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internals.c revision 1.38
      1 /*	$NetBSD: internals.c,v 1.38 2016/03/09 19:47:13 christos Exp $	*/
      2 
      3 /*-
      4  * Copyright (c) 1998-1999 Brett Lymn
      5  *                         (blymn (at) baea.com.au, brett_lymn (at) yahoo.com.au)
      6  * All rights reserved.
      7  *
      8  * This code has been donated to The NetBSD Foundation by the Author.
      9  *
     10  * Redistribution and use in source and binary forms, with or without
     11  * modification, are permitted provided that the following conditions
     12  * are met:
     13  * 1. Redistributions of source code must retain the above copyright
     14  *    notice, this list of conditions and the following disclaimer.
     15  * 2. The name of the author may not be used to endorse or promote products
     16  *    derived from this software without specific prior written permission
     17  *
     18  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
     19  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
     20  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
     21  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
     22  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
     23  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
     24  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
     25  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
     26  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
     27  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
     28  *
     29  *
     30  */
     31 
     32 #include <sys/cdefs.h>
     33 __RCSID("$NetBSD: internals.c,v 1.38 2016/03/09 19:47:13 christos Exp $");
     34 
     35 #include <limits.h>
     36 #include <ctype.h>
     37 #include <stdio.h>
     38 #include <stdlib.h>
     39 #include <strings.h>
     40 #include <assert.h>
     41 #include <err.h>
     42 #include <stdarg.h>
     43 #include "internals.h"
     44 #include "form.h"
     45 
     46 #ifdef DEBUG
     47 /*
     48  *  file handle to write debug info to, this will be initialised when
     49  *  the form is first posted.
     50  */
     51 
     52 /*
     53  * map the request numbers to strings for debug
     54  */
     55 static const char *reqs[] = {
     56 	"NEXT_PAGE", "PREV_PAGE", "FIRST_PAGE",	"LAST_PAGE", "NEXT_FIELD",
     57 	"PREV_FIELD", "FIRST_FIELD", "LAST_FIELD", "SNEXT_FIELD",
     58 	"SPREV_FIELD", "SFIRST_FIELD", "SLAST_FIELD", "LEFT_FIELD",
     59 	"RIGHT_FIELD", "UP_FIELD", "DOWN_FIELD", "NEXT_CHAR", "PREV_CHAR",
     60 	"NEXT_LINE", "PREV_LINE", "NEXT_WORD", "PREV_WORD", "BEG_FIELD",
     61 	"END_FIELD", "BEG_LINE", "END_LINE", "LEFT_CHAR", "RIGHT_CHAR",
     62 	"UP_CHAR", "DOWN_CHAR", "NEW_LINE", "INS_CHAR", "INS_LINE",
     63 	"DEL_CHAR", "DEL_PREV", "DEL_LINE", "DEL_WORD", "CLR_EOL",
     64 	"CLR_EOF", "CLR_FIELD", "OVL_MODE", "INS_MODE", "SCR_FLINE",
     65 	"SCR_BLINE", "SCR_FPAGE", "SCR_BPAGE", "SCR_FHPAGE", "SCR_BHPAGE",
     66 	"SCR_FCHAR", "SCR_BCHAR", "SCR_HFLINE", "SCR_HBLINE", "SCR_HFHALF",
     67 	"SCR_HBHALF", "VALIDATION", "PREV_CHOICE", "NEXT_CHOICE" };
     68 #endif
     69 
     70 /* define our own min function - this is not generic but will do here
     71  * (don't believe me?  think about what value you would get
     72  * from min(x++, y++)
     73  */
     74 #define min(a,b) (((a) > (b))? (b) : (a))
     75 
     76 /* for the line joining function... */
     77 #define JOIN_NEXT    1
     78 #define JOIN_NEXT_NW 2 /* next join, don't wrap the joined line */
     79 #define JOIN_PREV    3
     80 #define JOIN_PREV_NW 4 /* previous join, don't wrap the joined line */
     81 
     82 /* for the bump_lines function... */
     83 #define _FORMI_USE_CURRENT -1 /* indicates current cursor pos to be used */
     84 
     85 /* used in add_char for initial memory allocation for string in row */
     86 #define INITIAL_LINE_ALLOC 16
     87 
     88 unsigned
     89 field_skip_blanks(unsigned int start, _FORMI_FIELD_LINES **rowp);
     90 static void
     91 _formi_do_char_validation(FIELD *field, FIELDTYPE *type, char c, int *ret_val);
     92 static void
     93 _formi_do_validation(FIELD *field, FIELDTYPE *type, int *ret_val);
     94 static int
     95 _formi_join_line(FIELD *field, _FORMI_FIELD_LINES **rowp, int direction);
     96 void
     97 _formi_hscroll_back(FIELD *field, _FORMI_FIELD_LINES *row, unsigned int amt);
     98 void
     99 _formi_hscroll_fwd(FIELD *field, _FORMI_FIELD_LINES *row, unsigned int amt);
    100 static void
    101 _formi_scroll_back(FIELD *field, unsigned int amt);
    102 static void
    103 _formi_scroll_fwd(FIELD *field, unsigned int amt);
    104 static int
    105 _formi_set_cursor_xpos(FIELD *field, int no_scroll);
    106 static int
    107 find_sow(unsigned int offset, _FORMI_FIELD_LINES **rowp);
    108 static int
    109 split_line(FIELD *field, bool hard_split, unsigned pos,
    110 	   _FORMI_FIELD_LINES **rowp);
    111 static bool
    112 check_field_size(FIELD *field);
    113 static int
    114 add_tab(FORM *form, _FORMI_FIELD_LINES *row, unsigned int i, char c);
    115 static int
    116 tab_size(_FORMI_FIELD_LINES *row, unsigned int i);
    117 static unsigned int
    118 tab_fit_len(_FORMI_FIELD_LINES *row, unsigned int len);
    119 static int
    120 tab_fit_window(FIELD *field, unsigned int pos, unsigned int window);
    121 static void
    122 add_to_free(FIELD *field, _FORMI_FIELD_LINES *line);
    123 static void
    124 adjust_ypos(FIELD *field, _FORMI_FIELD_LINES *line);
    125 static _FORMI_FIELD_LINES *
    126 copy_row(_FORMI_FIELD_LINES *row);
    127 static void
    128 destroy_row_list(_FORMI_FIELD_LINES *start);
    129 
    130 /*
    131  * Calculate the cursor y position to make the given row appear on the
    132  * field.  This may be as simple as just changing the ypos (if at all) but
    133  * may encompass resetting the start_line of the field to place the line
    134  * at the bottom of the field.  The field is assumed to be a multi-line one.
    135  */
    136 static void
    137 adjust_ypos(FIELD *field, _FORMI_FIELD_LINES *line)
    138 {
    139 	unsigned ypos;
    140 	_FORMI_FIELD_LINES *rs;
    141 
    142 	ypos = 0;
    143 	rs = field->alines;
    144 	while (rs != line) {
    145 		rs = rs->next;
    146 		ypos++;
    147 	}
    148 
    149 	field->cursor_ypos = ypos;
    150 	field->start_line = field->alines;
    151 	if (ypos > (field->rows - 1)) {
    152 		  /*
    153 		   * cur_line off the end of the field,
    154 		   * adjust start_line so fix this.
    155 		   */
    156 		field->cursor_ypos = field->rows - 1;
    157 		ypos = ypos - (field->rows - 1);
    158 		while (ypos > 0) {
    159 			ypos--;
    160 			field->start_line = field->start_line->next;
    161 		}
    162 	}
    163 }
    164 
    165 
    166 /*
    167  * Delete the given row and add it to the free list of the given field.
    168  */
    169 static void
    170 add_to_free(FIELD *field, _FORMI_FIELD_LINES *line)
    171 {
    172 	_FORMI_FIELD_LINES *saved;
    173 
    174 	saved = line;
    175 
    176 	  /* don't remove if only one line... */
    177 	if ((line->prev == NULL) && (line->next == NULL))
    178 		return;
    179 
    180 	if (line->prev == NULL) {
    181 		/* handle top of list */
    182 		field->alines = line->next;
    183 		field->alines->prev = NULL;
    184 
    185 		if (field->cur_line == saved)
    186 			field->cur_line = field->alines;
    187 		if (field->start_line == saved)
    188 			field->start_line = saved;
    189 	} else if (line->next == NULL) {
    190 		/* handle bottom of list */
    191 		line->prev->next = NULL;
    192 		if (field->cur_line == saved)
    193 			field->cur_line = saved->prev;
    194 		if (field->start_line == saved)
    195 			field->cur_line = saved->prev;
    196 	} else {
    197 		saved->next->prev = saved->prev;
    198 		saved->prev->next = saved->next;
    199 		if (field->cur_line == saved)
    200 			field->cur_line = saved->prev;
    201 		if (field->start_line == saved)
    202 			field->start_line = saved;
    203 	}
    204 
    205 	saved->next = field->free;
    206 	field->free = saved;
    207 	saved->prev = NULL;
    208 	if (saved->next != NULL)
    209 		saved->next->prev = line;
    210 }
    211 
    212 /*
    213  * Duplicate the given row, return the pointer to the new copy or
    214  * NULL if the copy fails.
    215  */
    216 static _FORMI_FIELD_LINES *
    217 copy_row(_FORMI_FIELD_LINES *row)
    218 {
    219 	_FORMI_FIELD_LINES *new;
    220 	_formi_tab_t *tp, *newt;
    221 
    222 	if ((new = (_FORMI_FIELD_LINES *) malloc(sizeof(_FORMI_FIELD_LINES)))
    223 	    == NULL) {
    224 		return NULL;
    225 	}
    226 
    227 	memcpy(new, row, sizeof(_FORMI_FIELD_LINES));
    228 
    229 	  /* nuke the pointers from the source row so we don't get confused */
    230 	new->next = NULL;
    231 	new->prev = NULL;
    232 	new->tabs = NULL;
    233 
    234 	if ((new->string = (char *) malloc((size_t)new->allocated)) == NULL) {
    235 		free(new);
    236 		return NULL;
    237 	}
    238 
    239 	memcpy(new->string, row->string, (size_t) row->length + 1);
    240 
    241 	if (row->tabs != NULL) {
    242 		tp = row->tabs;
    243 		if ((new->tabs = (_formi_tab_t *) malloc(sizeof(_formi_tab_t)))
    244 		    == NULL) {
    245 			free(new->string);
    246 			free(new);
    247 			return NULL;
    248 		}
    249 
    250 		memcpy(new->tabs, row->tabs, sizeof(_formi_tab_t));
    251 		new->tabs->back = NULL;
    252 		new->tabs->fwd = NULL;
    253 
    254 		tp = tp->fwd;
    255 		newt = new->tabs;
    256 
    257 		while (tp != NULL) {
    258 			if ((newt->fwd =
    259 			     (_formi_tab_t *) malloc(sizeof(_formi_tab_t)))
    260 			    == NULL) {
    261 				/* error... unwind allocations */
    262 				tp = new->tabs;
    263 				while (tp != NULL) {
    264 					newt = tp->fwd;
    265 					free(tp);
    266 					tp = newt;
    267 				}
    268 
    269 				free(new->string);
    270 				free(new);
    271 				return NULL;
    272 			}
    273 
    274 			memcpy(newt->fwd, tp, sizeof(_formi_tab_t));
    275 			newt->fwd->back = newt;
    276 			newt = newt->fwd;
    277 			newt->fwd = NULL;
    278 			tp = tp->fwd;
    279 		}
    280 	}
    281 
    282 	return new;
    283 }
    284 
    285 /*
    286  * Initialise the row offset for a field, depending on the type of
    287  * field it is and the type of justification used.  The justification
    288  * is only used on static single line fields, everything else will
    289  * have the cursor_xpos set to 0.
    290  */
    291 void
    292 _formi_init_field_xpos(FIELD *field)
    293 {
    294 	  /* not static or is multi-line which are not justified, so 0 it is */
    295 	if (((field->opts & O_STATIC) != O_STATIC) ||
    296 	    ((field->rows + field->nrows) != 1)) {
    297 		field->cursor_xpos = 0;
    298 		return;
    299 	}
    300 
    301 	switch (field->justification) {
    302 	case JUSTIFY_RIGHT:
    303 		field->cursor_xpos = field->cols - 1;
    304 		break;
    305 
    306 	case JUSTIFY_CENTER:
    307 		field->cursor_xpos = (field->cols - 1) / 2;
    308 		break;
    309 
    310 	default: /* assume left justify */
    311 		field->cursor_xpos = 0;
    312 		break;
    313 	}
    314 }
    315 
    316 
    317 /*
    318  * Open the debug file if it is not already open....
    319  */
    320 #ifdef DEBUG
    321 static FILE *dbg;
    322 static const char dbg_file[] = "___form_dbg.out";
    323 
    324 void
    325 _formi_dbg_printf(const char *fmt, ...)
    326 {
    327 	va_list ap;
    328 
    329 	if (dbg == NULL && (dbg = fopen(dbg_file, "w")) == NULL) {
    330 		warn("Cannot open debug file `%s'", dbg_file);
    331 		return;
    332 	}
    333 	va_start(ap, fmt);
    334 	vfprintf(dbg, fmt, ap);
    335 	va_end(ap);
    336 }
    337 #endif
    338 
    339 /*
    340  * Check the sizing of the field, if the maximum size is set for a
    341  * dynamic field then check that the number of rows or columns does
    342  * not exceed the set maximum.  The decision to check the rows or
    343  * columns is made on the basis of how many rows are in the field -
    344  * one row means the max applies to the number of columns otherwise it
    345  * applies to the number of rows.  If the row/column count is less
    346  * than the maximum then return TRUE.
    347  *
    348  */
    349 static bool
    350 check_field_size(FIELD *field)
    351 {
    352 	if ((field->opts & O_STATIC) != O_STATIC) {
    353 		  /* dynamic field */
    354 		if (field->max == 0) /* unlimited */
    355 			return TRUE;
    356 
    357 		if (field->rows == 1) {
    358 			return (field->alines->length < field->max);
    359 		} else {
    360 			return (field->row_count <= field->max);
    361 		}
    362 	} else {
    363 		if ((field->rows + field->nrows) == 1) {
    364 			return (field->alines->length <= field->cols);
    365 		} else {
    366 			return (field->row_count <= (field->rows
    367 						     + field->nrows));
    368 		}
    369 	}
    370 }
    371 
    372 /*
    373  * Set the form's current field to the first valid field on the page.
    374  * Assume the fields have been sorted and stitched.
    375  */
    376 int
    377 _formi_pos_first_field(FORM *form)
    378 {
    379 	FIELD *cur;
    380 	int old_page;
    381 
    382 	old_page = form->page;
    383 
    384 	  /* scan forward for an active page....*/
    385 	while (form->page_starts[form->page].in_use == 0) {
    386 		form->page++;
    387 		if (form->page > form->max_page) {
    388 			form->page = old_page;
    389 			return E_REQUEST_DENIED;
    390 		}
    391 	}
    392 
    393 	  /* then scan for a field we can use */
    394 	cur = form->fields[form->page_starts[form->page].first];
    395 	while ((cur->opts & (O_VISIBLE | O_ACTIVE))
    396 	       != (O_VISIBLE | O_ACTIVE)) {
    397 		cur = TAILQ_NEXT(cur, glue);
    398 		if (cur == NULL) {
    399 			form->page = old_page;
    400 			return E_REQUEST_DENIED;
    401 		}
    402 	}
    403 
    404 	form->cur_field = cur->index;
    405 	return E_OK;
    406 }
    407 
    408 /*
    409  * Set the field to the next active and visible field, the fields are
    410  * traversed in index order in the direction given.  If the parameter
    411  * use_sorted is TRUE then the sorted field list will be traversed instead
    412  * of using the field index.
    413  */
    414 int
    415 _formi_pos_new_field(FORM *form, unsigned direction, unsigned use_sorted)
    416 {
    417 	FIELD *cur;
    418 	int i;
    419 
    420 	i = form->cur_field;
    421 	cur = form->fields[i];
    422 
    423 	do {
    424 		if (direction == _FORMI_FORWARD) {
    425 			if (use_sorted == TRUE) {
    426 				if ((form->wrap == FALSE) &&
    427 				    (cur == TAILQ_LAST(&form->sorted_fields,
    428 					_formi_sort_head)))
    429 					return E_REQUEST_DENIED;
    430 				cur = TAILQ_NEXT(cur, glue);
    431 				i = cur->index;
    432 			} else {
    433 				if ((form->wrap == FALSE) &&
    434 				    ((i + 1) >= form->field_count))
    435 					return E_REQUEST_DENIED;
    436 				i++;
    437 				if (i >= form->field_count)
    438 					i = 0;
    439 			}
    440 		} else {
    441 			if (use_sorted == TRUE) {
    442 				if ((form->wrap == FALSE) &&
    443 				    (cur == TAILQ_FIRST(&form->sorted_fields)))
    444 					return E_REQUEST_DENIED;
    445 				cur = TAILQ_PREV(cur, _formi_sort_head, glue);
    446 				i = cur->index;
    447 			} else {
    448 				if ((form->wrap == FALSE) && (i <= 0))
    449 					return E_REQUEST_DENIED;
    450 				i--;
    451 				if (i < 0)
    452 					i = form->field_count - 1;
    453 			}
    454 		}
    455 
    456 		if ((form->fields[i]->opts & (O_VISIBLE | O_ACTIVE))
    457 			== (O_VISIBLE | O_ACTIVE)) {
    458 			form->cur_field = i;
    459 			return E_OK;
    460 		}
    461 	}
    462 	while (i != form->cur_field);
    463 
    464 	return E_REQUEST_DENIED;
    465 }
    466 
    467 /*
    468  * Destroy the list of line structs passed by freeing all allocated
    469  * memory.
    470  */
    471 static void
    472 destroy_row_list(_FORMI_FIELD_LINES *start)
    473 {
    474 	_FORMI_FIELD_LINES *temp, *row;
    475 	_formi_tab_t *tt, *tp;
    476 
    477 	row = start;
    478 	while (row != NULL) {
    479 		if (row->tabs != NULL) {
    480 			  /* free up the tab linked list... */
    481 			tp = row->tabs;
    482 			while (tp != NULL) {
    483 				tt = tp->fwd;
    484 				free(tp);
    485 				tp = tt;
    486 			}
    487 		}
    488 
    489 		if (row->string != NULL)
    490 			free(row->string);
    491 
    492 		temp = row->next;
    493 		free(row);
    494 		row = temp;
    495 	}
    496 }
    497 
    498 /*
    499  * Word wrap the contents of the field's buffer 0 if this is allowed.
    500  * If the wrap is successful, that is, the row count nor the buffer
    501  * size is exceeded then the function will return E_OK, otherwise it
    502  * will return E_REQUEST_DENIED.
    503  */
    504 int
    505 _formi_wrap_field(FIELD *field, _FORMI_FIELD_LINES *loc)
    506 {
    507 	int width, wrap_err;
    508 	unsigned int pos, saved_xpos, saved_ypos, saved_cur_xpos;
    509 	unsigned int saved_row_count;
    510 	_FORMI_FIELD_LINES *saved_row, *row, *row_backup, *saved_cur_line;
    511 	_FORMI_FIELD_LINES *saved_start_line, *temp;
    512 
    513 	if ((field->opts & O_STATIC) == O_STATIC) {
    514 		if ((field->rows + field->nrows) == 1) {
    515 			return E_OK; /* cannot wrap a single line */
    516 		}
    517 		width = field->cols;
    518 	} else {
    519 		  /* if we are limited to one line then don't try to wrap */
    520 		if ((field->drows + field->nrows) == 1) {
    521 			return E_OK;
    522 		}
    523 
    524 		  /*
    525 		   * hueristic - if a dynamic field has more than one line
    526 		   * on the screen then the field grows rows, otherwise
    527 		   * it grows columns, effectively a single line field.
    528 		   * This is documented AT&T behaviour.
    529 		   */
    530 		if (field->rows > 1) {
    531 			width = field->cols;
    532 		} else {
    533 			return E_OK;
    534 		}
    535 	}
    536 
    537 	row = loc;
    538 
    539 	  /* if we are not at the top of the field then back up one
    540 	   * row because we may be able to merge the current row into
    541 	   * the one above.
    542 	   */
    543 	if (row->prev != NULL)
    544 		row = row->prev;
    545 
    546 	saved_row = row;
    547 	saved_xpos = field->row_xpos;
    548 	saved_cur_xpos = field->cursor_xpos;
    549 	saved_ypos = field->cursor_ypos;
    550 	saved_row_count = field->row_count;
    551 
    552 	  /*
    553 	   * Save a copy of the lines affected, just in case things
    554 	   * don't work out.
    555 	   */
    556 	if ((row_backup = copy_row(row)) == NULL)
    557 		return E_SYSTEM_ERROR;
    558 
    559 	temp = row_backup;
    560 	row = row->next;
    561 
    562 	saved_cur_line = temp;
    563 	saved_start_line = temp;
    564 
    565 	while (row != NULL) {
    566 		if ((temp->next = copy_row(row)) == NULL) {
    567 			  /* a row copy failed... free up allocations */
    568 			destroy_row_list(row_backup);
    569 			return E_SYSTEM_ERROR;
    570 		}
    571 
    572 		temp->next->prev = temp;
    573 		temp = temp->next;
    574 
    575 		if (row == field->start_line)
    576 			saved_start_line = temp;
    577 		if (row == field->cur_line)
    578 			saved_cur_line = temp;
    579 
    580 		row = row->next;
    581 	}
    582 
    583 	row = saved_row;
    584 	while (row != NULL) {
    585 		pos = row->length - 1;
    586 		if (row->expanded < width) {
    587 			  /* line may be too short, try joining some lines */
    588 			if ((row->hard_ret == TRUE) && (row->next != NULL)) {
    589 				/*
    590 				 * Skip the line if it has a hard return
    591 				 * and it is not the last, we cannot join
    592 				 * anything to it.
    593 				 */
    594 				row = row->next;
    595 				continue;
    596 			}
    597 
    598 			if (row->next == NULL) {
    599 				/*
    600 				 * If there are no more lines and this line
    601 				 * is too short then our job is over.
    602 				 */
    603 				break;
    604 			}
    605 
    606 			if (_formi_join_line(field, &row,
    607 					     JOIN_NEXT_NW) == E_OK) {
    608 				continue;
    609 			} else
    610 				break;
    611 		} else if (row->expanded > width) {
    612 			  /* line is too long, split it */
    613 
    614 			  /*
    615 			   * split on first whitespace before current word
    616 			   * if the line has tabs we need to work out where
    617 			   * the field border lies when the tabs are expanded.
    618 			   */
    619 			if (row->tabs == NULL) {
    620 				pos = width - 1;
    621 				if (pos >= row->expanded)
    622 					pos = row->expanded - 1;
    623 			} else {
    624 				pos = tab_fit_len(row, field->cols);
    625 			}
    626 
    627 			if ((!isblank((unsigned char)row->string[pos])) &&
    628 			    ((field->opts & O_WRAP) == O_WRAP)) {
    629 				if (!isblank((unsigned char)row->string[pos - 1]))
    630 					pos = find_sow((unsigned int) pos,
    631 						       &row);
    632 				/*
    633 				 * If we cannot split the line then return
    634 				 * NO_ROOM so the driver can tell that it
    635 				 * should not autoskip (if that is enabled)
    636 				 */
    637 				if ((pos == 0)
    638 				    || (!isblank((unsigned char)row->string[pos - 1]))) {
    639 					wrap_err = E_NO_ROOM;
    640 					goto restore_and_exit;
    641 				}
    642 			}
    643 
    644 			  /* if we are at the end of the string and it has
    645 			   * a trailing blank, don't wrap the blank.
    646 			   */
    647 			if ((row->next == NULL) && (pos == row->length - 1) &&
    648 			    (isblank((unsigned char)row->string[pos])) &&
    649 			    row->expanded <= field->cols)
    650 				continue;
    651 
    652 			  /*
    653 			   * otherwise, if we are still sitting on a
    654 			   * blank but not at the end of the line
    655 			   * move forward one char so the blank
    656 			   * is on the line boundary.
    657 			   */
    658 			if ((isblank((unsigned char)row->string[pos])) &&
    659 			    (pos != row->length - 1))
    660 				pos++;
    661 
    662 			if (split_line(field, FALSE, pos, &row) != E_OK) {
    663 				wrap_err = E_REQUEST_DENIED;
    664 				goto restore_and_exit;
    665 			}
    666 		} else
    667 			  /* line is exactly the right length, do next one */
    668 			row = row->next;
    669 	}
    670 
    671 	  /* Check if we have not run out of room */
    672 	if ((((field->opts & O_STATIC) == O_STATIC) &&
    673 	     field->row_count > (field->rows + field->nrows)) ||
    674 	    ((field->max != 0) && (field->row_count > field->max))) {
    675 
    676 		wrap_err = E_REQUEST_DENIED;
    677 
    678 	  restore_and_exit:
    679 		if (saved_row->prev == NULL) {
    680 			field->alines = row_backup;
    681 		} else {
    682 			saved_row->prev->next = row_backup;
    683 			row_backup->prev = saved_row->prev;
    684 		}
    685 
    686 		field->row_xpos = saved_xpos;
    687 		field->cursor_xpos = saved_cur_xpos;
    688 		field->cursor_ypos = saved_ypos;
    689 		field->row_count = saved_row_count;
    690 		field->start_line = saved_start_line;
    691 		field->cur_line = saved_cur_line;
    692 
    693 		destroy_row_list(saved_row);
    694 		return wrap_err;
    695 	}
    696 
    697 	destroy_row_list(row_backup);
    698 	return E_OK;
    699 }
    700 
    701 /*
    702  * Join the two lines that surround the location pos, the type
    703  * variable indicates the direction of the join, JOIN_NEXT will join
    704  * the next line to the current line, JOIN_PREV will join the current
    705  * line to the previous line, the new lines will be wrapped unless the
    706  * _NW versions of the directions are used.  Returns E_OK if the join
    707  * was successful or E_REQUEST_DENIED if the join cannot happen.
    708  */
    709 static int
    710 _formi_join_line(FIELD *field, _FORMI_FIELD_LINES **rowp, int direction)
    711 {
    712 	int old_len, count;
    713 	struct _formi_field_lines *saved;
    714 	char *newp;
    715 	_FORMI_FIELD_LINES *row = *rowp;
    716 
    717 	_formi_dbg_printf("%s: working on row %p, row_count = %d\n",
    718 	    __func__, row, field->row_count);
    719 
    720 	if ((direction == JOIN_NEXT) || (direction == JOIN_NEXT_NW)) {
    721 		  /*
    722 		   * See if there is another line following, or if the
    723 		   * line contains a hard return then we don't join
    724 		   * any lines to it.
    725 		   */
    726 		if ((row->next == NULL) || (row->hard_ret == TRUE)) {
    727 			return E_REQUEST_DENIED;
    728 		}
    729 
    730 		_formi_dbg_printf(
    731 		    "%s: join_next before length = %d, expanded = %d",
    732 		    __func__, row->length, row->expanded);
    733 		_formi_dbg_printf(
    734 		    " :: next row length = %d, expanded = %d\n",
    735 		    row->length, row->expanded);
    736 
    737 		if (row->allocated < (row->length + row->next->length + 1)) {
    738 			if ((newp = realloc(row->string, (size_t)(row->length +
    739 							  row->next->length
    740 							  + 1))) == NULL)
    741 				return E_REQUEST_DENIED;
    742 			row->string = newp;
    743 			row->allocated = row->length + row->next->length + 1;
    744 		}
    745 
    746 		strcat(row->string, row->next->string);
    747 		old_len = row->length;
    748 		row->length += row->next->length;
    749 		if (row->length > 0)
    750 			row->expanded =
    751 				_formi_tab_expanded_length(row->string, 0,
    752 							   row->length - 1);
    753 		else
    754 			row->expanded = 0;
    755 
    756 		_formi_calculate_tabs(row);
    757 		row->hard_ret = row->next->hard_ret;
    758 
    759 		  /* adjust current line if it is on the row being eaten */
    760 		if (field->cur_line == row->next) {
    761 			field->cur_line = row;
    762 			field->row_xpos += old_len;
    763 			field->cursor_xpos =
    764 				_formi_tab_expanded_length(row->string, 0,
    765 							   field->row_xpos);
    766 			if (field->cursor_xpos > 0)
    767 				field->cursor_xpos--;
    768 
    769 			if (field->cursor_ypos > 0)
    770 				field->cursor_ypos--;
    771 			else {
    772 				if (field->start_line->prev != NULL)
    773 					field->start_line =
    774 						field->start_line->prev;
    775 			}
    776 		}
    777 
    778 		  /* remove joined line record from the row list */
    779 		add_to_free(field, row->next);
    780 
    781 		_formi_dbg_printf(
    782 		    "%s: exit length = %d, expanded = %d\n",
    783 		    __func__, row->length, row->expanded);
    784 	} else {
    785 		if (row->prev == NULL) {
    786 			return E_REQUEST_DENIED;
    787 		}
    788 
    789 		saved = row->prev;
    790 
    791 		  /*
    792 		   * Don't try to join if the line above has a hard
    793 		   * return on it.
    794 		   */
    795 		if (saved->hard_ret == TRUE) {
    796 			return E_REQUEST_DENIED;
    797 		}
    798 
    799 		_formi_dbg_printf(
    800 		    "%s: join_prev before length = %d, expanded = %d",
    801 		    __func__, row->length, row->expanded);
    802 		_formi_dbg_printf(
    803 		    " :: prev row length = %d, expanded = %d\n",
    804 		    saved->length, saved->expanded);
    805 
    806 		if (saved->allocated < (row->length + saved->length + 1)) {
    807 			if ((newp = realloc(saved->string,
    808 					    (size_t) (row->length +
    809 						      saved->length
    810 						      + 1))) == NULL)
    811 				return E_REQUEST_DENIED;
    812 			saved->string = newp;
    813 			saved->allocated = row->length + saved->length + 1;
    814 		}
    815 
    816 		strcat(saved->string, row->string);
    817 		old_len = saved->length;
    818 		saved->length += row->length;
    819 		if (saved->length > 0)
    820 			saved->expanded =
    821 				_formi_tab_expanded_length(saved->string, 0,
    822 							   saved->length - 1);
    823 		else
    824 			saved->length = 0;
    825 
    826 		saved->hard_ret = row->hard_ret;
    827 
    828 		  /* adjust current line if it was on the row being eaten */
    829 		if (field->cur_line == row) {
    830 			field->cur_line = saved;
    831 			field->row_xpos += old_len;
    832 			field->cursor_xpos =
    833 				_formi_tab_expanded_length(saved->string, 0,
    834 							   field->row_xpos);
    835 			if (field->cursor_xpos > 0)
    836 				field->cursor_xpos--;
    837 		}
    838 
    839 		add_to_free(field, row);
    840 
    841 		_formi_dbg_printf(
    842 		    "%s: exit length = %d, expanded = %d\n", __func__,
    843 		    saved->length, saved->expanded);
    844 		row = saved;
    845 	}
    846 
    847 
    848 	  /*
    849 	   * Work out where the line lies in the field in relation to
    850 	   * the cursor_ypos.  First count the rows from the start of
    851 	   * the field until we hit the row we just worked on.
    852 	   */
    853 	saved = field->start_line;
    854 	count = 0;
    855 	while (saved->next != NULL) {
    856 		if (saved == row)
    857 			break;
    858 		count++;
    859 		saved = saved->next;
    860 	}
    861 
    862 	  /* now check if we need to adjust cursor_ypos */
    863 	if (field->cursor_ypos > count) {
    864 		field->cursor_ypos--;
    865 	}
    866 
    867 	field->row_count--;
    868 	*rowp = row;
    869 
    870 	  /* wrap the field if required, if this fails undo the change */
    871 	if ((direction == JOIN_NEXT) || (direction == JOIN_PREV)) {
    872 		if (_formi_wrap_field(field, row) != E_OK) {
    873 			return E_REQUEST_DENIED;
    874 		}
    875 	}
    876 
    877 	return E_OK;
    878 }
    879 
    880 /*
    881  * Split the line at the given position, if possible.  If hard_split is
    882  * TRUE then split the line regardless of the position, otherwise don't
    883  * split at the beginning of a line.
    884  */
    885 static int
    886 split_line(FIELD *field, bool hard_split, unsigned pos,
    887 	   _FORMI_FIELD_LINES **rowp)
    888 {
    889 	struct _formi_field_lines *new_line;
    890 	char *newp;
    891 	_FORMI_FIELD_LINES *row = *rowp;
    892 
    893 	  /* if asked to split right where the line already starts then
    894 	   * just return - nothing to do unless we are appending a line
    895 	   * to the buffer.
    896 	   */
    897 	if ((pos == 0) && (hard_split == FALSE))
    898 		return E_OK;
    899 
    900 	_formi_dbg_printf("%s: splitting line at %d\n", __func__, pos);
    901 
    902 	  /* Need an extra line struct, check free list first */
    903 	if (field->free != NULL) {
    904 		new_line = field->free;
    905 		field->free = new_line->next;
    906 		if (field->free != NULL)
    907 			field->free->prev = NULL;
    908 	} else {
    909 		if ((new_line = malloc(sizeof(*new_line))) == NULL)
    910 			return E_SYSTEM_ERROR;
    911 		new_line->prev = NULL;
    912 		new_line->next = NULL;
    913 		new_line->allocated = 0;
    914 		new_line->length = 0;
    915 		new_line->expanded = 0;
    916 		new_line->string = NULL;
    917 		new_line->hard_ret = FALSE;
    918 		new_line->tabs = NULL;
    919 	}
    920 
    921 	_formi_dbg_printf("%s: enter: length = %d, expanded = %d\n", __func__,
    922 	    row->length, row->expanded);
    923 
    924 	assert((row->length < INT_MAX) && (row->expanded < INT_MAX));
    925 
    926 
    927 	  /* add new line to the row list */
    928 	new_line->next = row->next;
    929 	new_line->prev = row;
    930 	row->next = new_line;
    931 	if (new_line->next != NULL)
    932 		new_line->next->prev = new_line;
    933 
    934 	new_line->length = row->length - pos;
    935 	if (new_line->length >= new_line->allocated) {
    936 		if ((newp = realloc(new_line->string,
    937 				    (size_t) new_line->length + 1)) == NULL)
    938 			return E_SYSTEM_ERROR;
    939 		new_line->string = newp;
    940 		new_line->allocated = new_line->length + 1;
    941 	}
    942 
    943 	strcpy(new_line->string, &row->string[pos]);
    944 
    945 	row->length = pos;
    946 	row->string[pos] = '\0';
    947 
    948 	if (row->length != 0)
    949 		row->expanded = _formi_tab_expanded_length(row->string, 0,
    950 							   row->length - 1);
    951 	else
    952 		row->expanded = 0;
    953 	_formi_calculate_tabs(row);
    954 
    955 	if (new_line->length != 0)
    956 		new_line->expanded =
    957 			_formi_tab_expanded_length(new_line->string, 0,
    958 						   new_line->length - 1);
    959 	else
    960 		new_line->expanded = 0;
    961 
    962 	_formi_calculate_tabs(new_line);
    963 
    964 	  /*
    965 	   * If the given row was the current line then adjust the
    966 	   * current line pointer if necessary
    967 	   */
    968 	if ((field->cur_line == row) && (field->row_xpos >= pos)) {
    969 		field->cur_line = new_line;
    970 		field->row_xpos -= pos;
    971 		field->cursor_xpos =
    972 			_formi_tab_expanded_length(new_line->string, 0,
    973 						   field->row_xpos);
    974 		if (field->cursor_xpos > 0)
    975 			field->cursor_xpos--;
    976 
    977 		field->cursor_ypos++;
    978 		if (field->cursor_ypos >= field->rows) {
    979 			if (field->start_line->next != NULL) {
    980 				field->start_line = field->start_line->next;
    981 				field->cursor_ypos = field->rows - 1;
    982 			}
    983 			else
    984 				assert(field->start_line->next == NULL);
    985 		}
    986 	}
    987 
    988 	  /*
    989 	   * If the line split had a hard return then replace the
    990 	   * current line's hard return with a soft return and carry
    991 	   * the hard return onto the line after.
    992 	   */
    993 	if (row->hard_ret == TRUE) {
    994 		new_line->hard_ret = TRUE;
    995 		row->hard_ret = FALSE;
    996 	}
    997 
    998 	  /*
    999 	   * except where we are doing a hard split then the current
   1000 	   * row must have a hard return on it too...
   1001 	   */
   1002 	if (hard_split == TRUE) {
   1003 		row->hard_ret = TRUE;
   1004 	}
   1005 
   1006 	assert(((row->expanded < INT_MAX) &&
   1007 		(new_line->expanded < INT_MAX) &&
   1008 		(row->length < INT_MAX) &&
   1009 		(new_line->length < INT_MAX)));
   1010 
   1011 	_formi_dbg_printf("%s: exit: ", __func__);
   1012 	_formi_dbg_printf("row.length = %d, row.expanded = %d, ",
   1013 	    row->length, row->expanded);
   1014 	_formi_dbg_printf("next_line.length = %d, next_line.expanded = %d, ",
   1015 	    new_line->length, new_line->expanded);
   1016 	_formi_dbg_printf("row_count = %d\n", field->row_count + 1);
   1017 
   1018 	field->row_count++;
   1019 	*rowp = new_line;
   1020 
   1021 	return E_OK;
   1022 }
   1023 
   1024 /*
   1025  * skip the blanks in the given string, start at the index start and
   1026  * continue forward until either the end of the string or a non-blank
   1027  * character is found.  Return the index of either the end of the string or
   1028  * the first non-blank character.
   1029  */
   1030 unsigned
   1031 _formi_skip_blanks(char *string, unsigned int start)
   1032 {
   1033 	unsigned int i;
   1034 
   1035 	i = start;
   1036 
   1037 	while ((string[i] != '\0') && isblank((unsigned char)string[i]))
   1038 		i++;
   1039 
   1040 	return i;
   1041 }
   1042 
   1043 /*
   1044  * Skip the blanks in the string associated with the given row, pass back
   1045  * the row and the offset at which the first non-blank is found.  If no
   1046  * non-blank character is found then return the index to the last
   1047  * character on the last line.
   1048  */
   1049 
   1050 unsigned
   1051 field_skip_blanks(unsigned int start, _FORMI_FIELD_LINES **rowp)
   1052 {
   1053 	unsigned int i;
   1054 	_FORMI_FIELD_LINES *row, *last = NULL;
   1055 
   1056 	row = *rowp;
   1057 	i = start;
   1058 
   1059 	do {
   1060 		i = _formi_skip_blanks(&row->string[i], i);
   1061 		if (!isblank((unsigned char)row->string[i])) {
   1062 			last = row;
   1063 			row = row->next;
   1064 			  /*
   1065 			   * don't reset if last line otherwise we will
   1066 			   * not be at the end of the string.
   1067 			   */
   1068 			if (row != NULL)
   1069 				i = 0;
   1070 		} else
   1071 			break;
   1072 	}
   1073 	while (row != NULL);
   1074 
   1075 	  /*
   1076 	   * If we hit the end of the row list then point at the last row
   1077 	   * otherwise we return the row we found the blank on.
   1078 	   */
   1079 	if (row == NULL)
   1080 		*rowp = last;
   1081 	else
   1082 		*rowp = row;
   1083 
   1084 	return i;
   1085 }
   1086 
   1087 /*
   1088  * Return the index of the top left most field of the two given fields.
   1089  */
   1090 static int
   1091 _formi_top_left(FORM *form, int a, int b)
   1092 {
   1093 	  /* lower row numbers always win here.... */
   1094 	if (form->fields[a]->form_row < form->fields[b]->form_row)
   1095 		return a;
   1096 
   1097 	if (form->fields[a]->form_row > form->fields[b]->form_row)
   1098 		return b;
   1099 
   1100 	  /* rows must be equal, check columns */
   1101 	if (form->fields[a]->form_col < form->fields[b]->form_col)
   1102 		return a;
   1103 
   1104 	if (form->fields[a]->form_col > form->fields[b]->form_col)
   1105 		return b;
   1106 
   1107 	  /* if we get here fields must be in exactly the same place, punt */
   1108 	return a;
   1109 }
   1110 
   1111 /*
   1112  * Return the index to the field that is the bottom-right-most of the
   1113  * two given fields.
   1114  */
   1115 static int
   1116 _formi_bottom_right(FORM *form, int a, int b)
   1117 {
   1118 	  /* check the rows first, biggest row wins */
   1119 	if (form->fields[a]->form_row > form->fields[b]->form_row)
   1120 		return a;
   1121 	if (form->fields[a]->form_row < form->fields[b]->form_row)
   1122 		return b;
   1123 
   1124 	  /* rows must be equal, check cols, biggest wins */
   1125 	if (form->fields[a]->form_col > form->fields[b]->form_col)
   1126 		return a;
   1127 	if (form->fields[a]->form_col < form->fields[b]->form_col)
   1128 		return b;
   1129 
   1130 	  /* fields in the same place, punt */
   1131 	return a;
   1132 }
   1133 
   1134 /*
   1135  * Find the end of the current word in the string str, starting at
   1136  * offset - the end includes any trailing whitespace.  If the end of
   1137  * the string is found before a new word then just return the offset
   1138  * to the end of the string.  If do_join is TRUE then lines will be
   1139  * joined (without wrapping) until either the end of the field or the
   1140  * end of a word is found (whichever comes first).
   1141  */
   1142 static int
   1143 find_eow(FIELD *cur, unsigned int offset, bool do_join,
   1144 	 _FORMI_FIELD_LINES **rowp)
   1145 {
   1146 	int start;
   1147 	_FORMI_FIELD_LINES *row;
   1148 
   1149 	row = *rowp;
   1150 	start = offset;
   1151 
   1152 	do {
   1153 		  /* first skip any non-whitespace */
   1154 		while ((row->string[start] != '\0')
   1155 		       && !isblank((unsigned char)row->string[start]))
   1156 			start++;
   1157 
   1158 		  /* see if we hit the end of the string */
   1159 		if (row->string[start] == '\0') {
   1160 			if (do_join == TRUE) {
   1161 				if (row->next == NULL)
   1162 					return start;
   1163 
   1164 				if (_formi_join_line(cur, &row, JOIN_NEXT_NW)
   1165 				    != E_OK)
   1166 					return E_REQUEST_DENIED;
   1167 			} else {
   1168 				do {
   1169 					if (row->next == NULL) {
   1170 						*rowp = row;
   1171 						return start;
   1172 					} else {
   1173 						row = row->next;
   1174 						start = 0;
   1175 					}
   1176 				} while (row->length == 0);
   1177 			}
   1178 		}
   1179 	} while (!isblank((unsigned char)row->string[start]));
   1180 
   1181 	do {
   1182 		  /* otherwise skip the whitespace.... */
   1183 		while ((row->string[start] != '\0')
   1184 		       && isblank((unsigned char)row->string[start]))
   1185 			start++;
   1186 
   1187 		if (row->string[start] == '\0') {
   1188 			if (do_join == TRUE) {
   1189 				if (row->next == NULL)
   1190 					return start;
   1191 
   1192 				if (_formi_join_line(cur, &row, JOIN_NEXT_NW)
   1193 				    != E_OK)
   1194 					return E_REQUEST_DENIED;
   1195 			} else {
   1196 				do {
   1197 					if (row->next == NULL) {
   1198 						*rowp = row;
   1199 						return start;
   1200 					} else {
   1201 						row = row->next;
   1202 						start = 0;
   1203 					}
   1204 				} while (row->length == 0);
   1205 			}
   1206 		}
   1207 	} while (isblank((unsigned char)row->string[start]));
   1208 
   1209 	*rowp = row;
   1210 	return start;
   1211 }
   1212 
   1213 /*
   1214  * Find the beginning of the current word in the string str, starting
   1215  * at offset.
   1216  */
   1217 static int
   1218 find_sow(unsigned int offset, _FORMI_FIELD_LINES **rowp)
   1219 {
   1220 	int start;
   1221 	char *str;
   1222 	_FORMI_FIELD_LINES *row;
   1223 
   1224 	row = *rowp;
   1225 	str = row->string;
   1226 	start = offset;
   1227 
   1228 	do {
   1229 		if (start > 0) {
   1230 			if (isblank((unsigned char)str[start]) ||
   1231 			    isblank((unsigned char)str[start - 1])) {
   1232 				if (isblank((unsigned char)str[start - 1]))
   1233 					start--;
   1234 				  /* skip the whitespace.... */
   1235 				while ((start >= 0) &&
   1236 				    isblank((unsigned char)str[start]))
   1237 					start--;
   1238 			}
   1239 		}
   1240 
   1241 		  /* see if we hit the start of the string */
   1242 		if (start < 0) {
   1243 			do {
   1244 				if (row->prev == NULL) {
   1245 					*rowp = row;
   1246 					start = 0;
   1247 					return start;
   1248 				} else {
   1249 					row = row->prev;
   1250 					str = row->string;
   1251 					if (row->length > 0)
   1252 						start = row->length - 1;
   1253 					else
   1254 						start = 0;
   1255 				}
   1256 			} while (row->length == 0);
   1257 		}
   1258 	} while (isblank((unsigned char)row->string[start]));
   1259 
   1260 	  /* see if we hit the start of the string */
   1261 	if (start < 0) {
   1262 		*rowp = row;
   1263 		return 0;
   1264 	}
   1265 
   1266 	  /* now skip any non-whitespace */
   1267 	do {
   1268 		while ((start >= 0) && !isblank((unsigned char)str[start]))
   1269 			start--;
   1270 
   1271 
   1272 		if (start < 0) {
   1273 			do {
   1274 				if (row->prev == NULL) {
   1275 					*rowp = row;
   1276 					start = 0;
   1277 					return start;
   1278 				} else {
   1279 					row = row->prev;
   1280 					str = row->string;
   1281 					if (row->length > 0)
   1282 						start = row->length - 1;
   1283 					else
   1284 						start = 0;
   1285 				}
   1286 			} while (row->length == 0);
   1287 		}
   1288 	} while (!isblank((unsigned char)str[start]));
   1289 
   1290 	if (start > 0) {
   1291 		start++; /* last loop has us pointing at a space, adjust */
   1292 		if (start >= row->length) {
   1293 			if (row->next != NULL) {
   1294 				start = 0;
   1295 				row = row->next;
   1296 			} else {
   1297 				start = row->length - 1;
   1298 			}
   1299 		}
   1300 	}
   1301 
   1302 	if (start < 0)
   1303 		start = 0;
   1304 
   1305 	*rowp = row;
   1306 	return start;
   1307 }
   1308 
   1309 /*
   1310  * Scroll the field forward the given number of lines.
   1311  */
   1312 static void
   1313 _formi_scroll_fwd(FIELD *field, unsigned int amt)
   1314 {
   1315 	unsigned int count;
   1316 	_FORMI_FIELD_LINES *end_row;
   1317 
   1318 	end_row = field->start_line;
   1319 	  /* walk the line structs forward to find the bottom of the field */
   1320 	count = field->rows - 1;
   1321 	while ((count > 0) && (end_row->next != NULL))
   1322 	{
   1323 		count--;
   1324 		end_row = end_row->next;
   1325 	}
   1326 
   1327 	  /* check if there are lines to scroll */
   1328 	if ((count > 0) && (end_row->next == NULL))
   1329 		return;
   1330 
   1331 	  /*
   1332 	   * ok, lines to scroll - do this by walking both the start_line
   1333 	   * and the end_row at the same time for amt lines, we stop when
   1334 	   * either we have done the number of lines or end_row hits the
   1335 	   * last line in the field.
   1336 	   */
   1337 	count = amt;
   1338 	while ((count > 0) && (end_row->next != NULL)) {
   1339 		count--;
   1340 		field->start_line = field->start_line->next;
   1341 		end_row = end_row->next;
   1342 	}
   1343 }
   1344 
   1345 /*
   1346  * Scroll the field backward the given number of lines.
   1347  */
   1348 static void
   1349 _formi_scroll_back(FIELD *field, unsigned int amt)
   1350 {
   1351 	unsigned int count;
   1352 
   1353 	  /* check for lines above */
   1354 	if (field->start_line->prev == NULL)
   1355 		return;
   1356 
   1357 	  /*
   1358 	   * Backward scroll is easy, follow row struct chain backward until
   1359 	   * the number of lines done or we reach the top of the field.
   1360 	   */
   1361 	count = amt;
   1362 	while ((count > 0) && (field->start_line->prev != NULL)) {
   1363 		count--;
   1364 		field->start_line = field->start_line->prev;
   1365 	}
   1366 }
   1367 
   1368 /*
   1369  * Scroll the field forward the given number of characters.
   1370  */
   1371 void
   1372 _formi_hscroll_fwd(FIELD *field, _FORMI_FIELD_LINES *row, int unsigned amt)
   1373 {
   1374 	unsigned int end, scroll_amt, expanded;
   1375 	_formi_tab_t *ts;
   1376 
   1377 
   1378 	if ((row->tabs == NULL) || (row->tabs->in_use == FALSE)) {
   1379 		  /* if the line has no tabs things are easy... */
   1380 		end =  field->start_char + field->cols + amt - 1;
   1381 		scroll_amt = amt;
   1382 		if (end > row->length) {
   1383 			end = row->length;
   1384 			scroll_amt = end - field->start_char - field->cols + 1;
   1385 		}
   1386 	} else {
   1387 		  /*
   1388 		   * If there are tabs we need to add on the scroll amount,
   1389 		   * find the last char position that will fit into
   1390 		   * the field and finally fix up the start_char.  This
   1391 		   * is a lot of work but handling the case where there
   1392 		   * are not enough chars to scroll by amt is difficult.
   1393 		   */
   1394 		end = field->start_char + field->row_xpos + amt;
   1395 		if (end >= row->length)
   1396 			end = row->length - 1;
   1397 		else {
   1398 			expanded = _formi_tab_expanded_length(
   1399 				row->string,
   1400 				field->start_char + amt,
   1401 				field->start_char + field->row_xpos + amt);
   1402 			ts = row->tabs;
   1403 			  /* skip tabs to the lhs of our starting point */
   1404 			while ((ts != NULL) && (ts->in_use == TRUE)
   1405 			       && (ts->pos < end))
   1406 				ts = ts->fwd;
   1407 
   1408 			while ((expanded <= field->cols)
   1409 			       && (end < row->length)) {
   1410 				if (row->string[end] == '\t') {
   1411 					assert((ts != NULL)
   1412 					       && (ts->in_use == TRUE));
   1413 					if (ts->pos == end) {
   1414 						if ((expanded + ts->size)
   1415 						    > field->cols)
   1416 							break;
   1417 						expanded += ts->size;
   1418 						ts = ts->fwd;
   1419 					}
   1420 					else
   1421 						assert(ts->pos == end);
   1422 				} else
   1423 					expanded++;
   1424 				end++;
   1425 			}
   1426 		}
   1427 
   1428 		scroll_amt = tab_fit_window(field, end, field->cols);
   1429 		if (scroll_amt < field->start_char)
   1430 			scroll_amt = 1;
   1431 		else
   1432 			scroll_amt -= field->start_char;
   1433 
   1434 		scroll_amt = min(scroll_amt, amt);
   1435 	}
   1436 
   1437 	field->start_char += scroll_amt;
   1438 	field->cursor_xpos =
   1439 		_formi_tab_expanded_length(row->string,
   1440 					   field->start_char,
   1441 					   field->row_xpos
   1442 					   + field->start_char) - 1;
   1443 
   1444 }
   1445 
   1446 /*
   1447  * Scroll the field backward the given number of characters.
   1448  */
   1449 void
   1450 _formi_hscroll_back(FIELD *field, _FORMI_FIELD_LINES *row, unsigned int amt)
   1451 {
   1452 	field->start_char -= min(field->start_char, amt);
   1453 	field->cursor_xpos =
   1454 		_formi_tab_expanded_length(row->string, field->start_char,
   1455 					   field->row_xpos
   1456 					   + field->start_char) - 1;
   1457 	if (field->cursor_xpos >= field->cols) {
   1458 		field->row_xpos = 0;
   1459 		field->cursor_xpos = 0;
   1460 	}
   1461 }
   1462 
   1463 /*
   1464  * Find the different pages in the form fields and assign the form
   1465  * page_starts array with the information to find them.
   1466  */
   1467 int
   1468 _formi_find_pages(FORM *form)
   1469 {
   1470 	int i, cur_page = 0;
   1471 
   1472 	if ((form->page_starts = (_FORMI_PAGE_START *)
   1473 	     malloc((form->max_page + 1) * sizeof(_FORMI_PAGE_START))) == NULL)
   1474 		return E_SYSTEM_ERROR;
   1475 
   1476 	  /* initialise the page starts array */
   1477 	memset(form->page_starts, 0,
   1478 	       (form->max_page + 1) * sizeof(_FORMI_PAGE_START));
   1479 
   1480 	for (i =0; i < form->field_count; i++) {
   1481 		if (form->fields[i]->page_break == 1)
   1482 			cur_page++;
   1483 		if (form->page_starts[cur_page].in_use == 0) {
   1484 			form->page_starts[cur_page].in_use = 1;
   1485 			form->page_starts[cur_page].first = i;
   1486 			form->page_starts[cur_page].last = i;
   1487 			form->page_starts[cur_page].top_left = i;
   1488 			form->page_starts[cur_page].bottom_right = i;
   1489 		} else {
   1490 			form->page_starts[cur_page].last = i;
   1491 			form->page_starts[cur_page].top_left =
   1492 				_formi_top_left(form,
   1493 						form->page_starts[cur_page].top_left,
   1494 						i);
   1495 			form->page_starts[cur_page].bottom_right =
   1496 				_formi_bottom_right(form,
   1497 						    form->page_starts[cur_page].bottom_right,
   1498 						    i);
   1499 		}
   1500 	}
   1501 
   1502 	return E_OK;
   1503 }
   1504 
   1505 /*
   1506  * Completely redraw the field of the given form.
   1507  */
   1508 void
   1509 _formi_redraw_field(FORM *form, int field)
   1510 {
   1511 	unsigned int pre, post, flen, slen, i, j, start, line;
   1512 	unsigned int tab, cpos, len;
   1513 	char *str, c;
   1514 	FIELD *cur;
   1515 	_FORMI_FIELD_LINES *row;
   1516 #ifdef DEBUG
   1517 	char buffer[100];
   1518 #endif
   1519 
   1520 	cur = form->fields[field];
   1521 	flen = cur->cols;
   1522 	slen = 0;
   1523 	start = 0;
   1524 	line = 0;
   1525 
   1526 	for (row = cur->start_line; ((row != NULL) && (line < cur->rows));
   1527 	     row = row->next, line++) {
   1528 		wmove(form->scrwin, (int) (cur->form_row + line),
   1529 		      (int) cur->form_col);
   1530 		if ((cur->rows + cur->nrows) == 1) {
   1531 			if ((cur->cols + cur->start_char) >= row->length)
   1532 				len = row->length;
   1533 			else
   1534 				len = cur->cols + cur->start_char;
   1535 			if (row->string != NULL)
   1536 				slen = _formi_tab_expanded_length(
   1537 					row->string, cur->start_char, len);
   1538 			else
   1539 				slen = 0;
   1540 
   1541 			if (slen > cur->cols)
   1542 				slen = cur->cols;
   1543 			slen += cur->start_char;
   1544 		} else
   1545 			slen = row->expanded;
   1546 
   1547 		if ((cur->opts & O_STATIC) == O_STATIC) {
   1548 			switch (cur->justification) {
   1549 			case JUSTIFY_RIGHT:
   1550 				post = 0;
   1551 				if (flen < slen)
   1552 					pre = 0;
   1553 				else
   1554 					pre = flen - slen;
   1555 				break;
   1556 
   1557 			case JUSTIFY_CENTER:
   1558 				if (flen < slen) {
   1559 					pre = 0;
   1560 					post = 0;
   1561 				} else {
   1562 					pre = flen - slen;
   1563 					post = pre = pre / 2;
   1564 					  /* get padding right if
   1565 					     centring is not even */
   1566 					if ((post + pre + slen) < flen)
   1567 						post++;
   1568 				}
   1569 				break;
   1570 
   1571 			case NO_JUSTIFICATION:
   1572 			case JUSTIFY_LEFT:
   1573 			default:
   1574 				pre = 0;
   1575 				if (flen <= slen)
   1576 					post = 0;
   1577 				else {
   1578 					post = flen - slen;
   1579 					if (post > flen)
   1580 						post = flen;
   1581 				}
   1582 				break;
   1583 			}
   1584 		} else {
   1585 			  /* dynamic fields are not justified */
   1586 			pre = 0;
   1587 			if (flen <= slen)
   1588 				post = 0;
   1589 			else {
   1590 				post = flen - slen;
   1591 				if (post > flen)
   1592 					post = flen;
   1593 			}
   1594 
   1595 			  /* but they do scroll.... */
   1596 
   1597 			if (pre > cur->start_char - start)
   1598 				pre = pre - cur->start_char + start;
   1599 			else
   1600 				pre = 0;
   1601 
   1602 			if (slen > cur->start_char) {
   1603 				slen -= cur->start_char;
   1604 				if (slen > flen)
   1605 					post = 0;
   1606 				else
   1607 					post = flen - slen;
   1608 
   1609 				if (post > flen)
   1610 					post = flen;
   1611 			} else {
   1612 				slen = 0;
   1613 				post = flen - pre;
   1614 			}
   1615 		}
   1616 
   1617 		if (form->cur_field == field)
   1618 			wattrset(form->scrwin, cur->fore);
   1619 		else
   1620 			wattrset(form->scrwin, cur->back);
   1621 
   1622 		str = &row->string[cur->start_char];
   1623 
   1624 #ifdef DEBUG
   1625 		_formi_dbg_printf(
   1626 		    "%s: start=%d, pre=%d, slen=%d, flen=%d, post=%d, "
   1627 		    "start_char=%d\n", __func__,
   1628 		    start, pre, slen, flen, post, cur->start_char);
   1629 		if (str != NULL) {
   1630 			if (row->expanded != 0) {
   1631 				strncpy(buffer, str, flen);
   1632 			} else {
   1633 				strcpy(buffer, "(empty)");
   1634 			}
   1635 		} else {
   1636 			strcpy(buffer, "(null)");
   1637 		}
   1638 		buffer[flen] = '\0';
   1639 		_formi_dbg_printf("%s: %s\n", __func__,  buffer);
   1640 #endif
   1641 
   1642 		for (i = start + cur->start_char; i < pre; i++)
   1643 			waddch(form->scrwin, cur->pad);
   1644 
   1645 		_formi_dbg_printf("%s: will add %d chars\n", __func__,
   1646 			min(slen, flen));
   1647 		for (i = 0, cpos = cur->start_char; i < min(slen, flen);
   1648 		     i++, str++, cpos++)
   1649 		{
   1650 			c = *str;
   1651 			tab = 0; /* just to shut gcc up */
   1652 			_formi_dbg_printf("adding char str[%d]=%c\n",
   1653 			    cpos + cur->start_char,	c);
   1654 			if (((cur->opts & O_PUBLIC) != O_PUBLIC)) {
   1655 				if (c == '\t')
   1656 					tab = add_tab(form, row, cpos,
   1657 						      cur->pad);
   1658 				else
   1659 					waddch(form->scrwin, cur->pad);
   1660 			} else if ((cur->opts & O_VISIBLE) == O_VISIBLE) {
   1661 				if (c == '\t')
   1662 					tab = add_tab(form, row, cpos, ' ');
   1663 				else
   1664 					waddch(form->scrwin, c);
   1665 			} else {
   1666 				if (c == '\t')
   1667 					tab = add_tab(form, row, cpos, ' ');
   1668 				else
   1669 					waddch(form->scrwin, ' ');
   1670 			}
   1671 
   1672 			  /*
   1673 			   * If we have had a tab then skip forward
   1674 			   * the requisite number of chars to keep
   1675 			   * things in sync.
   1676 			   */
   1677 			if (c == '\t')
   1678 				i += tab - 1;
   1679 		}
   1680 
   1681 		for (i = 0; i < post; i++)
   1682 			waddch(form->scrwin, cur->pad);
   1683 	}
   1684 
   1685 	for (i = line; i < cur->rows; i++) {
   1686 		wmove(form->scrwin, (int) (cur->form_row + i),
   1687 		      (int) cur->form_col);
   1688 
   1689 		if (form->cur_field == field)
   1690 			wattrset(form->scrwin, cur->fore);
   1691 		else
   1692 			wattrset(form->scrwin, cur->back);
   1693 
   1694 		for (j = 0; j < cur->cols; j++) {
   1695 			waddch(form->scrwin, cur->pad);
   1696 		}
   1697 	}
   1698 
   1699 	wattrset(form->scrwin, cur->back);
   1700 	return;
   1701 }
   1702 
   1703 /*
   1704  * Add the correct number of the given character to simulate a tab
   1705  * in the field.
   1706  */
   1707 static int
   1708 add_tab(FORM *form, _FORMI_FIELD_LINES *row, unsigned int i, char c)
   1709 {
   1710 	int j;
   1711 	_formi_tab_t *ts = row->tabs;
   1712 
   1713 	while ((ts != NULL) && (ts->pos != i))
   1714 		ts = ts->fwd;
   1715 
   1716 	assert(ts != NULL);
   1717 
   1718 	for (j = 0; j < ts->size; j++)
   1719 		waddch(form->scrwin, c);
   1720 
   1721 	return ts->size;
   1722 }
   1723 
   1724 
   1725 /*
   1726  * Display the fields attached to the form that are on the current page
   1727  * on the screen.
   1728  *
   1729  */
   1730 int
   1731 _formi_draw_page(FORM *form)
   1732 {
   1733 	int i;
   1734 
   1735 	if (form->page_starts[form->page].in_use == 0)
   1736 		return E_BAD_ARGUMENT;
   1737 
   1738 	wclear(form->scrwin);
   1739 
   1740 	for (i = form->page_starts[form->page].first;
   1741 	     i <= form->page_starts[form->page].last; i++)
   1742 		_formi_redraw_field(form, i);
   1743 
   1744 	return E_OK;
   1745 }
   1746 
   1747 /*
   1748  * Add the character c at the position pos in buffer 0 of the given field
   1749  */
   1750 int
   1751 _formi_add_char(FIELD *field, unsigned int pos, char c)
   1752 {
   1753 	char *new, old_c;
   1754 	unsigned int new_size;
   1755 	int status;
   1756 	_FORMI_FIELD_LINES *row, *temp, *next_temp;
   1757 
   1758 	row = field->cur_line;
   1759 
   1760 	  /*
   1761 	   * If buffer has not had a string before, set it to a blank
   1762 	   * string.  Everything should flow from there....
   1763 	   */
   1764 	if (row->string == NULL) {
   1765 		if ((row->string = (char *) malloc((size_t)INITIAL_LINE_ALLOC))
   1766 		    == NULL)
   1767 			return E_SYSTEM_ERROR;
   1768 		row->string[0] = '\0';
   1769 		row->allocated = INITIAL_LINE_ALLOC;
   1770 		row->length = 0;
   1771 		row->expanded = 0;
   1772 	}
   1773 
   1774 	if (_formi_validate_char(field, c) != E_OK) {
   1775 		_formi_dbg_printf("%s: char %c failed char validation\n",
   1776 		    __func__, c);
   1777 		return E_INVALID_FIELD;
   1778 	}
   1779 
   1780 	if ((c == '\t') && (field->cols <= 8)) {
   1781 		_formi_dbg_printf("%s: field too small for a tab\n", __func__);
   1782 		return E_NO_ROOM;
   1783 	}
   1784 
   1785 	_formi_dbg_printf("%s: pos=%d, char=%c\n", __func__, pos, c);
   1786 	_formi_dbg_printf("%s: xpos=%d, row_pos=%d, start=%d\n", __func__,
   1787 		field->cursor_xpos, field->row_xpos, field->start_char);
   1788 	_formi_dbg_printf("%s: length=%d(%d), allocated=%d\n", __func__,
   1789 		row->expanded, row->length, row->allocated);
   1790 	_formi_dbg_printf("%s: %s\n", __func__, row->string);
   1791 	_formi_dbg_printf("%s: buf0_status=%d\n", __func__, field->buf0_status);
   1792 	if (((field->opts & O_BLANK) == O_BLANK) &&
   1793 	    (field->buf0_status == FALSE) &&
   1794 	    ((field->row_xpos + field->start_char) == 0)) {
   1795 		row = field->alines;
   1796 		if (row->next != NULL) {
   1797 			  /* shift all but one line structs to free list */
   1798 			temp = row->next;
   1799 			do {
   1800 				next_temp = temp->next;
   1801 				add_to_free(field, temp);
   1802 				temp = next_temp;
   1803 			} while (temp != NULL);
   1804 		}
   1805 
   1806 		row->length = 0;
   1807 		row->string[0] = '\0';
   1808 		pos = 0;
   1809 		field->start_char = 0;
   1810 		field->start_line = row;
   1811 		field->cur_line = row;
   1812 		field->row_count = 1;
   1813 		field->row_xpos = 0;
   1814 		field->cursor_ypos = 0;
   1815 		row->expanded = 0;
   1816 		row->length = 0;
   1817 		_formi_init_field_xpos(field);
   1818 	}
   1819 
   1820 
   1821 	if ((field->overlay == 0)
   1822 	    || ((field->overlay == 1) && (pos >= row->length))) {
   1823 		  /* first check if the field can have more chars...*/
   1824 		if (check_field_size(field) == FALSE)
   1825 			return E_REQUEST_DENIED;
   1826 
   1827 		if (row->length + 2
   1828 		    >= row->allocated) {
   1829 			new_size = row->allocated + 16 - (row->allocated % 16);
   1830 			if ((new = (char *) realloc(row->string,
   1831 						  (size_t) new_size )) == NULL)
   1832 				return E_SYSTEM_ERROR;
   1833 			row->allocated = new_size;
   1834 			row->string = new;
   1835 		}
   1836 	}
   1837 
   1838 	if ((field->overlay == 0) && (row->length > pos)) {
   1839 		bcopy(&row->string[pos], &row->string[pos + 1],
   1840 		      (size_t) (row->length - pos + 1));
   1841 	}
   1842 
   1843 	old_c = row->string[pos];
   1844 	row->string[pos] = c;
   1845 	if (pos >= row->length) {
   1846 		  /* make sure the string is terminated if we are at the
   1847 		   * end of the string, the terminator would be missing
   1848 		   * if we are are at the end of the field.
   1849 		   */
   1850 		row->string[pos + 1] = '\0';
   1851 	}
   1852 
   1853 	  /* only increment the length if we are inserting characters
   1854 	   * OR if we are at the end of the field in overlay mode.
   1855 	   */
   1856 	if ((field->overlay == 0)
   1857 	    || ((field->overlay == 1) && (pos >= row->length))) {
   1858 		row->length++;
   1859 	}
   1860 
   1861 	_formi_calculate_tabs(row);
   1862 	row->expanded = _formi_tab_expanded_length(row->string, 0,
   1863 						   row->length - 1);
   1864 
   1865 	  /* wrap the field, if needed */
   1866 	status = _formi_wrap_field(field, row);
   1867 
   1868 	row = field->cur_line;
   1869 	pos = field->row_xpos;
   1870 
   1871 	  /*
   1872 	   * check the wrap worked or that we have not exceeded the
   1873 	   * max field size - this can happen if the field is re-wrapped
   1874 	   * and the row count is increased past the set limit.
   1875 	   */
   1876 	if ((status != E_OK) || (check_field_size(field) == FALSE)) {
   1877 		if ((field->overlay == 0)
   1878 		    || ((field->overlay == 1)
   1879 			&& (pos >= (row->length - 1) /*XXXX- append check???*/))) {
   1880 			  /*
   1881 			   * wrap failed for some reason, back out the
   1882 			   * char insert
   1883 			   */
   1884 			bcopy(&row->string[pos + 1], &row->string[pos],
   1885 			      (size_t) (row->length - pos));
   1886 			row->length--;
   1887 			if (pos > 0)
   1888 				pos--;
   1889 		} else if (field->overlay == 1) {
   1890 			  /* back out character overlay */
   1891 			row->string[pos] = old_c;
   1892 		}
   1893 
   1894 		_formi_calculate_tabs(row);
   1895 
   1896 		_formi_wrap_field(field, row);
   1897 		  /*
   1898 		   * If we are here then either the status is bad or we
   1899 		   * simply ran out of room.  If the status is E_OK then
   1900 		   * we ran out of room, let the form driver know this.
   1901 		   */
   1902 		if (status == E_OK)
   1903 			status = E_REQUEST_DENIED;
   1904 
   1905 	} else {
   1906 		field->buf0_status = TRUE;
   1907 		field->row_xpos++;
   1908 		if ((field->rows + field->nrows) == 1) {
   1909 			status = _formi_set_cursor_xpos(field, FALSE);
   1910 		} else {
   1911 			field->cursor_xpos =
   1912 				_formi_tab_expanded_length(
   1913 					row->string, 0,	field->row_xpos - 1);
   1914 
   1915 			  /*
   1916 			   * Annoying corner case - if we are right in
   1917 			   * the bottom right corner of the field we
   1918 			   * need to scroll the field one line so the
   1919 			   * cursor is positioned correctly in the
   1920 			   * field.
   1921 			   */
   1922 			if ((field->cursor_xpos >= field->cols) &&
   1923 			    (field->cursor_ypos == (field->rows - 1))) {
   1924 				field->cursor_ypos--;
   1925 				field->start_line = field->start_line->next;
   1926 			}
   1927 		}
   1928 	}
   1929 
   1930 	assert((field->cursor_xpos <= field->cols)
   1931 	       && (field->cursor_ypos < 400000));
   1932 
   1933 	_formi_dbg_printf("%s: xpos=%d, row_pos=%d, start=%d\n", __func__,
   1934 		field->cursor_xpos, field->row_xpos, field->start_char);
   1935 	_formi_dbg_printf("%s: length=%d(%d), allocated=%d\n", __func__,
   1936 		row->expanded, row->length, row->allocated);
   1937 	_formi_dbg_printf("%s: ypos=%d, start_line=%p\n", __func__,
   1938 		field->cursor_ypos, field->start_line);
   1939 	_formi_dbg_printf("%s: %s\n", __func__, row->string);
   1940 	_formi_dbg_printf("%s: buf0_status=%d\n", __func__, field->buf0_status);
   1941 	_formi_dbg_printf("%s: status = %s\n", __func__,
   1942 		(status == E_OK)? "OK" : "FAILED");
   1943 	return status;
   1944 }
   1945 
   1946 /*
   1947  * Set the position of the cursor on the screen in the row depending on
   1948  * where the current position in the string is and the justification
   1949  * that is to be applied to the field.  Justification is only applied
   1950  * to single row, static fields.
   1951  */
   1952 static int
   1953 _formi_set_cursor_xpos(FIELD *field, int noscroll)
   1954 {
   1955 	int just, pos;
   1956 
   1957 	just = field->justification;
   1958 	pos = field->start_char + field->row_xpos;
   1959 
   1960 	_formi_dbg_printf(
   1961 	    "%s: pos %d, start_char %d, row_xpos %d, xpos %d\n", __func__,
   1962 	    pos, field->start_char, field->row_xpos, field->cursor_xpos);
   1963 
   1964 	  /*
   1965 	   * make sure we apply the correct justification to non-static
   1966 	   * fields.
   1967 	   */
   1968 	if (((field->rows + field->nrows) != 1) ||
   1969 	    ((field->opts & O_STATIC) != O_STATIC))
   1970 		just = JUSTIFY_LEFT;
   1971 
   1972 	switch (just) {
   1973 	case JUSTIFY_RIGHT:
   1974 		field->cursor_xpos = field->cols - 1
   1975 			- _formi_tab_expanded_length(
   1976 				field->cur_line->string, 0,
   1977 				field->cur_line->length - 1)
   1978 			+ _formi_tab_expanded_length(
   1979 				field->cur_line->string, 0,
   1980 				field->row_xpos);
   1981 		break;
   1982 
   1983 	case JUSTIFY_CENTER:
   1984 		field->cursor_xpos = ((field->cols - 1)
   1985 			- _formi_tab_expanded_length(
   1986 				field->cur_line->string, 0,
   1987 				field->cur_line->length - 1) + 1) / 2
   1988 			+ _formi_tab_expanded_length(field->cur_line->string,
   1989 						     0, field->row_xpos);
   1990 
   1991 		if (field->cursor_xpos > (field->cols - 1))
   1992 			field->cursor_xpos = (field->cols - 1);
   1993 		break;
   1994 
   1995 	default:
   1996 		field->cursor_xpos = _formi_tab_expanded_length(
   1997 			field->cur_line->string,
   1998 			field->start_char,
   1999 			field->row_xpos	+ field->start_char);
   2000 		if ((field->cursor_xpos <= (field->cols - 1)) &&
   2001 		    ((field->start_char + field->row_xpos)
   2002 		     < field->cur_line->length))
   2003 			field->cursor_xpos--;
   2004 
   2005 		if (field->cursor_xpos > (field->cols - 1)) {
   2006 			if ((field->opts & O_STATIC) == O_STATIC) {
   2007 				field->start_char = 0;
   2008 
   2009 				if (field->row_xpos
   2010 				    == (field->cur_line->length - 1)) {
   2011 					field->cursor_xpos = field->cols - 1;
   2012 				} else {
   2013 					field->cursor_xpos =
   2014 						_formi_tab_expanded_length(
   2015 						  field->cur_line->string,
   2016 						  field->start_char,
   2017 						  field->row_xpos
   2018 						    + field->start_char
   2019 						  - 1) - 1;
   2020 				}
   2021 			} else {
   2022 				if (noscroll == FALSE) {
   2023 					field->start_char =
   2024 						tab_fit_window(
   2025 							field,
   2026 							field->start_char
   2027 							+ field->row_xpos,
   2028 							field->cols);
   2029 					field->row_xpos = pos
   2030 						- field->start_char;
   2031 					field->cursor_xpos =
   2032 						_formi_tab_expanded_length(
   2033 						   field->cur_line->string,
   2034 						   field->start_char,
   2035 						   field->row_xpos
   2036 						      + field->start_char - 1);
   2037 				} else {
   2038 					field->cursor_xpos = (field->cols - 1);
   2039 				}
   2040 			}
   2041 
   2042 		}
   2043 		break;
   2044 	}
   2045 
   2046 	_formi_dbg_printf(
   2047 	    "%s: pos %d, start_char %d, row_xpos %d, xpos %d\n", __func__,
   2048 	    pos, field->start_char, field->row_xpos, field->cursor_xpos);
   2049 	return E_OK;
   2050 }
   2051 
   2052 /*
   2053  * Manipulate the text in a field, this takes the given form and performs
   2054  * the passed driver command on the current text field.  Returns 1 if the
   2055  * text field was modified.
   2056  */
   2057 int
   2058 _formi_manipulate_field(FORM *form, int c)
   2059 {
   2060 	FIELD *cur;
   2061 	char *str, saved;
   2062 	unsigned int start, end, pos, status, old_count, size;
   2063 	unsigned int old_xpos, old_row_pos;
   2064 	int len, wb;
   2065 	bool eat_char;
   2066 	_FORMI_FIELD_LINES *row, *rs;
   2067 
   2068 	cur = form->fields[form->cur_field];
   2069 	if (cur->cur_line->string == NULL)
   2070 		return E_REQUEST_DENIED;
   2071 
   2072 	_formi_dbg_printf("%s: request is REQ_%s\n",
   2073 	    __func__, reqs[c - REQ_MIN_REQUEST]);
   2074 	_formi_dbg_printf(
   2075 	    "%s: xpos=%d, row_pos=%d, start_char=%d, length=%d, allocated=%d\n",
   2076 	    __func__, cur->cursor_xpos, cur->row_xpos, cur->start_char,
   2077 	    cur->cur_line->length, cur->cur_line->allocated);
   2078 	_formi_dbg_printf("%s: start_line=%p, ypos=%d\n", __func__,
   2079 	    cur->start_line, cur->cursor_ypos);
   2080 	if (cur->cur_line->string == NULL)
   2081 		_formi_dbg_printf("%s: string=(null)\n", __func__);
   2082 	else
   2083 		_formi_dbg_printf("%s: string=\"%s\"\n", __func__,
   2084 		    cur->cur_line->string);
   2085 
   2086 	  /* Cannot manipulate a null string! */
   2087 	if (cur->cur_line->string == NULL)
   2088 		return E_REQUEST_DENIED;
   2089 
   2090 	saved = '\0';
   2091 	row = cur->cur_line;
   2092 
   2093 	switch (c) {
   2094 	case REQ_RIGHT_CHAR:
   2095 		  /*
   2096 		   * The right_char request performs the same function
   2097 		   * as the next_char request except that the cursor is
   2098 		   * not wrapped if it is at the end of the line, so
   2099 		   * check if the cursor is at the end of the line and
   2100 		   * deny the request otherwise just fall through to
   2101 		   * the next_char request handler.
   2102 		   */
   2103 		if (cur->cursor_xpos >= cur->cols - 1)
   2104 			return E_REQUEST_DENIED;
   2105 
   2106 		  /* FALLTHRU */
   2107 
   2108 	case REQ_NEXT_CHAR:
   2109 		  /* for a dynamic field allow an offset of one more
   2110 		   * char so we can insert chars after end of string.
   2111 		   * Static fields cannot do this so deny request if
   2112 		   * cursor is at the end of the field.
   2113 		   */
   2114 		if (((cur->opts & O_STATIC) == O_STATIC) &&
   2115 		    (cur->row_xpos == cur->cols - 1) &&
   2116 		    ((cur->rows + cur->nrows) == 1))
   2117 			return E_REQUEST_DENIED;
   2118 
   2119 		if (((cur->rows + cur->nrows) == 1) &&
   2120 		    (cur->row_xpos + cur->start_char + 1) > row->length)
   2121 			return E_REQUEST_DENIED;
   2122 
   2123 		if ((cur->rows + cur->nrows) == 1) {
   2124 			cur->row_xpos++;
   2125 			_formi_set_cursor_xpos(cur, (c == REQ_RIGHT_CHAR));
   2126 		} else {
   2127 			if (cur->cursor_xpos >= (row->expanded - 1)) {
   2128 				if ((row->next == NULL) ||
   2129 				    (c == REQ_RIGHT_CHAR))
   2130 					return E_REQUEST_DENIED;
   2131 
   2132 				cur->cursor_xpos = 0;
   2133 				cur->row_xpos = 0;
   2134 				cur->cur_line = cur->cur_line->next;
   2135 				if (cur->cursor_ypos == (cur->rows - 1))
   2136 					cur->start_line =
   2137 						cur->start_line->next;
   2138 				else
   2139 					cur->cursor_ypos++;
   2140 			} else {
   2141 				old_xpos = cur->cursor_xpos;
   2142 				old_row_pos = cur->row_xpos;
   2143 				if (row->string[cur->row_xpos] == '\t')
   2144 					cur->cursor_xpos += tab_size(row,
   2145 							cur->row_xpos);
   2146 				else
   2147 					cur->cursor_xpos++;
   2148 				cur->row_xpos++;
   2149 				if (cur->cursor_xpos
   2150 				    >= row->expanded) {
   2151 					if ((row->next == NULL) ||
   2152 					    (c == REQ_RIGHT_CHAR)) {
   2153 						cur->cursor_xpos = old_xpos;
   2154 						cur->row_xpos = old_row_pos;
   2155 						return E_REQUEST_DENIED;
   2156 					}
   2157 
   2158 					cur->cursor_xpos = 0;
   2159 					cur->row_xpos = 0;
   2160 					cur->cur_line = cur->cur_line->next;
   2161 					if (cur->cursor_ypos
   2162 					    == (cur->rows - 1))
   2163 						cur->start_line =
   2164 							cur->start_line->next;
   2165 					else
   2166 						cur->cursor_ypos++;
   2167 				}
   2168 			}
   2169 		}
   2170 
   2171 		break;
   2172 
   2173 	case REQ_LEFT_CHAR:
   2174 		  /*
   2175 		   * The behaviour of left_char is the same as prev_char
   2176 		   * except that the cursor will not wrap if it has
   2177 		   * reached the LHS of the field, so just check this
   2178 		   * and fall through if we are not at the LHS.
   2179 		   */
   2180 		if (cur->cursor_xpos == 0)
   2181 			return E_REQUEST_DENIED;
   2182 
   2183 		  /* FALLTHRU */
   2184 	case REQ_PREV_CHAR:
   2185 		if ((cur->rows + cur->nrows) == 1) {
   2186 			if (cur->row_xpos == 0) {
   2187 				if (cur->start_char > 0)
   2188 					cur->start_char--;
   2189 				else
   2190 					return E_REQUEST_DENIED;
   2191 			} else {
   2192 				cur->row_xpos--;
   2193 				_formi_set_cursor_xpos(cur, FALSE);
   2194 			}
   2195 		} else {
   2196 			if ((cur->cursor_xpos == 0) &&
   2197 			    (cur->cursor_ypos == 0) &&
   2198 			    (cur->start_line->prev == NULL))
   2199 				return E_REQUEST_DENIED;
   2200 
   2201 			pos = cur->row_xpos;
   2202 			if (cur->cursor_xpos > 0) {
   2203 				if (row->string[pos] == '\t') {
   2204 					size = tab_size(row, pos);
   2205 					if (size > cur->cursor_xpos) {
   2206 						cur->cursor_xpos = 0;
   2207 						cur->row_xpos = 0;
   2208 					} else {
   2209 						cur->row_xpos--;
   2210 						cur->cursor_xpos -= size;
   2211 					}
   2212 				} else {
   2213 					cur->cursor_xpos--;
   2214 					cur->row_xpos--;
   2215 				}
   2216 			} else {
   2217 				cur->cur_line = cur->cur_line->prev;
   2218 				if (cur->cursor_ypos > 0)
   2219 					cur->cursor_ypos--;
   2220 				else
   2221 					cur->start_line =
   2222 						cur->start_line->prev;
   2223 				row = cur->cur_line;
   2224 				if (row->expanded > 0) {
   2225 					cur->cursor_xpos = row->expanded - 1;
   2226 				} else {
   2227 					cur->cursor_xpos = 0;
   2228 				}
   2229 
   2230 				if (row->length > 0)
   2231 					cur->row_xpos = row->length - 1;
   2232 				else
   2233 					cur->row_xpos = 0;
   2234 			}
   2235 		}
   2236 
   2237 		break;
   2238 
   2239 	case REQ_DOWN_CHAR:
   2240 		  /*
   2241 		   * The down_char request has the same functionality as
   2242 		   * the next_line request excepting that the field is not
   2243 		   * scrolled if the cursor is at the bottom of the field.
   2244 		   * Check to see if the cursor is at the bottom of the field
   2245 		   * and if it is then deny the request otherwise fall
   2246 		   * through to the next_line handler.
   2247 		   */
   2248 		if (cur->cursor_ypos >= cur->rows - 1)
   2249 			return E_REQUEST_DENIED;
   2250 
   2251 		  /* FALLTHRU */
   2252 
   2253 	case REQ_NEXT_LINE:
   2254 		if ((row->next == NULL) || (cur->cur_line->next == NULL))
   2255 			return E_REQUEST_DENIED;
   2256 
   2257 		cur->cur_line = cur->cur_line->next;
   2258 		if ((cur->cursor_ypos + 1) >= cur->rows) {
   2259 			cur->start_line = cur->start_line->next;
   2260 		} else
   2261 			cur->cursor_ypos++;
   2262 		row = cur->cur_line;
   2263 
   2264 		if (row->length == 0) {
   2265 			cur->row_xpos = 0;
   2266 			cur->cursor_xpos = 0;
   2267 		} else {
   2268 			if (cur->cursor_xpos > (row->expanded - 1))
   2269 				cur->cursor_xpos = row->expanded - 1;
   2270 
   2271 			cur->row_xpos =	tab_fit_len(row, cur->cursor_xpos + 1);
   2272 			if (cur->row_xpos == 0)
   2273 				cur->cursor_xpos = 0;
   2274 			else
   2275 				cur->cursor_xpos =
   2276 					_formi_tab_expanded_length(
   2277 						row->string, 0, cur->row_xpos);
   2278 			if (cur->cursor_xpos > 0)
   2279 				cur->cursor_xpos--;
   2280 		}
   2281 		break;
   2282 
   2283 	case REQ_UP_CHAR:
   2284 		  /*
   2285 		   * The up_char request has the same functionality as
   2286 		   * the prev_line request excepting the field is not
   2287 		   * scrolled, check if the cursor is at the top of the
   2288 		   * field, if it is deny the request otherwise fall
   2289 		   * through to the prev_line handler.
   2290 		   */
   2291 		if (cur->cursor_ypos == 0)
   2292 			return E_REQUEST_DENIED;
   2293 
   2294 		  /* FALLTHRU */
   2295 
   2296 	case REQ_PREV_LINE:
   2297 		if (cur->cur_line->prev == NULL)
   2298 			return E_REQUEST_DENIED;
   2299 
   2300 		if (cur->cursor_ypos == 0) {
   2301 			if (cur->start_line->prev == NULL)
   2302 				return E_REQUEST_DENIED;
   2303 			cur->start_line = cur->start_line->prev;
   2304 		} else
   2305 			cur->cursor_ypos--;
   2306 
   2307 		cur->cur_line = cur->cur_line->prev;
   2308 		row = cur->cur_line;
   2309 
   2310 		if (row->length == 0) {
   2311 			cur->row_xpos = 0;
   2312 			cur->cursor_xpos = 0;
   2313 		} else {
   2314 			if (cur->cursor_xpos > (row->expanded - 1))
   2315 				cur->cursor_xpos = row->expanded - 1;
   2316 
   2317 			cur->row_xpos =	tab_fit_len(row, cur->cursor_xpos + 1);
   2318 			cur->cursor_xpos =
   2319 				_formi_tab_expanded_length(row->string,
   2320 							   0, cur->row_xpos);
   2321 			if (cur->cursor_xpos > 0)
   2322 				cur->cursor_xpos--;
   2323 		}
   2324 		break;
   2325 
   2326 	case REQ_NEXT_WORD:
   2327 		start = cur->row_xpos + cur->start_char;
   2328 		str = row->string;
   2329 
   2330 		wb = find_eow(cur, start, FALSE, &row);
   2331 		if (wb < 0)
   2332 			return wb;
   2333 
   2334 		start = wb;
   2335 		  /* check if we hit the end */
   2336 		if (str[start] == '\0')
   2337 			return E_REQUEST_DENIED;
   2338 
   2339 		  /* otherwise we must have found the start of a word...*/
   2340 		if ((cur->rows + cur->nrows) == 1) {
   2341 			  /* single line field */
   2342 			size = _formi_tab_expanded_length(str,
   2343 				cur->start_char, start);
   2344 			if (size < cur->cols) {
   2345 				cur->row_xpos = start - cur->start_char;
   2346 			} else {
   2347 				cur->start_char = start;
   2348 				cur->row_xpos = 0;
   2349 			}
   2350 			_formi_set_cursor_xpos(cur, FALSE);
   2351 		} else {
   2352 			  /* multiline field */
   2353 			cur->cur_line = row;
   2354 			adjust_ypos(cur, row);
   2355 
   2356 			cur->row_xpos = start;
   2357 			cur->cursor_xpos =
   2358 				_formi_tab_expanded_length(
   2359 					row->string, 0, cur->row_xpos) - 1;
   2360 		}
   2361 		break;
   2362 
   2363 	case REQ_PREV_WORD:
   2364 		start = cur->start_char + cur->row_xpos;
   2365 		if (cur->start_char > 0)
   2366 			start--;
   2367 
   2368 		if ((start == 0) && (row->prev == NULL))
   2369 			return E_REQUEST_DENIED;
   2370 
   2371 		if (start == 0) {
   2372 			row = row->prev;
   2373 			if (row->length > 0)
   2374 				start = row->length - 1;
   2375 			else
   2376 				start = 0;
   2377 		}
   2378 
   2379 		str = row->string;
   2380 
   2381 		start = find_sow(start, &row);
   2382 
   2383 		if ((cur->rows + cur->nrows) == 1) {
   2384 			  /* single line field */
   2385 			size = _formi_tab_expanded_length(str,
   2386 				cur->start_char, start);
   2387 
   2388 			if (start > cur->start_char) {
   2389 				cur->row_xpos = start - cur->start_char;
   2390 			} else {
   2391 				cur->start_char = start;
   2392 				cur->row_xpos = 0;
   2393 			}
   2394 			_formi_set_cursor_xpos(cur, FALSE);
   2395 		} else {
   2396 			  /* multiline field */
   2397 			cur->cur_line = row;
   2398 			adjust_ypos(cur, row);
   2399 			cur->row_xpos = start;
   2400 			cur->cursor_xpos =
   2401 				_formi_tab_expanded_length(
   2402 					row->string, 0,
   2403 					cur->row_xpos) - 1;
   2404 		}
   2405 
   2406 		break;
   2407 
   2408 	case REQ_BEG_FIELD:
   2409 		cur->start_char = 0;
   2410 		while (cur->start_line->prev != NULL)
   2411 			cur->start_line = cur->start_line->prev;
   2412 		cur->cur_line = cur->start_line;
   2413 		cur->row_xpos = 0;
   2414 		_formi_init_field_xpos(cur);
   2415 		cur->cursor_ypos = 0;
   2416 		break;
   2417 
   2418 	case REQ_BEG_LINE:
   2419 		cur->row_xpos = 0;
   2420 		_formi_init_field_xpos(cur);
   2421 		cur->start_char = 0;
   2422 		break;
   2423 
   2424 	case REQ_END_FIELD:
   2425 		while (cur->cur_line->next != NULL)
   2426 			cur->cur_line = cur->cur_line->next;
   2427 
   2428 		if (cur->row_count > cur->rows) {
   2429 			cur->start_line = cur->cur_line;
   2430 			pos = cur->rows - 1;
   2431 			while (pos > 0) {
   2432 				cur->start_line = cur->start_line->prev;
   2433 				pos--;
   2434 			}
   2435 			cur->cursor_ypos = cur->rows - 1;
   2436 		} else {
   2437 			cur->cursor_ypos = cur->row_count - 1;
   2438 		}
   2439 
   2440 		  /* we fall through here deliberately, we are on the
   2441 		   * correct row, now we need to get to the end of the
   2442 		   * line.
   2443 		   */
   2444 		  /* FALLTHRU */
   2445 
   2446 	case REQ_END_LINE:
   2447 		row = cur->cur_line;
   2448 
   2449 		if ((cur->rows + cur->nrows) == 1) {
   2450 			if (row->expanded > cur->cols - 1) {
   2451 				if ((cur->opts & O_STATIC) != O_STATIC) {
   2452 					cur->start_char = tab_fit_window(
   2453 						cur, row->length,
   2454 						cur->cols) + 1;
   2455 					cur->row_xpos = row->length
   2456 						- cur->start_char;
   2457 				} else {
   2458 					cur->start_char = 0;
   2459 					cur->row_xpos = cur->cols - 1;
   2460 				}
   2461 			} else {
   2462 				cur->row_xpos = row->length + 1;
   2463 				cur->start_char = 0;
   2464 			}
   2465 			_formi_set_cursor_xpos(cur, FALSE);
   2466 		} else {
   2467 			cur->row_xpos = row->length - 1;
   2468 			cur->cursor_xpos = row->expanded - 1;
   2469 			if (row->next == NULL) {
   2470 				cur->row_xpos++;
   2471 				cur->cursor_xpos++;
   2472 			}
   2473 		}
   2474 		break;
   2475 
   2476 	case REQ_NEW_LINE:
   2477 		start = cur->start_char	+ cur->row_xpos;
   2478 		if ((status = split_line(cur, TRUE, start, &row)) != E_OK)
   2479 			return status;
   2480 		cur->cur_line->hard_ret = TRUE;
   2481 		cur->cursor_xpos = 0;
   2482 		cur->row_xpos = 0;
   2483 		break;
   2484 
   2485 	case REQ_INS_CHAR:
   2486 		if ((status = _formi_add_char(cur, cur->start_char
   2487 					      + cur->row_xpos,
   2488 					      cur->pad)) != E_OK)
   2489 			return status;
   2490 		break;
   2491 
   2492 	case REQ_INS_LINE:
   2493 		if ((status = split_line(cur, TRUE, 0, &row)) != E_OK)
   2494 			return status;
   2495 		cur->cur_line->hard_ret = TRUE;
   2496 		break;
   2497 
   2498 	case REQ_DEL_CHAR:
   2499 		row = cur->cur_line;
   2500 		start = cur->start_char + cur->row_xpos;
   2501 		end = row->length - 1;
   2502 		if ((start >= row->length) && (row->next == NULL))
   2503 			return E_REQUEST_DENIED;
   2504 
   2505 		if ((start == row->length - 1) || (row->length == 0)) {
   2506 			if ((cur->rows + cur->nrows) > 1) {
   2507 				/*
   2508 				 * Firstly, check if the current line has
   2509 				 * a hard return.  In this case we just
   2510 				 * want to "delete" the hard return and
   2511 				 * re-wrap the field.  The hard return
   2512 				 * does not occupy a character space in
   2513 				 * the buffer but we must make it appear
   2514 				 * like it does for a deletion.
   2515 				 */
   2516 				if (row->hard_ret == TRUE) {
   2517 					row->hard_ret = FALSE;
   2518 					if (_formi_join_line(cur, &row,
   2519 							     JOIN_NEXT)
   2520 					    != E_OK) {
   2521 						row->hard_ret = TRUE;
   2522 						return 0;
   2523 					} else {
   2524 						return 1;
   2525 					}
   2526 				}
   2527 
   2528 				/*
   2529 				 * If we have more than one row, join the
   2530 				 * next row to make things easier unless
   2531 				 * we are at the end of the string, in
   2532 				 * that case the join would fail but we
   2533 				 * really want to delete the last char
   2534 				 * in the field.
   2535 				 */
   2536 				if (row->next != NULL) {
   2537 					if (_formi_join_line(cur, &row,
   2538 							     JOIN_NEXT_NW)
   2539 					    != E_OK) {
   2540 						return E_REQUEST_DENIED;
   2541 					}
   2542 				}
   2543 			}
   2544 		}
   2545 
   2546 		saved = row->string[start];
   2547 		bcopy(&row->string[start + 1], &row->string[start],
   2548 		      (size_t) (end - start + 1));
   2549 		row->string[end] = '\0';
   2550 		row->length--;
   2551 		if (row->length > 0)
   2552 			row->expanded = _formi_tab_expanded_length(
   2553 				row->string, 0, row->length - 1);
   2554 		else
   2555 			row->expanded = 0;
   2556 
   2557 		  /*
   2558 		   * recalculate tabs for a single line field, multiline
   2559 		   * fields will do this when the field is wrapped.
   2560 		   */
   2561 		if ((cur->rows + cur->nrows) == 1)
   2562 			_formi_calculate_tabs(row);
   2563 		  /*
   2564 		   * if we are at the end of the string then back the
   2565 		   * cursor pos up one to stick on the end of the line
   2566 		   */
   2567 		if (start == row->length) {
   2568 			if (row->length > 1) {
   2569 				if ((cur->rows + cur->nrows) == 1) {
   2570 					pos = cur->row_xpos + cur->start_char;
   2571 					cur->start_char =
   2572 						tab_fit_window(
   2573 							cur,
   2574 							cur->start_char + cur->row_xpos,
   2575 							cur->cols);
   2576 					cur->row_xpos = pos - cur->start_char
   2577 						- 1;
   2578 					_formi_set_cursor_xpos(cur, FALSE);
   2579 				} else {
   2580 					if (cur->row_xpos == 0) {
   2581 						if (row->next != NULL) {
   2582 							if (_formi_join_line(
   2583 								cur, &row,
   2584 								JOIN_PREV_NW)
   2585 							    != E_OK) {
   2586 								return E_REQUEST_DENIED;
   2587 							}
   2588 						} else {
   2589 							if (cur->row_count > 1)
   2590 								cur->row_count--;
   2591 						}
   2592 
   2593 					}
   2594 
   2595 					cur->row_xpos = start - 1;
   2596 					cur->cursor_xpos =
   2597 						_formi_tab_expanded_length(
   2598 							row->string,
   2599 							0, cur->row_xpos - 1);
   2600 					if ((cur->cursor_xpos > 0)
   2601 					    && (start != (row->expanded - 1)))
   2602 						cur->cursor_xpos--;
   2603 				}
   2604 
   2605 				start--;
   2606 			} else {
   2607 				start = 0;
   2608 				cur->row_xpos = 0;
   2609 				_formi_init_field_xpos(cur);
   2610 			}
   2611 		}
   2612 
   2613 		if ((cur->rows + cur->nrows) > 1) {
   2614 			if (_formi_wrap_field(cur, row) != E_OK) {
   2615 				bcopy(&row->string[start],
   2616 				      &row->string[start + 1],
   2617 				      (size_t) (end - start));
   2618 				row->length++;
   2619 				row->string[start] = saved;
   2620 				_formi_wrap_field(cur, row);
   2621 				return E_REQUEST_DENIED;
   2622 			}
   2623 		}
   2624 		break;
   2625 
   2626 	case REQ_DEL_PREV:
   2627 		if ((cur->cursor_xpos == 0) && (cur->start_char == 0)
   2628 		    && (cur->start_line->prev == NULL)
   2629 		    && (cur->cursor_ypos == 0))
   2630 			   return E_REQUEST_DENIED;
   2631 
   2632 		row = cur->cur_line;
   2633 		start = cur->row_xpos + cur->start_char;
   2634 		end = row->length - 1;
   2635 		eat_char = TRUE;
   2636 
   2637 		if ((cur->start_char + cur->row_xpos) == 0) {
   2638 			if (row->prev == NULL)
   2639 				return E_REQUEST_DENIED;
   2640 
   2641 			  /*
   2642 			   * If we are a multiline field then check if
   2643 			   * the line above has a hard return.  If it does
   2644 			   * then just "eat" the hard return and re-wrap
   2645 			   * the field.
   2646 			   */
   2647 			if (row->prev->hard_ret == TRUE) {
   2648 				row->prev->hard_ret = FALSE;
   2649 				if (_formi_join_line(cur, &row,
   2650 						     JOIN_PREV) != E_OK) {
   2651 					row->prev->hard_ret = TRUE;
   2652 					return 0;
   2653 				}
   2654 
   2655 				eat_char = FALSE;
   2656 			} else {
   2657 				start = row->prev->length;
   2658 				  /*
   2659 				   * Join this line to the previous
   2660 				   * one.
   2661 				   */
   2662 				if (_formi_join_line(cur, &row,
   2663 						     JOIN_PREV_NW) != E_OK) {
   2664 					return 0;
   2665 				}
   2666 				end = row->length - 1;
   2667 			}
   2668 		}
   2669 
   2670 		if (eat_char == TRUE) {
   2671 			  /*
   2672 			   * eat a char from the buffer.  Normally we do
   2673 			   * this unless we have deleted a "hard return"
   2674 			   * in which case we just want to join the lines
   2675 			   * without losing a char.
   2676 			   */
   2677 			saved = row->string[start - 1];
   2678 			bcopy(&row->string[start], &row->string[start - 1],
   2679 			      (size_t) (end - start + 1));
   2680 			row->length--;
   2681 			row->string[row->length] = '\0';
   2682 			row->expanded = _formi_tab_expanded_length(
   2683 				row->string, 0, row->length - 1);
   2684 		}
   2685 
   2686 		if ((cur->rows + cur->nrows) == 1) {
   2687 			_formi_calculate_tabs(row);
   2688 			pos = cur->row_xpos + cur->start_char;
   2689 			if (pos > 0)
   2690 				pos--;
   2691 			cur->start_char =
   2692 				tab_fit_window(cur,
   2693 					       cur->start_char + cur->row_xpos,
   2694 					       cur->cols);
   2695 			cur->row_xpos = pos - cur->start_char;
   2696 			_formi_set_cursor_xpos(cur, FALSE);
   2697 		} else {
   2698 			if (eat_char == TRUE) {
   2699 				cur->row_xpos--;
   2700 				if (cur->row_xpos > 0)
   2701 					cur->cursor_xpos =
   2702 						_formi_tab_expanded_length(
   2703 							row->string, 0,
   2704 							cur->row_xpos - 1);
   2705 				else
   2706 					cur->cursor_xpos = 0;
   2707 			}
   2708 
   2709 			if ((_formi_wrap_field(cur, row) != E_OK)) {
   2710 				bcopy(&row->string[start - 1],
   2711 				      &row->string[start],
   2712 				      (size_t) (end - start));
   2713 				row->length++;
   2714 				row->string[start - 1] = saved;
   2715 				row->string[row->length] = '\0';
   2716 				_formi_wrap_field(cur, row);
   2717 				return E_REQUEST_DENIED;
   2718 			}
   2719 		}
   2720 		break;
   2721 
   2722 	case REQ_DEL_LINE:
   2723 		if (((cur->rows + cur->nrows) == 1) ||
   2724 		    (cur->row_count == 1)) {
   2725 			  /* single line case */
   2726 			row->length = 0;
   2727 			row->expanded = row->length = 0;
   2728 			cur->row_xpos = 0;
   2729 			_formi_init_field_xpos(cur);
   2730 			cur->cursor_ypos = 0;
   2731 		} else {
   2732 			  /* multiline field */
   2733 			old_count = cur->row_count;
   2734 			cur->row_count--;
   2735 			if (cur->row_count == 0)
   2736 				cur->row_count = 1;
   2737 
   2738 			if (old_count == 1) {
   2739 				row->expanded = row->length = 0;
   2740 				cur->cursor_xpos = 0;
   2741 				cur->row_xpos = 0;
   2742 				cur->cursor_ypos = 0;
   2743 			} else
   2744 				add_to_free(cur, row);
   2745 
   2746 			if (row->next == NULL) {
   2747 				if (cur->cursor_ypos == 0) {
   2748 					if (cur->start_line->prev != NULL) {
   2749 						cur->start_line =
   2750 							cur->start_line->prev;
   2751 					}
   2752 				} else {
   2753 					cur->cursor_ypos--;
   2754 				}
   2755 			}
   2756 
   2757 			if (old_count > 1) {
   2758 				if (cur->cursor_xpos > row->expanded) {
   2759 					cur->cursor_xpos = row->expanded - 1;
   2760 					cur->row_xpos = row->length - 1;
   2761 				}
   2762 
   2763 				cur->start_line = cur->alines;
   2764 				rs = cur->start_line;
   2765 				cur->cursor_ypos = 0;
   2766 				while (rs != row) {
   2767 					if (cur->cursor_ypos < cur->rows)
   2768 						cur->cursor_ypos++;
   2769 					else
   2770 						cur->start_line =
   2771 							cur->start_line->next;
   2772 					rs = rs->next;
   2773 				}
   2774 			}
   2775 		}
   2776 		break;
   2777 
   2778 	case REQ_DEL_WORD:
   2779 		start = cur->start_char + cur->row_xpos;
   2780 		str = row->string;
   2781 
   2782 		wb = find_eow(cur, start, TRUE, &row);
   2783 		if (wb < 0)
   2784 			return wb;
   2785 
   2786 		end = wb;
   2787 
   2788 		  /*
   2789 		   * If not at the start of a word then find the start,
   2790 		   * we cannot blindly call find_sow because this will
   2791 		   * skip back a word if we are already at the start of
   2792 		   * a word.
   2793 		   */
   2794 		if ((start > 0)
   2795 		    && !(isblank((unsigned char)str[start - 1]) &&
   2796 			!isblank((unsigned char)str[start])))
   2797 			start = find_sow(start, &row);
   2798 		str = row->string;
   2799 		  /* XXXX hmmmm what if start and end on diff rows? XXXX */
   2800 		bcopy(&str[end], &str[start],
   2801 		      (size_t) (row->length - end + 1));
   2802 		len = end - start;
   2803 		row->length -= len;
   2804 
   2805 		if ((cur->rows + cur->nrows) > 1) {
   2806 			row = cur->start_line + cur->cursor_ypos;
   2807 			if (row->next != NULL) {
   2808 				/*
   2809 				 * if not on the last row we need to
   2810 				 * join on the next row so the line
   2811 				 * will be re-wrapped.
   2812 				 */
   2813 				_formi_join_line(cur, &row, JOIN_NEXT_NW);
   2814 			}
   2815 			_formi_wrap_field(cur, row);
   2816 			cur->row_xpos = start;
   2817 			cur->cursor_xpos = _formi_tab_expanded_length(
   2818 				row->string, 0, cur->row_xpos);
   2819 			if (cur->cursor_xpos > 0)
   2820 				cur->cursor_xpos--;
   2821 		} else {
   2822 			_formi_calculate_tabs(row);
   2823 			cur->row_xpos = start - cur->start_char;
   2824 			if (cur->row_xpos > 0)
   2825 				cur->row_xpos--;
   2826 			_formi_set_cursor_xpos(cur, FALSE);
   2827 		}
   2828 		break;
   2829 
   2830 	case REQ_CLR_EOL:
   2831 		row->string[cur->row_xpos + 1] = '\0';
   2832 		row->length = cur->row_xpos + 1;
   2833 		row->expanded = cur->cursor_xpos + 1;
   2834 		break;
   2835 
   2836 	case REQ_CLR_EOF:
   2837 		row = cur->cur_line->next;
   2838 		while (row != NULL) {
   2839 			rs = row->next;
   2840 			add_to_free(cur, row);
   2841 			row = rs;
   2842 			cur->row_count--;
   2843 		}
   2844 		break;
   2845 
   2846 	case REQ_CLR_FIELD:
   2847 		row = cur->alines->next;
   2848 		cur->cur_line = cur->alines;
   2849 		cur->start_line = cur->alines;
   2850 
   2851 		while (row != NULL) {
   2852 			rs = row->next;
   2853 			add_to_free(cur, row);
   2854 			row = rs;
   2855 		}
   2856 
   2857 		cur->alines->string[0] = '\0';
   2858 		cur->alines->length = 0;
   2859 		cur->alines->expanded = 0;
   2860 		cur->row_count = 1;
   2861 		cur->cursor_ypos = 0;
   2862 		cur->row_xpos = 0;
   2863 		_formi_init_field_xpos(cur);
   2864 		cur->start_char = 0;
   2865 		break;
   2866 
   2867 	case REQ_OVL_MODE:
   2868 		cur->overlay = 1;
   2869 		break;
   2870 
   2871 	case REQ_INS_MODE:
   2872 		cur->overlay = 0;
   2873 		break;
   2874 
   2875 	case REQ_SCR_FLINE:
   2876 		_formi_scroll_fwd(cur, 1);
   2877 		break;
   2878 
   2879 	case REQ_SCR_BLINE:
   2880 		_formi_scroll_back(cur, 1);
   2881 		break;
   2882 
   2883 	case REQ_SCR_FPAGE:
   2884 		_formi_scroll_fwd(cur, cur->rows);
   2885 		break;
   2886 
   2887 	case REQ_SCR_BPAGE:
   2888 		_formi_scroll_back(cur, cur->rows);
   2889 		break;
   2890 
   2891 	case REQ_SCR_FHPAGE:
   2892 		_formi_scroll_fwd(cur, cur->rows / 2);
   2893 		break;
   2894 
   2895 	case REQ_SCR_BHPAGE:
   2896 		_formi_scroll_back(cur, cur->rows / 2);
   2897 		break;
   2898 
   2899 	case REQ_SCR_FCHAR:
   2900 		_formi_hscroll_fwd(cur, row, 1);
   2901 		break;
   2902 
   2903 	case REQ_SCR_BCHAR:
   2904 		_formi_hscroll_back(cur, row, 1);
   2905 		break;
   2906 
   2907 	case REQ_SCR_HFLINE:
   2908 		_formi_hscroll_fwd(cur, row, cur->cols);
   2909 		break;
   2910 
   2911 	case REQ_SCR_HBLINE:
   2912 		_formi_hscroll_back(cur, row, cur->cols);
   2913 		break;
   2914 
   2915 	case REQ_SCR_HFHALF:
   2916 		_formi_hscroll_fwd(cur, row, cur->cols / 2);
   2917 		break;
   2918 
   2919 	case REQ_SCR_HBHALF:
   2920 		_formi_hscroll_back(cur, row, cur->cols / 2);
   2921 		break;
   2922 
   2923 	default:
   2924 		return 0;
   2925 	}
   2926 
   2927 	_formi_dbg_printf(
   2928 	     "%s: cursor_xpos=%d, row_xpos=%d, start_char=%d, length=%d, "
   2929 	     "allocated=%d\n", __func__, cur->cursor_xpos, cur->row_xpos,
   2930 	     cur->start_char, cur->cur_line->length, cur->cur_line->allocated);
   2931 	_formi_dbg_printf("%s: start_line=%p, ypos=%d\n", __func__,
   2932 	    cur->start_line, cur->cursor_ypos);
   2933 	_formi_dbg_printf("%s: string=\"%s\"\n", __func__,
   2934 	    cur->cur_line->string);
   2935 	assert ((cur->cursor_xpos < INT_MAX) && (cur->row_xpos < INT_MAX)
   2936 		&& (cur->cursor_xpos >= cur->row_xpos));
   2937 	return 1;
   2938 }
   2939 
   2940 /*
   2941  * Validate the given character by passing it to any type character
   2942  * checking routines, if they exist.
   2943  */
   2944 int
   2945 _formi_validate_char(FIELD *field, char c)
   2946 {
   2947 	int ret_val;
   2948 
   2949 	if (field->type == NULL)
   2950 		return E_OK;
   2951 
   2952 	ret_val = E_INVALID_FIELD;
   2953 	_formi_do_char_validation(field, field->type, c, &ret_val);
   2954 
   2955 	return ret_val;
   2956 }
   2957 
   2958 
   2959 /*
   2960  * Perform the validation of the character, invoke all field_type validation
   2961  * routines.  If the field is ok then update ret_val to E_OK otherwise
   2962  * ret_val is not changed.
   2963  */
   2964 static void
   2965 _formi_do_char_validation(FIELD *field, FIELDTYPE *type, char c, int *ret_val)
   2966 {
   2967 	if ((type->flags & _TYPE_IS_LINKED) == _TYPE_IS_LINKED) {
   2968 		_formi_do_char_validation(field, type->link->next, c, ret_val);
   2969 		_formi_do_char_validation(field, type->link->prev, c, ret_val);
   2970 	} else {
   2971 		if (type->char_check == NULL)
   2972 			*ret_val = E_OK;
   2973 		else {
   2974 			if (type->char_check((int)(unsigned char) c,
   2975 					     field->args) == TRUE)
   2976 				*ret_val = E_OK;
   2977 		}
   2978 	}
   2979 }
   2980 
   2981 /*
   2982  * Validate the current field.  If the field validation returns success then
   2983  * return E_OK otherwise return E_INVALID_FIELD.
   2984  *
   2985  */
   2986 int
   2987 _formi_validate_field(FORM *form)
   2988 {
   2989 	FIELD *cur;
   2990 	int ret_val, count;
   2991 
   2992 
   2993 	if ((form == NULL) || (form->fields == NULL) ||
   2994 	    (form->fields[0] == NULL))
   2995 		return E_INVALID_FIELD;
   2996 
   2997 	cur = form->fields[form->cur_field];
   2998 
   2999 	  /*
   3000 	   * Sync the buffer if it has been modified so the field
   3001 	   * validation routines can use it and because this is
   3002 	   * the correct behaviour according to AT&T implementation.
   3003 	   */
   3004 	if ((cur->buf0_status == TRUE)
   3005 	    && ((ret_val = _formi_sync_buffer(cur)) != E_OK))
   3006 			return ret_val;
   3007 
   3008 	  /*
   3009 	   * If buffer is untouched then the string pointer may be
   3010 	   * NULL, see if this is ok or not.
   3011 	   */
   3012 	if (cur->buffers[0].string == NULL) {
   3013 		if ((cur->opts & O_NULLOK) == O_NULLOK)
   3014 			return E_OK;
   3015 		else
   3016 			return E_INVALID_FIELD;
   3017 	}
   3018 
   3019 	count = _formi_skip_blanks(cur->buffers[0].string, 0);
   3020 
   3021 	  /* check if we have a null field, depending on the nullok flag
   3022 	   * this may be acceptable or not....
   3023 	   */
   3024 	if (cur->buffers[0].string[count] == '\0') {
   3025 		if ((cur->opts & O_NULLOK) == O_NULLOK)
   3026 			return E_OK;
   3027 		else
   3028 			return E_INVALID_FIELD;
   3029 	}
   3030 
   3031 	  /* check if an unmodified field is ok */
   3032 	if (cur->buf0_status == 0) {
   3033 		if ((cur->opts & O_PASSOK) == O_PASSOK)
   3034 			return E_OK;
   3035 		else
   3036 			return E_INVALID_FIELD;
   3037 	}
   3038 
   3039 	  /* if there is no type then just accept the field */
   3040 	if (cur->type == NULL)
   3041 		return E_OK;
   3042 
   3043 	ret_val = E_INVALID_FIELD;
   3044 	_formi_do_validation(cur, cur->type, &ret_val);
   3045 
   3046 	return ret_val;
   3047 }
   3048 
   3049 /*
   3050  * Perform the validation of the field, invoke all field_type validation
   3051  * routines.  If the field is ok then update ret_val to E_OK otherwise
   3052  * ret_val is not changed.
   3053  */
   3054 static void
   3055 _formi_do_validation(FIELD *field, FIELDTYPE *type, int *ret_val)
   3056 {
   3057 	if ((type->flags & _TYPE_IS_LINKED) == _TYPE_IS_LINKED) {
   3058 		_formi_do_validation(field, type->link->next, ret_val);
   3059 		_formi_do_validation(field, type->link->prev, ret_val);
   3060 	} else {
   3061 		if (type->field_check == NULL)
   3062 			*ret_val = E_OK;
   3063 		else {
   3064 			if (type->field_check(field, field_buffer(field, 0))
   3065 			    == TRUE)
   3066 				*ret_val = E_OK;
   3067 		}
   3068 	}
   3069 }
   3070 
   3071 /*
   3072  * Select the next/previous choice for the field, the driver command
   3073  * selecting the direction will be passed in c.  Return 1 if a choice
   3074  * selection succeeded, 0 otherwise.
   3075  */
   3076 int
   3077 _formi_field_choice(FORM *form, int c)
   3078 {
   3079 	FIELDTYPE *type;
   3080 	FIELD *field;
   3081 
   3082 	if ((form == NULL) || (form->fields == NULL) ||
   3083 	    (form->fields[0] == NULL) ||
   3084 	    (form->fields[form->cur_field]->type == NULL))
   3085 		return 0;
   3086 
   3087 	field = form->fields[form->cur_field];
   3088 	type = field->type;
   3089 
   3090 	switch (c) {
   3091 	case REQ_NEXT_CHOICE:
   3092 		if (type->next_choice == NULL)
   3093 			return 0;
   3094 		else
   3095 			return type->next_choice(field,
   3096 						 field_buffer(field, 0));
   3097 
   3098 	case REQ_PREV_CHOICE:
   3099 		if (type->prev_choice == NULL)
   3100 			return 0;
   3101 		else
   3102 			return type->prev_choice(field,
   3103 						 field_buffer(field, 0));
   3104 
   3105 	default: /* should never happen! */
   3106 		return 0;
   3107 	}
   3108 }
   3109 
   3110 /*
   3111  * Update the fields if they have changed.  The parameter old has the
   3112  * previous current field as the current field may have been updated by
   3113  * the driver.  Return 1 if the form page needs updating.
   3114  *
   3115  */
   3116 int
   3117 _formi_update_field(FORM *form, int old_field)
   3118 {
   3119 	int cur, i;
   3120 
   3121 	cur = form->cur_field;
   3122 
   3123 	if (old_field != cur) {
   3124 		if (!((cur >= form->page_starts[form->page].first) &&
   3125 		      (cur <= form->page_starts[form->page].last))) {
   3126 			  /* not on same page any more */
   3127 			for (i = 0; i < form->max_page; i++) {
   3128 				if ((form->page_starts[i].in_use == 1) &&
   3129 				    (form->page_starts[i].first <= cur) &&
   3130 				    (form->page_starts[i].last >= cur)) {
   3131 					form->page = i;
   3132 					return 1;
   3133 				}
   3134 			}
   3135 		}
   3136 	}
   3137 
   3138 	_formi_redraw_field(form, old_field);
   3139 	_formi_redraw_field(form, form->cur_field);
   3140 	return 0;
   3141 }
   3142 
   3143 /*
   3144  * Compare function for the field sorting
   3145  *
   3146  */
   3147 static int
   3148 field_sort_compare(const void *one, const void *two)
   3149 {
   3150 	const FIELD *a, *b;
   3151 	int tl;
   3152 
   3153 	  /* LINTED const castaway; we don't modify these! */
   3154 	a = (const FIELD *) *((const FIELD **) one);
   3155 	b = (const FIELD *) *((const FIELD **) two);
   3156 
   3157 	if (a == NULL)
   3158 		return 1;
   3159 
   3160 	if (b == NULL)
   3161 		return -1;
   3162 
   3163 	  /*
   3164 	   * First check the page, we want the fields sorted by page.
   3165 	   *
   3166 	   */
   3167 	if (a->page != b->page)
   3168 		return ((a->page > b->page)? 1 : -1);
   3169 
   3170 	tl = _formi_top_left(a->parent, a->index, b->index);
   3171 
   3172 	  /*
   3173 	   * sort fields left to right, top to bottom so the top left is
   3174 	   * the lesser value....
   3175 	   */
   3176 	return ((tl == a->index)? -1 : 1);
   3177 }
   3178 
   3179 /*
   3180  * Sort the fields in a form ready for driver traversal.
   3181  */
   3182 void
   3183 _formi_sort_fields(FORM *form)
   3184 {
   3185 	FIELD **sort_area;
   3186 	int i;
   3187 
   3188 	TAILQ_INIT(&form->sorted_fields);
   3189 
   3190 	if ((sort_area = malloc(sizeof(*sort_area) * form->field_count))
   3191 	    == NULL)
   3192 		return;
   3193 
   3194 	bcopy(form->fields, sort_area,
   3195 	      (size_t) (sizeof(FIELD *) * form->field_count));
   3196 	qsort(sort_area, (size_t) form->field_count, sizeof(FIELD *),
   3197 	      field_sort_compare);
   3198 
   3199 	for (i = 0; i < form->field_count; i++)
   3200 		TAILQ_INSERT_TAIL(&form->sorted_fields, sort_area[i], glue);
   3201 
   3202 	free(sort_area);
   3203 }
   3204 
   3205 /*
   3206  * Set the neighbours for all the fields in the given form.
   3207  */
   3208 void
   3209 _formi_stitch_fields(FORM *form)
   3210 {
   3211 	int above_row, below_row, end_above, end_below, cur_row, real_end;
   3212 	FIELD *cur, *above, *below;
   3213 
   3214 	  /*
   3215 	   * check if the sorted fields circle queue is empty, just
   3216 	   * return if it is.
   3217 	   */
   3218 	if (TAILQ_EMPTY(&form->sorted_fields))
   3219 		return;
   3220 
   3221 	  /* initially nothing is above..... */
   3222 	above_row = -1;
   3223 	end_above = TRUE;
   3224 	above = NULL;
   3225 
   3226 	  /* set up the first field as the current... */
   3227 	cur = TAILQ_FIRST(&form->sorted_fields);
   3228 	cur_row = cur->form_row;
   3229 
   3230 	  /* find the first field on the next row if any */
   3231 	below = TAILQ_NEXT(cur, glue);
   3232 	below_row = -1;
   3233 	end_below = TRUE;
   3234 	real_end = TRUE;
   3235 	while (below != NULL) {
   3236 		if (below->form_row != cur_row) {
   3237 			below_row = below->form_row;
   3238 			end_below = FALSE;
   3239 			real_end = FALSE;
   3240 			break;
   3241 		}
   3242 		below = TAILQ_NEXT(below, glue);
   3243 	}
   3244 
   3245 	  /* walk the sorted fields, setting the neighbour pointers */
   3246 	while (cur != NULL) {
   3247 		if (cur == TAILQ_FIRST(&form->sorted_fields))
   3248 			cur->left = NULL;
   3249 		else
   3250 			cur->left = TAILQ_PREV(cur, _formi_sort_head, glue);
   3251 
   3252 		if (cur == TAILQ_LAST(&form->sorted_fields, _formi_sort_head))
   3253 			cur->right = NULL;
   3254 		else
   3255 			cur->right = TAILQ_NEXT(cur, glue);
   3256 
   3257 		if (end_above == TRUE)
   3258 			cur->up = NULL;
   3259 		else {
   3260 			cur->up = above;
   3261 			above = TAILQ_NEXT(above, glue);
   3262 			if (above_row != above->form_row) {
   3263 				end_above = TRUE;
   3264 				above_row = above->form_row;
   3265 			}
   3266 		}
   3267 
   3268 		if (end_below == TRUE)
   3269 			cur->down = NULL;
   3270 		else {
   3271 			cur->down = below;
   3272 			below = TAILQ_NEXT(below, glue);
   3273 			if (below == NULL) {
   3274 				end_below = TRUE;
   3275 				real_end = TRUE;
   3276 			} else if (below_row != below->form_row) {
   3277 				end_below = TRUE;
   3278 				below_row = below->form_row;
   3279 			}
   3280 		}
   3281 
   3282 		cur = TAILQ_NEXT(cur, glue);
   3283 		if ((cur != NULL)
   3284 		    && (cur_row != cur->form_row)) {
   3285 			cur_row = cur->form_row;
   3286 			if (end_above == FALSE) {
   3287 				for (; above !=
   3288 				    TAILQ_FIRST(&form->sorted_fields);
   3289 				    above = TAILQ_NEXT(above, glue)) {
   3290 					if (above->form_row != above_row) {
   3291 						above_row = above->form_row;
   3292 						break;
   3293 					}
   3294 				}
   3295 			} else if (above == NULL) {
   3296 				above = TAILQ_FIRST(&form->sorted_fields);
   3297 				end_above = FALSE;
   3298 				above_row = above->form_row;
   3299 			} else
   3300 				end_above = FALSE;
   3301 
   3302 			if (end_below == FALSE) {
   3303 				while (below_row == below->form_row) {
   3304 					below = TAILQ_NEXT(below, glue);
   3305 					if (below == NULL) {
   3306 						real_end = TRUE;
   3307 						end_below = TRUE;
   3308 						break;
   3309 					}
   3310 				}
   3311 
   3312 				if (below != NULL)
   3313 					below_row = below->form_row;
   3314 			} else if (real_end == FALSE)
   3315 				end_below = FALSE;
   3316 
   3317 		}
   3318 	}
   3319 }
   3320 
   3321 /*
   3322  * Calculate the length of the displayed line allowing for any tab
   3323  * characters that need to be expanded.  We assume that the tab stops
   3324  * are 8 characters apart.  The parameters start and end are the
   3325  * character positions in the string str we want to get the length of,
   3326  * the function returns the number of characters from the start
   3327  * position to the end position that should be displayed after any
   3328  * intervening tabs have been expanded.
   3329  */
   3330 int
   3331 _formi_tab_expanded_length(char *str, unsigned int start, unsigned int end)
   3332 {
   3333 	int len, start_len, i;
   3334 
   3335 	  /* if we have a null string then there is no length */
   3336 	if (str[0] == '\0')
   3337 		return 0;
   3338 
   3339 	len = 0;
   3340 	start_len = 0;
   3341 
   3342 	  /*
   3343 	   * preceding tabs affect the length tabs in the span, so
   3344 	   * we need to calculate the length including the stuff before
   3345 	   * start and then subtract off the unwanted bit.
   3346 	   */
   3347 	for (i = 0; i <= end; i++) {
   3348 		if (i == start) /* stash preamble length for later */
   3349 			start_len = len;
   3350 
   3351 		if (str[i] == '\0')
   3352 			break;
   3353 
   3354 		if (str[i] == '\t')
   3355 			len = len - (len % 8) + 8;
   3356 		else
   3357 			len++;
   3358 	}
   3359 
   3360 	_formi_dbg_printf(
   3361 	    "%s: start=%d, end=%d, expanded=%d (diff=%d)\n", __func__,
   3362 	    start, end, (len - start_len), (end - start));
   3363 
   3364 	return (len - start_len);
   3365 }
   3366 
   3367 /*
   3368  * Calculate the tab stops on a given line in the field and set up
   3369  * the tabs list with the results.  We do this by scanning the line for tab
   3370  * characters and if one is found, noting the position and the number of
   3371  * characters to get to the next tab stop.  This information is kept to
   3372  * make manipulating the field (scrolling and so on) easier to handle.
   3373  */
   3374 void
   3375 _formi_calculate_tabs(_FORMI_FIELD_LINES *row)
   3376 {
   3377 	_formi_tab_t *ts = row->tabs, *old_ts = NULL, **tsp;
   3378 	int i, j;
   3379 
   3380 	  /*
   3381 	   * If the line already has tabs then invalidate them by
   3382 	   * walking the list and killing the in_use flag.
   3383 	   */
   3384 	for (; ts != NULL; ts = ts->fwd)
   3385 		ts->in_use = FALSE;
   3386 
   3387 
   3388 	  /*
   3389 	   * Now look for tabs in the row and record the info...
   3390 	   */
   3391 	tsp = &row->tabs;
   3392 	for (i = 0, j = 0; i < row->length; i++, j++) {
   3393 		if (row->string[i] == '\t') {
   3394 			if (*tsp == NULL) {
   3395 				if ((*tsp = (_formi_tab_t *)
   3396 				     malloc(sizeof(_formi_tab_t))) == NULL)
   3397 					return;
   3398 				(*tsp)->back = old_ts;
   3399 				(*tsp)->fwd = NULL;
   3400 			}
   3401 
   3402 			(*tsp)->in_use = TRUE;
   3403 			(*tsp)->pos = i;
   3404 			(*tsp)->size = 8 - (j % 8);
   3405 			j += (*tsp)->size - 1;
   3406 			old_ts = *tsp;
   3407 			tsp = &(*tsp)->fwd;
   3408 		}
   3409 	}
   3410 }
   3411 
   3412 /*
   3413  * Return the size of the tab padding for a tab character at the given
   3414  * position.  Return 1 if there is not a tab char entry matching the
   3415  * given location.
   3416  */
   3417 static int
   3418 tab_size(_FORMI_FIELD_LINES *row, unsigned int i)
   3419 {
   3420 	_formi_tab_t *ts;
   3421 
   3422 	ts = row->tabs;
   3423 	while ((ts != NULL) && (ts->pos != i))
   3424 		ts = ts->fwd;
   3425 
   3426 	if (ts == NULL)
   3427 		return 1;
   3428 	else
   3429 		return ts->size;
   3430 }
   3431 
   3432 /*
   3433  * Find the character offset that corresponds to longest tab expanded
   3434  * string that will fit into the given window.  Walk the string backwards
   3435  * evaluating the sizes of any tabs that are in the string.  Note that
   3436  * using this function on a multi-line window will produce undefined
   3437  * results - it is really only required for a single row field.
   3438  */
   3439 static int
   3440 tab_fit_window(FIELD *field, unsigned int pos, unsigned int window)
   3441 {
   3442 	int scroll_amt, i;
   3443 	_formi_tab_t *ts;
   3444 
   3445 	  /* first find the last tab */
   3446 	ts = field->alines->tabs;
   3447 
   3448 	  /*
   3449 	   * unless there are no tabs - just return the window size,
   3450 	   * if there is enough room, otherwise 0.
   3451 	   */
   3452 	if (ts == NULL) {
   3453 		if (field->alines->length < window)
   3454 			return 0;
   3455 		else
   3456 			return field->alines->length - window + 1;
   3457 	}
   3458 
   3459 	while ((ts->fwd != NULL) && (ts->fwd->in_use == TRUE))
   3460 		ts = ts->fwd;
   3461 
   3462 	  /*
   3463 	   * now walk backwards finding the first tab that is to the
   3464 	   * left of our starting pos.
   3465 	   */
   3466 	while ((ts != NULL) && (ts->in_use == TRUE) && (ts->pos > pos))
   3467 		ts = ts->back;
   3468 
   3469 	scroll_amt = 0;
   3470 	for (i = pos; i >= 0; i--) {
   3471 		if (field->alines->string[i] == '\t') {
   3472 			assert((ts != NULL) && (ts->in_use == TRUE));
   3473 			if (ts->pos == i) {
   3474 				if ((scroll_amt + ts->size) > window) {
   3475 					break;
   3476 				}
   3477 				scroll_amt += ts->size;
   3478 				ts = ts->back;
   3479 			}
   3480 			else
   3481 				assert(ts->pos == i);
   3482 		} else {
   3483 			scroll_amt++;
   3484 			if (scroll_amt > window)
   3485 				break;
   3486 		}
   3487 	}
   3488 
   3489 	return ++i;
   3490 }
   3491 
   3492 /*
   3493  * Return the position of the last character that will fit into the
   3494  * given width after tabs have been expanded for a given row of a given
   3495  * field.
   3496  */
   3497 static unsigned int
   3498 tab_fit_len(_FORMI_FIELD_LINES *row, unsigned int width)
   3499 {
   3500 	unsigned int pos, len, row_pos;
   3501 	_formi_tab_t *ts;
   3502 
   3503 	ts = row->tabs;
   3504 	pos = 0;
   3505 	len = 0;
   3506 	row_pos = 0;
   3507 
   3508 	if (width == 0)
   3509 		return 0;
   3510 
   3511 	while ((len < width) && (pos < row->length)) {
   3512 		if (row->string[pos] == '\t') {
   3513 			assert((ts != NULL) && (ts->in_use == TRUE));
   3514 			if (ts->pos == row_pos) {
   3515 				if ((len + ts->size) > width)
   3516 					break;
   3517 				len += ts->size;
   3518 				ts = ts->fwd;
   3519 			}
   3520 			else
   3521 				assert(ts->pos == row_pos);
   3522 		} else
   3523 			len++;
   3524 		pos++;
   3525 		row_pos++;
   3526 	}
   3527 
   3528 	if (pos > 0)
   3529 		pos--;
   3530 	return pos;
   3531 }
   3532 
   3533 /*
   3534  * Sync the field line structures with the contents of buffer 0 for that
   3535  * field.  We do this by walking all the line structures and concatenating
   3536  * all the strings into one single string in buffer 0.
   3537  */
   3538 int
   3539 _formi_sync_buffer(FIELD *field)
   3540 {
   3541 	_FORMI_FIELD_LINES *line;
   3542 	char *nstr, *tmp;
   3543 	unsigned length;
   3544 
   3545 	if (field->alines == NULL)
   3546 		return E_BAD_ARGUMENT;
   3547 
   3548 	if (field->alines->string == NULL)
   3549 		return E_BAD_ARGUMENT;
   3550 
   3551 	  /*
   3552 	   * init nstr up front, just in case there are no line contents,
   3553 	   * this could happen if the field just contains hard returns.
   3554 	   */
   3555 	if ((nstr = malloc(sizeof(char))) == NULL)
   3556 		return E_SYSTEM_ERROR;
   3557 	nstr[0] = '\0';
   3558 
   3559 	line = field->alines;
   3560 	length = 1; /* allow for terminating null */
   3561 
   3562 	while (line != NULL) {
   3563 		if (line->length != 0) {
   3564 			if ((tmp = realloc(nstr,
   3565 					   (size_t) (length + line->length)))
   3566 			    == NULL) {
   3567 				if (nstr != NULL)
   3568 					free(nstr);
   3569 				return (E_SYSTEM_ERROR);
   3570 			}
   3571 
   3572 			nstr = tmp;
   3573 			strcat(nstr, line->string);
   3574 			length += line->length;
   3575 		}
   3576 
   3577 		line = line->next;
   3578 	}
   3579 
   3580 	if (field->buffers[0].string != NULL)
   3581 		free(field->buffers[0].string);
   3582 	field->buffers[0].allocated = length;
   3583 	field->buffers[0].length = length - 1;
   3584 	field->buffers[0].string = nstr;
   3585 	return E_OK;
   3586 }
   3587 
   3588 
   3589 
   3590