
3310            because this is already executed in a page navigation
3311            context that contains field navigation 
3312          */
3313         res = FN_First_Field(form);
3314     }
3315   return(res);
3316 }
3317
3318 /*---------------------------------------------------------------------------
3319 |   Facility      :  libnform  
3320 |   Function      :  static int Next_Page_Number(const FORM * form)
3321 |   
3322 |   Description   :  Calculate the page number following the current page
3323 |                    number. This cycles if the highest page number is
3324 |                    reached.  
3325 |
3326 |   Return Values :  The next page number
3327 +--------------------------------------------------------------------------*/
3328 INLINE static int Next_Page_Number(const FORM * form)
3329 {
3330   return (form->curpage + 1) % form->maxpage;
3331 }
3332
3333 /*---------------------------------------------------------------------------
3334 |   Facility      :  libnform  
3335 |   Function      :  static int Previous_Page_Number(const FORM * form)
3336 |   
3337 |   Description   :  Calculate the page number before the current page
3338 |                    number. This cycles if the first page number is
3339 |                    reached.  
3340 |
3341 |   Return Values :  The previous page number
3342 +--------------------------------------------------------------------------*/
3343 INLINE static int Previous_Page_Number(const FORM * form)
3344 {
3345   return (form->curpage!=0 ? form->curpage - 1 : form->maxpage - 1);
3346 }
3347 \f
3348 /*----------------------------------------------------------------------------
3349   Page Navigation routines 
3350   --------------------------------------------------------------------------*/
3351
3352 /*---------------------------------------------------------------------------
3353 |   Facility      :  libnform  
3354 |   Function      :  static int Page_Navigation(
3355 |                                               int (* const fct) (FORM *),
3356 |                                               FORM * form)
3357 |   
3358 |   Description   :  Generic behaviour for changing a page. This means
3359 |                    that the field is left and a new field is entered.
3360 |                    So the field must be validated and the field init/term
3361 |                    hooks must be called. Because also the page is changed,
3362 |                    the forms init/term hooks must be called also.
3363 |
3364 |   Return Values :  E_OK                - success
3365 |                    E_INVALID_FIELD     - field is invalid
3366 |                    some other          - error from subordinate call
3367 +--------------------------------------------------------------------------*/
3368 static int Page_Navigation(int (* const fct) (FORM *), FORM * form)
3369 {
3370   int res;
3371
3372   if (!_nc_Internal_Validation(form)) 
3373     res = E_INVALID_FIELD;
3374   else
3375     {
3376       Call_Hook(form,fieldterm);
3377       Call_Hook(form,formterm);
3378       res = fct(form);
3379       Call_Hook(form,forminit);
3380       Call_Hook(form,fieldinit);
3381     }
3382   return res;
3383 }
3384
3385 /*---------------------------------------------------------------------------
3386 |   Facility      :  libnform  
3387 |   Function      :  static int PN_Next_Page(FORM * form)
3388 |   
3389 |   Description   :  Move to the next page of the form
3390 |
3391 |   Return Values :  E_OK                - success
3392 |                    != E_OK             - error from subordinate call
3393 +--------------------------------------------------------------------------*/
3394 static int PN_Next_Page(FORM * form)
3395
3396   return _nc_Set_Form_Page(form,Next_Page_Number(form),(FIELD *)0);
3397 }
3398
3399 /*---------------------------------------------------------------------------
3400 |   Facility      :  libnform  
3401 |   Function      :  static int PN_Previous_Page(FORM * form)
3402 |   
3403 |   Description   :  Move to the previous page of the form
3404 |
3405 |   Return Values :  E_OK              - success
3406 |                    != E_OK           - error from subordinate call
3407 +--------------------------------------------------------------------------*/
3408 static int PN_Previous_Page(FORM * form)
3409 {
3410   return _nc_Set_Form_Page(form,Previous_Page_Number(form),(FIELD *)0);
3411 }
3412
3413 /*---------------------------------------------------------------------------
3414 |   Facility      :  libnform  
3415 |   Function      :  static int PN_First_Page(FORM * form)
3416 |   
3417 |   Description   :  Move to the first page of the form
3418 |
3419 |   Return Values :  E_OK              - success
3420 |                    != E_OK           - error from subordinate call
3421 +--------------------------------------------------------------------------*/
3422 static int PN_First_Page(FORM * form)
3423 {
3424   return _nc_Set_Form_Page(form,0,(FIELD *)0);
3425 }
3426
3427 /*---------------------------------------------------------------------------
3428 |   Facility      :  libnform  
3429 |   Function      :  static int PN_Last_Page(FORM * form)
3430 |   
3431 |   Description   :  Move to the last page of the form
3432 |
3433 |   Return Values :  E_OK              - success
3434 |                    != E_OK           - error from subordinate call
3435 +--------------------------------------------------------------------------*/
3436 static int PN_Last_Page(FORM * form)
3437 {
3438   return _nc_Set_Form_Page(form,form->maxpage-1,(FIELD *)0);
3439 }
3440 /*----------------------------------------------------------------------------
3441   END of Field Navigation routines 
3442   --------------------------------------------------------------------------*/
3443 \f
3444 /*----------------------------------------------------------------------------
3445   Helper routines for the core form driver.
3446   --------------------------------------------------------------------------*/
3447
3448 /*---------------------------------------------------------------------------
3449 |   Facility      :  libnform  
3450 |   Function      :  static int Data_Entry(FORM * form,int c)
3451 |   
3452 |   Description   :  Enter character c into at the current position of the
3453 |                    current field of the form.
3454 |
3455 |   Return Values :  E_OK              -
3456 |                    E_REQUEST_DENIED  -
3457 |                    E_SYSTEM_ERROR    -
3458 +--------------------------------------------------------------------------*/
3459 static int Data_Entry(FORM * form, int c)
3460 {
3461   FIELD  *field = form->current;
3462   int result = E_REQUEST_DENIED;
3463
3464   if ( (field->opts & O_EDIT) 
3465 #if FIX_FORM_INACTIVE_BUG
3466        && (field->opts & O_ACTIVE) 
3467 #endif
3468        )
3469     {
3470       if ( (field->opts & O_BLANK) &&
3471            First_Position_In_Current_Field(form) &&
3472            !(form->status & _FCHECK_REQUIRED) && 
3473            !(form->status & _WINDOW_MODIFIED) )
3474         werase(form->w);
3475
3476       if (form->status & _OVLMODE)
3477         {
3478           waddch(form->w,(chtype)c);
3479         } 
3480       else /* no _OVLMODE */ 
3481         {
3482           bool There_Is_Room = Is_There_Room_For_A_Char_In_Line(form);
3483
3484           if (!(There_Is_Room ||
3485                 ((Single_Line_Field(field) && Growable(field)))))
3486               return E_REQUEST_DENIED;
3487
3488           if (!There_Is_Room && !Field_Grown(field,1))
3489             return E_SYSTEM_ERROR;
3490
3491           winsch(form->w,(chtype)c);
3492         }
3493
3494       if ((result=Wrapping_Not_Necessary_Or_Wrapping_Ok(form))==E_OK)
3495         {
3496           bool End_Of_Field= (((field->drows-1)==form->currow) &&
3497                               ((field->dcols-1)==form->curcol));
3498           form->status |= _WINDOW_MODIFIED;
3499           if (End_Of_Field && !Growable(field) && (field->opts & O_AUTOSKIP))
3500             result = Inter_Field_Navigation(FN_Next_Field,form);
3501           else
3502             {
3503               if (End_Of_Field && Growable(field) && !Field_Grown(field,1))
3504                 result = E_SYSTEM_ERROR;
3505               else
3506                 {
3507                   IFN_Next_Character(form);
3508                   result = E_OK;
3509                 }
3510             }
3511         }
3512     }
3513   return result;
3514 }
3515 \f
3516 /* Structure to describe the binding of a request code to a function.
3517    The member keycode codes the request value as well as the generic
3518    routine to use for the request. The code for the generic routine
3519    is coded in the upper 16 Bits while the request code is coded in
3520    the lower 16 bits. 
3521
3522    In terms of C++ you might think of a request as a class with a
3523    virtual method "perform". The different types of request are
3524    derived from this base class and overload (or not) the base class
3525    implementation of perform.
3526 */
3527 typedef struct {
3528   int keycode;           /* must be at least 32 bit: hi:mode, lo: key */
3529   int (*cmd)(FORM *);    /* low level driver routine for this key     */
3530 } Binding_Info;
3531
3532 /* You may see this is the class-id of the request type class */
3533 #define ID_PN    (0x00000000)    /* Page navigation           */
3534 #define ID_FN    (0x00010000)    /* Inter-Field navigation    */
3535 #define ID_IFN   (0x00020000)    /* Intra-Field navigation    */
3536 #define ID_VSC   (0x00030000)    /* Vertical Scrolling        */
3537 #define ID_HSC   (0x00040000)    /* Horizontal Scrolling      */
3538 #define ID_FE    (0x00050000)    /* Field Editing             */
3539 #define ID_EM    (0x00060000)    /* Edit Mode                 */
3540 #define ID_FV    (0x00070000)    /* Field Validation          */
3541 #define ID_CH    (0x00080000)    /* Choice                    */
3542 #define ID_Mask  (0xffff0000)
3543 #define Key_Mask (0x0000ffff)
3544 #define ID_Shft  (16)
3545
3546 /* This array holds all the Binding Infos */
3547 static const Binding_Info bindings[MAX_FORM_COMMAND - MIN_FORM_COMMAND + 1] = 
3548 {
3549   { REQ_NEXT_PAGE    |ID_PN  ,PN_Next_Page},
3550   { REQ_PREV_PAGE    |ID_PN  ,PN_Previous_Page},
3551   { REQ_FIRST_PAGE   |ID_PN  ,PN_First_Page},
3552   { REQ_LAST_PAGE    |ID_PN  ,PN_Last_Page},
3553   
3554   { REQ_NEXT_FIELD   |ID_FN  ,FN_Next_Field},
3555   { REQ_PREV_FIELD   |ID_FN  ,FN_Previous_Field},
3556   { REQ_FIRST_FIELD  |ID_FN  ,FN_First_Field},
3557   { REQ_LAST_FIELD   |ID_FN  ,FN_Last_Field},
3558   { REQ_SNEXT_FIELD  |ID_FN  ,FN_Sorted_Next_Field},
3559   { REQ_SPREV_FIELD  |ID_FN  ,FN_Sorted_Previous_Field},
3560   { REQ_SFIRST_FIELD |ID_FN  ,FN_Sorted_First_Field},
3561   { REQ_SLAST_FIELD  |ID_FN  ,FN_Sorted_Last_Field},
3562   { REQ_LEFT_FIELD   |ID_FN  ,FN_Left_Field},
3563   { REQ_RIGHT_FIELD  |ID_FN  ,FN_Right_Field},
3564   { REQ_UP_FIELD     |ID_FN  ,FN_Up_Field},
3565   { REQ_DOWN_FIELD   |ID_FN  ,FN_Down_Field},
3566   
3567   { REQ_NEXT_CHAR    |ID_IFN ,IFN_Next_Character},
3568   { REQ_PREV_CHAR    |ID_IFN ,IFN_Previous_Character},
3569   { REQ_NEXT_LINE    |ID_IFN ,IFN_Next_Line},
3570   { REQ_PREV_LINE    |ID_IFN ,IFN_Previous_Line},
3571   { REQ_NEXT_WORD    |ID_IFN ,IFN_Next_Word},
3572   { REQ_PREV_WORD    |ID_IFN ,IFN_Previous_Word},
3573   { REQ_BEG_FIELD    |ID_IFN ,IFN_Beginning_Of_Field},
3574   { REQ_END_FIELD    |ID_IFN ,IFN_End_Of_Field},
3575   { REQ_BEG_LINE     |ID_IFN ,IFN_Beginning_Of_Line},
3576   { REQ_END_LINE     |ID_IFN ,IFN_End_Of_Line},
3577   { REQ_LEFT_CHAR    |ID_IFN ,IFN_Left_Character},
3578   { REQ_RIGHT_CHAR   |ID_IFN ,IFN_Right_Character},
3579   { REQ_UP_CHAR      |ID_IFN ,IFN_Up_Character},
3580   { REQ_DOWN_CHAR    |ID_IFN ,IFN_Down_Character},
3581   
3582   { REQ_NEW_LINE     |ID_FE  ,FE_New_Line},
3583   { REQ_INS_CHAR     |ID_FE  ,FE_Insert_Character},
3584   { REQ_INS_LINE     |ID_FE  ,FE_Insert_Line},
3585   { REQ_DEL_CHAR     |ID_FE  ,FE_Delete_Character},
3586   { REQ_DEL_PREV     |ID_FE  ,FE_Delete_Previous},
3587   { REQ_DEL_LINE     |ID_FE  ,FE_Delete_Line},
3588   { REQ_DEL_WORD     |ID_FE  ,FE_Delete_Word},
3589   { REQ_CLR_EOL      |ID_FE  ,FE_Clear_To_End_Of_Line},
3590   { REQ_CLR_EOF      |ID_FE  ,FE_Clear_To_End_Of_Form},
3591   { REQ_CLR_FIELD    |ID_FE  ,FE_Clear_Field},
3592   
3593   { REQ_OVL_MODE     |ID_EM  ,EM_Overlay_Mode},
3594   { REQ_INS_MODE     |ID_EM  ,EM_Insert_Mode},
3595   
3596   { REQ_SCR_FLINE    |ID_VSC ,VSC_Scroll_Line_Forward},
3597   { REQ_SCR_BLINE    |ID_VSC ,VSC_Scroll_Line_Backward},
3598   { REQ_SCR_FPAGE    |ID_VSC ,VSC_Scroll_Page_Forward},
3599   { REQ_SCR_BPAGE    |ID_VSC ,VSC_Scroll_Page_Backward},
3600   { REQ_SCR_FHPAGE   |ID_VSC ,VSC_Scroll_Half_Page_Forward},
3601   { REQ_SCR_BHPAGE   |ID_VSC ,VSC_Scroll_Half_Page_Backward},
3602   
3603   { REQ_SCR_FCHAR    |ID_HSC ,HSC_Scroll_Char_Forward},
3604   { REQ_SCR_BCHAR    |ID_HSC ,HSC_Scroll_Char_Backward},
3605   { REQ_SCR_HFLINE   |ID_HSC ,HSC_Horizontal_Line_Forward},
3606   { REQ_SCR_HBLINE   |ID_HSC ,HSC_Horizontal_Line_Backward},
3607   { REQ_SCR_HFHALF   |ID_HSC ,HSC_Horizontal_Half_Line_Forward},
3608   { REQ_SCR_HBHALF   |ID_HSC ,HSC_Horizontal_Half_Line_Backward},
3609   
3610   { REQ_VALIDATION   |ID_FV  ,FV_Validation},
3611
3612   { REQ_NEXT_CHOICE  |ID_CH  ,CR_Next_Choice},
3613   { REQ_PREV_CHOICE  |ID_CH  ,CR_Previous_Choice}
3614 };
3615
3616 /*---------------------------------------------------------------------------
3617 |   Facility      :  libnform  
3618 |   Function      :  int form_driver(FORM * form,int  c)
3619 |   
3620 |   Description   :  This is the workhorse of the forms system. It checks
3621 |                    to determine whether the character c is a request or
3622 |                    data. If it is a request, the form driver executes
3623 |                    the request and returns the result. If it is data
3624 |                    (printable character), it enters the data into the
3625 |                    current position in the current field. If it is not
3626 |                    recognized, the form driver assumes it is an application
3627 |                    defined command and returns E_UNKNOWN_COMMAND.
3628 |                    Application defined command should be defined relative
3629 |                    to MAX_FORM_COMMAND, the maximum value of a request.
3630 |
3631 |   Return Values :  E_OK              - success
3632 |                    E_SYSTEM_ERROR    - system error
3633 |                    E_BAD_ARGUMENT    - an argument is incorrect
3634 |                    E_NOT_POSTED      - form is not posted
3635 |                    E_INVALID_FIELD   - field contents are invalid
3636 |                    E_BAD_STATE       - called from inside a hook routine
3637 |                    E_REQUEST_DENIED  - request failed
3638 |                    E_UNKNOWN_COMMAND - command not known
3639 +--------------------------------------------------------------------------*/
3640 int form_driver(FORM * form, int  c)
3641 {
3642   const Binding_Info* BI = (Binding_Info *)0;
3643   int res = E_UNKNOWN_COMMAND;
3644
3645   if (!form)
3646     RETURN(E_BAD_ARGUMENT);
3647
3648   if (!(form->field))
3649     RETURN(E_NOT_CONNECTED);
3650   
3651   assert(form->page);
3652   
3653   if (c==FIRST_ACTIVE_MAGIC)
3654     {
3655       form->current = _nc_First_Active_Field(form);
3656       return E_OK;
3657     }
3658   
3659   assert(form->current && 
3660          form->current->buf && 
3661          (form->current->form == form)
3662         );
3663   
3664   if ( form->status & _IN_DRIVER )
3665     RETURN(E_BAD_STATE);
3666
3667   if ( !( form->status & _POSTED ) ) 
3668     RETURN(E_NOT_POSTED);
3669   
3670   if ((c>=MIN_FORM_COMMAND && c<=MAX_FORM_COMMAND) &&
3671       ((bindings[c-MIN_FORM_COMMAND].keycode & Key_Mask) == c))
3672     BI = &(bindings[c-MIN_FORM_COMMAND]);
3673   
3674   if (BI)
3675     {
3676       typedef int (*Generic_Method)(int (* const)(FORM *),FORM *);
3677       static const Generic_Method Generic_Methods[] = 
3678         {
3679           Page_Navigation,         /* overloaded to call field&form hooks */
3680           Inter_Field_Navigation,  /* overloaded to call field hooks      */
3681           NULL,                    /* Intra-Field is generic              */
3682           Vertical_Scrolling,      /* Overloaded to check multi-line      */
3683           Horizontal_Scrolling,    /* Overloaded to check single-line     */
3684           Field_Editing,           /* Overloaded to mark modification     */
3685           NULL,                    /* Edit Mode is generic                */
3686           NULL,                    /* Field Validation is generic         */
3687           NULL                     /* Choice Request is generic           */
3688         };
3689       size_t nMethods = (sizeof(Generic_Methods)/sizeof(Generic_Methods[0]));
3690       size_t method   = ((BI->keycode & ID_Mask) >> ID_Shft) & 0xffff;
3691       
3692       if ( (method >= nMethods) || !(BI->cmd) )
3693         res = E_SYSTEM_ERROR;
3694       else
3695         {
3696           Generic_Method fct = Generic_Methods[method];
3697           if (fct)
3698             res = fct(BI->cmd,form);
3699           else
3700             res = (BI->cmd)(form);
3701         }
3702     } 
3703   else 
3704     {
3705       if (!(c & (~(int)MAX_REGULAR_CHARACTER)) &&
3706           isprint((unsigned char)c) &&                      
3707           Check_Char(form->current->type,c,
3708                      (TypeArgument *)(form->current->arg)))
3709         res = Data_Entry(form,c);
3710     }
3711   _nc_Refresh_Current_Field(form);
3712   RETURN(res);
3713 }
3714 \f
3715 /*----------------------------------------------------------------------------
3716   Field-Buffer manipulation routines.
3717   The effects of setting a buffer is tightly coupled to the core of the form
3718   driver logic. This is especially true in the case of growable fields.
3719   So I don't separate this into an own module. 
3720   --------------------------------------------------------------------------*/
3721
3722 /*---------------------------------------------------------------------------
3723 |   Facility      :  libnform  
3724 |   Function      :  int set_field_buffer(FIELD *field,
3725 |                                         int buffer, char *value)
3726 |   
3727 |   Description   :  Set the given buffer of the field to the given value.
3728 |                    Buffer 0 stores the displayed content of the field.
3729 |                    For dynamic fields this may grow the fieldbuffers if
3730 |                    the length of the value exceeds the current buffer
3731 |                    length. For buffer 0 only printable values are allowed.
3732 |                    For static fields, the value needs not to be zero ter-
3733 |                    minated. It is copied up to the length of the buffer.   
3734 |
3735 |   Return Values :  E_OK            - success
3736 |                    E_BAD_ARGUMENT  - invalid argument
3737 |                    E_SYSTEM_ERROR  - system error
3738 +--------------------------------------------------------------------------*/
3739 int set_field_buffer(FIELD * field, int buffer, const char * value)
3740 {
3741   char *s, *p;
3742   int res = E_OK;
3743   unsigned int len;
3744
3745   if ( !field || !value || ((buffer < 0)||(buffer > field->nbuf)) )
3746     RETURN(E_BAD_ARGUMENT);
3747
3748   len  = Buffer_Length(field);
3749
3750   if (buffer==0)
3751     {
3752       const char *v;
3753       unsigned int i = 0;
3754
3755       for(v=value; *v && (i<len); v++,i++)
3756         {
3757           if (!isprint((unsigned char)*v))
3758             RETURN(E_BAD_ARGUMENT);
3759         }
3760     }
3761
3762   if (Growable(field))
3763     {
3764       /* for a growable field we must assume zero terminated strings, because
3765          somehow we have to detect the length of what should be copied.
3766       */
3767       unsigned int vlen = strlen(value);
3768       if (vlen > len)
3769         {
3770           if (!Field_Grown(field,
3771                            (int)(1 + (vlen-len)/((field->rows+field->nrow)*field->cols))))
3772             RETURN(E_SYSTEM_ERROR);
3773
3774           /* in this case we also have to check, wether or not the remaining
3775              characters in value are also printable for buffer 0. */
3776           if (buffer==0)
3777             {
3778               unsigned int i;
3779           
3780               for(i=len; i<vlen; i++)
3781                 if (!isprint(value[i]))
3782                   RETURN(E_BAD_ARGUMENT);
3783             }
3784           len = vlen;
3785         }
3786     }
3787   
3788   p   = Address_Of_Nth_Buffer(field,buffer);
3789
3790 #if HAVE_MEMCCPY
3791   s = memccpy(p,value,0,len);
3792 #else
3793   for(s=(char *)value; *s && (s < (value+len)); s++)
3794     p[s-value] = *s;
3795   if (s < (value+len))
3796     {
3797       p[s-value] = *s++;
3798       s = p + (s-value);
3799     }
3800   else 
3801     s=(char *)0;
3802 #endif
3803
3804   if (s) 
3805     { /* this means, value was null terminated and not greater than the
3806          buffer. We have to pad with blanks. Please note that due to memccpy
3807          logic s points after the terminating null. */
3808       s--; /* now we point to the terminator. */
3809       assert(len >= (unsigned int)(s-p));
3810       if (len > (unsigned int)(s-p))
3811         memset(s,C_BLANK,len-(unsigned int)(s-p));
3812     }
3813
3814   if (buffer==0)
3815     {
3816       int syncres;
3817       if (((syncres=Synchronize_Field( field ))!=E_OK) && 
3818           (res==E_OK))
3819         res = syncres;
3820       if (((syncres=Synchronize_Linked_Fields(field ))!=E_OK) &&
3821           (res==E_OK))
3822         res = syncres;
3823     }
3824   RETURN(res);
3825 }               
3826
3827 /*---------------------------------------------------------------------------
3828 |   Facility      :  libnform  
3829 |   Function      :  char *field_buffer(const FIELD *field,int buffer)
3830 |   
3831 |   Description   :  Return the address of the buffer for the field.
3832 |
3833 |   Return Values :  Pointer to buffer or NULL if arguments were invalid.
3834 +--------------------------------------------------------------------------*/
3835 char *field_buffer(const FIELD * field, int  buffer)
3836 {
3837   if (field && (buffer >= 0) && (buffer <= field->nbuf))
3838     return Address_Of_Nth_Buffer(field,buffer);
3839   else
3840     return (char *)0;
3841 }
3842
3843 /* frm_driver.c ends here */