1 /*	$NetBSD: keymacro.c,v 1.21 2016/04/18 17:01:19 christos Exp $	*/
2 
3 /*-
4  * Copyright (c) 1992, 1993
5  *	The Regents of the University of California.  All rights reserved.
6  *
7  * This code is derived from software contributed to Berkeley by
8  * Christos Zoulas of Cornell University.
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. Redistributions in binary form must reproduce the above copyright
16  *    notice, this list of conditions and the following disclaimer in the
17  *    documentation and/or other materials provided with the distribution.
18  * 3. Neither the name of the University nor the names of its contributors
19  *    may be used to endorse or promote products derived from this software
20  *    without specific prior written permission.
21  *
22  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
23  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
24  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
25  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
26  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
27  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
28  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
29  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
30  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
31  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
32  * SUCH DAMAGE.
33  */
34 
35 #include "config.h"
36 #if !defined(lint) && !defined(SCCSID)
37 #if 0
38 static char sccsid[] = "@(#)key.c	8.1 (Berkeley) 6/4/93";
39 #else
40 __RCSID("$NetBSD: keymacro.c,v 1.21 2016/04/18 17:01:19 christos Exp $");
41 #endif
42 #endif /* not lint && not SCCSID */
43 
44 /*
45  * keymacro.c: This module contains the procedures for maintaining
46  *	       the extended-key map.
47  *
48  *      An extended-key (key) is a sequence of keystrokes introduced
49  *	with a sequence introducer and consisting of an arbitrary
50  *	number of characters.  This module maintains a map (the
51  *	el->el_keymacro.map)
52  *	to convert these extended-key sequences into input strs
53  *	(XK_STR) or editor functions (XK_CMD).
54  *
55  *      Warning:
56  *	  If key is a substr of some other keys, then the longer
57  *	  keys are lost!!  That is, if the keys "abcd" and "abcef"
58  *	  are in el->el_keymacro.map, adding the key "abc" will cause
59  *	  the first two definitions to be lost.
60  *
61  *      Restrictions:
62  *      -------------
63  *      1) It is not possible to have one key that is a
64  *	   substr of another.
65  */
66 #include <stdlib.h>
67 #include <string.h>
68 
69 #include "el.h"
70 #include "fcns.h"
71 
72 /*
73  * The Nodes of the el->el_keymacro.map.  The el->el_keymacro.map is a
74  * linked list of these node elements
75  */
76 struct keymacro_node_t {
77 	wchar_t		 ch;		/* single character of key	 */
78 	int		 type;		/* node type			 */
79 	keymacro_value_t val;		/* command code or pointer to str,  */
80 					/* if this is a leaf		 */
81 	struct keymacro_node_t *next;	/* ptr to next char of this key  */
82 	struct keymacro_node_t *sibling;/* ptr to another key with same prefix*/
83 };
84 
85 static int		 node_trav(EditLine *, keymacro_node_t *, wchar_t *,
86     keymacro_value_t *);
87 static int		 node__try(EditLine *, keymacro_node_t *,
88     const wchar_t *, keymacro_value_t *, int);
89 static keymacro_node_t	*node__get(wint_t);
90 static void		 node__free(keymacro_node_t *);
91 static void		 node__put(EditLine *, keymacro_node_t *);
92 static int		 node__delete(EditLine *, keymacro_node_t **,
93     const wchar_t *);
94 static int		 node_lookup(EditLine *, const wchar_t *,
95     keymacro_node_t *, size_t);
96 static int		 node_enum(EditLine *, keymacro_node_t *, size_t);
97 
98 #define	KEY_BUFSIZ	EL_BUFSIZ
99 
100 
101 /* keymacro_init():
102  *	Initialize the key maps
103  */
104 protected int
keymacro_init(EditLine * el)105 keymacro_init(EditLine *el)
106 {
107 
108 	el->el_keymacro.buf = el_malloc(KEY_BUFSIZ *
109 	    sizeof(*el->el_keymacro.buf));
110 	if (el->el_keymacro.buf == NULL)
111 		return -1;
112 	el->el_keymacro.map = NULL;
113 	keymacro_reset(el);
114 	return 0;
115 }
116 
117 /* keymacro_end():
118  *	Free the key maps
119  */
120 protected void
keymacro_end(EditLine * el)121 keymacro_end(EditLine *el)
122 {
123 
124 	el_free(el->el_keymacro.buf);
125 	el->el_keymacro.buf = NULL;
126 	node__free(el->el_keymacro.map);
127 }
128 
129 
130 /* keymacro_map_cmd():
131  *	Associate cmd with a key value
132  */
133 protected keymacro_value_t *
keymacro_map_cmd(EditLine * el,int cmd)134 keymacro_map_cmd(EditLine *el, int cmd)
135 {
136 
137 	el->el_keymacro.val.cmd = (el_action_t) cmd;
138 	return &el->el_keymacro.val;
139 }
140 
141 
142 /* keymacro_map_str():
143  *	Associate str with a key value
144  */
145 protected keymacro_value_t *
keymacro_map_str(EditLine * el,wchar_t * str)146 keymacro_map_str(EditLine *el, wchar_t *str)
147 {
148 
149 	el->el_keymacro.val.str = str;
150 	return &el->el_keymacro.val;
151 }
152 
153 
154 /* keymacro_reset():
155  *	Takes all nodes on el->el_keymacro.map and puts them on free list.
156  *	Then initializes el->el_keymacro.map with arrow keys
157  *	[Always bind the ansi arrow keys?]
158  */
159 protected void
keymacro_reset(EditLine * el)160 keymacro_reset(EditLine *el)
161 {
162 
163 	node__put(el, el->el_keymacro.map);
164 	el->el_keymacro.map = NULL;
165 	return;
166 }
167 
168 
169 /* keymacro_get():
170  *	Calls the recursive function with entry point el->el_keymacro.map
171  *      Looks up *ch in map and then reads characters until a
172  *      complete match is found or a mismatch occurs. Returns the
173  *      type of the match found (XK_STR or XK_CMD).
174  *      Returns NULL in val.str and XK_STR for no match.
175  *      The last character read is returned in *ch.
176  */
177 protected int
keymacro_get(EditLine * el,wchar_t * ch,keymacro_value_t * val)178 keymacro_get(EditLine *el, wchar_t *ch, keymacro_value_t *val)
179 {
180 
181 	return node_trav(el, el->el_keymacro.map, ch, val);
182 }
183 
184 
185 /* keymacro_add():
186  *      Adds key to the el->el_keymacro.map and associates the value in
187  *	val with it. If key is already is in el->el_keymacro.map, the new
188  *	code is applied to the existing key. Ntype specifies if code is a
189  *	command, an out str or a unix command.
190  */
191 protected void
keymacro_add(EditLine * el,const wchar_t * key,keymacro_value_t * val,int ntype)192 keymacro_add(EditLine *el, const wchar_t *key, keymacro_value_t *val,
193     int ntype)
194 {
195 
196 	if (key[0] == '\0') {
197 		(void) fprintf(el->el_errfile,
198 		    "keymacro_add: Null extended-key not allowed.\n");
199 		return;
200 	}
201 	if (ntype == XK_CMD && val->cmd == ED_SEQUENCE_LEAD_IN) {
202 		(void) fprintf(el->el_errfile,
203 		    "keymacro_add: sequence-lead-in command not allowed\n");
204 		return;
205 	}
206 	if (el->el_keymacro.map == NULL)
207 		/* tree is initially empty.  Set up new node to match key[0] */
208 		el->el_keymacro.map = node__get(key[0]);
209 			/* it is properly initialized */
210 
211 	/* Now recurse through el->el_keymacro.map */
212 	(void) node__try(el, el->el_keymacro.map, key, val, ntype);
213 	return;
214 }
215 
216 
217 /* keymacro_clear():
218  *
219  */
220 protected void
keymacro_clear(EditLine * el,el_action_t * map,const wchar_t * in)221 keymacro_clear(EditLine *el, el_action_t *map, const wchar_t *in)
222 {
223         if (*in > N_KEYS) /* can't be in the map */
224                 return;
225 	if ((map[(unsigned char)*in] == ED_SEQUENCE_LEAD_IN) &&
226 	    ((map == el->el_map.key &&
227 	    el->el_map.alt[(unsigned char)*in] != ED_SEQUENCE_LEAD_IN) ||
228 	    (map == el->el_map.alt &&
229 	    el->el_map.key[(unsigned char)*in] != ED_SEQUENCE_LEAD_IN)))
230 		(void) keymacro_delete(el, in);
231 }
232 
233 
234 /* keymacro_delete():
235  *      Delete the key and all longer keys staring with key, if
236  *      they exists.
237  */
238 protected int
keymacro_delete(EditLine * el,const wchar_t * key)239 keymacro_delete(EditLine *el, const wchar_t *key)
240 {
241 
242 	if (key[0] == '\0') {
243 		(void) fprintf(el->el_errfile,
244 		    "keymacro_delete: Null extended-key not allowed.\n");
245 		return -1;
246 	}
247 	if (el->el_keymacro.map == NULL)
248 		return 0;
249 
250 	(void) node__delete(el, &el->el_keymacro.map, key);
251 	return 0;
252 }
253 
254 
255 /* keymacro_print():
256  *	Print the binding associated with key key.
257  *	Print entire el->el_keymacro.map if null
258  */
259 protected void
keymacro_print(EditLine * el,const wchar_t * key)260 keymacro_print(EditLine *el, const wchar_t *key)
261 {
262 
263 	/* do nothing if el->el_keymacro.map is empty and null key specified */
264 	if (el->el_keymacro.map == NULL && *key == 0)
265 		return;
266 
267 	el->el_keymacro.buf[0] = '"';
268 	if (node_lookup(el, key, el->el_keymacro.map, (size_t)1) <= -1)
269 		/* key is not bound */
270 		(void) fprintf(el->el_errfile, "Unbound extended key \"%ls"
271 		    "\"\n", key);
272 	return;
273 }
274 
275 
276 /* node_trav():
277  *	recursively traverses node in tree until match or mismatch is
278  *	found.  May read in more characters.
279  */
280 static int
node_trav(EditLine * el,keymacro_node_t * ptr,wchar_t * ch,keymacro_value_t * val)281 node_trav(EditLine *el, keymacro_node_t *ptr, wchar_t *ch,
282     keymacro_value_t *val)
283 {
284 
285 	if (ptr->ch == *ch) {
286 		/* match found */
287 		if (ptr->next) {
288 			/* key not complete so get next char */
289 			if (el_wgetc(el, ch) != 1) {/* if EOF or error */
290 				val->cmd = ED_END_OF_FILE;
291 				return XK_CMD;
292 				/* PWP: Pretend we just read an end-of-file */
293 			}
294 			return node_trav(el, ptr->next, ch, val);
295 		} else {
296 			*val = ptr->val;
297 			if (ptr->type != XK_CMD)
298 				*ch = '\0';
299 			return ptr->type;
300 		}
301 	} else {
302 		/* no match found here */
303 		if (ptr->sibling) {
304 			/* try next sibling */
305 			return node_trav(el, ptr->sibling, ch, val);
306 		} else {
307 			/* no next sibling -- mismatch */
308 			val->str = NULL;
309 			return XK_STR;
310 		}
311 	}
312 }
313 
314 
315 /* node__try():
316  *	Find a node that matches *str or allocate a new one
317  */
318 static int
node__try(EditLine * el,keymacro_node_t * ptr,const wchar_t * str,keymacro_value_t * val,int ntype)319 node__try(EditLine *el, keymacro_node_t *ptr, const wchar_t *str,
320     keymacro_value_t *val, int ntype)
321 {
322 
323 	if (ptr->ch != *str) {
324 		keymacro_node_t *xm;
325 
326 		for (xm = ptr; xm->sibling != NULL; xm = xm->sibling)
327 			if (xm->sibling->ch == *str)
328 				break;
329 		if (xm->sibling == NULL)
330 			xm->sibling = node__get(*str);	/* setup new node */
331 		ptr = xm->sibling;
332 	}
333 	if (*++str == '\0') {
334 		/* we're there */
335 		if (ptr->next != NULL) {
336 			node__put(el, ptr->next);
337 				/* lose longer keys with this prefix */
338 			ptr->next = NULL;
339 		}
340 		switch (ptr->type) {
341 		case XK_CMD:
342 		case XK_NOD:
343 			break;
344 		case XK_STR:
345 			if (ptr->val.str)
346 				el_free(ptr->val.str);
347 			break;
348 		default:
349 			EL_ABORT((el->el_errfile, "Bad XK_ type %d\n",
350 			    ptr->type));
351 			break;
352 		}
353 
354 		switch (ptr->type = ntype) {
355 		case XK_CMD:
356 			ptr->val = *val;
357 			break;
358 		case XK_STR:
359 			if ((ptr->val.str = wcsdup(val->str)) == NULL)
360 				return -1;
361 			break;
362 		default:
363 			EL_ABORT((el->el_errfile, "Bad XK_ type %d\n", ntype));
364 			break;
365 		}
366 	} else {
367 		/* still more chars to go */
368 		if (ptr->next == NULL)
369 			ptr->next = node__get(*str);	/* setup new node */
370 		(void) node__try(el, ptr->next, str, val, ntype);
371 	}
372 	return 0;
373 }
374 
375 
376 /* node__delete():
377  *	Delete node that matches str
378  */
379 static int
node__delete(EditLine * el,keymacro_node_t ** inptr,const wchar_t * str)380 node__delete(EditLine *el, keymacro_node_t **inptr, const wchar_t *str)
381 {
382 	keymacro_node_t *ptr;
383 	keymacro_node_t *prev_ptr = NULL;
384 
385 	ptr = *inptr;
386 
387 	if (ptr->ch != *str) {
388 		keymacro_node_t *xm;
389 
390 		for (xm = ptr; xm->sibling != NULL; xm = xm->sibling)
391 			if (xm->sibling->ch == *str)
392 				break;
393 		if (xm->sibling == NULL)
394 			return 0;
395 		prev_ptr = xm;
396 		ptr = xm->sibling;
397 	}
398 	if (*++str == '\0') {
399 		/* we're there */
400 		if (prev_ptr == NULL)
401 			*inptr = ptr->sibling;
402 		else
403 			prev_ptr->sibling = ptr->sibling;
404 		ptr->sibling = NULL;
405 		node__put(el, ptr);
406 		return 1;
407 	} else if (ptr->next != NULL &&
408 	    node__delete(el, &ptr->next, str) == 1) {
409 		if (ptr->next != NULL)
410 			return 0;
411 		if (prev_ptr == NULL)
412 			*inptr = ptr->sibling;
413 		else
414 			prev_ptr->sibling = ptr->sibling;
415 		ptr->sibling = NULL;
416 		node__put(el, ptr);
417 		return 1;
418 	} else {
419 		return 0;
420 	}
421 }
422 
423 
424 /* node__put():
425  *	Puts a tree of nodes onto free list using free(3).
426  */
427 static void
node__put(EditLine * el,keymacro_node_t * ptr)428 node__put(EditLine *el, keymacro_node_t *ptr)
429 {
430 	if (ptr == NULL)
431 		return;
432 
433 	if (ptr->next != NULL) {
434 		node__put(el, ptr->next);
435 		ptr->next = NULL;
436 	}
437 	node__put(el, ptr->sibling);
438 
439 	switch (ptr->type) {
440 	case XK_CMD:
441 	case XK_NOD:
442 		break;
443 	case XK_STR:
444 		if (ptr->val.str != NULL)
445 			el_free(ptr->val.str);
446 		break;
447 	default:
448 		EL_ABORT((el->el_errfile, "Bad XK_ type %d\n", ptr->type));
449 		break;
450 	}
451 	el_free(ptr);
452 }
453 
454 
455 /* node__get():
456  *	Returns pointer to a keymacro_node_t for ch.
457  */
458 static keymacro_node_t *
node__get(wint_t ch)459 node__get(wint_t ch)
460 {
461 	keymacro_node_t *ptr;
462 
463 	ptr = el_malloc(sizeof(*ptr));
464 	if (ptr == NULL)
465 		return NULL;
466 	ptr->ch = ch;
467 	ptr->type = XK_NOD;
468 	ptr->val.str = NULL;
469 	ptr->next = NULL;
470 	ptr->sibling = NULL;
471 	return ptr;
472 }
473 
474 static void
node__free(keymacro_node_t * k)475 node__free(keymacro_node_t *k)
476 {
477 	if (k == NULL)
478 		return;
479 	node__free(k->sibling);
480 	node__free(k->next);
481 	el_free(k);
482 }
483 
484 /* node_lookup():
485  *	look for the str starting at node ptr.
486  *	Print if last node
487  */
488 static int
node_lookup(EditLine * el,const wchar_t * str,keymacro_node_t * ptr,size_t cnt)489 node_lookup(EditLine *el, const wchar_t *str, keymacro_node_t *ptr,
490     size_t cnt)
491 {
492 	ssize_t used;
493 
494 	if (ptr == NULL)
495 		return -1;	/* cannot have null ptr */
496 
497 	if (!str || *str == 0) {
498 		/* no more chars in str.  node_enum from here. */
499 		(void) node_enum(el, ptr, cnt);
500 		return 0;
501 	} else {
502 		/* If match put this char into el->el_keymacro.buf.  Recurse */
503 		if (ptr->ch == *str) {
504 			/* match found */
505 			used = ct_visual_char(el->el_keymacro.buf + cnt,
506 			    KEY_BUFSIZ - cnt, ptr->ch);
507 			if (used == -1)
508 				return -1; /* ran out of buffer space */
509 			if (ptr->next != NULL)
510 				/* not yet at leaf */
511 				return (node_lookup(el, str + 1, ptr->next,
512 				    (size_t)used + cnt));
513 			else {
514 			    /* next node is null so key should be complete */
515 				if (str[1] == 0) {
516 					size_t px = cnt + (size_t)used;
517 					el->el_keymacro.buf[px] = '"';
518 					el->el_keymacro.buf[px + 1] = '\0';
519 					keymacro_kprint(el, el->el_keymacro.buf,
520 					    &ptr->val, ptr->type);
521 					return 0;
522 				} else
523 					return -1;
524 					/* mismatch -- str still has chars */
525 			}
526 		} else {
527 			/* no match found try sibling */
528 			if (ptr->sibling)
529 				return (node_lookup(el, str, ptr->sibling,
530 				    cnt));
531 			else
532 				return -1;
533 		}
534 	}
535 }
536 
537 
538 /* node_enum():
539  *	Traverse the node printing the characters it is bound in buffer
540  */
541 static int
node_enum(EditLine * el,keymacro_node_t * ptr,size_t cnt)542 node_enum(EditLine *el, keymacro_node_t *ptr, size_t cnt)
543 {
544         ssize_t used;
545 
546 	if (cnt >= KEY_BUFSIZ - 5) {	/* buffer too small */
547 		el->el_keymacro.buf[++cnt] = '"';
548 		el->el_keymacro.buf[++cnt] = '\0';
549 		(void) fprintf(el->el_errfile,
550 		    "Some extended keys too long for internal print buffer");
551 		(void) fprintf(el->el_errfile, " \"%ls...\"\n",
552 		    el->el_keymacro.buf);
553 		return 0;
554 	}
555 	if (ptr == NULL) {
556 #ifdef DEBUG_EDIT
557 		(void) fprintf(el->el_errfile,
558 		    "node_enum: BUG!! Null ptr passed\n!");
559 #endif
560 		return -1;
561 	}
562 	/* put this char at end of str */
563         used = ct_visual_char(el->el_keymacro.buf + cnt, KEY_BUFSIZ - cnt,
564 	    ptr->ch);
565 	if (ptr->next == NULL) {
566 		/* print this key and function */
567 		el->el_keymacro.buf[cnt + (size_t)used   ] = '"';
568 		el->el_keymacro.buf[cnt + (size_t)used + 1] = '\0';
569 		keymacro_kprint(el, el->el_keymacro.buf, &ptr->val, ptr->type);
570 	} else
571 		(void) node_enum(el, ptr->next, cnt + (size_t)used);
572 
573 	/* go to sibling if there is one */
574 	if (ptr->sibling)
575 		(void) node_enum(el, ptr->sibling, cnt);
576 	return 0;
577 }
578 
579 
580 /* keymacro_kprint():
581  *	Print the specified key and its associated
582  *	function specified by val
583  */
584 protected void
keymacro_kprint(EditLine * el,const wchar_t * key,keymacro_value_t * val,int ntype)585 keymacro_kprint(EditLine *el, const wchar_t *key, keymacro_value_t *val,
586     int ntype)
587 {
588 	el_bindings_t *fp;
589 	char unparsbuf[EL_BUFSIZ];
590 	static const char fmt[] = "%-15s->  %s\n";
591 
592 	if (val != NULL)
593 		switch (ntype) {
594 		case XK_STR:
595 			(void) keymacro__decode_str(val->str, unparsbuf,
596 			    sizeof(unparsbuf),
597 			    ntype == XK_STR ? "\"\"" : "[]");
598 			(void) fprintf(el->el_outfile, fmt,
599 			    ct_encode_string(key, &el->el_scratch), unparsbuf);
600 			break;
601 		case XK_CMD:
602 			for (fp = el->el_map.help; fp->name; fp++)
603 				if (val->cmd == fp->func) {
604                     wcstombs(unparsbuf, fp->name, sizeof(unparsbuf));
605                     unparsbuf[sizeof(unparsbuf) -1] = '\0';
606 					(void) fprintf(el->el_outfile, fmt,
607                         ct_encode_string(key, &el->el_scratch), unparsbuf);
608 					break;
609 				}
610 #ifdef DEBUG_KEY
611 			if (fp->name == NULL)
612 				(void) fprintf(el->el_outfile,
613 				    "BUG! Command not found.\n");
614 #endif
615 
616 			break;
617 		default:
618 			EL_ABORT((el->el_errfile, "Bad XK_ type %d\n", ntype));
619 			break;
620 		}
621 	else
622 		(void) fprintf(el->el_outfile, fmt, ct_encode_string(key,
623 		    &el->el_scratch), "no input");
624 }
625 
626 
627 #define ADDC(c) \
628 	if (b < eb) \
629 		*b++ = c; \
630 	else \
631 		b++
632 /* keymacro__decode_str():
633  *	Make a printable version of the ey
634  */
635 protected size_t
keymacro__decode_str(const wchar_t * str,char * buf,size_t len,const char * sep)636 keymacro__decode_str(const wchar_t *str, char *buf, size_t len,
637     const char *sep)
638 {
639 	char *b = buf, *eb = b + len;
640 	const wchar_t *p;
641 
642 	b = buf;
643 	if (sep[0] != '\0') {
644 		ADDC(sep[0]);
645 	}
646 	if (*str == '\0') {
647 		ADDC('^');
648 		ADDC('@');
649 		goto add_endsep;
650 	}
651 	for (p = str; *p != 0; p++) {
652 		wchar_t dbuf[VISUAL_WIDTH_MAX];
653 		wchar_t *p2 = dbuf;
654 		ssize_t l = ct_visual_char(dbuf, VISUAL_WIDTH_MAX, *p);
655 		while (l-- > 0) {
656 			ssize_t n = ct_encode_char(b, (size_t)(eb - b), *p2++);
657 			if (n == -1) /* ran out of space */
658 				goto add_endsep;
659 			else
660 				b += n;
661 		}
662 	}
663 add_endsep:
664 	if (sep[0] != '\0' && sep[1] != '\0') {
665 		ADDC(sep[1]);
666 	}
667 	ADDC('\0');
668 	if ((size_t)(b - buf) >= len)
669 	    buf[len - 1] = '\0';
670 	return (size_t)(b - buf);
671 }
672