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      1 /*	$NetBSD: internals.c,v 1.43 2023/08/01 07:56:23 mrg 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 1.43 2023/08/01 07:56:23 mrg 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 = malloc(sizeof(*new))) == NULL) {
    223 		return NULL;
    224 	}
    225 
    226 	memcpy(new, row, sizeof(*new));
    227 
    228 	  /* nuke the pointers from the source row so we don't get confused */
    229 	new->next = NULL;
    230 	new->prev = NULL;
    231 	new->tabs = NULL;
    232 
    233 	if ((new->string = malloc((size_t)new->allocated)) == NULL) {
    234 		free(new);
    235 		return NULL;
    236 	}
    237 
    238 	memcpy(new->string, row->string, (size_t) row->length + 1);
    239 
    240 	if (row->tabs != NULL) {
    241 		tp = row->tabs;
    242 		if ((new->tabs = malloc(sizeof(*new->tabs))) == NULL) {
    243 			free(new->string);
    244 			free(new);
    245 			return NULL;
    246 		}
    247 
    248 		memcpy(new->tabs, row->tabs, sizeof(*new->tabs));
    249 		new->tabs->back = NULL;
    250 		new->tabs->fwd = NULL;
    251 
    252 		tp = tp->fwd;
    253 		newt = new->tabs;
    254 
    255 		while (tp != NULL) {
    256 			if ((newt->fwd = malloc(sizeof(*newt->fwd))) == NULL) {
    257 				/* error... unwind allocations */
    258 				tp = new->tabs;
    259 				while (tp != NULL) {
    260 					newt = tp->fwd;
    261 					free(tp);
    262 					tp = newt;
    263 				}
    264 
    265 				free(new->string);
    266 				free(new);
    267 				return NULL;
    268 			}
    269 
    270 			memcpy(newt->fwd, tp, sizeof(*newt->fwd));
    271 			newt->fwd->back = newt;
    272 			newt = newt->fwd;
    273 			newt->fwd = NULL;
    274 			tp = tp->fwd;
    275 		}
    276 	}
    277 
    278 	return new;
    279 }
    280 
    281 /*
    282  * Initialise the row offset for a field, depending on the type of
    283  * field it is and the type of justification used.  The justification
    284  * is only used on static single line fields, everything else will
    285  * have the cursor_xpos set to 0.
    286  */
    287 void
    288 _formi_init_field_xpos(FIELD *field)
    289 {
    290 	  /* not static or is multi-line which are not justified, so 0 it is */
    291 	if (((field->opts & O_STATIC) != O_STATIC) ||
    292 	    ((field->rows + field->nrows) != 1)) {
    293 		field->cursor_xpos = 0;
    294 		return;
    295 	}
    296 
    297 	switch (field->justification) {
    298 	case JUSTIFY_RIGHT:
    299 		field->cursor_xpos = field->cols - 1;
    300 		break;
    301 
    302 	case JUSTIFY_CENTER:
    303 		field->cursor_xpos = (field->cols - 1) / 2;
    304 		break;
    305 
    306 	default: /* assume left justify */
    307 		field->cursor_xpos = 0;
    308 		break;
    309 	}
    310 }
    311 
    312 
    313 /*
    314  * Open the debug file if it is not already open....
    315  */
    316 #ifdef DEBUG
    317 static FILE *dbg;
    318 static const char dbg_file[] = "___form_dbg.out";
    319 
    320 void
    321 _formi_dbg_printf(const char *fmt, ...)
    322 {
    323 	va_list ap;
    324 
    325 	if (dbg == NULL && (dbg = fopen(dbg_file, "w")) == NULL) {
    326 		warn("Cannot open debug file `%s'", dbg_file);
    327 		return;
    328 	}
    329 	va_start(ap, fmt);
    330 	vfprintf(dbg, fmt, ap);
    331 	va_end(ap);
    332 }
    333 #endif
    334 
    335 /*
    336  * Check the sizing of the field, if the maximum size is set for a
    337  * dynamic field then check that the number of rows or columns does
    338  * not exceed the set maximum.  The decision to check the rows or
    339  * columns is made on the basis of how many rows are in the field -
    340  * one row means the max applies to the number of columns otherwise it
    341  * applies to the number of rows.  If the row/column count is less
    342  * than the maximum then return TRUE.
    343  *
    344  */
    345 static bool
    346 check_field_size(FIELD *field)
    347 {
    348 	if ((field->opts & O_STATIC) != O_STATIC) {
    349 		  /* dynamic field */
    350 		if (field->max == 0) /* unlimited */
    351 			return TRUE;
    352 
    353 		if (field->rows == 1) {
    354 			return (field->alines->length < field->max);
    355 		} else {
    356 			return (field->row_count <= field->max);
    357 		}
    358 	} else {
    359 		if ((field->rows + field->nrows) == 1) {
    360 			return (field->alines->length <= field->cols);
    361 		} else {
    362 			return (field->row_count <= (field->rows
    363 						     + field->nrows));
    364 		}
    365 	}
    366 }
    367 
    368 /*
    369  * Set the form's current field to the first valid field on the page.
    370  * Assume the fields have been sorted and stitched.
    371  */
    372 int
    373 _formi_pos_first_field(FORM *form)
    374 {
    375 	FIELD *cur;
    376 	int old_page;
    377 
    378 	old_page = form->page;
    379 
    380 	  /* scan forward for an active page....*/
    381 	while (form->page_starts[form->page].in_use == 0) {
    382 		form->page++;
    383 		if (form->page > form->max_page) {
    384 			form->page = old_page;
    385 			return E_REQUEST_DENIED;
    386 		}
    387 	}
    388 
    389 	  /* then scan for a field we can use */
    390 	cur = form->fields[form->page_starts[form->page].first];
    391 	while ((cur->opts & (O_VISIBLE | O_ACTIVE))
    392 	       != (O_VISIBLE | O_ACTIVE)) {
    393 		cur = TAILQ_NEXT(cur, glue);
    394 		if (cur == NULL) {
    395 			form->page = old_page;
    396 			return E_REQUEST_DENIED;
    397 		}
    398 	}
    399 
    400 	form->cur_field = cur->index;
    401 	return E_OK;
    402 }
    403 
    404 /*
    405  * Set the field to the next active and visible field, the fields are
    406  * traversed in index order in the direction given.  If the parameter
    407  * use_sorted is TRUE then the sorted field list will be traversed instead
    408  * of using the field index.
    409  */
    410 int
    411 _formi_pos_new_field(FORM *form, unsigned direction, unsigned use_sorted)
    412 {
    413 	FIELD *cur;
    414 	int i;
    415 
    416 	i = form->cur_field;
    417 	cur = form->fields[i];
    418 
    419 	do {
    420 		if (direction == _FORMI_FORWARD) {
    421 			if (use_sorted == TRUE) {
    422 				if ((form->wrap == FALSE) &&
    423 				    (cur == TAILQ_LAST(&form->sorted_fields,
    424 					_formi_sort_head)))
    425 					return E_REQUEST_DENIED;
    426 				cur = TAILQ_NEXT(cur, glue);
    427 				i = cur->index;
    428 			} else {
    429 				if ((form->wrap == FALSE) &&
    430 				    ((i + 1) >= form->field_count))
    431 					return E_REQUEST_DENIED;
    432 				i++;
    433 				if (i >= form->field_count)
    434 					i = 0;
    435 			}
    436 		} else {
    437 			if (use_sorted == TRUE) {
    438 				if ((form->wrap == FALSE) &&
    439 				    (cur == TAILQ_FIRST(&form->sorted_fields)))
    440 					return E_REQUEST_DENIED;
    441 				cur = TAILQ_PREV(cur, _formi_sort_head, glue);
    442 				i = cur->index;
    443 			} else {
    444 				if ((form->wrap == FALSE) && (i <= 0))
    445 					return E_REQUEST_DENIED;
    446 				i--;
    447 				if (i < 0)
    448 					i = form->field_count - 1;
    449 			}
    450 		}
    451 
    452 		if ((form->fields[i]->opts & (O_VISIBLE | O_ACTIVE))
    453 			== (O_VISIBLE | O_ACTIVE)) {
    454 			form->cur_field = i;
    455 			return E_OK;
    456 		}
    457 	}
    458 	while (i != form->cur_field);
    459 
    460 	return E_REQUEST_DENIED;
    461 }
    462 
    463 /*
    464  * Destroy the list of line structs passed by freeing all allocated
    465  * memory.
    466  */
    467 static void
    468 destroy_row_list(_FORMI_FIELD_LINES *start)
    469 {
    470 	_FORMI_FIELD_LINES *temp, *row;
    471 	_formi_tab_t *tt, *tp;
    472 
    473 	row = start;
    474 	while (row != NULL) {
    475 		if (row->tabs != NULL) {
    476 			  /* free up the tab linked list... */
    477 			tp = row->tabs;
    478 			while (tp != NULL) {
    479 				tt = tp->fwd;
    480 				free(tp);
    481 				tp = tt;
    482 			}
    483 		}
    484 
    485 		if (row->string != NULL)
    486 			free(row->string);
    487 
    488 		temp = row->next;
    489 		free(row);
    490 		row = temp;
    491 	}
    492 }
    493 
    494 /*
    495  * Word wrap the contents of the field's buffer 0 if this is allowed.
    496  * If the wrap is successful, that is, the row count nor the buffer
    497  * size is exceeded then the function will return E_OK, otherwise it
    498  * will return E_REQUEST_DENIED.
    499  */
    500 int
    501 _formi_wrap_field(FIELD *field, _FORMI_FIELD_LINES *loc)
    502 {
    503 	int width, wrap_err;
    504 	unsigned int pos, saved_xpos, saved_ypos, saved_cur_xpos;
    505 	unsigned int saved_row_count;
    506 	_FORMI_FIELD_LINES *saved_row, *row, *row_backup, *saved_cur_line;
    507 	_FORMI_FIELD_LINES *saved_start_line, *temp;
    508 
    509 	if ((field->opts & O_STATIC) == O_STATIC) {
    510 		if ((field->rows + field->nrows) == 1) {
    511 			return E_OK; /* cannot wrap a single line */
    512 		}
    513 		width = field->cols;
    514 	} else {
    515 		  /* if we are limited to one line then don't try to wrap */
    516 		if ((field->drows + field->nrows) == 1) {
    517 			return E_OK;
    518 		}
    519 
    520 		  /*
    521 		   * hueristic - if a dynamic field has more than one line
    522 		   * on the screen then the field grows rows, otherwise
    523 		   * it grows columns, effectively a single line field.
    524 		   * This is documented AT&T behaviour.
    525 		   */
    526 		if (field->rows > 1) {
    527 			width = field->cols;
    528 		} else {
    529 			return E_OK;
    530 		}
    531 	}
    532 
    533 	row = loc;
    534 
    535 	  /* if we are not at the top of the field then back up one
    536 	   * row because we may be able to merge the current row into
    537 	   * the one above.
    538 	   */
    539 	if (row->prev != NULL)
    540 		row = row->prev;
    541 
    542 	saved_row = row;
    543 	saved_xpos = field->row_xpos;
    544 	saved_cur_xpos = field->cursor_xpos;
    545 	saved_ypos = field->cursor_ypos;
    546 	saved_row_count = field->row_count;
    547 
    548 	  /*
    549 	   * Save a copy of the lines affected, just in case things
    550 	   * don't work out.
    551 	   */
    552 	if ((row_backup = copy_row(row)) == NULL)
    553 		return E_SYSTEM_ERROR;
    554 
    555 	temp = row_backup;
    556 	row = row->next;
    557 
    558 	saved_cur_line = temp;
    559 	saved_start_line = temp;
    560 
    561 	while (row != NULL) {
    562 		if ((temp->next = copy_row(row)) == NULL) {
    563 			  /* a row copy failed... free up allocations */
    564 			destroy_row_list(row_backup);
    565 			return E_SYSTEM_ERROR;
    566 		}
    567 
    568 		temp->next->prev = temp;
    569 		temp = temp->next;
    570 
    571 		if (row == field->start_line)
    572 			saved_start_line = temp;
    573 		if (row == field->cur_line)
    574 			saved_cur_line = temp;
    575 
    576 		row = row->next;
    577 	}
    578 
    579 	row = saved_row;
    580 	while (row != NULL) {
    581 		pos = row->length - 1;
    582 		if (row->expanded < width) {
    583 			  /* line may be too short, try joining some lines */
    584 			if ((row->hard_ret == TRUE) && (row->next != NULL)) {
    585 				/*
    586 				 * Skip the line if it has a hard return
    587 				 * and it is not the last, we cannot join
    588 				 * anything to it.
    589 				 */
    590 				row = row->next;
    591 				continue;
    592 			}
    593 
    594 			if (row->next == NULL) {
    595 				/*
    596 				 * If there are no more lines and this line
    597 				 * is too short then our job is over.
    598 				 */
    599 				break;
    600 			}
    601 
    602 			if (_formi_join_line(field, &row,
    603 					     JOIN_NEXT_NW) == E_OK) {
    604 				continue;
    605 			} else
    606 				break;
    607 		} else if (row->expanded > width) {
    608 			  /* line is too long, split it */
    609 
    610 			  /*
    611 			   * split on first whitespace before current word
    612 			   * if the line has tabs we need to work out where
    613 			   * the field border lies when the tabs are expanded.
    614 			   */
    615 			if (row->tabs == NULL) {
    616 				pos = width - 1;
    617 				if (pos >= row->expanded)
    618 					pos = row->expanded - 1;
    619 			} else {
    620 				pos = tab_fit_len(row, field->cols);
    621 			}
    622 
    623 			if ((!isblank((unsigned char)row->string[pos])) &&
    624 			    ((field->opts & O_WRAP) == O_WRAP)) {
    625 				if (!isblank((unsigned char)row->string[pos - 1]))
    626 					pos = find_sow((unsigned int) pos,
    627 						       &row);
    628 				/*
    629 				 * If we cannot split the line then return
    630 				 * NO_ROOM so the driver can tell that it
    631 				 * should not autoskip (if that is enabled)
    632 				 */
    633 				if ((pos == 0)
    634 				    || (!isblank((unsigned char)row->string[pos - 1]))) {
    635 					wrap_err = E_NO_ROOM;
    636 					goto restore_and_exit;
    637 				}
    638 			}
    639 
    640 			  /* if we are at the end of the string and it has
    641 			   * a trailing blank, don't wrap the blank.
    642 			   */
    643 			if ((row->next == NULL) && (pos == row->length - 1) &&
    644 			    (isblank((unsigned char)row->string[pos])) &&
    645 			    row->expanded <= field->cols)
    646 				continue;
    647 
    648 			  /*
    649 			   * otherwise, if we are still sitting on a
    650 			   * blank but not at the end of the line
    651 			   * move forward one char so the blank
    652 			   * is on the line boundary.
    653 			   */
    654 			if ((isblank((unsigned char)row->string[pos])) &&
    655 			    (pos != row->length - 1))
    656 				pos++;
    657 
    658 			if (split_line(field, FALSE, pos, &row) != E_OK) {
    659 				wrap_err = E_REQUEST_DENIED;
    660 				goto restore_and_exit;
    661 			}
    662 		} else
    663 			  /* line is exactly the right length, do next one */
    664 			row = row->next;
    665 	}
    666 
    667 	  /* Check if we have not run out of room */
    668 	if ((((field->opts & O_STATIC) == O_STATIC) &&
    669 	     field->row_count > (field->rows + field->nrows)) ||
    670 	    ((field->max != 0) && (field->row_count > field->max))) {
    671 
    672 		wrap_err = E_REQUEST_DENIED;
    673 
    674 	  restore_and_exit:
    675 		if (saved_row->prev == NULL) {
    676 			field->alines = row_backup;
    677 		} else {
    678 			saved_row->prev->next = row_backup;
    679 			row_backup->prev = saved_row->prev;
    680 		}
    681 
    682 		field->row_xpos = saved_xpos;
    683 		field->cursor_xpos = saved_cur_xpos;
    684 		field->cursor_ypos = saved_ypos;
    685 		field->row_count = saved_row_count;
    686 		field->start_line = saved_start_line;
    687 		field->cur_line = saved_cur_line;
    688 
    689 		destroy_row_list(saved_row);
    690 		return wrap_err;
    691 	}
    692 
    693 	destroy_row_list(row_backup);
    694 	return E_OK;
    695 }
    696 
    697 /*
    698  * Join the two lines that surround the location pos, the type
    699  * variable indicates the direction of the join, JOIN_NEXT will join
    700  * the next line to the current line, JOIN_PREV will join the current
    701  * line to the previous line, the new lines will be wrapped unless the
    702  * _NW versions of the directions are used.  Returns E_OK if the join
    703  * was successful or E_REQUEST_DENIED if the join cannot happen.
    704  */
    705 static int
    706 _formi_join_line(FIELD *field, _FORMI_FIELD_LINES **rowp, int direction)
    707 {
    708 	int old_len, count;
    709 	struct _formi_field_lines *saved;
    710 	char *newp;
    711 	_FORMI_FIELD_LINES *row = *rowp;
    712 
    713 	_formi_dbg_printf("%s: working on row %p, row_count = %d\n",
    714 	    __func__, row, field->row_count);
    715 
    716 	if ((direction == JOIN_NEXT) || (direction == JOIN_NEXT_NW)) {
    717 		  /*
    718 		   * See if there is another line following, or if the
    719 		   * line contains a hard return then we don't join
    720 		   * any lines to it.
    721 		   */
    722 		if ((row->next == NULL) || (row->hard_ret == TRUE)) {
    723 			return E_REQUEST_DENIED;
    724 		}
    725 
    726 		_formi_dbg_printf(
    727 		    "%s: join_next before length = %d, expanded = %d",
    728 		    __func__, row->length, row->expanded);
    729 		_formi_dbg_printf(
    730 		    " :: next row length = %d, expanded = %d\n",
    731 		    row->length, row->expanded);
    732 
    733 		if (row->allocated < (row->length + row->next->length + 1)) {
    734 			if ((newp = realloc(row->string, (size_t)(row->length +
    735 							  row->next->length
    736 							  + 1))) == NULL)
    737 				return E_REQUEST_DENIED;
    738 			row->string = newp;
    739 			row->allocated = row->length + row->next->length + 1;
    740 		}
    741 
    742 		strcat(row->string, row->next->string);
    743 		old_len = row->length;
    744 		row->length += row->next->length;
    745 		if (row->length > 0)
    746 			row->expanded =
    747 				_formi_tab_expanded_length(row->string, 0,
    748 							   row->length - 1);
    749 		else
    750 			row->expanded = 0;
    751 
    752 		_formi_calculate_tabs(row);
    753 		row->hard_ret = row->next->hard_ret;
    754 
    755 		  /* adjust current line if it is on the row being eaten */
    756 		if (field->cur_line == row->next) {
    757 			field->cur_line = row;
    758 			field->row_xpos += old_len;
    759 			field->cursor_xpos =
    760 				_formi_tab_expanded_length(row->string, 0,
    761 							   field->row_xpos);
    762 			if (field->cursor_xpos > 0)
    763 				field->cursor_xpos--;
    764 
    765 			if (field->cursor_ypos > 0)
    766 				field->cursor_ypos--;
    767 			else {
    768 				if (field->start_line->prev != NULL)
    769 					field->start_line =
    770 						field->start_line->prev;
    771 			}
    772 		}
    773 
    774 		  /* remove joined line record from the row list */
    775 		add_to_free(field, row->next);
    776 
    777 		_formi_dbg_printf(
    778 		    "%s: exit length = %d, expanded = %d\n",
    779 		    __func__, row->length, row->expanded);
    780 	} else {
    781 		if (row->prev == NULL) {
    782 			return E_REQUEST_DENIED;
    783 		}
    784 
    785 		saved = row->prev;
    786 
    787 		  /*
    788 		   * Don't try to join if the line above has a hard
    789 		   * return on it.
    790 		   */
    791 		if (saved->hard_ret == TRUE) {
    792 			return E_REQUEST_DENIED;
    793 		}
    794 
    795 		_formi_dbg_printf(
    796 		    "%s: join_prev before length = %d, expanded = %d",
    797 		    __func__, row->length, row->expanded);
    798 		_formi_dbg_printf(
    799 		    " :: prev row length = %d, expanded = %d\n",
    800 		    saved->length, saved->expanded);
    801 
    802 		if (saved->allocated < (row->length + saved->length + 1)) {
    803 			if ((newp = realloc(saved->string,
    804 					    (size_t) (row->length +
    805 						      saved->length
    806 						      + 1))) == NULL)
    807 				return E_REQUEST_DENIED;
    808 			saved->string = newp;
    809 			saved->allocated = row->length + saved->length + 1;
    810 		}
    811 
    812 		strcat(saved->string, row->string);
    813 		old_len = saved->length;
    814 		saved->length += row->length;
    815 		if (saved->length > 0)
    816 			saved->expanded =
    817 				_formi_tab_expanded_length(saved->string, 0,
    818 							   saved->length - 1);
    819 		else
    820 			saved->length = 0;
    821 
    822 		saved->hard_ret = row->hard_ret;
    823 
    824 		  /* adjust current line if it was on the row being eaten */
    825 		if (field->cur_line == row) {
    826 			field->cur_line = saved;
    827 			field->row_xpos += old_len;
    828 			field->cursor_xpos =
    829 				_formi_tab_expanded_length(saved->string, 0,
    830 							   field->row_xpos);
    831 			if (field->cursor_xpos > 0)
    832 				field->cursor_xpos--;
    833 		}
    834 
    835 		add_to_free(field, row);
    836 
    837 		_formi_dbg_printf(
    838 		    "%s: exit length = %d, expanded = %d\n", __func__,
    839 		    saved->length, saved->expanded);
    840 		row = saved;
    841 	}
    842 
    843 
    844 	  /*
    845 	   * Work out where the line lies in the field in relation to
    846 	   * the cursor_ypos.  First count the rows from the start of
    847 	   * the field until we hit the row we just worked on.
    848 	   */
    849 	saved = field->start_line;
    850 	count = 0;
    851 	while (saved->next != NULL) {
    852 		if (saved == row)
    853 			break;
    854 		count++;
    855 		saved = saved->next;
    856 	}
    857 
    858 	  /* now check if we need to adjust cursor_ypos */
    859 	if (field->cursor_ypos > count) {
    860 		field->cursor_ypos--;
    861 	}
    862 
    863 	field->row_count--;
    864 	*rowp = row;
    865 
    866 	  /* wrap the field if required, if this fails undo the change */
    867 	if ((direction == JOIN_NEXT) || (direction == JOIN_PREV)) {
    868 		if (_formi_wrap_field(field, row) != E_OK) {
    869 			return E_REQUEST_DENIED;
    870 		}
    871 	}
    872 
    873 	return E_OK;
    874 }
    875 
    876 /*
    877  * Split the line at the given position, if possible.  If hard_split is
    878  * TRUE then split the line regardless of the position, otherwise don't
    879  * split at the beginning of a line.
    880  */
    881 static int
    882 split_line(FIELD *field, bool hard_split, unsigned pos,
    883 	   _FORMI_FIELD_LINES **rowp)
    884 {
    885 	struct _formi_field_lines *new_line;
    886 	char *newp;
    887 	_FORMI_FIELD_LINES *row = *rowp;
    888 
    889 	  /* if asked to split right where the line already starts then
    890 	   * just return - nothing to do unless we are appending a line
    891 	   * to the buffer.
    892 	   */
    893 	if ((pos == 0) && (hard_split == FALSE))
    894 		return E_OK;
    895 
    896 	_formi_dbg_printf("%s: splitting line at %d\n", __func__, pos);
    897 
    898 	  /* Need an extra line struct, check free list first */
    899 	if (field->free != NULL) {
    900 		new_line = field->free;
    901 		field->free = new_line->next;
    902 		if (field->free != NULL)
    903 			field->free->prev = NULL;
    904 	} else {
    905 		if ((new_line = malloc(sizeof(*new_line))) == NULL)
    906 			return E_SYSTEM_ERROR;
    907 		new_line->prev = NULL;
    908 		new_line->next = NULL;
    909 		new_line->allocated = 0;
    910 		new_line->length = 0;
    911 		new_line->expanded = 0;
    912 		new_line->string = NULL;
    913 		new_line->hard_ret = FALSE;
    914 		new_line->tabs = NULL;
    915 	}
    916 
    917 	_formi_dbg_printf("%s: enter: length = %d, expanded = %d\n", __func__,
    918 	    row->length, row->expanded);
    919 
    920 	assert((row->length < INT_MAX) && (row->expanded < INT_MAX));
    921 
    922 
    923 	  /* add new line to the row list */
    924 	new_line->next = row->next;
    925 	new_line->prev = row;
    926 	row->next = new_line;
    927 	if (new_line->next != NULL)
    928 		new_line->next->prev = new_line;
    929 
    930 	new_line->length = row->length - pos;
    931 	if (new_line->length >= new_line->allocated) {
    932 		if ((newp = realloc(new_line->string,
    933 				    (size_t) new_line->length + 1)) == NULL)
    934 			return E_SYSTEM_ERROR;
    935 		new_line->string = newp;
    936 		new_line->allocated = new_line->length + 1;
    937 	}
    938 
    939 	strcpy(new_line->string, &row->string[pos]);
    940 
    941 	row->length = pos;
    942 	row->string[pos] = '\0';
    943 
    944 	if (row->length != 0)
    945 		row->expanded = _formi_tab_expanded_length(row->string, 0,
    946 							   row->length - 1);
    947 	else
    948 		row->expanded = 0;
    949 	_formi_calculate_tabs(row);
    950 
    951 	if (new_line->length != 0)
    952 		new_line->expanded =
    953 			_formi_tab_expanded_length(new_line->string, 0,
    954 						   new_line->length - 1);
    955 	else
    956 		new_line->expanded = 0;
    957 
    958 	_formi_calculate_tabs(new_line);
    959 
    960 	  /*
    961 	   * If the given row was the current line then adjust the
    962 	   * current line pointer if necessary
    963 	   */
    964 	if ((field->cur_line == row) && (field->row_xpos >= pos)) {
    965 		field->cur_line = new_line;
    966 		field->row_xpos -= pos;
    967 		field->cursor_xpos =
    968 			_formi_tab_expanded_length(new_line->string, 0,
    969 						   field->row_xpos);
    970 		if (field->cursor_xpos > 0)
    971 			field->cursor_xpos--;
    972 
    973 		field->cursor_ypos++;
    974 		if (field->cursor_ypos >= field->rows) {
    975 			if (field->start_line->next != NULL) {
    976 				field->start_line = field->start_line->next;
    977 				field->cursor_ypos = field->rows - 1;
    978 			}
    979 			else
    980 				assert(field->start_line->next == NULL);
    981 		}
    982 	}
    983 
    984 	  /*
    985 	   * If the line split had a hard return then replace the
    986 	   * current line's hard return with a soft return and carry
    987 	   * the hard return onto the line after.
    988 	   */
    989 	if (row->hard_ret == TRUE) {
    990 		new_line->hard_ret = TRUE;
    991 		row->hard_ret = FALSE;
    992 	}
    993 
    994 	  /*
    995 	   * except where we are doing a hard split then the current
    996 	   * row must have a hard return on it too...
    997 	   */
    998 	if (hard_split == TRUE) {
    999 		row->hard_ret = TRUE;
   1000 	}
   1001 
   1002 	assert(((row->expanded < INT_MAX) &&
   1003 		(new_line->expanded < INT_MAX) &&
   1004 		(row->length < INT_MAX) &&
   1005 		(new_line->length < INT_MAX)));
   1006 
   1007 	_formi_dbg_printf("%s: exit: ", __func__);
   1008 	_formi_dbg_printf("row.length = %d, row.expanded = %d, ",
   1009 	    row->length, row->expanded);
   1010 	_formi_dbg_printf("next_line.length = %d, next_line.expanded = %d, ",
   1011 	    new_line->length, new_line->expanded);
   1012 	_formi_dbg_printf("row_count = %d\n", field->row_count + 1);
   1013 
   1014 	field->row_count++;
   1015 	*rowp = new_line;
   1016 
   1017 	return E_OK;
   1018 }
   1019 
   1020 /*
   1021  * skip the blanks in the given string, start at the index start and
   1022  * continue forward until either the end of the string or a non-blank
   1023  * character is found.  Return the index of either the end of the string or
   1024  * the first non-blank character.
   1025  */
   1026 unsigned
   1027 _formi_skip_blanks(char *string, unsigned int start)
   1028 {
   1029 	unsigned int i;
   1030 
   1031 	i = start;
   1032 
   1033 	while ((string[i] != '\0') && isblank((unsigned char)string[i]))
   1034 		i++;
   1035 
   1036 	return i;
   1037 }
   1038 
   1039 /*
   1040  * Skip the blanks in the string associated with the given row, pass back
   1041  * the row and the offset at which the first non-blank is found.  If no
   1042  * non-blank character is found then return the index to the last
   1043  * character on the last line.
   1044  */
   1045 
   1046 unsigned
   1047 field_skip_blanks(unsigned int start, _FORMI_FIELD_LINES **rowp)
   1048 {
   1049 	unsigned int i;
   1050 	_FORMI_FIELD_LINES *row, *last = NULL;
   1051 
   1052 	row = *rowp;
   1053 	i = start;
   1054 
   1055 	do {
   1056 		i = _formi_skip_blanks(&row->string[i], i);
   1057 		if (!isblank((unsigned char)row->string[i])) {
   1058 			last = row;
   1059 			row = row->next;
   1060 			  /*
   1061 			   * don't reset if last line otherwise we will
   1062 			   * not be at the end of the string.
   1063 			   */
   1064 			if (row != NULL)
   1065 				i = 0;
   1066 		} else
   1067 			break;
   1068 	}
   1069 	while (row != NULL);
   1070 
   1071 	  /*
   1072 	   * If we hit the end of the row list then point at the last row
   1073 	   * otherwise we return the row we found the blank on.
   1074 	   */
   1075 	if (row == NULL)
   1076 		*rowp = last;
   1077 	else
   1078 		*rowp = row;
   1079 
   1080 	return i;
   1081 }
   1082 
   1083 /*
   1084  * Return the index of the top left most field of the two given fields.
   1085  */
   1086 static int
   1087 _formi_top_left(FORM *form, int a, int b)
   1088 {
   1089 	  /* lower row numbers always win here.... */
   1090 	if (form->fields[a]->form_row < form->fields[b]->form_row)
   1091 		return a;
   1092 
   1093 	if (form->fields[a]->form_row > form->fields[b]->form_row)
   1094 		return b;
   1095 
   1096 	  /* rows must be equal, check columns */
   1097 	if (form->fields[a]->form_col < form->fields[b]->form_col)
   1098 		return a;
   1099 
   1100 	if (form->fields[a]->form_col > form->fields[b]->form_col)
   1101 		return b;
   1102 
   1103 	  /* if we get here fields must be in exactly the same place, punt */
   1104 	return a;
   1105 }
   1106 
   1107 /*
   1108  * Return the index to the field that is the bottom-right-most of the
   1109  * two given fields.
   1110  */
   1111 static int
   1112 _formi_bottom_right(FORM *form, int a, int b)
   1113 {
   1114 	  /* check the rows first, biggest row wins */
   1115 	if (form->fields[a]->form_row > form->fields[b]->form_row)
   1116 		return a;
   1117 	if (form->fields[a]->form_row < form->fields[b]->form_row)
   1118 		return b;
   1119 
   1120 	  /* rows must be equal, check cols, biggest wins */
   1121 	if (form->fields[a]->form_col > form->fields[b]->form_col)
   1122 		return a;
   1123 	if (form->fields[a]->form_col < form->fields[b]->form_col)
   1124 		return b;
   1125 
   1126 	  /* fields in the same place, punt */
   1127 	return a;
   1128 }
   1129 
   1130 /*
   1131  * Find the end of the current word in the string str, starting at
   1132  * offset - the end includes any trailing whitespace.  If the end of
   1133  * the string is found before a new word then just return the offset
   1134  * to the end of the string.  If do_join is TRUE then lines will be
   1135  * joined (without wrapping) until either the end of the field or the
   1136  * end of a word is found (whichever comes first).
   1137  */
   1138 static int
   1139 find_eow(FIELD *cur, unsigned int offset, bool do_join,
   1140 	 _FORMI_FIELD_LINES **rowp)
   1141 {
   1142 	int start;
   1143 	_FORMI_FIELD_LINES *row;
   1144 
   1145 	row = *rowp;
   1146 	start = offset;
   1147 
   1148 	do {
   1149 		  /* first skip any non-whitespace */
   1150 		while ((row->string[start] != '\0')
   1151 		       && !isblank((unsigned char)row->string[start]))
   1152 			start++;
   1153 
   1154 		  /* see if we hit the end of the string */
   1155 		if (row->string[start] == '\0') {
   1156 			if (do_join == TRUE) {
   1157 				if (row->next == NULL)
   1158 					return start;
   1159 
   1160 				if (_formi_join_line(cur, &row, JOIN_NEXT_NW)
   1161 				    != E_OK)
   1162 					return E_REQUEST_DENIED;
   1163 			} else {
   1164 				do {
   1165 					if (row->next == NULL) {
   1166 						*rowp = row;
   1167 						return start;
   1168 					} else {
   1169 						row = row->next;
   1170 						start = 0;
   1171 					}
   1172 				} while (row->length == 0);
   1173 			}
   1174 		}
   1175 	} while (!isblank((unsigned char)row->string[start]));
   1176 
   1177 	do {
   1178 		  /* otherwise skip the whitespace.... */
   1179 		while ((row->string[start] != '\0')
   1180 		       && isblank((unsigned char)row->string[start]))
   1181 			start++;
   1182 
   1183 		if (row->string[start] == '\0') {
   1184 			if (do_join == TRUE) {
   1185 				if (row->next == NULL)
   1186 					return start;
   1187 
   1188 				if (_formi_join_line(cur, &row, JOIN_NEXT_NW)
   1189 				    != E_OK)
   1190 					return E_REQUEST_DENIED;
   1191 			} else {
   1192 				do {
   1193 					if (row->next == NULL) {
   1194 						*rowp = row;
   1195 						return start;
   1196 					} else {
   1197 						row = row->next;
   1198 						start = 0;
   1199 					}
   1200 				} while (row->length == 0);
   1201 			}
   1202 		}
   1203 	} while (isblank((unsigned char)row->string[start]));
   1204 
   1205 	*rowp = row;
   1206 	return start;
   1207 }
   1208 
   1209 /*
   1210  * Find the beginning of the current word in the string str, starting
   1211  * at offset.
   1212  */
   1213 static int
   1214 find_sow(unsigned int offset, _FORMI_FIELD_LINES **rowp)
   1215 {
   1216 	int start;
   1217 	char *str;
   1218 	_FORMI_FIELD_LINES *row;
   1219 
   1220 	row = *rowp;
   1221 	str = row->string;
   1222 	start = offset;
   1223 
   1224 	do {
   1225 		if (start > 0) {
   1226 			if (isblank((unsigned char)str[start]) ||
   1227 			    isblank((unsigned char)str[start - 1])) {
   1228 				if (isblank((unsigned char)str[start - 1]))
   1229 					start--;
   1230 				  /* skip the whitespace.... */
   1231 				while ((start >= 0) &&
   1232 				    isblank((unsigned char)str[start]))
   1233 					start--;
   1234 			}
   1235 		}
   1236 
   1237 		  /* see if we hit the start of the string */
   1238 		if (start < 0) {
   1239 			do {
   1240 				if (row->prev == NULL) {
   1241 					*rowp = row;
   1242 					start = 0;
   1243 					return start;
   1244 				} else {
   1245 					row = row->prev;
   1246 					str = row->string;
   1247 					if (row->length > 0)
   1248 						start = row->length - 1;
   1249 					else
   1250 						start = 0;
   1251 				}
   1252 			} while (row->length == 0);
   1253 		}
   1254 	} while (isblank((unsigned char)row->string[start]));
   1255 
   1256 	  /* see if we hit the start of the string */
   1257 	if (start < 0) {
   1258 		*rowp = row;
   1259 		return 0;
   1260 	}
   1261 
   1262 	  /* now skip any non-whitespace */
   1263 	do {
   1264 		while ((start >= 0) && !isblank((unsigned char)str[start]))
   1265 			start--;
   1266 
   1267 
   1268 		if (start < 0) {
   1269 			do {
   1270 				if (row->prev == NULL) {
   1271 					*rowp = row;
   1272 					start = 0;
   1273 					return start;
   1274 				} else {
   1275 					row = row->prev;
   1276 					str = row->string;
   1277 					if (row->length > 0)
   1278 						start = row->length - 1;
   1279 					else
   1280 						start = 0;
   1281 				}
   1282 			} while (row->length == 0);
   1283 		}
   1284 	} while (!isblank((unsigned char)str[start]));
   1285 
   1286 	if (start > 0) {
   1287 		start++; /* last loop has us pointing at a space, adjust */
   1288 		if (start >= row->length) {
   1289 			if (row->next != NULL) {
   1290 				start = 0;
   1291 				row = row->next;
   1292 			} else {
   1293 				start = row->length - 1;
   1294 			}
   1295 		}
   1296 	}
   1297 
   1298 	if (start < 0)
   1299 		start = 0;
   1300 
   1301 	*rowp = row;
   1302 	return start;
   1303 }
   1304 
   1305 /*
   1306  * Scroll the field forward the given number of lines.
   1307  */
   1308 static void
   1309 _formi_scroll_fwd(FIELD *field, unsigned int amt)
   1310 {
   1311 	unsigned int count;
   1312 	_FORMI_FIELD_LINES *end_row;
   1313 
   1314 	end_row = field->start_line;
   1315 	  /* walk the line structs forward to find the bottom of the field */
   1316 	count = field->rows - 1;
   1317 	while ((count > 0) && (end_row->next != NULL))
   1318 	{
   1319 		count--;
   1320 		end_row = end_row->next;
   1321 	}
   1322 
   1323 	  /* check if there are lines to scroll */
   1324 	if ((count > 0) && (end_row->next == NULL))
   1325 		return;
   1326 
   1327 	  /*
   1328 	   * ok, lines to scroll - do this by walking both the start_line
   1329 	   * and the end_row at the same time for amt lines, we stop when
   1330 	   * either we have done the number of lines or end_row hits the
   1331 	   * last line in the field.
   1332 	   */
   1333 	count = amt;
   1334 	while ((count > 0) && (end_row->next != NULL)) {
   1335 		count--;
   1336 		field->start_line = field->start_line->next;
   1337 		end_row = end_row->next;
   1338 	}
   1339 }
   1340 
   1341 /*
   1342  * Scroll the field backward the given number of lines.
   1343  */
   1344 static void
   1345 _formi_scroll_back(FIELD *field, unsigned int amt)
   1346 {
   1347 	unsigned int count;
   1348 
   1349 	  /* check for lines above */
   1350 	if (field->start_line->prev == NULL)
   1351 		return;
   1352 
   1353 	  /*
   1354 	   * Backward scroll is easy, follow row struct chain backward until
   1355 	   * the number of lines done or we reach the top of the field.
   1356 	   */
   1357 	count = amt;
   1358 	while ((count > 0) && (field->start_line->prev != NULL)) {
   1359 		count--;
   1360 		field->start_line = field->start_line->prev;
   1361 	}
   1362 }
   1363 
   1364 /*
   1365  * Scroll the field forward the given number of characters.
   1366  */
   1367 void
   1368 _formi_hscroll_fwd(FIELD *field, _FORMI_FIELD_LINES *row, int unsigned amt)
   1369 {
   1370 	unsigned int end, scroll_amt, expanded;
   1371 	_formi_tab_t *ts;
   1372 
   1373 
   1374 	if ((row->tabs == NULL) || (row->tabs->in_use == FALSE)) {
   1375 		  /* if the line has no tabs things are easy... */
   1376 		end =  field->start_char + field->cols + amt - 1;
   1377 		scroll_amt = amt;
   1378 		if (end > row->length) {
   1379 			end = row->length;
   1380 			scroll_amt = end - field->start_char - field->cols + 1;
   1381 		}
   1382 	} else {
   1383 		  /*
   1384 		   * If there are tabs we need to add on the scroll amount,
   1385 		   * find the last char position that will fit into
   1386 		   * the field and finally fix up the start_char.  This
   1387 		   * is a lot of work but handling the case where there
   1388 		   * are not enough chars to scroll by amt is difficult.
   1389 		   */
   1390 		end = field->start_char + field->row_xpos + amt;
   1391 		if (end >= row->length)
   1392 			end = row->length - 1;
   1393 		else {
   1394 			expanded = _formi_tab_expanded_length(
   1395 				row->string,
   1396 				field->start_char + amt,
   1397 				field->start_char + field->row_xpos + amt);
   1398 			ts = row->tabs;
   1399 			  /* skip tabs to the lhs of our starting point */
   1400 			while ((ts != NULL) && (ts->in_use == TRUE)
   1401 			       && (ts->pos < end))
   1402 				ts = ts->fwd;
   1403 
   1404 			while ((expanded <= field->cols)
   1405 			       && (end < row->length)) {
   1406 				if (row->string[end] == '\t') {
   1407 					assert((ts != NULL)
   1408 					       && (ts->in_use == TRUE));
   1409 					if (ts->pos == end) {
   1410 						if ((expanded + ts->size)
   1411 						    > field->cols)
   1412 							break;
   1413 						expanded += ts->size;
   1414 						ts = ts->fwd;
   1415 					}
   1416 					else
   1417 						assert(ts->pos == end);
   1418 				} else
   1419 					expanded++;
   1420 				end++;
   1421 			}
   1422 		}
   1423 
   1424 		scroll_amt = tab_fit_window(field, end, field->cols);
   1425 		if (scroll_amt < field->start_char)
   1426 			scroll_amt = 1;
   1427 		else
   1428 			scroll_amt -= field->start_char;
   1429 
   1430 		scroll_amt = min(scroll_amt, amt);
   1431 	}
   1432 
   1433 	field->start_char += scroll_amt;
   1434 	field->cursor_xpos =
   1435 		_formi_tab_expanded_length(row->string,
   1436 					   field->start_char,
   1437 					   field->row_xpos
   1438 					   + field->start_char) - 1;
   1439 
   1440 }
   1441 
   1442 /*
   1443  * Scroll the field backward the given number of characters.
   1444  */
   1445 void
   1446 _formi_hscroll_back(FIELD *field, _FORMI_FIELD_LINES *row, unsigned int amt)
   1447 {
   1448 	field->start_char -= min(field->start_char, amt);
   1449 	field->cursor_xpos =
   1450 		_formi_tab_expanded_length(row->string, field->start_char,
   1451 					   field->row_xpos
   1452 					   + field->start_char) - 1;
   1453 	if (field->cursor_xpos >= field->cols) {
   1454 		field->row_xpos = 0;
   1455 		field->cursor_xpos = 0;
   1456 	}
   1457 }
   1458 
   1459 /*
   1460  * Find the different pages in the form fields and assign the form
   1461  * page_starts array with the information to find them.
   1462  */
   1463 int
   1464 _formi_find_pages(FORM *form)
   1465 {
   1466 	int i, cur_page = 0;
   1467 
   1468 	if ((form->page_starts = calloc((form->max_page + 1),
   1469 	    sizeof(*form->page_starts))) == NULL)
   1470 		return E_SYSTEM_ERROR;
   1471 
   1472 	for (i = 0; i < form->field_count; i++) {
   1473 		if (form->fields[i]->page_break == 1)
   1474 			cur_page++;
   1475 		if (form->page_starts[cur_page].in_use == 0) {
   1476 			form->page_starts[cur_page].in_use = 1;
   1477 			form->page_starts[cur_page].first = i;
   1478 			form->page_starts[cur_page].last = i;
   1479 			form->page_starts[cur_page].top_left = i;
   1480 			form->page_starts[cur_page].bottom_right = i;
   1481 		} else {
   1482 			form->page_starts[cur_page].last = i;
   1483 			form->page_starts[cur_page].top_left =
   1484 				_formi_top_left(form,
   1485 						form->page_starts[cur_page].top_left,
   1486 						i);
   1487 			form->page_starts[cur_page].bottom_right =
   1488 				_formi_bottom_right(form,
   1489 						    form->page_starts[cur_page].bottom_right,
   1490 						    i);
   1491 		}
   1492 	}
   1493 
   1494 	return E_OK;
   1495 }
   1496 
   1497 /*
   1498  * Completely redraw the field of the given form.
   1499  */
   1500 void
   1501 _formi_redraw_field(FORM *form, int field)
   1502 {
   1503 	unsigned int pre, post, flen, slen, i, j, start, line;
   1504 	unsigned int tab, cpos, len;
   1505 	char *str, c;
   1506 	FIELD *cur;
   1507 	_FORMI_FIELD_LINES *row;
   1508 #ifdef DEBUG
   1509 	char buffer[100];
   1510 #endif
   1511 
   1512 	cur = form->fields[field];
   1513 	flen = cur->cols;
   1514 	slen = 0;
   1515 	start = 0;
   1516 	line = 0;
   1517 
   1518 	for (row = cur->start_line; ((row != NULL) && (line < cur->rows));
   1519 	     row = row->next, line++) {
   1520 		wmove(form->scrwin, (int) (cur->form_row + line),
   1521 		      (int) cur->form_col);
   1522 		if ((cur->rows + cur->nrows) == 1) {
   1523 			if ((cur->cols + cur->start_char) >= row->length)
   1524 				len = row->length;
   1525 			else
   1526 				len = cur->cols + cur->start_char;
   1527 			if (row->string != NULL)
   1528 				slen = _formi_tab_expanded_length(
   1529 					row->string, cur->start_char, len);
   1530 			else
   1531 				slen = 0;
   1532 
   1533 			if (slen > cur->cols)
   1534 				slen = cur->cols;
   1535 			slen += cur->start_char;
   1536 		} else
   1537 			slen = row->expanded;
   1538 
   1539 		if ((cur->opts & O_STATIC) == O_STATIC) {
   1540 			switch (cur->justification) {
   1541 			case JUSTIFY_RIGHT:
   1542 				post = 0;
   1543 				if (flen < slen)
   1544 					pre = 0;
   1545 				else
   1546 					pre = flen - slen;
   1547 				break;
   1548 
   1549 			case JUSTIFY_CENTER:
   1550 				if (flen < slen) {
   1551 					pre = 0;
   1552 					post = 0;
   1553 				} else {
   1554 					pre = flen - slen;
   1555 					post = pre = pre / 2;
   1556 					  /* get padding right if
   1557 					     centring is not even */
   1558 					if ((post + pre + slen) < flen)
   1559 						post++;
   1560 				}
   1561 				break;
   1562 
   1563 			case NO_JUSTIFICATION:
   1564 			case JUSTIFY_LEFT:
   1565 			default:
   1566 				pre = 0;
   1567 				if (flen <= slen)
   1568 					post = 0;
   1569 				else {
   1570 					post = flen - slen;
   1571 					if (post > flen)
   1572 						post = flen;
   1573 				}
   1574 				break;
   1575 			}
   1576 		} else {
   1577 			  /* dynamic fields are not justified */
   1578 			pre = 0;
   1579 			if (flen <= slen)
   1580 				post = 0;
   1581 			else {
   1582 				post = flen - slen;
   1583 				if (post > flen)
   1584 					post = flen;
   1585 			}
   1586 
   1587 			  /* but they do scroll.... */
   1588 
   1589 			if (pre > cur->start_char - start)
   1590 				pre = pre - cur->start_char + start;
   1591 			else
   1592 				pre = 0;
   1593 
   1594 			if (slen > cur->start_char) {
   1595 				slen -= cur->start_char;
   1596 				if (slen > flen)
   1597 					post = 0;
   1598 				else
   1599 					post = flen - slen;
   1600 
   1601 				if (post > flen)
   1602 					post = flen;
   1603 			} else {
   1604 				slen = 0;
   1605 				post = flen - pre;
   1606 			}
   1607 		}
   1608 
   1609 		str = &row->string[cur->start_char];
   1610 
   1611 #ifdef DEBUG
   1612 		_formi_dbg_printf(
   1613 		    "%s: start=%d, pre=%d, slen=%d, flen=%d, post=%d, "
   1614 		    "start_char=%d\n", __func__,
   1615 		    start, pre, slen, flen, post, cur->start_char);
   1616 		if (str != NULL) {
   1617 			if (row->expanded != 0) {
   1618 				strncpy(buffer, str, flen);
   1619 			} else {
   1620 				strcpy(buffer, "(empty)");
   1621 			}
   1622 		} else {
   1623 			strcpy(buffer, "(null)");
   1624 		}
   1625 		buffer[flen] = '\0';
   1626 		_formi_dbg_printf("%s: %s\n", __func__,  buffer);
   1627 #endif
   1628 
   1629 		wattrset(form->scrwin, cur->back);
   1630 
   1631 		for (i = start + cur->start_char; i < pre; i++)
   1632 			waddch(form->scrwin, cur->pad);
   1633 
   1634 		_formi_dbg_printf("%s: will add %d chars\n", __func__,
   1635 			min(slen, flen));
   1636 		wattrset(form->scrwin, cur->fore);
   1637 		for (i = 0, cpos = cur->start_char; i < min(slen, flen);
   1638 		     i++, str++, cpos++)
   1639 		{
   1640 			c = *str;
   1641 			tab = 0; /* just to shut gcc up */
   1642 			_formi_dbg_printf("adding char str[%d]=%c\n",
   1643 			    cpos + cur->start_char,	c);
   1644 			if (((cur->opts & O_PUBLIC) != O_PUBLIC)) {
   1645 				if (c == '\t')
   1646 					tab = add_tab(form, row, cpos,
   1647 						      cur->pad);
   1648 				else {
   1649 					wattrset(form->scrwin, cur->back);
   1650 					waddch(form->scrwin, cur->pad);
   1651 					wattrset(form->scrwin, cur->fore);
   1652 				}
   1653 			} else if ((cur->opts & O_VISIBLE) == O_VISIBLE) {
   1654 				if (c == '\t')
   1655 					tab = add_tab(form, row, cpos, ' ');
   1656 				else
   1657 					waddch(form->scrwin, c);
   1658 			} else {
   1659 				if (c == '\t')
   1660 					tab = add_tab(form, row, cpos, ' ');
   1661 				else
   1662 					waddch(form->scrwin, ' ');
   1663 			}
   1664 
   1665 			  /*
   1666 			   * If we have had a tab then skip forward
   1667 			   * the requisite number of chars to keep
   1668 			   * things in sync.
   1669 			   */
   1670 			if (c == '\t')
   1671 				i += tab - 1;
   1672 		}
   1673 
   1674 		wattrset(form->scrwin, cur->back);
   1675 		for (i = 0; i < post; i++)
   1676 			waddch(form->scrwin, cur->pad);
   1677 	}
   1678 
   1679 	for (i = line; i < cur->rows; i++) {
   1680 		wmove(form->scrwin, (int) (cur->form_row + i),
   1681 		      (int) cur->form_col);
   1682 
   1683 		wattrset(form->scrwin, cur->back);
   1684 
   1685 		for (j = 0; j < cur->cols; j++) {
   1686 			waddch(form->scrwin, cur->pad);
   1687 		}
   1688 	}
   1689 
   1690 	wattrset(form->scrwin, cur->back);
   1691 
   1692 	cur = form->fields[form->cur_field];
   1693 	wmove(form->scrwin, cur->form_row + cur->cursor_ypos,
   1694 	    cur->form_col + cur->cursor_xpos);
   1695 	wcursyncup(form->scrwin);
   1696 
   1697 	return;
   1698 }
   1699 
   1700 /*
   1701  * Add the correct number of the given character to simulate a tab
   1702  * in the field.
   1703  */
   1704 static int
   1705 add_tab(FORM *form, _FORMI_FIELD_LINES *row, unsigned int i, char c)
   1706 {
   1707 	int j;
   1708 	_formi_tab_t *ts = row->tabs;
   1709 
   1710 	while ((ts != NULL) && (ts->pos != i))
   1711 		ts = ts->fwd;
   1712 
   1713 	assert(ts != NULL);
   1714 
   1715 	for (j = 0; j < ts->size; j++)
   1716 		waddch(form->scrwin, c);
   1717 
   1718 	return ts->size;
   1719 }
   1720 
   1721 
   1722 /*
   1723  * Display the fields attached to the form that are on the current page
   1724  * on the screen.
   1725  *
   1726  */
   1727 int
   1728 _formi_draw_page(FORM *form)
   1729 {
   1730 	int i;
   1731 
   1732 	if (form->page_starts[form->page].in_use == 0)
   1733 		return E_BAD_ARGUMENT;
   1734 
   1735 	wclear(form->scrwin);
   1736 
   1737 	for (i = form->page_starts[form->page].first;
   1738 	     i <= form->page_starts[form->page].last; i++)
   1739 		_formi_redraw_field(form, i);
   1740 
   1741 	return E_OK;
   1742 }
   1743 
   1744 /*
   1745  * Add the character c at the position pos in buffer 0 of the given field
   1746  */
   1747 int
   1748 _formi_add_char(FIELD *field, unsigned int pos, char c)
   1749 {
   1750 	char *new, old_c;
   1751 	unsigned int new_size;
   1752 	int status;
   1753 	_FORMI_FIELD_LINES *row, *temp, *next_temp;
   1754 
   1755 	row = field->cur_line;
   1756 
   1757 	  /*
   1758 	   * If buffer has not had a string before, set it to a blank
   1759 	   * string.  Everything should flow from there....
   1760 	   */
   1761 	if (row->string == NULL) {
   1762 		if ((row->string = malloc((size_t)INITIAL_LINE_ALLOC)) == NULL)
   1763 			return E_SYSTEM_ERROR;
   1764 		row->string[0] = '\0';
   1765 		row->allocated = INITIAL_LINE_ALLOC;
   1766 		row->length = 0;
   1767 		row->expanded = 0;
   1768 	}
   1769 
   1770 	if (_formi_validate_char(field, c) != E_OK) {
   1771 		_formi_dbg_printf("%s: char %c failed char validation\n",
   1772 		    __func__, c);
   1773 		return E_INVALID_FIELD;
   1774 	}
   1775 
   1776 	if ((c == '\t') && (field->cols <= 8)) {
   1777 		_formi_dbg_printf("%s: field too small for a tab\n", __func__);
   1778 		return E_NO_ROOM;
   1779 	}
   1780 
   1781 	_formi_dbg_printf("%s: pos=%d, char=%c\n", __func__, pos, c);
   1782 	_formi_dbg_printf("%s: xpos=%d, row_pos=%d, start=%d\n", __func__,
   1783 		field->cursor_xpos, field->row_xpos, field->start_char);
   1784 	_formi_dbg_printf("%s: length=%d(%d), allocated=%d\n", __func__,
   1785 		row->expanded, row->length, row->allocated);
   1786 	_formi_dbg_printf("%s: %s\n", __func__, row->string);
   1787 	_formi_dbg_printf("%s: buf0_status=%d\n", __func__, field->buf0_status);
   1788 	if (((field->opts & O_BLANK) == O_BLANK) &&
   1789 	    (field->buf0_status == FALSE) &&
   1790 	    ((field->row_xpos + field->start_char) == 0)) {
   1791 		row = field->alines;
   1792 		if (row->next != NULL) {
   1793 			  /* shift all but one line structs to free list */
   1794 			temp = row->next;
   1795 			do {
   1796 				next_temp = temp->next;
   1797 				add_to_free(field, temp);
   1798 				temp = next_temp;
   1799 			} while (temp != NULL);
   1800 		}
   1801 
   1802 		row->length = 0;
   1803 		row->string[0] = '\0';
   1804 		pos = 0;
   1805 		field->start_char = 0;
   1806 		field->start_line = row;
   1807 		field->cur_line = row;
   1808 		field->row_count = 1;
   1809 		field->row_xpos = 0;
   1810 		field->cursor_ypos = 0;
   1811 		row->expanded = 0;
   1812 		row->length = 0;
   1813 		_formi_init_field_xpos(field);
   1814 	}
   1815 
   1816 
   1817 	if ((field->overlay == 0)
   1818 	    || ((field->overlay == 1) && (pos >= row->length))) {
   1819 		  /* first check if the field can have more chars...*/
   1820 		if (check_field_size(field) == FALSE)
   1821 			return E_REQUEST_DENIED;
   1822 
   1823 		if (row->length + 2
   1824 		    >= row->allocated) {
   1825 			new_size = row->allocated + 16 - (row->allocated % 16);
   1826 			if ((new = realloc(row->string,
   1827 						  (size_t) new_size )) == NULL)
   1828 				return E_SYSTEM_ERROR;
   1829 			row->allocated = new_size;
   1830 			row->string = new;
   1831 		}
   1832 	}
   1833 
   1834 	if ((field->overlay == 0) && (row->length > pos)) {
   1835 		memmove(&row->string[pos + 1], &row->string[pos],
   1836 		      (size_t) (row->length - pos + 1));
   1837 	}
   1838 
   1839 	old_c = row->string[pos];
   1840 	row->string[pos] = c;
   1841 	if (pos >= row->length) {
   1842 		  /* make sure the string is terminated if we are at the
   1843 		   * end of the string, the terminator would be missing
   1844 		   * if we are at the end of the field.
   1845 		   */
   1846 		row->string[pos + 1] = '\0';
   1847 	}
   1848 
   1849 	  /* only increment the length if we are inserting characters
   1850 	   * OR if we are at the end of the field in overlay mode.
   1851 	   */
   1852 	if ((field->overlay == 0)
   1853 	    || ((field->overlay == 1) && (pos >= row->length))) {
   1854 		row->length++;
   1855 	}
   1856 
   1857 	_formi_calculate_tabs(row);
   1858 	row->expanded = _formi_tab_expanded_length(row->string, 0,
   1859 						   row->length - 1);
   1860 
   1861 	  /* wrap the field, if needed */
   1862 	status = _formi_wrap_field(field, row);
   1863 
   1864 	row = field->cur_line;
   1865 	pos = field->row_xpos;
   1866 
   1867 	  /*
   1868 	   * check the wrap worked or that we have not exceeded the
   1869 	   * max field size - this can happen if the field is re-wrapped
   1870 	   * and the row count is increased past the set limit.
   1871 	   */
   1872 	if ((status != E_OK) || (check_field_size(field) == FALSE)) {
   1873 		if ((field->overlay == 0)
   1874 		    || ((field->overlay == 1)
   1875 			&& (pos >= (row->length - 1) /*XXXX- append check???*/))) {
   1876 			  /*
   1877 			   * wrap failed for some reason, back out the
   1878 			   * char insert
   1879 			   */
   1880 			memmove(&row->string[pos], &row->string[pos + 1],
   1881 			      (size_t) (row->length - pos));
   1882 			row->length--;
   1883 			if (pos > 0)
   1884 				pos--;
   1885 		} else if (field->overlay == 1) {
   1886 			  /* back out character overlay */
   1887 			row->string[pos] = old_c;
   1888 		}
   1889 
   1890 		_formi_calculate_tabs(row);
   1891 
   1892 		_formi_wrap_field(field, row);
   1893 		  /*
   1894 		   * If we are here then either the status is bad or we
   1895 		   * simply ran out of room.  If the status is E_OK then
   1896 		   * we ran out of room, let the form driver know this.
   1897 		   */
   1898 		if (status == E_OK)
   1899 			status = E_REQUEST_DENIED;
   1900 
   1901 	} else {
   1902 		field->buf0_status = TRUE;
   1903 		field->row_xpos++;
   1904 		if ((field->rows + field->nrows) == 1) {
   1905 			status = _formi_set_cursor_xpos(field, FALSE);
   1906 		} else {
   1907 			field->cursor_xpos =
   1908 				_formi_tab_expanded_length(
   1909 					row->string, 0,	field->row_xpos - 1);
   1910 
   1911 			  /*
   1912 			   * Annoying corner case - if we are right in
   1913 			   * the bottom right corner of the field we
   1914 			   * need to scroll the field one line so the
   1915 			   * cursor is positioned correctly in the
   1916 			   * field.
   1917 			   */
   1918 			if ((field->cursor_xpos >= field->cols) &&
   1919 			    (field->cursor_ypos == (field->rows - 1))) {
   1920 				field->cursor_ypos--;
   1921 				field->start_line = field->start_line->next;
   1922 			}
   1923 		}
   1924 	}
   1925 
   1926 	assert((field->cursor_xpos <= field->cols)
   1927 	       && (field->cursor_ypos < 400000));
   1928 
   1929 	_formi_dbg_printf("%s: xpos=%d, row_pos=%d, start=%d\n", __func__,
   1930 		field->cursor_xpos, field->row_xpos, field->start_char);
   1931 	_formi_dbg_printf("%s: length=%d(%d), allocated=%d\n", __func__,
   1932 		row->expanded, row->length, row->allocated);
   1933 	_formi_dbg_printf("%s: ypos=%d, start_line=%p\n", __func__,
   1934 		field->cursor_ypos, field->start_line);
   1935 	_formi_dbg_printf("%s: %s\n", __func__, row->string);
   1936 	_formi_dbg_printf("%s: buf0_status=%d\n", __func__, field->buf0_status);
   1937 	_formi_dbg_printf("%s: status = %s\n", __func__,
   1938 		(status == E_OK)? "OK" : "FAILED");
   1939 	return status;
   1940 }
   1941 
   1942 /*
   1943  * Set the position of the cursor on the screen in the row depending on
   1944  * where the current position in the string is and the justification
   1945  * that is to be applied to the field.  Justification is only applied
   1946  * to single row, static fields.
   1947  */
   1948 static int
   1949 _formi_set_cursor_xpos(FIELD *field, int noscroll)
   1950 {
   1951 	int just, pos;
   1952 
   1953 	just = field->justification;
   1954 	pos = field->start_char + field->row_xpos;
   1955 
   1956 	_formi_dbg_printf(
   1957 	    "%s: pos %d, start_char %d, row_xpos %d, xpos %d\n", __func__,
   1958 	    pos, field->start_char, field->row_xpos, field->cursor_xpos);
   1959 
   1960 	  /*
   1961 	   * make sure we apply the correct justification to non-static
   1962 	   * fields.
   1963 	   */
   1964 	if (((field->rows + field->nrows) != 1) ||
   1965 	    ((field->opts & O_STATIC) != O_STATIC))
   1966 		just = JUSTIFY_LEFT;
   1967 
   1968 	switch (just) {
   1969 	case JUSTIFY_RIGHT:
   1970 		field->cursor_xpos = field->cols - 1
   1971 			- _formi_tab_expanded_length(
   1972 				field->cur_line->string, 0,
   1973 				field->cur_line->length - 1)
   1974 			+ _formi_tab_expanded_length(
   1975 				field->cur_line->string, 0,
   1976 				field->row_xpos);
   1977 		break;
   1978 
   1979 	case JUSTIFY_CENTER:
   1980 		field->cursor_xpos = ((field->cols - 1)
   1981 			- _formi_tab_expanded_length(
   1982 				field->cur_line->string, 0,
   1983 				field->cur_line->length - 1) + 1) / 2
   1984 			+ _formi_tab_expanded_length(field->cur_line->string,
   1985 						     0, field->row_xpos);
   1986 
   1987 		if (field->cursor_xpos > (field->cols - 1))
   1988 			field->cursor_xpos = (field->cols - 1);
   1989 		break;
   1990 
   1991 	default:
   1992 		field->cursor_xpos = _formi_tab_expanded_length(
   1993 			field->cur_line->string,
   1994 			field->start_char,
   1995 			field->row_xpos	+ field->start_char);
   1996 		if ((field->cursor_xpos <= (field->cols - 1)) &&
   1997 		    ((field->start_char + field->row_xpos)
   1998 		     < field->cur_line->length))
   1999 			field->cursor_xpos--;
   2000 
   2001 		if (field->cursor_xpos > (field->cols - 1)) {
   2002 			if ((field->opts & O_STATIC) == O_STATIC) {
   2003 				field->start_char = 0;
   2004 
   2005 				if (field->row_xpos
   2006 				    == (field->cur_line->length - 1)) {
   2007 					field->cursor_xpos = field->cols - 1;
   2008 				} else {
   2009 					field->cursor_xpos =
   2010 						_formi_tab_expanded_length(
   2011 						  field->cur_line->string,
   2012 						  field->start_char,
   2013 						  field->row_xpos
   2014 						    + field->start_char
   2015 						  - 1) - 1;
   2016 				}
   2017 			} else {
   2018 				if (noscroll == FALSE) {
   2019 					field->start_char =
   2020 						tab_fit_window(
   2021 							field,
   2022 							field->start_char
   2023 							+ field->row_xpos,
   2024 							field->cols);
   2025 					field->row_xpos = pos
   2026 						- field->start_char;
   2027 					field->cursor_xpos =
   2028 						_formi_tab_expanded_length(
   2029 						   field->cur_line->string,
   2030 						   field->start_char,
   2031 						   field->row_xpos
   2032 						      + field->start_char - 1);
   2033 				} else {
   2034 					field->cursor_xpos = (field->cols - 1);
   2035 				}
   2036 			}
   2037 
   2038 		}
   2039 		break;
   2040 	}
   2041 
   2042 	_formi_dbg_printf(
   2043 	    "%s: pos %d, start_char %d, row_xpos %d, xpos %d\n", __func__,
   2044 	    pos, field->start_char, field->row_xpos, field->cursor_xpos);
   2045 	return E_OK;
   2046 }
   2047 
   2048 /*
   2049  * Manipulate the text in a field, this takes the given form and performs
   2050  * the passed driver command on the current text field.  Returns 1 if the
   2051  * text field was modified.
   2052  */
   2053 int
   2054 _formi_manipulate_field(FORM *form, int c)
   2055 {
   2056 	FIELD *cur;
   2057 	char *str, saved;
   2058 	unsigned int start, end, pos, status, old_count, size;
   2059 	unsigned int old_xpos, old_row_pos;
   2060 	int len, wb;
   2061 	bool eat_char;
   2062 	_FORMI_FIELD_LINES *row, *rs;
   2063 
   2064 	cur = form->fields[form->cur_field];
   2065 	if (cur->cur_line->string == NULL)
   2066 		return E_REQUEST_DENIED;
   2067 
   2068 	_formi_dbg_printf("%s: request is REQ_%s\n",
   2069 	    __func__, reqs[c - REQ_MIN_REQUEST]);
   2070 	_formi_dbg_printf(
   2071 	    "%s: xpos=%d, row_pos=%d, start_char=%d, length=%d, allocated=%d\n",
   2072 	    __func__, cur->cursor_xpos, cur->row_xpos, cur->start_char,
   2073 	    cur->cur_line->length, cur->cur_line->allocated);
   2074 	_formi_dbg_printf("%s: start_line=%p, ypos=%d\n", __func__,
   2075 	    cur->start_line, cur->cursor_ypos);
   2076 	if (cur->cur_line->string == NULL)
   2077 		_formi_dbg_printf("%s: string=(null)\n", __func__);
   2078 	else
   2079 		_formi_dbg_printf("%s: string=\"%s\"\n", __func__,
   2080 		    cur->cur_line->string);
   2081 
   2082 	  /* Cannot manipulate a null string! */
   2083 	if (cur->cur_line->string == NULL)
   2084 		return E_REQUEST_DENIED;
   2085 
   2086 	saved = '\0';
   2087 	row = cur->cur_line;
   2088 
   2089 	switch (c) {
   2090 	case REQ_RIGHT_CHAR:
   2091 		  /*
   2092 		   * The right_char request performs the same function
   2093 		   * as the next_char request except that the cursor is
   2094 		   * not wrapped if it is at the end of the line, so
   2095 		   * check if the cursor is at the end of the line and
   2096 		   * deny the request otherwise just fall through to
   2097 		   * the next_char request handler.
   2098 		   */
   2099 		if (cur->cursor_xpos >= cur->cols - 1)
   2100 			return E_REQUEST_DENIED;
   2101 
   2102 		  /* FALLTHRU */
   2103 
   2104 	case REQ_NEXT_CHAR:
   2105 		  /* for a dynamic field allow an offset of one more
   2106 		   * char so we can insert chars after end of string.
   2107 		   * Static fields cannot do this so deny request if
   2108 		   * cursor is at the end of the field.
   2109 		   */
   2110 		if (((cur->opts & O_STATIC) == O_STATIC) &&
   2111 		    (cur->row_xpos == cur->cols - 1) &&
   2112 		    ((cur->rows + cur->nrows) == 1))
   2113 			return E_REQUEST_DENIED;
   2114 
   2115 		if (((cur->rows + cur->nrows) == 1) &&
   2116 		    (cur->row_xpos + cur->start_char + 1) > row->length)
   2117 			return E_REQUEST_DENIED;
   2118 
   2119 		if ((cur->rows + cur->nrows) == 1) {
   2120 			cur->row_xpos++;
   2121 			_formi_set_cursor_xpos(cur, (c == REQ_RIGHT_CHAR));
   2122 		} else {
   2123 			if (cur->cursor_xpos >= (row->expanded - 1)) {
   2124 				if ((row->next == NULL) ||
   2125 				    (c == REQ_RIGHT_CHAR))
   2126 					return E_REQUEST_DENIED;
   2127 
   2128 				cur->cursor_xpos = 0;
   2129 				cur->row_xpos = 0;
   2130 				cur->cur_line = cur->cur_line->next;
   2131 				if (cur->cursor_ypos == (cur->rows - 1))
   2132 					cur->start_line =
   2133 						cur->start_line->next;
   2134 				else
   2135 					cur->cursor_ypos++;
   2136 			} else {
   2137 				old_xpos = cur->cursor_xpos;
   2138 				old_row_pos = cur->row_xpos;
   2139 				if (row->string[cur->row_xpos] == '\t')
   2140 					cur->cursor_xpos += tab_size(row,
   2141 							cur->row_xpos);
   2142 				else
   2143 					cur->cursor_xpos++;
   2144 				cur->row_xpos++;
   2145 				if (cur->cursor_xpos
   2146 				    >= row->expanded) {
   2147 					if ((row->next == NULL) ||
   2148 					    (c == REQ_RIGHT_CHAR)) {
   2149 						cur->cursor_xpos = old_xpos;
   2150 						cur->row_xpos = old_row_pos;
   2151 						return E_REQUEST_DENIED;
   2152 					}
   2153 
   2154 					cur->cursor_xpos = 0;
   2155 					cur->row_xpos = 0;
   2156 					cur->cur_line = cur->cur_line->next;
   2157 					if (cur->cursor_ypos
   2158 					    == (cur->rows - 1))
   2159 						cur->start_line =
   2160 							cur->start_line->next;
   2161 					else
   2162 						cur->cursor_ypos++;
   2163 				}
   2164 			}
   2165 		}
   2166 
   2167 		break;
   2168 
   2169 	case REQ_LEFT_CHAR:
   2170 		  /*
   2171 		   * The behaviour of left_char is the same as prev_char
   2172 		   * except that the cursor will not wrap if it has
   2173 		   * reached the LHS of the field, so just check this
   2174 		   * and fall through if we are not at the LHS.
   2175 		   */
   2176 		if (cur->cursor_xpos == 0)
   2177 			return E_REQUEST_DENIED;
   2178 
   2179 		  /* FALLTHRU */
   2180 	case REQ_PREV_CHAR:
   2181 		if ((cur->rows + cur->nrows) == 1) {
   2182 			if (cur->row_xpos == 0) {
   2183 				if (cur->start_char > 0)
   2184 					cur->start_char--;
   2185 				else
   2186 					return E_REQUEST_DENIED;
   2187 			} else {
   2188 				cur->row_xpos--;
   2189 				_formi_set_cursor_xpos(cur, FALSE);
   2190 			}
   2191 		} else {
   2192 			if ((cur->cursor_xpos == 0) &&
   2193 			    (cur->cursor_ypos == 0) &&
   2194 			    (cur->start_line->prev == NULL))
   2195 				return E_REQUEST_DENIED;
   2196 
   2197 			pos = cur->row_xpos;
   2198 			if (cur->cursor_xpos > 0) {
   2199 				if (row->string[pos] == '\t') {
   2200 					size = tab_size(row, pos);
   2201 					if (size > cur->cursor_xpos) {
   2202 						cur->cursor_xpos = 0;
   2203 						cur->row_xpos = 0;
   2204 					} else {
   2205 						cur->row_xpos--;
   2206 						cur->cursor_xpos -= size;
   2207 					}
   2208 				} else {
   2209 					cur->cursor_xpos--;
   2210 					cur->row_xpos--;
   2211 				}
   2212 			} else {
   2213 				cur->cur_line = cur->cur_line->prev;
   2214 				if (cur->cursor_ypos > 0)
   2215 					cur->cursor_ypos--;
   2216 				else
   2217 					cur->start_line =
   2218 						cur->start_line->prev;
   2219 				row = cur->cur_line;
   2220 				if (row->expanded > 0) {
   2221 					cur->cursor_xpos = row->expanded - 1;
   2222 				} else {
   2223 					cur->cursor_xpos = 0;
   2224 				}
   2225 
   2226 				if (row->length > 0)
   2227 					cur->row_xpos = row->length - 1;
   2228 				else
   2229 					cur->row_xpos = 0;
   2230 			}
   2231 		}
   2232 
   2233 		break;
   2234 
   2235 	case REQ_DOWN_CHAR:
   2236 		  /*
   2237 		   * The down_char request has the same functionality as
   2238 		   * the next_line request excepting that the field is not
   2239 		   * scrolled if the cursor is at the bottom of the field.
   2240 		   * Check to see if the cursor is at the bottom of the field
   2241 		   * and if it is then deny the request otherwise fall
   2242 		   * through to the next_line handler.
   2243 		   */
   2244 		if (cur->cursor_ypos >= cur->rows - 1)
   2245 			return E_REQUEST_DENIED;
   2246 
   2247 		  /* FALLTHRU */
   2248 
   2249 	case REQ_NEXT_LINE:
   2250 		if ((row->next == NULL) || (cur->cur_line->next == NULL))
   2251 			return E_REQUEST_DENIED;
   2252 
   2253 		cur->cur_line = cur->cur_line->next;
   2254 		if ((cur->cursor_ypos + 1) >= cur->rows) {
   2255 			cur->start_line = cur->start_line->next;
   2256 		} else
   2257 			cur->cursor_ypos++;
   2258 		row = cur->cur_line;
   2259 
   2260 		if (row->length == 0) {
   2261 			cur->row_xpos = 0;
   2262 			cur->cursor_xpos = 0;
   2263 		} else {
   2264 			if (cur->cursor_xpos > (row->expanded - 1))
   2265 				cur->cursor_xpos = row->expanded - 1;
   2266 
   2267 			cur->row_xpos =	tab_fit_len(row, cur->cursor_xpos + 1);
   2268 			if (cur->row_xpos == 0)
   2269 				cur->cursor_xpos = 0;
   2270 			else
   2271 				cur->cursor_xpos =
   2272 					_formi_tab_expanded_length(
   2273 						row->string, 0, cur->row_xpos);
   2274 			if (cur->cursor_xpos > 0)
   2275 				cur->cursor_xpos--;
   2276 		}
   2277 		break;
   2278 
   2279 	case REQ_UP_CHAR:
   2280 		  /*
   2281 		   * The up_char request has the same functionality as
   2282 		   * the prev_line request excepting the field is not
   2283 		   * scrolled, check if the cursor is at the top of the
   2284 		   * field, if it is deny the request otherwise fall
   2285 		   * through to the prev_line handler.
   2286 		   */
   2287 		if (cur->cursor_ypos == 0)
   2288 			return E_REQUEST_DENIED;
   2289 
   2290 		  /* FALLTHRU */
   2291 
   2292 	case REQ_PREV_LINE:
   2293 		if (cur->cur_line->prev == NULL)
   2294 			return E_REQUEST_DENIED;
   2295 
   2296 		if (cur->cursor_ypos == 0) {
   2297 			if (cur->start_line->prev == NULL)
   2298 				return E_REQUEST_DENIED;
   2299 			cur->start_line = cur->start_line->prev;
   2300 		} else
   2301 			cur->cursor_ypos--;
   2302 
   2303 		cur->cur_line = cur->cur_line->prev;
   2304 		row = cur->cur_line;
   2305 
   2306 		if (row->length == 0) {
   2307 			cur->row_xpos = 0;
   2308 			cur->cursor_xpos = 0;
   2309 		} else {
   2310 			if (cur->cursor_xpos > (row->expanded - 1))
   2311 				cur->cursor_xpos = row->expanded - 1;
   2312 
   2313 			cur->row_xpos =	tab_fit_len(row, cur->cursor_xpos + 1);
   2314 			cur->cursor_xpos =
   2315 				_formi_tab_expanded_length(row->string,
   2316 							   0, cur->row_xpos);
   2317 			if (cur->cursor_xpos > 0)
   2318 				cur->cursor_xpos--;
   2319 		}
   2320 		break;
   2321 
   2322 	case REQ_NEXT_WORD:
   2323 		start = cur->row_xpos + cur->start_char;
   2324 		str = row->string;
   2325 
   2326 		wb = find_eow(cur, start, FALSE, &row);
   2327 		if (wb < 0)
   2328 			return wb;
   2329 
   2330 		start = wb;
   2331 		  /* check if we hit the end */
   2332 		if (str[start] == '\0')
   2333 			return E_REQUEST_DENIED;
   2334 
   2335 		  /* otherwise we must have found the start of a word...*/
   2336 		if ((cur->rows + cur->nrows) == 1) {
   2337 			  /* single line field */
   2338 			size = _formi_tab_expanded_length(str,
   2339 				cur->start_char, start);
   2340 			if (size < cur->cols) {
   2341 				cur->row_xpos = start - cur->start_char;
   2342 			} else {
   2343 				cur->start_char = start;
   2344 				cur->row_xpos = 0;
   2345 			}
   2346 			_formi_set_cursor_xpos(cur, FALSE);
   2347 		} else {
   2348 			  /* multiline field */
   2349 			cur->cur_line = row;
   2350 			adjust_ypos(cur, row);
   2351 
   2352 			cur->row_xpos = start;
   2353 			cur->cursor_xpos =
   2354 				_formi_tab_expanded_length(
   2355 					row->string, 0, cur->row_xpos) - 1;
   2356 		}
   2357 		break;
   2358 
   2359 	case REQ_PREV_WORD:
   2360 		start = cur->start_char + cur->row_xpos;
   2361 		if (cur->start_char > 0)
   2362 			start--;
   2363 
   2364 		if ((start == 0) && (row->prev == NULL))
   2365 			return E_REQUEST_DENIED;
   2366 
   2367 		if (start == 0) {
   2368 			row = row->prev;
   2369 			if (row->length > 0)
   2370 				start = row->length - 1;
   2371 			else
   2372 				start = 0;
   2373 		}
   2374 
   2375 		str = row->string;
   2376 
   2377 		start = find_sow(start, &row);
   2378 
   2379 		if ((cur->rows + cur->nrows) == 1) {
   2380 			  /* single line field */
   2381 			size = _formi_tab_expanded_length(str,
   2382 				cur->start_char, start);
   2383 
   2384 			if (start > cur->start_char) {
   2385 				cur->row_xpos = start - cur->start_char;
   2386 			} else {
   2387 				cur->start_char = start;
   2388 				cur->row_xpos = 0;
   2389 			}
   2390 			_formi_set_cursor_xpos(cur, FALSE);
   2391 		} else {
   2392 			  /* multiline field */
   2393 			cur->cur_line = row;
   2394 			adjust_ypos(cur, row);
   2395 			cur->row_xpos = start;
   2396 			cur->cursor_xpos =
   2397 				_formi_tab_expanded_length(
   2398 					row->string, 0,
   2399 					cur->row_xpos) - 1;
   2400 		}
   2401 
   2402 		break;
   2403 
   2404 	case REQ_BEG_FIELD:
   2405 		cur->start_char = 0;
   2406 		while (cur->start_line->prev != NULL)
   2407 			cur->start_line = cur->start_line->prev;
   2408 		cur->cur_line = cur->start_line;
   2409 		cur->row_xpos = 0;
   2410 		_formi_init_field_xpos(cur);
   2411 		cur->cursor_ypos = 0;
   2412 		break;
   2413 
   2414 	case REQ_BEG_LINE:
   2415 		cur->row_xpos = 0;
   2416 		_formi_init_field_xpos(cur);
   2417 		cur->start_char = 0;
   2418 		break;
   2419 
   2420 	case REQ_END_FIELD:
   2421 		while (cur->cur_line->next != NULL)
   2422 			cur->cur_line = cur->cur_line->next;
   2423 
   2424 		if (cur->row_count > cur->rows) {
   2425 			cur->start_line = cur->cur_line;
   2426 			pos = cur->rows - 1;
   2427 			while (pos > 0) {
   2428 				cur->start_line = cur->start_line->prev;
   2429 				pos--;
   2430 			}
   2431 			cur->cursor_ypos = cur->rows - 1;
   2432 		} else {
   2433 			cur->cursor_ypos = cur->row_count - 1;
   2434 		}
   2435 
   2436 		  /* we fall through here deliberately, we are on the
   2437 		   * correct row, now we need to get to the end of the
   2438 		   * line.
   2439 		   */
   2440 		  /* FALLTHRU */
   2441 
   2442 	case REQ_END_LINE:
   2443 		row = cur->cur_line;
   2444 
   2445 		if ((cur->rows + cur->nrows) == 1) {
   2446 			if (row->expanded > cur->cols - 1) {
   2447 				if ((cur->opts & O_STATIC) != O_STATIC) {
   2448 					cur->start_char = tab_fit_window(
   2449 						cur, row->length,
   2450 						cur->cols) + 1;
   2451 					cur->row_xpos = row->length
   2452 						- cur->start_char;
   2453 				} else {
   2454 					cur->start_char = 0;
   2455 					cur->row_xpos = cur->cols - 1;
   2456 				}
   2457 			} else {
   2458 				cur->row_xpos = row->length + 1;
   2459 				cur->start_char = 0;
   2460 			}
   2461 			_formi_set_cursor_xpos(cur, FALSE);
   2462 		} else {
   2463 			cur->row_xpos = row->length - 1;
   2464 			cur->cursor_xpos = row->expanded - 1;
   2465 			if (row->next == NULL) {
   2466 				cur->row_xpos++;
   2467 				cur->cursor_xpos++;
   2468 			}
   2469 		}
   2470 		break;
   2471 
   2472 	case REQ_NEW_LINE:
   2473 		start = cur->start_char	+ cur->row_xpos;
   2474 		if ((status = split_line(cur, TRUE, start, &row)) != E_OK)
   2475 			return status;
   2476 		cur->cur_line->hard_ret = TRUE;
   2477 		cur->cursor_xpos = 0;
   2478 		cur->row_xpos = 0;
   2479 		break;
   2480 
   2481 	case REQ_INS_CHAR:
   2482 		if ((status = _formi_add_char(cur, cur->start_char
   2483 					      + cur->row_xpos,
   2484 					      cur->pad)) != E_OK)
   2485 			return status;
   2486 		break;
   2487 
   2488 	case REQ_INS_LINE:
   2489 		if ((status = split_line(cur, TRUE, 0, &row)) != E_OK)
   2490 			return status;
   2491 		cur->cur_line->hard_ret = TRUE;
   2492 		break;
   2493 
   2494 	case REQ_DEL_CHAR:
   2495 		row = cur->cur_line;
   2496 		start = cur->start_char + cur->row_xpos;
   2497 		end = row->length - 1;
   2498 		if ((start >= row->length) && (row->next == NULL))
   2499 			return E_REQUEST_DENIED;
   2500 
   2501 		if ((start == row->length - 1) || (row->length == 0)) {
   2502 			if ((cur->rows + cur->nrows) > 1) {
   2503 				/*
   2504 				 * Firstly, check if the current line has
   2505 				 * a hard return.  In this case we just
   2506 				 * want to "delete" the hard return and
   2507 				 * re-wrap the field.  The hard return
   2508 				 * does not occupy a character space in
   2509 				 * the buffer but we must make it appear
   2510 				 * like it does for a deletion.
   2511 				 */
   2512 				if (row->hard_ret == TRUE) {
   2513 					row->hard_ret = FALSE;
   2514 					if (_formi_join_line(cur, &row,
   2515 							     JOIN_NEXT)
   2516 					    != E_OK) {
   2517 						row->hard_ret = TRUE;
   2518 						return 0;
   2519 					} else {
   2520 						return 1;
   2521 					}
   2522 				}
   2523 
   2524 				/*
   2525 				 * If we have more than one row, join the
   2526 				 * next row to make things easier unless
   2527 				 * we are at the end of the string, in
   2528 				 * that case the join would fail but we
   2529 				 * really want to delete the last char
   2530 				 * in the field.
   2531 				 */
   2532 				if (row->next != NULL) {
   2533 					if (_formi_join_line(cur, &row,
   2534 							     JOIN_NEXT_NW)
   2535 					    != E_OK) {
   2536 						return E_REQUEST_DENIED;
   2537 					}
   2538 				}
   2539 			}
   2540 		}
   2541 
   2542 		saved = row->string[start];
   2543 		memmove(&row->string[start], &row->string[start + 1],
   2544 		      (size_t) (end - start + 1));
   2545 		row->string[end] = '\0';
   2546 		row->length--;
   2547 		if (row->length > 0)
   2548 			row->expanded = _formi_tab_expanded_length(
   2549 				row->string, 0, row->length - 1);
   2550 		else
   2551 			row->expanded = 0;
   2552 
   2553 		  /*
   2554 		   * recalculate tabs for a single line field, multiline
   2555 		   * fields will do this when the field is wrapped.
   2556 		   */
   2557 		if ((cur->rows + cur->nrows) == 1)
   2558 			_formi_calculate_tabs(row);
   2559 		  /*
   2560 		   * if we are at the end of the string then back the
   2561 		   * cursor pos up one to stick on the end of the line
   2562 		   */
   2563 		if (start == row->length) {
   2564 			if (row->length > 1) {
   2565 				if ((cur->rows + cur->nrows) == 1) {
   2566 					pos = cur->row_xpos + cur->start_char;
   2567 					cur->start_char =
   2568 						tab_fit_window(
   2569 							cur,
   2570 							cur->start_char + cur->row_xpos,
   2571 							cur->cols);
   2572 					cur->row_xpos = pos - cur->start_char
   2573 						- 1;
   2574 					_formi_set_cursor_xpos(cur, FALSE);
   2575 				} else {
   2576 					if (cur->row_xpos == 0) {
   2577 						if (row->next != NULL) {
   2578 							if (_formi_join_line(
   2579 								cur, &row,
   2580 								JOIN_PREV_NW)
   2581 							    != E_OK) {
   2582 								return E_REQUEST_DENIED;
   2583 							}
   2584 						} else {
   2585 							if (cur->row_count > 1)
   2586 								cur->row_count--;
   2587 						}
   2588 
   2589 					}
   2590 
   2591 					cur->row_xpos = start - 1;
   2592 					cur->cursor_xpos =
   2593 						_formi_tab_expanded_length(
   2594 							row->string,
   2595 							0, cur->row_xpos - 1);
   2596 					if ((cur->cursor_xpos > 0)
   2597 					    && (start != (row->expanded - 1)))
   2598 						cur->cursor_xpos--;
   2599 				}
   2600 
   2601 				start--;
   2602 			} else {
   2603 				start = 0;
   2604 				cur->row_xpos = 0;
   2605 				_formi_init_field_xpos(cur);
   2606 			}
   2607 		}
   2608 
   2609 		if ((cur->rows + cur->nrows) > 1) {
   2610 			if (_formi_wrap_field(cur, row) != E_OK) {
   2611 				memmove(&row->string[start + 1],
   2612 				      &row->string[start],
   2613 				      (size_t) (end - start));
   2614 				row->length++;
   2615 				row->string[start] = saved;
   2616 				_formi_wrap_field(cur, row);
   2617 				return E_REQUEST_DENIED;
   2618 			}
   2619 		}
   2620 		break;
   2621 
   2622 	case REQ_DEL_PREV:
   2623 		if ((cur->cursor_xpos == 0) && (cur->start_char == 0)
   2624 		    && (cur->start_line->prev == NULL)
   2625 		    && (cur->cursor_ypos == 0))
   2626 			   return E_REQUEST_DENIED;
   2627 
   2628 		row = cur->cur_line;
   2629 		start = cur->row_xpos + cur->start_char;
   2630 		end = row->length - 1;
   2631 		eat_char = TRUE;
   2632 
   2633 		if ((cur->start_char + cur->row_xpos) == 0) {
   2634 			if (row->prev == NULL)
   2635 				return E_REQUEST_DENIED;
   2636 
   2637 			  /*
   2638 			   * If we are a multiline field then check if
   2639 			   * the line above has a hard return.  If it does
   2640 			   * then just "eat" the hard return and re-wrap
   2641 			   * the field.
   2642 			   */
   2643 			if (row->prev->hard_ret == TRUE) {
   2644 				row->prev->hard_ret = FALSE;
   2645 				if (_formi_join_line(cur, &row,
   2646 						     JOIN_PREV) != E_OK) {
   2647 					row->prev->hard_ret = TRUE;
   2648 					return 0;
   2649 				}
   2650 
   2651 				eat_char = FALSE;
   2652 			} else {
   2653 				start = row->prev->length;
   2654 				  /*
   2655 				   * Join this line to the previous
   2656 				   * one.
   2657 				   */
   2658 				if (_formi_join_line(cur, &row,
   2659 						     JOIN_PREV_NW) != E_OK) {
   2660 					return 0;
   2661 				}
   2662 				end = row->length - 1;
   2663 			}
   2664 		}
   2665 
   2666 		if (eat_char == TRUE) {
   2667 			  /*
   2668 			   * eat a char from the buffer.  Normally we do
   2669 			   * this unless we have deleted a "hard return"
   2670 			   * in which case we just want to join the lines
   2671 			   * without losing a char.
   2672 			   */
   2673 			saved = row->string[start - 1];
   2674 			memmove(&row->string[start - 1], &row->string[start],
   2675 			      (size_t) (end - start + 1));
   2676 			row->length--;
   2677 			row->string[row->length] = '\0';
   2678 			row->expanded = _formi_tab_expanded_length(
   2679 				row->string, 0, row->length - 1);
   2680 		}
   2681 
   2682 		if ((cur->rows + cur->nrows) == 1) {
   2683 			_formi_calculate_tabs(row);
   2684 			pos = cur->row_xpos + cur->start_char;
   2685 			if (pos > 0)
   2686 				pos--;
   2687 			cur->start_char =
   2688 				tab_fit_window(cur,
   2689 					       cur->start_char + cur->row_xpos,
   2690 					       cur->cols);
   2691 			cur->row_xpos = pos - cur->start_char;
   2692 			_formi_set_cursor_xpos(cur, FALSE);
   2693 		} else {
   2694 			if (eat_char == TRUE) {
   2695 				cur->row_xpos--;
   2696 				if (cur->row_xpos > 0)
   2697 					cur->cursor_xpos =
   2698 						_formi_tab_expanded_length(
   2699 							row->string, 0,
   2700 							cur->row_xpos - 1);
   2701 				else
   2702 					cur->cursor_xpos = 0;
   2703 			}
   2704 
   2705 			if ((_formi_wrap_field(cur, row) != E_OK)) {
   2706 				memmove(&row->string[start],
   2707 				      &row->string[start - 1],
   2708 				      (size_t) (end - start));
   2709 				row->length++;
   2710 				row->string[start - 1] = saved;
   2711 				row->string[row->length] = '\0';
   2712 				_formi_wrap_field(cur, row);
   2713 				return E_REQUEST_DENIED;
   2714 			}
   2715 		}
   2716 		break;
   2717 
   2718 	case REQ_DEL_LINE:
   2719 		if (((cur->rows + cur->nrows) == 1) ||
   2720 		    (cur->row_count == 1)) {
   2721 			  /* single line case */
   2722 			row->length = 0;
   2723 			row->expanded = row->length = 0;
   2724 			cur->row_xpos = 0;
   2725 			_formi_init_field_xpos(cur);
   2726 			cur->cursor_ypos = 0;
   2727 		} else {
   2728 			  /* multiline field */
   2729 			old_count = cur->row_count;
   2730 			cur->row_count--;
   2731 			if (cur->row_count == 0)
   2732 				cur->row_count = 1;
   2733 
   2734 			if (old_count == 1) {
   2735 				row->expanded = row->length = 0;
   2736 				cur->cursor_xpos = 0;
   2737 				cur->row_xpos = 0;
   2738 				cur->cursor_ypos = 0;
   2739 			} else
   2740 				add_to_free(cur, row);
   2741 
   2742 			if (row->next == NULL) {
   2743 				if (cur->cursor_ypos == 0) {
   2744 					if (cur->start_line->prev != NULL) {
   2745 						cur->start_line =
   2746 							cur->start_line->prev;
   2747 					}
   2748 				} else {
   2749 					cur->cursor_ypos--;
   2750 				}
   2751 			}
   2752 
   2753 			if (old_count > 1) {
   2754 				if (cur->cursor_xpos > row->expanded) {
   2755 					cur->cursor_xpos = row->expanded - 1;
   2756 					cur->row_xpos = row->length - 1;
   2757 				}
   2758 
   2759 				cur->start_line = cur->alines;
   2760 				rs = cur->start_line;
   2761 				cur->cursor_ypos = 0;
   2762 				while (rs != row) {
   2763 					if (cur->cursor_ypos < cur->rows)
   2764 						cur->cursor_ypos++;
   2765 					else
   2766 						cur->start_line =
   2767 							cur->start_line->next;
   2768 					rs = rs->next;
   2769 				}
   2770 			}
   2771 		}
   2772 		break;
   2773 
   2774 	case REQ_DEL_WORD:
   2775 		start = cur->start_char + cur->row_xpos;
   2776 		str = row->string;
   2777 
   2778 		wb = find_eow(cur, start, TRUE, &row);
   2779 		if (wb < 0)
   2780 			return wb;
   2781 
   2782 		end = wb;
   2783 
   2784 		  /*
   2785 		   * If not at the start of a word then find the start,
   2786 		   * we cannot blindly call find_sow because this will
   2787 		   * skip back a word if we are already at the start of
   2788 		   * a word.
   2789 		   */
   2790 		if ((start > 0)
   2791 		    && !(isblank((unsigned char)str[start - 1]) &&
   2792 			!isblank((unsigned char)str[start])))
   2793 			start = find_sow(start, &row);
   2794 		str = row->string;
   2795 		  /* XXXX hmmmm what if start and end on diff rows? XXXX */
   2796 		memmove(&str[start], &str[end],
   2797 		      (size_t) (row->length - end + 1));
   2798 		len = end - start;
   2799 		row->length -= len;
   2800 
   2801 		if ((cur->rows + cur->nrows) > 1) {
   2802 			row = cur->start_line + cur->cursor_ypos;
   2803 			if (row->next != NULL) {
   2804 				/*
   2805 				 * if not on the last row we need to
   2806 				 * join on the next row so the line
   2807 				 * will be re-wrapped.
   2808 				 */
   2809 				_formi_join_line(cur, &row, JOIN_NEXT_NW);
   2810 			}
   2811 			_formi_wrap_field(cur, row);
   2812 			cur->row_xpos = start;
   2813 			cur->cursor_xpos = _formi_tab_expanded_length(
   2814 				row->string, 0, cur->row_xpos);
   2815 			if (cur->cursor_xpos > 0)
   2816 				cur->cursor_xpos--;
   2817 		} else {
   2818 			_formi_calculate_tabs(row);
   2819 			cur->row_xpos = start - cur->start_char;
   2820 			if (cur->row_xpos > 0)
   2821 				cur->row_xpos--;
   2822 			_formi_set_cursor_xpos(cur, FALSE);
   2823 		}
   2824 		break;
   2825 
   2826 	case REQ_CLR_EOL:
   2827 		row->string[cur->row_xpos + 1] = '\0';
   2828 		row->length = cur->row_xpos + 1;
   2829 		row->expanded = cur->cursor_xpos + 1;
   2830 		break;
   2831 
   2832 	case REQ_CLR_EOF:
   2833 		row = cur->cur_line->next;
   2834 		while (row != NULL) {
   2835 			rs = row->next;
   2836 			add_to_free(cur, row);
   2837 			row = rs;
   2838 			cur->row_count--;
   2839 		}
   2840 		break;
   2841 
   2842 	case REQ_CLR_FIELD:
   2843 		row = cur->alines->next;
   2844 		cur->cur_line = cur->alines;
   2845 		cur->start_line = cur->alines;
   2846 
   2847 		while (row != NULL) {
   2848 			rs = row->next;
   2849 			add_to_free(cur, row);
   2850 			row = rs;
   2851 		}
   2852 
   2853 		cur->alines->string[0] = '\0';
   2854 		cur->alines->length = 0;
   2855 		cur->alines->expanded = 0;
   2856 		cur->row_count = 1;
   2857 		cur->cursor_ypos = 0;
   2858 		cur->row_xpos = 0;
   2859 		_formi_init_field_xpos(cur);
   2860 		cur->start_char = 0;
   2861 		break;
   2862 
   2863 	case REQ_OVL_MODE:
   2864 		cur->overlay = 1;
   2865 		break;
   2866 
   2867 	case REQ_INS_MODE:
   2868 		cur->overlay = 0;
   2869 		break;
   2870 
   2871 	case REQ_SCR_FLINE:
   2872 		_formi_scroll_fwd(cur, 1);
   2873 		break;
   2874 
   2875 	case REQ_SCR_BLINE:
   2876 		_formi_scroll_back(cur, 1);
   2877 		break;
   2878 
   2879 	case REQ_SCR_FPAGE:
   2880 		_formi_scroll_fwd(cur, cur->rows);
   2881 		break;
   2882 
   2883 	case REQ_SCR_BPAGE:
   2884 		_formi_scroll_back(cur, cur->rows);
   2885 		break;
   2886 
   2887 	case REQ_SCR_FHPAGE:
   2888 		_formi_scroll_fwd(cur, cur->rows / 2);
   2889 		break;
   2890 
   2891 	case REQ_SCR_BHPAGE:
   2892 		_formi_scroll_back(cur, cur->rows / 2);
   2893 		break;
   2894 
   2895 	case REQ_SCR_FCHAR:
   2896 		_formi_hscroll_fwd(cur, row, 1);
   2897 		break;
   2898 
   2899 	case REQ_SCR_BCHAR:
   2900 		_formi_hscroll_back(cur, row, 1);
   2901 		break;
   2902 
   2903 	case REQ_SCR_HFLINE:
   2904 		_formi_hscroll_fwd(cur, row, cur->cols);
   2905 		break;
   2906 
   2907 	case REQ_SCR_HBLINE:
   2908 		_formi_hscroll_back(cur, row, cur->cols);
   2909 		break;
   2910 
   2911 	case REQ_SCR_HFHALF:
   2912 		_formi_hscroll_fwd(cur, row, cur->cols / 2);
   2913 		break;
   2914 
   2915 	case REQ_SCR_HBHALF:
   2916 		_formi_hscroll_back(cur, row, cur->cols / 2);
   2917 		break;
   2918 
   2919 	default:
   2920 		return 0;
   2921 	}
   2922 
   2923 	_formi_dbg_printf(
   2924 	     "%s: cursor_xpos=%d, row_xpos=%d, start_char=%d, length=%d, "
   2925 	     "allocated=%d\n", __func__, cur->cursor_xpos, cur->row_xpos,
   2926 	     cur->start_char, cur->cur_line->length, cur->cur_line->allocated);
   2927 	_formi_dbg_printf("%s: start_line=%p, ypos=%d\n", __func__,
   2928 	    cur->start_line, cur->cursor_ypos);
   2929 	_formi_dbg_printf("%s: string=\"%s\"\n", __func__,
   2930 	    cur->cur_line->string);
   2931 	assert ((cur->cursor_xpos < INT_MAX) && (cur->row_xpos < INT_MAX)
   2932 		&& (cur->cursor_xpos >= cur->row_xpos));
   2933 	return 1;
   2934 }
   2935 
   2936 /*
   2937  * Validate the given character by passing it to any type character
   2938  * checking routines, if they exist.
   2939  */
   2940 int
   2941 _formi_validate_char(FIELD *field, char c)
   2942 {
   2943 	int ret_val;
   2944 
   2945 	if (field->type == NULL)
   2946 		return E_OK;
   2947 
   2948 	ret_val = E_INVALID_FIELD;
   2949 	_formi_do_char_validation(field, field->type, c, &ret_val);
   2950 
   2951 	return ret_val;
   2952 }
   2953 
   2954 
   2955 /*
   2956  * Perform the validation of the character, invoke all field_type validation
   2957  * routines.  If the field is ok then update ret_val to E_OK otherwise
   2958  * ret_val is not changed.
   2959  */
   2960 static void
   2961 _formi_do_char_validation(FIELD *field, FIELDTYPE *type, char c, int *ret_val)
   2962 {
   2963 	if ((type->flags & _TYPE_IS_LINKED) == _TYPE_IS_LINKED) {
   2964 		_formi_do_char_validation(field, type->link->next, c, ret_val);
   2965 		_formi_do_char_validation(field, type->link->prev, c, ret_val);
   2966 	} else {
   2967 		if (type->char_check == NULL)
   2968 			*ret_val = E_OK;
   2969 		else {
   2970 			if (type->char_check((int)(unsigned char) c,
   2971 					     field->args) == TRUE)
   2972 				*ret_val = E_OK;
   2973 		}
   2974 	}
   2975 }
   2976 
   2977 /*
   2978  * Validate the current field.  If the field validation returns success then
   2979  * return E_OK otherwise return E_INVALID_FIELD.
   2980  *
   2981  */
   2982 int
   2983 _formi_validate_field(FORM *form)
   2984 {
   2985 	FIELD *cur;
   2986 	int ret_val, count;
   2987 
   2988 
   2989 	if ((form == NULL) || (form->fields == NULL) ||
   2990 	    (form->fields[0] == NULL))
   2991 		return E_INVALID_FIELD;
   2992 
   2993 	cur = form->fields[form->cur_field];
   2994 
   2995 	  /*
   2996 	   * Sync the buffer if it has been modified so the field
   2997 	   * validation routines can use it and because this is
   2998 	   * the correct behaviour according to AT&T implementation.
   2999 	   */
   3000 	if ((cur->buf0_status == TRUE)
   3001 	    && ((ret_val = _formi_sync_buffer(cur)) != E_OK))
   3002 			return ret_val;
   3003 
   3004 	  /*
   3005 	   * If buffer is untouched then the string pointer may be
   3006 	   * NULL, see if this is ok or not.
   3007 	   */
   3008 	if (cur->buffers[0].string == NULL) {
   3009 		if ((cur->opts & O_NULLOK) == O_NULLOK)
   3010 			return E_OK;
   3011 		else
   3012 			return E_INVALID_FIELD;
   3013 	}
   3014 
   3015 	count = _formi_skip_blanks(cur->buffers[0].string, 0);
   3016 
   3017 	  /* check if we have a null field, depending on the nullok flag
   3018 	   * this may be acceptable or not....
   3019 	   */
   3020 	if (cur->buffers[0].string[count] == '\0') {
   3021 		if ((cur->opts & O_NULLOK) == O_NULLOK)
   3022 			return E_OK;
   3023 		else
   3024 			return E_INVALID_FIELD;
   3025 	}
   3026 
   3027 	  /* check if an unmodified field is ok */
   3028 	if (cur->buf0_status == 0) {
   3029 		if ((cur->opts & O_PASSOK) == O_PASSOK)
   3030 			return E_OK;
   3031 		else
   3032 			return E_INVALID_FIELD;
   3033 	}
   3034 
   3035 	  /* if there is no type then just accept the field */
   3036 	if (cur->type == NULL)
   3037 		return E_OK;
   3038 
   3039 	ret_val = E_INVALID_FIELD;
   3040 	_formi_do_validation(cur, cur->type, &ret_val);
   3041 
   3042 	return ret_val;
   3043 }
   3044 
   3045 /*
   3046  * Perform the validation of the field, invoke all field_type validation
   3047  * routines.  If the field is ok then update ret_val to E_OK otherwise
   3048  * ret_val is not changed.
   3049  */
   3050 static void
   3051 _formi_do_validation(FIELD *field, FIELDTYPE *type, int *ret_val)
   3052 {
   3053 	if ((type->flags & _TYPE_IS_LINKED) == _TYPE_IS_LINKED) {
   3054 		_formi_do_validation(field, type->link->next, ret_val);
   3055 		_formi_do_validation(field, type->link->prev, ret_val);
   3056 	} else {
   3057 		if (type->field_check == NULL)
   3058 			*ret_val = E_OK;
   3059 		else {
   3060 			if (type->field_check(field, field_buffer(field, 0))
   3061 			    == TRUE)
   3062 				*ret_val = E_OK;
   3063 		}
   3064 	}
   3065 }
   3066 
   3067 /*
   3068  * Select the next/previous choice for the field, the driver command
   3069  * selecting the direction will be passed in c.  Return 1 if a choice
   3070  * selection succeeded, 0 otherwise.
   3071  */
   3072 int
   3073 _formi_field_choice(FORM *form, int c)
   3074 {
   3075 	FIELDTYPE *type;
   3076 	FIELD *field;
   3077 
   3078 	if ((form == NULL) || (form->fields == NULL) ||
   3079 	    (form->fields[0] == NULL) ||
   3080 	    (form->fields[form->cur_field]->type == NULL))
   3081 		return 0;
   3082 
   3083 	field = form->fields[form->cur_field];
   3084 	type = field->type;
   3085 
   3086 	switch (c) {
   3087 	case REQ_NEXT_CHOICE:
   3088 		if (type->next_choice == NULL)
   3089 			return 0;
   3090 		else
   3091 			return type->next_choice(field,
   3092 						 field_buffer(field, 0));
   3093 
   3094 	case REQ_PREV_CHOICE:
   3095 		if (type->prev_choice == NULL)
   3096 			return 0;
   3097 		else
   3098 			return type->prev_choice(field,
   3099 						 field_buffer(field, 0));
   3100 
   3101 	default: /* should never happen! */
   3102 		return 0;
   3103 	}
   3104 }
   3105 
   3106 /*
   3107  * Update the fields if they have changed.  The parameter old has the
   3108  * previous current field as the current field may have been updated by
   3109  * the driver.  Return 1 if the form page needs updating.
   3110  *
   3111  */
   3112 int
   3113 _formi_update_field(FORM *form, int old_field)
   3114 {
   3115 	int cur, i;
   3116 
   3117 	cur = form->cur_field;
   3118 
   3119 	if (old_field != cur) {
   3120 		if (!((cur >= form->page_starts[form->page].first) &&
   3121 		      (cur <= form->page_starts[form->page].last))) {
   3122 			  /* not on same page any more */
   3123 			for (i = 0; i < form->max_page; i++) {
   3124 				if ((form->page_starts[i].in_use == 1) &&
   3125 				    (form->page_starts[i].first <= cur) &&
   3126 				    (form->page_starts[i].last >= cur)) {
   3127 					form->page = i;
   3128 					return 1;
   3129 				}
   3130 			}
   3131 		}
   3132 	}
   3133 
   3134 	_formi_redraw_field(form, old_field);
   3135 	_formi_redraw_field(form, form->cur_field);
   3136 	return 0;
   3137 }
   3138 
   3139 /*
   3140  * Compare function for the field sorting
   3141  *
   3142  */
   3143 static int
   3144 field_sort_compare(const void *one, const void *two)
   3145 {
   3146 	const FIELD *a, *b;
   3147 	int tl;
   3148 
   3149 	a = *(const FIELD **) __UNCONST(one);
   3150 	b = *(const FIELD **) __UNCONST(two);
   3151 
   3152 	if (a == NULL)
   3153 		return 1;
   3154 
   3155 	if (b == NULL)
   3156 		return -1;
   3157 
   3158 	  /*
   3159 	   * First check the page, we want the fields sorted by page.
   3160 	   *
   3161 	   */
   3162 	if (a->page != b->page)
   3163 		return ((a->page > b->page)? 1 : -1);
   3164 
   3165 	tl = _formi_top_left(a->parent, a->index, b->index);
   3166 
   3167 	  /*
   3168 	   * sort fields left to right, top to bottom so the top left is
   3169 	   * the lesser value....
   3170 	   */
   3171 	return ((tl == a->index)? -1 : 1);
   3172 }
   3173 
   3174 /*
   3175  * Sort the fields in a form ready for driver traversal.
   3176  */
   3177 void
   3178 _formi_sort_fields(FORM *form)
   3179 {
   3180 	FIELD **sort_area;
   3181 	int i;
   3182 
   3183 	TAILQ_INIT(&form->sorted_fields);
   3184 
   3185 	if ((sort_area = malloc(sizeof(*sort_area) * form->field_count))
   3186 	    == NULL)
   3187 		return;
   3188 
   3189 	memcpy(sort_area, form->fields, sizeof(*sort_area) * form->field_count);
   3190 	qsort(sort_area, (size_t) form->field_count, sizeof(FIELD *),
   3191 	      field_sort_compare);
   3192 
   3193 	for (i = 0; i < form->field_count; i++)
   3194 		TAILQ_INSERT_TAIL(&form->sorted_fields, sort_area[i], glue);
   3195 
   3196 	free(sort_area);
   3197 }
   3198 
   3199 /*
   3200  * Set the neighbours for all the fields in the given form.
   3201  */
   3202 void
   3203 _formi_stitch_fields(FORM *form)
   3204 {
   3205 	int above_row, below_row, end_above, end_below, cur_row, real_end;
   3206 	FIELD *cur, *above, *below;
   3207 
   3208 	  /*
   3209 	   * check if the sorted fields circle queue is empty, just
   3210 	   * return if it is.
   3211 	   */
   3212 	if (TAILQ_EMPTY(&form->sorted_fields))
   3213 		return;
   3214 
   3215 	  /* initially nothing is above..... */
   3216 	above_row = -1;
   3217 	end_above = TRUE;
   3218 	above = NULL;
   3219 
   3220 	  /* set up the first field as the current... */
   3221 	cur = TAILQ_FIRST(&form->sorted_fields);
   3222 	cur_row = cur->form_row;
   3223 
   3224 	  /* find the first field on the next row if any */
   3225 	below = TAILQ_NEXT(cur, glue);
   3226 	below_row = -1;
   3227 	end_below = TRUE;
   3228 	real_end = TRUE;
   3229 	while (below != NULL) {
   3230 		if (below->form_row != cur_row) {
   3231 			below_row = below->form_row;
   3232 			end_below = FALSE;
   3233 			real_end = FALSE;
   3234 			break;
   3235 		}
   3236 		below = TAILQ_NEXT(below, glue);
   3237 	}
   3238 
   3239 	  /* walk the sorted fields, setting the neighbour pointers */
   3240 	while (cur != NULL) {
   3241 		if (cur == TAILQ_FIRST(&form->sorted_fields))
   3242 			cur->left = NULL;
   3243 		else
   3244 			cur->left = TAILQ_PREV(cur, _formi_sort_head, glue);
   3245 
   3246 		if (cur == TAILQ_LAST(&form->sorted_fields, _formi_sort_head))
   3247 			cur->right = NULL;
   3248 		else
   3249 			cur->right = TAILQ_NEXT(cur, glue);
   3250 
   3251 		if (end_above == TRUE)
   3252 			cur->up = NULL;
   3253 		else {
   3254 			cur->up = above;
   3255 			above = TAILQ_NEXT(above, glue);
   3256 			if (above_row != above->form_row) {
   3257 				end_above = TRUE;
   3258 				above_row = above->form_row;
   3259 			}
   3260 		}
   3261 
   3262 		if (end_below == TRUE)
   3263 			cur->down = NULL;
   3264 		else {
   3265 			cur->down = below;
   3266 			below = TAILQ_NEXT(below, glue);
   3267 			if (below == NULL) {
   3268 				end_below = TRUE;
   3269 				real_end = TRUE;
   3270 			} else if (below_row != below->form_row) {
   3271 				end_below = TRUE;
   3272 				below_row = below->form_row;
   3273 			}
   3274 		}
   3275 
   3276 		cur = TAILQ_NEXT(cur, glue);
   3277 		if ((cur != NULL)
   3278 		    && (cur_row != cur->form_row)) {
   3279 			cur_row = cur->form_row;
   3280 			if (end_above == FALSE) {
   3281 				for (; above !=
   3282 				    TAILQ_FIRST(&form->sorted_fields);
   3283 				    above = TAILQ_NEXT(above, glue)) {
   3284 					if (above->form_row != above_row) {
   3285 						above_row = above->form_row;
   3286 						break;
   3287 					}
   3288 				}
   3289 			} else if (above == NULL) {
   3290 				above = TAILQ_FIRST(&form->sorted_fields);
   3291 				end_above = FALSE;
   3292 				above_row = above->form_row;
   3293 			} else
   3294 				end_above = FALSE;
   3295 
   3296 			if (end_below == FALSE) {
   3297 				while (below_row == below->form_row) {
   3298 					below = TAILQ_NEXT(below, glue);
   3299 					if (below == NULL) {
   3300 						real_end = TRUE;
   3301 						end_below = TRUE;
   3302 						break;
   3303 					}
   3304 				}
   3305 
   3306 				if (below != NULL)
   3307 					below_row = below->form_row;
   3308 			} else if (real_end == FALSE)
   3309 				end_below = FALSE;
   3310 
   3311 		}
   3312 	}
   3313 }
   3314 
   3315 /*
   3316  * Calculate the length of the displayed line allowing for any tab
   3317  * characters that need to be expanded.  We assume that the tab stops
   3318  * are 8 characters apart.  The parameters start and end are the
   3319  * character positions in the string str we want to get the length of,
   3320  * the function returns the number of characters from the start
   3321  * position to the end position that should be displayed after any
   3322  * intervening tabs have been expanded.
   3323  */
   3324 int
   3325 _formi_tab_expanded_length(char *str, unsigned int start, unsigned int end)
   3326 {
   3327 	int len, start_len, i;
   3328 
   3329 	  /* if we have a null string then there is no length */
   3330 	if (str[0] == '\0')
   3331 		return 0;
   3332 
   3333 	len = 0;
   3334 	start_len = 0;
   3335 
   3336 	  /*
   3337 	   * preceding tabs affect the length tabs in the span, so
   3338 	   * we need to calculate the length including the stuff before
   3339 	   * start and then subtract off the unwanted bit.
   3340 	   */
   3341 	for (i = 0; i <= end; i++) {
   3342 		if (i == start) /* stash preamble length for later */
   3343 			start_len = len;
   3344 
   3345 		if (str[i] == '\0')
   3346 			break;
   3347 
   3348 		if (str[i] == '\t')
   3349 			len = len - (len % 8) + 8;
   3350 		else
   3351 			len++;
   3352 	}
   3353 
   3354 	_formi_dbg_printf(
   3355 	    "%s: start=%d, end=%d, expanded=%d (diff=%d)\n", __func__,
   3356 	    start, end, (len - start_len), (end - start));
   3357 
   3358 	return (len - start_len);
   3359 }
   3360 
   3361 /*
   3362  * Calculate the tab stops on a given line in the field and set up
   3363  * the tabs list with the results.  We do this by scanning the line for tab
   3364  * characters and if one is found, noting the position and the number of
   3365  * characters to get to the next tab stop.  This information is kept to
   3366  * make manipulating the field (scrolling and so on) easier to handle.
   3367  */
   3368 void
   3369 _formi_calculate_tabs(_FORMI_FIELD_LINES *row)
   3370 {
   3371 	_formi_tab_t *ts = row->tabs, *old_ts = NULL, **tsp;
   3372 	int i, j;
   3373 
   3374 	  /*
   3375 	   * If the line already has tabs then invalidate them by
   3376 	   * walking the list and killing the in_use flag.
   3377 	   */
   3378 	for (; ts != NULL; ts = ts->fwd)
   3379 		ts->in_use = FALSE;
   3380 
   3381 
   3382 	  /*
   3383 	   * Now look for tabs in the row and record the info...
   3384 	   */
   3385 	tsp = &row->tabs;
   3386 	for (i = 0, j = 0; i < row->length; i++, j++) {
   3387 		if (row->string[i] == '\t') {
   3388 			if (*tsp == NULL) {
   3389 				if ((*tsp = malloc(sizeof(**tsp))) == NULL)
   3390 					return;
   3391 				(*tsp)->back = old_ts;
   3392 				(*tsp)->fwd = NULL;
   3393 			}
   3394 
   3395 			(*tsp)->in_use = TRUE;
   3396 			(*tsp)->pos = i;
   3397 			(*tsp)->size = 8 - (j % 8);
   3398 			j += (*tsp)->size - 1;
   3399 			old_ts = *tsp;
   3400 			tsp = &(*tsp)->fwd;
   3401 		}
   3402 	}
   3403 }
   3404 
   3405 /*
   3406  * Return the size of the tab padding for a tab character at the given
   3407  * position.  Return 1 if there is not a tab char entry matching the
   3408  * given location.
   3409  */
   3410 static int
   3411 tab_size(_FORMI_FIELD_LINES *row, unsigned int i)
   3412 {
   3413 	_formi_tab_t *ts;
   3414 
   3415 	ts = row->tabs;
   3416 	while ((ts != NULL) && (ts->pos != i))
   3417 		ts = ts->fwd;
   3418 
   3419 	if (ts == NULL)
   3420 		return 1;
   3421 	else
   3422 		return ts->size;
   3423 }
   3424 
   3425 /*
   3426  * Find the character offset that corresponds to longest tab expanded
   3427  * string that will fit into the given window.  Walk the string backwards
   3428  * evaluating the sizes of any tabs that are in the string.  Note that
   3429  * using this function on a multi-line window will produce undefined
   3430  * results - it is really only required for a single row field.
   3431  */
   3432 static int
   3433 tab_fit_window(FIELD *field, unsigned int pos, unsigned int window)
   3434 {
   3435 	int scroll_amt, i;
   3436 	_formi_tab_t *ts;
   3437 
   3438 	  /* first find the last tab */
   3439 	ts = field->alines->tabs;
   3440 
   3441 	  /*
   3442 	   * unless there are no tabs - just return the window size,
   3443 	   * if there is enough room, otherwise 0.
   3444 	   */
   3445 	if (ts == NULL) {
   3446 		if (field->alines->length < window)
   3447 			return 0;
   3448 		else
   3449 			return field->alines->length - window + 1;
   3450 	}
   3451 
   3452 	while ((ts->fwd != NULL) && (ts->fwd->in_use == TRUE))
   3453 		ts = ts->fwd;
   3454 
   3455 	  /*
   3456 	   * now walk backwards finding the first tab that is to the
   3457 	   * left of our starting pos.
   3458 	   */
   3459 	while ((ts != NULL) && (ts->in_use == TRUE) && (ts->pos > pos))
   3460 		ts = ts->back;
   3461 
   3462 	scroll_amt = 0;
   3463 	for (i = pos; i >= 0; i--) {
   3464 		if (field->alines->string[i] == '\t') {
   3465 			assert((ts != NULL) && (ts->in_use == TRUE));
   3466 			if (ts->pos == i) {
   3467 				if ((scroll_amt + ts->size) > window) {
   3468 					break;
   3469 				}
   3470 				scroll_amt += ts->size;
   3471 				ts = ts->back;
   3472 			}
   3473 			else
   3474 				assert(ts->pos == i);
   3475 		} else {
   3476 			scroll_amt++;
   3477 			if (scroll_amt > window)
   3478 				break;
   3479 		}
   3480 	}
   3481 
   3482 	return ++i;
   3483 }
   3484 
   3485 /*
   3486  * Return the position of the last character that will fit into the
   3487  * given width after tabs have been expanded for a given row of a given
   3488  * field.
   3489  */
   3490 static unsigned int
   3491 tab_fit_len(_FORMI_FIELD_LINES *row, unsigned int width)
   3492 {
   3493 	unsigned int pos, len, row_pos;
   3494 	_formi_tab_t *ts;
   3495 
   3496 	ts = row->tabs;
   3497 	pos = 0;
   3498 	len = 0;
   3499 	row_pos = 0;
   3500 
   3501 	if (width == 0)
   3502 		return 0;
   3503 
   3504 	while ((len < width) && (pos < row->length)) {
   3505 		if (row->string[pos] == '\t') {
   3506 			assert((ts != NULL) && (ts->in_use == TRUE));
   3507 			if (ts->pos == row_pos) {
   3508 				if ((len + ts->size) > width)
   3509 					break;
   3510 				len += ts->size;
   3511 				ts = ts->fwd;
   3512 			}
   3513 			else
   3514 				assert(ts->pos == row_pos);
   3515 		} else
   3516 			len++;
   3517 		pos++;
   3518 		row_pos++;
   3519 	}
   3520 
   3521 	if (pos > 0)
   3522 		pos--;
   3523 	return pos;
   3524 }
   3525 
   3526 /*
   3527  * Sync the field line structures with the contents of buffer 0 for that
   3528  * field.  We do this by walking all the line structures and concatenating
   3529  * all the strings into one single string in buffer 0.
   3530  */
   3531 int
   3532 _formi_sync_buffer(FIELD *field)
   3533 {
   3534 	_FORMI_FIELD_LINES *line;
   3535 	char *nstr, *tmp;
   3536 	unsigned length;
   3537 
   3538 	if (field->alines == NULL)
   3539 		return E_BAD_ARGUMENT;
   3540 
   3541 	if (field->alines->string == NULL)
   3542 		return E_BAD_ARGUMENT;
   3543 
   3544 	  /*
   3545 	   * init nstr up front, just in case there are no line contents,
   3546 	   * this could happen if the field just contains hard returns.
   3547 	   */
   3548 	if ((nstr = malloc(sizeof(*nstr))) == NULL)
   3549 		return E_SYSTEM_ERROR;
   3550 	nstr[0] = '\0';
   3551 
   3552 	line = field->alines;
   3553 	length = 1; /* allow for terminating null */
   3554 
   3555 	while (line != NULL) {
   3556 		if (line->length != 0) {
   3557 			if ((tmp = realloc(nstr,
   3558 					   (size_t) (length + line->length)))
   3559 			    == NULL) {
   3560 				if (nstr != NULL)
   3561 					free(nstr);
   3562 				return (E_SYSTEM_ERROR);
   3563 			}
   3564 
   3565 			nstr = tmp;
   3566 			strcat(nstr, line->string);
   3567 			length += line->length;
   3568 		}
   3569 
   3570 		line = line->next;
   3571 	}
   3572 
   3573 	if (field->buffers[0].string != NULL)
   3574 		free(field->buffers[0].string);
   3575 	field->buffers[0].allocated = length;
   3576 	field->buffers[0].length = length - 1;
   3577 	field->buffers[0].string = nstr;
   3578 	return E_OK;
   3579 }
   3580 
   3581 
   3582 
   3583