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field.c revision 1.21
      1 /*	$NetBSD: field.c,v 1.21 2002/08/09 14:15:12 blymn Exp $	*/
      2 /*-
      3  * Copyright (c) 1998-1999 Brett Lymn
      4  *                         (blymn (at) baea.com.au, brett_lymn (at) yahoo.com.au)
      5  * All rights reserved.
      6  *
      7  * This code has been donated to The NetBSD Foundation by the Author.
      8  *
      9  * Redistribution and use in source and binary forms, with or without
     10  * modification, are permitted provided that the following conditions
     11  * are met:
     12  * 1. Redistributions of source code must retain the above copyright
     13  *    notice, this list of conditions and the following disclaimer.
     14  * 2. The name of the author may not be used to endorse or promote products
     15  *    derived from this software without specific prior written permission
     16  *
     17  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
     18  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
     19  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
     20  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
     21  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
     22  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
     23  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
     24  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
     25  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
     26  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
     27  *
     28  *
     29  */
     30 
     31 #include <stdlib.h>
     32 #include <strings.h>
     33 #include <stdarg.h>
     34 #include <form.h>
     35 #include "internals.h"
     36 
     37 extern FORM _formi_default_form;
     38 
     39 FIELD _formi_default_field = {
     40 	0, /* rows in the field */
     41 	0, /* columns in the field */
     42 	0, /* dynamic rows */
     43 	0, /* dynamic columns */
     44 	0, /* maximum growth */
     45 	0, /* starting row in the form subwindow */
     46 	0, /* starting column in the form subwindow */
     47 	0, /* number of off screen rows */
     48 	0, /* index of this field in form fields array. */
     49 	0, /* number of buffers associated with this field */
     50 	FALSE, /* set to true if buffer 0 has changed. */
     51 	NO_JUSTIFICATION, /* justification style of the field */
     52 	FALSE, /* set to true if field is in overlay mode */
     53 	0, /* starting char in string (horiz scroll) */
     54 	0, /* starting line in field (vert scroll) */
     55 	0, /* number of rows actually used in field */
     56 	0, /* actual pos of cursor in row, not same as x pos due to tabs */
     57 	0, /* x pos of cursor in field */
     58 	0, /* y pos of cursor in field */
     59 	0, /* start of a new page on the form if 1 */
     60 	0, /* number of the page this field is on */
     61 	A_NORMAL, /* character attributes for the foreground */
     62 	A_NORMAL, /* character attributes for the background */
     63 	' ', /* padding character */
     64 	DEFAULT_FORM_OPTS, /* options for the field */
     65 	NULL, /* the form this field is bound to, if any */
     66 	NULL, /* field above this one */
     67 	NULL, /* field below this one */
     68 	NULL, /* field to the left of this one */
     69 	NULL, /* field to the right of this one */
     70 	NULL,  /* user defined pointer. */
     71 	NULL, /* used if fields are linked */
     72 	NULL, /* type struct for the field */
     73 	{NULL, NULL}, /* circle queue glue for sorting fields */
     74 	NULL, /* args for field type. */
     75 	0,    /* number of allocated slots in lines array */
     76 	NULL, /* pointer to the array of lines structures. */
     77 	NULL, /* array of buffers for the field */
     78 };
     79 
     80 /* internal function prototypes */
     81 static int
     82 field_buffer_init(FIELD *field, int buffer, size_t len);
     83 static FIELD *
     84 _formi_create_field(FIELD *, int, int, int, int, int, int);
     85 
     86 
     87 /*
     88  * Set the userptr for the field
     89  */
     90 int
     91 set_field_userptr(FIELD *field, void *ptr)
     92 {
     93 	FIELD *fp = (field == NULL) ? &_formi_default_field : field;
     94 
     95 	fp->userptr = ptr;
     96 
     97 	return E_OK;
     98 }
     99 
    100 /*
    101  * Return the userptr for the field.
    102  */
    103 
    104 void *
    105 field_userptr(FIELD *field)
    106 {
    107 	if (field == NULL)
    108 		return _formi_default_field.userptr;
    109 	else
    110 		return field->userptr;
    111 }
    112 
    113 /*
    114  * Set the options for the designated field.
    115  */
    116 int
    117 set_field_opts(FIELD *field, Form_Options options)
    118 {
    119 	int i;
    120 
    121 	FIELD *fp = (field == NULL) ? &_formi_default_field : field;
    122 
    123 	  /* not allowed to set opts if the field is the current one */
    124 	if ((field != NULL) && (field->parent != NULL) &&
    125 	    (field->parent->cur_field == field->index))
    126 		return E_CURRENT;
    127 
    128 	if ((options & O_STATIC) == O_STATIC) {
    129 		for (i = 0; i < fp->nbuf; i++) {
    130 			if (fp->buffers[i].length > fp->cols)
    131 				fp->buffers[i].string[fp->cols] = '\0';
    132 		}
    133 	}
    134 
    135 	fp->opts = options;
    136 
    137 	  /* if appropriate, redraw the field */
    138 	if ((field != NULL) && (field->parent != NULL)
    139 	    && (field->parent->posted == 1)) {
    140 		_formi_redraw_field(field->parent, field->index);
    141 		pos_form_cursor(field->parent);
    142 		wrefresh(field->parent->scrwin);
    143 	}
    144 
    145 	return E_OK;
    146 }
    147 
    148 /*
    149  * Turn on the passed field options.
    150  */
    151 int
    152 field_opts_on(FIELD *field, Form_Options options)
    153 {
    154 	int i;
    155 
    156 	FIELD *fp = (field == NULL) ? &_formi_default_field : field;
    157 
    158 	  /* not allowed to set opts if the field is the current one */
    159 	if ((field != NULL) && (field->parent != NULL) &&
    160 	    (field->parent->cur_field == field->index))
    161 		return E_CURRENT;
    162 
    163 	if ((options & O_STATIC) == O_STATIC) {
    164 		for (i = 0; i < fp->nbuf; i++) {
    165 			if (fp->buffers[i].length > fp->cols)
    166 				fp->buffers[i].string[fp->cols] = '\0';
    167 		}
    168 	}
    169 
    170 	fp->opts |= options;
    171 
    172 	  /* if appropriate, redraw the field */
    173 	if ((field != NULL) && (field->parent != NULL)
    174 	    && (field->parent->posted == 1)) {
    175 		_formi_redraw_field(field->parent, field->index);
    176 		pos_form_cursor(field->parent);
    177 		wrefresh(field->parent->scrwin);
    178 	}
    179 
    180 	return E_OK;
    181 }
    182 
    183 /*
    184  * Turn off the passed field options.
    185  */
    186 int
    187 field_opts_off(FIELD *field, Form_Options options)
    188 {
    189 	FIELD *fp = (field == NULL) ? &_formi_default_field : field;
    190 
    191 	  /* not allowed to set opts if the field is the current one */
    192 	if ((field != NULL) && (field->parent != NULL) &&
    193 	    (field->parent->cur_field == field->index))
    194 		return E_CURRENT;
    195 
    196 	fp->opts &= ~options;
    197 
    198 	  /* if appropriate, redraw the field */
    199 	if ((field != NULL) && (field->parent != NULL)
    200 	    && (field->parent->posted == 1)) {
    201 		_formi_redraw_field(field->parent, field->index);
    202 		pos_form_cursor(field->parent);
    203 		wrefresh(field->parent->scrwin);
    204 	}
    205 
    206 	return E_OK;
    207 }
    208 
    209 /*
    210  * Return the field options associated with the passed field.
    211  */
    212 Form_Options
    213 field_opts(FIELD *field)
    214 {
    215 	if (field == NULL)
    216 		return _formi_default_field.opts;
    217 	else
    218 		return field->opts;
    219 }
    220 
    221 /*
    222  * Set the justification for the passed field.
    223  */
    224 int
    225 set_field_just(FIELD *field, int justification)
    226 {
    227 	FIELD *fp = (field == NULL) ? &_formi_default_field : field;
    228 
    229 	  /*
    230 	   * not allowed to set justification if the field is
    231 	   * the current one
    232 	   */
    233 	if ((field != NULL) && (field->parent != NULL) &&
    234 	    (field->parent->cur_field == field->index))
    235 		return E_CURRENT;
    236 
    237 	if ((justification < MIN_JUST_STYLE) /* check justification valid */
    238 	    || (justification > MAX_JUST_STYLE))
    239 		return E_BAD_ARGUMENT;
    240 
    241 	  /* only allow justification on static, single row fields */
    242 	if (((fp->opts & O_STATIC) != O_STATIC) ||
    243 	    ((fp->rows + fp->nrows) > 1))
    244 		return E_BAD_ARGUMENT;
    245 
    246 	fp->justification = justification;
    247 
    248 	_formi_init_field_xpos(fp);
    249 
    250 	return E_OK;
    251 }
    252 
    253 /*
    254  * Return the justification style of the field passed.
    255  */
    256 int
    257 field_just(FIELD *field)
    258 {
    259 	if (field == NULL)
    260 		return _formi_default_field.justification;
    261 	else
    262 		return field->justification;
    263 }
    264 
    265 /*
    266  * Return information about the field passed.
    267  */
    268 int
    269 field_info(FIELD *field, int *rows, int *cols, int *frow, int *fcol,
    270 	   int *nrow, int *nbuf)
    271 {
    272 	if (field == NULL)
    273 		return E_BAD_ARGUMENT;
    274 
    275 	*rows = field->rows;
    276 	*cols = field->cols;
    277 	*frow = field->form_row;
    278 	*fcol = field->form_col;
    279 	*nrow = field->nrows;
    280 	*nbuf = field->nbuf;
    281 
    282 	return E_OK;
    283 }
    284 
    285 /*
    286  * Report the dynamic field information.
    287  */
    288 int
    289 dynamic_field_info(FIELD *field, int *drows, int *dcols, int *max)
    290 {
    291 	if (field == NULL)
    292 		return E_BAD_ARGUMENT;
    293 
    294 	if ((field->opts & O_STATIC) == O_STATIC) {
    295 		*drows = field->rows;
    296 		*dcols = field->cols;
    297 	} else {
    298 		*drows = field->drows;
    299 		*dcols = field->dcols;
    300 	}
    301 
    302 	*max = field->max;
    303 
    304 	return E_OK;
    305 }
    306 
    307 /*
    308  * Init all the field variables, perform wrapping and other tasks
    309  * after the field buffer is set.
    310  */
    311 static int
    312 field_buffer_init(FIELD *field, int buffer, size_t len)
    313 {
    314 	int status;
    315 
    316 	if (buffer == 0) {
    317 		field->start_char = 0;
    318 		field->start_line = 0;
    319 		field->row_xpos = 0;
    320 		field->cursor_xpos = 0;
    321 		field->cursor_ypos = 0;
    322 		field->row_count = 1; /* must be at least one row */
    323 		field->lines[0].start = 0;
    324 		field->lines[0].end = (len > 0)? (len - 1) : 0;
    325 		field->lines[0].length =
    326 			_formi_tab_expanded_length(field->buffers[0].string,
    327 						   0, field->lines[0].end);
    328 
    329 		  /* we have to hope the wrap works - if it does not then the
    330 		     buffer is pretty much borked */
    331 		status = _formi_wrap_field(field, 0);
    332 		if (status != E_OK)
    333 			return status;
    334 
    335 		  /*
    336 		   * calculate the tabs for a single row field, the
    337 		   * multiline case is handled when the wrap is done.
    338 		   */
    339 		if (field->row_count == 1)
    340 			_formi_calculate_tabs(field, 0);
    341 
    342 		  /* redraw the field to reflect the new contents. If the field
    343 		   * is attached....
    344 		   */
    345 		if ((field->parent != NULL) && (field->parent->posted == 1)) {
    346 			_formi_redraw_field(field->parent, field->index);
    347 			  /* make sure cursor goes back to current field */
    348 			pos_form_cursor(field->parent);
    349 		}
    350 	}
    351 
    352 	return E_OK;
    353 }
    354 
    355 
    356 /*
    357  * Set the field buffer to the string that results from processing
    358  * the given format (fmt) using sprintf.
    359  */
    360 int
    361 set_field_printf(FIELD *field, int buffer, char *fmt, ...)
    362 {
    363 	int len;
    364 	va_list args;
    365 
    366 	if (field == NULL)
    367 		return E_BAD_ARGUMENT;
    368 
    369 	if (buffer >= field->nbuf)
    370 		return E_BAD_ARGUMENT;
    371 
    372 	va_start(args, fmt);
    373 	  /* check for buffer already existing, free the storage */
    374 	if (field->buffers[buffer].allocated != 0)
    375 		free(field->buffers[buffer].string);
    376 
    377 	len = vasprintf(&field->buffers[buffer].string, fmt, args);
    378 	va_end(args);
    379 	if (len < 0)
    380 		return E_SYSTEM_ERROR;
    381 
    382 	field->buffers[buffer].length = len;
    383 	field->buffers[buffer].allocated = len + 1;
    384 	if (((field->opts & O_STATIC) == O_STATIC) && (len > field->cols)
    385 	    && ((field->rows + field->nrows) == 1))
    386 		len = field->cols;
    387 
    388 	field->buffers[buffer].string[len] = '\0';
    389 	return field_buffer_init(field, buffer, (unsigned int) len);
    390 }
    391 
    392 /*
    393  * Set the value of the field buffer to the value given.
    394  */
    395 
    396 int
    397 set_field_buffer(FIELD *field, int buffer, char *value)
    398 {
    399 	size_t len;
    400 	int status;
    401 
    402 	if (field == NULL)
    403 		return E_BAD_ARGUMENT;
    404 
    405 	if (buffer >= field->nbuf) /* make sure buffer is valid */
    406 		return E_BAD_ARGUMENT;
    407 
    408 	len = strlen(value);
    409 	if (((field->opts & O_STATIC) == O_STATIC) && (len > field->cols)
    410 	    && ((field->rows + field->nrows) == 1))
    411 		len = field->cols;
    412 
    413 #ifdef DEBUG
    414 	if (_formi_create_dbg_file() != E_OK)
    415 		return E_SYSTEM_ERROR;
    416 
    417 	fprintf(dbg,
    418 		"set_field_buffer: entry: len = %d, value = %s, buffer=%d\n",
    419 		len, value, buffer);
    420 	fprintf(dbg, "set_field_buffer: entry: string = ");
    421 	if (field->buffers[buffer].string != NULL)
    422 		fprintf(dbg, "%s, len = %d\n", field->buffers[buffer].string,
    423 			field->buffers[buffer].length);
    424 	else
    425 		fprintf(dbg, "(null), len = 0\n");
    426 	fprintf(dbg, "set_field_buffer: entry: lines.len = %d\n",
    427 		field->lines[0].length);
    428 #endif
    429 
    430 	if ((field->buffers[buffer].string =
    431 	     (char *) realloc(field->buffers[buffer].string, len + 1)) == NULL)
    432 		return E_SYSTEM_ERROR;
    433 
    434 	strlcpy(field->buffers[buffer].string, value, len + 1);
    435 	field->buffers[buffer].length = len;
    436 	field->buffers[buffer].allocated = len + 1;
    437 	status = field_buffer_init(field, buffer, len);
    438 
    439 #ifdef DEBUG
    440 	fprintf(dbg, "set_field_buffer: exit: len = %d, value = %s\n",
    441 		len, value);
    442 	fprintf(dbg, "set_field_buffer: exit: string = %s, len = %d\n",
    443 		field->buffers[buffer].string, field->buffers[buffer].length);
    444 	fprintf(dbg, "set_field_buffer: exit: lines.len = %d\n",
    445 		field->lines[0].length);
    446 #endif
    447 
    448 	return status;
    449 }
    450 
    451 /*
    452  * Return the requested field buffer to the caller.
    453  */
    454 char *
    455 field_buffer(FIELD *field, int buffer)
    456 {
    457 
    458 	if (field == NULL)
    459 		return NULL;
    460 
    461 	if (buffer >= field->nbuf)
    462 		return NULL;
    463 
    464 	return field->buffers[buffer].string;
    465 }
    466 
    467 /*
    468  * Set the buffer 0 field status.
    469  */
    470 int
    471 set_field_status(FIELD *field, int status)
    472 {
    473 
    474 	if (field == NULL)
    475 		return E_BAD_ARGUMENT;
    476 
    477 	if (status != FALSE)
    478 		field->buf0_status = TRUE;
    479 	else
    480 		field->buf0_status = FALSE;
    481 
    482 	return E_OK;
    483 }
    484 
    485 /*
    486  * Return the buffer 0 status flag for the given field.
    487  */
    488 int
    489 field_status(FIELD *field)
    490 {
    491 
    492 	if (field == NULL) /* the default buffer 0 never changes :-) */
    493 		return FALSE;
    494 
    495 	return field->buf0_status;
    496 }
    497 
    498 /*
    499  * Set the maximum growth for a dynamic field.
    500  */
    501 int
    502 set_max_field(FIELD *fptr, int max)
    503 {
    504 	FIELD *field = (fptr == NULL)? &_formi_default_field : fptr;
    505 
    506 	if ((field->opts & O_STATIC) == O_STATIC) /* check if field dynamic */
    507 		return E_BAD_ARGUMENT;
    508 
    509 	if (max < 0) /* negative numbers are bad.... */
    510 		return E_BAD_ARGUMENT;
    511 
    512 	field->max = max;
    513 	return E_OK;
    514 }
    515 
    516 /*
    517  * Set the field foreground character attributes.
    518  */
    519 int
    520 set_field_fore(FIELD *fptr, chtype attribute)
    521 {
    522 	FIELD *field = (fptr == NULL)? &_formi_default_field : fptr;
    523 
    524 	field->fore = attribute;
    525 	return E_OK;
    526 }
    527 
    528 /*
    529  * Return the foreground character attribute for the given field.
    530  */
    531 chtype
    532 field_fore(FIELD *field)
    533 {
    534 	if (field == NULL)
    535 		return _formi_default_field.fore;
    536 	else
    537 		return field->fore;
    538 }
    539 
    540 /*
    541  * Set the background character attribute for the given field.
    542  */
    543 int
    544 set_field_back(FIELD *field, chtype attribute)
    545 {
    546 	if (field == NULL)
    547 		_formi_default_field.back = attribute;
    548 	else
    549 		field->back = attribute;
    550 
    551 	return E_OK;
    552 }
    553 
    554 /*
    555  * Get the background character attribute for the given field.
    556  */
    557 chtype
    558 field_back(FIELD *field)
    559 {
    560 	if (field == NULL)
    561 		return _formi_default_field.back;
    562 	else
    563 		return field->back;
    564 }
    565 
    566 /*
    567  * Set the pad character for the given field.
    568  */
    569 int
    570 set_field_pad(FIELD *field, int pad)
    571 {
    572 	if (field == NULL)
    573 		_formi_default_field.pad = pad;
    574 	else
    575 		field->pad = pad;
    576 
    577 	return E_OK;
    578 }
    579 
    580 /*
    581  * Return the padding character for the given field.
    582  */
    583 int
    584 field_pad(FIELD *field)
    585 {
    586 	if (field == NULL)
    587 		return _formi_default_field.pad;
    588 	else
    589 		return field->pad;
    590 }
    591 
    592 /*
    593  * Set the field initialisation function hook.
    594  */
    595 int
    596 set_field_init(FORM *form, Form_Hook function)
    597 {
    598 	if (form == NULL)
    599 		_formi_default_form.field_init = function;
    600 	else
    601 		form->field_init = function;
    602 
    603 	return E_OK;
    604 }
    605 
    606 /*
    607  * Return the function hook for the field initialisation.
    608  */
    609 Form_Hook
    610 field_init(FORM *form)
    611 {
    612 	if (form == NULL)
    613 		return _formi_default_form.field_init;
    614 	else
    615 		return form->field_init;
    616 }
    617 
    618 /*
    619  * Set the field termination function hook.
    620  */
    621 int
    622 set_field_term(FORM *form, Form_Hook function)
    623 {
    624 	if (form == NULL)
    625 		_formi_default_form.field_term = function;
    626 	else
    627 		form->field_term = function;
    628 
    629 	return E_OK;
    630 }
    631 
    632 /*
    633  * Return the function hook defined for the field termination.
    634  */
    635 Form_Hook
    636 field_term(FORM *form)
    637 {
    638 	if (form == NULL)
    639 		return _formi_default_form.field_term;
    640 	else
    641 		return form->field_term;
    642 }
    643 
    644 /*
    645  * Set the page flag on the given field to indicate it is the start of a
    646  * new page.
    647  */
    648 int
    649 set_new_page(FIELD *fptr, int page)
    650 {
    651 	FIELD *field = (fptr == NULL)? &_formi_default_field : fptr;
    652 
    653 	if (field->parent != NULL) /* check if field is connected to a form */
    654 		return E_CONNECTED;
    655 
    656 	field->page_break = (page != FALSE);
    657 	return E_OK;
    658 }
    659 
    660 /*
    661  * Return the page status for the given field.  TRUE is returned if the
    662  * field is the start of a new page.
    663  */
    664 int
    665 new_page(FIELD *field)
    666 {
    667 	if (field == NULL)
    668 		return _formi_default_field.page_break;
    669 	else
    670 		return field->page_break;
    671 }
    672 
    673 /*
    674  * Return the index of the field in the form fields array.
    675  */
    676 int
    677 field_index(FIELD *field)
    678 {
    679 	if (field == NULL)
    680 		return E_BAD_ARGUMENT;
    681 
    682 	if (field->parent == NULL)
    683 		return E_NOT_CONNECTED;
    684 
    685 	return field->index;
    686 }
    687 
    688 /*
    689  * Internal function that does most of the work to create a new field.
    690  * The new field is initialised from the information in the prototype
    691  * field passed.
    692  * Returns NULL on error.
    693  */
    694 static FIELD *
    695 _formi_create_field(FIELD *prototype, int rows, int cols, int frow,
    696 		    int fcol, int nrows, int nbuf)
    697 {
    698 	FIELD *new;
    699 
    700 	if ((rows <= 0) || (cols <= 0) || (frow < 0) || (fcol < 0) ||
    701 	    (nrows < 0) || (nbuf < 0))
    702 		return NULL;
    703 
    704 	if ((new = (FIELD *)malloc(sizeof(FIELD))) == NULL) {
    705 		return NULL;
    706 	}
    707 
    708 	  /* copy in the default field info */
    709 	bcopy(prototype, new, sizeof(FIELD));
    710 
    711 	new->nbuf = nbuf + 1;
    712 	new->rows = rows;
    713 	new->cols = cols;
    714 	new->form_row = frow;
    715 	new->form_col = fcol;
    716 	new->nrows = nrows;
    717 	new->link = new;
    718 	return new;
    719 }
    720 
    721 /*
    722  * Create a new field structure.
    723  */
    724 FIELD *
    725 new_field(int rows, int cols, int frow, int fcol, int nrows, int nbuf)
    726 {
    727 	FIELD *new;
    728 	size_t buf_len;
    729 	int i;
    730 
    731 
    732 	if ((new = _formi_create_field(&_formi_default_field, rows, cols,
    733 				       frow, fcol, nrows, nbuf)) == NULL)
    734 		return NULL;
    735 
    736 	buf_len = (nbuf + 1) * sizeof(FORM_STR);
    737 
    738 	if ((new->buffers = (FORM_STR *)malloc(buf_len)) == NULL) {
    739 		free(new);
    740 		return NULL;
    741 	}
    742 
    743 	  /* Initialise the strings to a zero length string */
    744 	for (i = 0; i < nbuf + 1; i++) {
    745 		if ((new->buffers[i].string =
    746 		     (char *) malloc(sizeof(char))) == NULL) {
    747 			free(new->buffers);
    748 			free(new);
    749 			return NULL;
    750 		}
    751 		new->buffers[i].string[0] = '\0';
    752 		new->buffers[i].length = 0;
    753 		new->buffers[i].allocated = 1;
    754 	}
    755 
    756 	if ((new->lines = (_FORMI_FIELD_LINES *)
    757 	     malloc(sizeof(struct _formi_field_lines))) == NULL) {
    758 		free(new->buffers);
    759 		free(new);
    760 		return NULL;
    761 	}
    762 
    763 	new->lines_alloced = 1;
    764 	new->lines[0].length = 0;
    765 	new->lines[0].start = 0;
    766 	new->lines[0].end = 0;
    767 	new->lines[0].tabs = NULL;
    768 
    769 	return new;
    770 }
    771 
    772 /*
    773  * Duplicate the given field, including it's buffers.
    774  */
    775 FIELD *
    776 dup_field(FIELD *field, int frow, int fcol)
    777 {
    778 	FIELD *new;
    779 	size_t row_len, buf_len;
    780 
    781 	if (field == NULL)
    782 		return NULL;
    783 
    784 	  /* XXXX this right???? */
    785 	if ((new = _formi_create_field(field, (int) field->rows,
    786 				       (int ) field->cols,
    787 				       frow, fcol, (int) field->nrows,
    788 				       field->nbuf - 1)) == NULL)
    789 		return NULL;
    790 
    791 	row_len = (field->rows + field->nrows + 1) * field->cols;
    792 	buf_len = (field->nbuf + 1) * row_len * sizeof(FORM_STR);
    793 
    794 	if ((new->buffers = (FORM_STR *)malloc(buf_len)) == NULL) {
    795 		free(new);
    796 		return NULL;
    797 	}
    798 
    799 	  /* copy the buffers from the source field into the new copy */
    800 	bcopy(field->buffers, new->buffers, buf_len);
    801 
    802 	return new;
    803 }
    804 
    805 /*
    806  * Create a new field at the specified location by duplicating the given
    807  * field.  The buffers are shared with the parent field.
    808  */
    809 FIELD *
    810 link_field(FIELD *field, int frow, int fcol)
    811 {
    812 	FIELD *new;
    813 
    814 	if (field == NULL)
    815 		return NULL;
    816 
    817 	if ((new = _formi_create_field(field, (int) field->rows,
    818 				       (int) field->cols,
    819 				       frow, fcol, (int) field->nrows,
    820 				       field->nbuf - 1)) == NULL)
    821 		return NULL;
    822 
    823 	new->link = field->link;
    824 	field->link = new;
    825 
    826 	  /* we are done.  The buffer pointer was copied during the field
    827 	     creation. */
    828 	return new;
    829 }
    830 
    831 /*
    832  * Release all storage allocated to the field
    833  */
    834 int
    835 free_field(FIELD *field)
    836 {
    837 	FIELD *flink;
    838 	int i;
    839 	_formi_tab_t *ts, *nts;
    840 
    841 	if (field == NULL)
    842 		return E_BAD_ARGUMENT;
    843 
    844 	if (field->parent != NULL)
    845 		return E_CONNECTED;
    846 
    847 	if (field->link == field) { /* check if field linked */
    848 		  /* no it is not - release the buffers */
    849 		free(field->buffers);
    850 		  /* free the tab structures */
    851 		for (i = 0; i < field->row_count - 1; i++) {
    852 			if (field->lines[i].tabs != NULL) {
    853 				ts = field->lines[i].tabs;
    854 				while (ts != NULL) {
    855 					nts = ts->fwd;
    856 					free(ts);
    857 					ts = nts;
    858 				}
    859 			}
    860 		}
    861 	} else {
    862 		  /* is linked, traverse the links to find the field referring
    863 		   * to the one to be freed.
    864 		   */
    865 		for (flink = field->link; flink != field; flink = flink->link);
    866 		flink->link = field->link;
    867 	}
    868 
    869 	free(field);
    870 	return E_OK;
    871 }
    872 
    873 
    874