Update libedit from version 2014-06-20 to 2015-03-25 on vendor branch
[dragonfly.git] / contrib / libedit / src / read.c
1 /*      $NetBSD: read.c,v 1.71 2014/07/06 18:15:34 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[] = "@(#)read.c      8.1 (Berkeley) 6/4/93";
39 #else
40 __RCSID("$NetBSD: read.c,v 1.71 2014/07/06 18:15:34 christos Exp $");
41 #endif
42 #endif /* not lint && not SCCSID */
43
44 /*
45  * read.c: Clean this junk up! This is horrible code.
46  *         Terminal read functions
47  */
48 #include <errno.h>
49 #include <fcntl.h>
50 #include <unistd.h>
51 #include <stdlib.h>
52 #include <limits.h>
53 #include "el.h"
54
55 #define OKCMD   -1      /* must be -1! */
56
57 private int     read__fixio(int, int);
58 private int     read_preread(EditLine *);
59 private int     read_char(EditLine *, Char *);
60 private int     read_getcmd(EditLine *, el_action_t *, Char *);
61 private void    read_pop(c_macro_t *);
62
63 /* read_init():
64  *      Initialize the read stuff
65  */
66 protected int
67 read_init(EditLine *el)
68 {
69         /* builtin read_char */
70         el->el_read.read_char = read_char;
71         return 0;
72 }
73
74
75 /* el_read_setfn():
76  *      Set the read char function to the one provided.
77  *      If it is set to EL_BUILTIN_GETCFN, then reset to the builtin one.
78  */
79 protected int
80 el_read_setfn(EditLine *el, el_rfunc_t rc)
81 {
82         el->el_read.read_char = (rc == EL_BUILTIN_GETCFN) ? read_char : rc;
83         return 0;
84 }
85
86
87 /* el_read_getfn():
88  *      return the current read char function, or EL_BUILTIN_GETCFN
89  *      if it is the default one
90  */
91 protected el_rfunc_t
92 el_read_getfn(EditLine *el)
93 {
94        return el->el_read.read_char == read_char ?
95             EL_BUILTIN_GETCFN : el->el_read.read_char;
96 }
97
98
99 #ifndef MIN
100 #define MIN(A,B) ((A) < (B) ? (A) : (B))
101 #endif
102
103 #ifdef DEBUG_EDIT
104 private void
105 read_debug(EditLine *el)
106 {
107
108         if (el->el_line.cursor > el->el_line.lastchar)
109                 (void) fprintf(el->el_errfile, "cursor > lastchar\r\n");
110         if (el->el_line.cursor < el->el_line.buffer)
111                 (void) fprintf(el->el_errfile, "cursor < buffer\r\n");
112         if (el->el_line.cursor > el->el_line.limit)
113                 (void) fprintf(el->el_errfile, "cursor > limit\r\n");
114         if (el->el_line.lastchar > el->el_line.limit)
115                 (void) fprintf(el->el_errfile, "lastchar > limit\r\n");
116         if (el->el_line.limit != &el->el_line.buffer[EL_BUFSIZ - 2])
117                 (void) fprintf(el->el_errfile, "limit != &buffer[EL_BUFSIZ-2]\r\n");
118 }
119 #endif /* DEBUG_EDIT */
120
121
122 /* read__fixio():
123  *      Try to recover from a read error
124  */
125 /* ARGSUSED */
126 private int
127 read__fixio(int fd __attribute__((__unused__)), int e)
128 {
129
130         switch (e) {
131         case -1:                /* Make sure that the code is reachable */
132
133 #ifdef EWOULDBLOCK
134         case EWOULDBLOCK:
135 #ifndef TRY_AGAIN
136 #define TRY_AGAIN
137 #endif
138 #endif /* EWOULDBLOCK */
139
140 #if defined(POSIX) && defined(EAGAIN)
141 #if defined(EWOULDBLOCK) && EWOULDBLOCK != EAGAIN
142         case EAGAIN:
143 #ifndef TRY_AGAIN
144 #define TRY_AGAIN
145 #endif
146 #endif /* EWOULDBLOCK && EWOULDBLOCK != EAGAIN */
147 #endif /* POSIX && EAGAIN */
148
149                 e = 0;
150 #ifdef TRY_AGAIN
151 #if defined(F_SETFL) && defined(O_NDELAY)
152                 if ((e = fcntl(fd, F_GETFL, 0)) == -1)
153                         return -1;
154
155                 if (fcntl(fd, F_SETFL, e & ~O_NDELAY) == -1)
156                         return -1;
157                 else
158                         e = 1;
159 #endif /* F_SETFL && O_NDELAY */
160
161 #ifdef FIONBIO
162                 {
163                         int zero = 0;
164
165                         if (ioctl(fd, FIONBIO, &zero) == -1)
166                                 return -1;
167                         else
168                                 e = 1;
169                 }
170 #endif /* FIONBIO */
171
172 #endif /* TRY_AGAIN */
173                 return e ? 0 : -1;
174
175         case EINTR:
176                 return 0;
177
178         default:
179                 return -1;
180         }
181 }
182
183
184 /* read_preread():
185  *      Try to read the stuff in the input queue;
186  */
187 private int
188 read_preread(EditLine *el)
189 {
190         int chrs = 0;
191
192         if (el->el_tty.t_mode == ED_IO)
193                 return 0;
194
195 #ifndef WIDECHAR
196 /* FIONREAD attempts to buffer up multiple bytes, and to make that work
197  * properly with partial wide/UTF-8 characters would need some careful work. */
198 #ifdef FIONREAD
199         (void) ioctl(el->el_infd, FIONREAD, &chrs);
200         if (chrs > 0) {
201                 char buf[EL_BUFSIZ];
202
203                 chrs = read(el->el_infd, buf,
204                     (size_t) MIN(chrs, EL_BUFSIZ - 1));
205                 if (chrs > 0) {
206                         buf[chrs] = '\0';
207                         el_push(el, buf);
208                 }
209         }
210 #endif /* FIONREAD */
211 #endif
212         return chrs > 0;
213 }
214
215
216 /* el_push():
217  *      Push a macro
218  */
219 public void
220 FUN(el,push)(EditLine *el, const Char *str)
221 {
222         c_macro_t *ma = &el->el_chared.c_macro;
223
224         if (str != NULL && ma->level + 1 < EL_MAXMACRO) {
225                 ma->level++;
226                 if ((ma->macro[ma->level] = Strdup(str)) != NULL)
227                         return;
228                 ma->level--;
229         }
230         terminal_beep(el);
231         terminal__flush(el);
232 }
233
234
235 /* read_getcmd():
236  *      Get next command from the input stream, return OKCMD on success.
237  *      Character values > 255 are not looked up in the map, but inserted.
238  */
239 private int
240 read_getcmd(EditLine *el, el_action_t *cmdnum, Char *ch)
241 {
242         el_action_t cmd;
243         int num;
244
245         el->el_errno = 0;
246         do {
247                 if ((num = FUN(el,getc)(el, ch)) != 1) {/* if EOF or error */
248                         el->el_errno = num == 0 ? 0 : errno;
249                         return 0;       /* not OKCMD */
250                 }
251
252 #ifdef  KANJI
253                 if ((*ch & 0200)) {
254                         el->el_state.metanext = 0;
255                         cmd = CcViMap[' '];
256                         break;
257                 } else
258 #endif /* KANJI */
259
260                 if (el->el_state.metanext) {
261                         el->el_state.metanext = 0;
262                         *ch |= 0200;
263                 }
264 #ifdef WIDECHAR
265                 if (*ch >= N_KEYS)
266                         cmd = ED_INSERT;
267                 else
268 #endif
269                         cmd = el->el_map.current[(unsigned char) *ch];
270                 if (cmd == ED_SEQUENCE_LEAD_IN) {
271                         keymacro_value_t val;
272                         switch (keymacro_get(el, ch, &val)) {
273                         case XK_CMD:
274                                 cmd = val.cmd;
275                                 break;
276                         case XK_STR:
277                                 FUN(el,push)(el, val.str);
278                                 break;
279 #ifdef notyet
280                         case XK_EXE:
281                                 /* XXX: In the future to run a user function */
282                                 RunCommand(val.str);
283                                 break;
284 #endif
285                         default:
286                                 EL_ABORT((el->el_errfile, "Bad XK_ type \n"));
287                                 break;
288                         }
289                 }
290                 if (el->el_map.alt == NULL)
291                         el->el_map.current = el->el_map.key;
292         } while (cmd == ED_SEQUENCE_LEAD_IN);
293         *cmdnum = cmd;
294         return OKCMD;
295 }
296
297 #ifdef WIDECHAR
298 /* utf8_islead():
299  *      Test whether a byte is a leading byte of a UTF-8 sequence.
300  */
301 private int
302 utf8_islead(int c)
303 {
304         return c < 0x80 ||             /* single byte char */
305                (c >= 0xc2 && c <= 0xf4); /* start of multibyte sequence */
306 }
307 #endif
308
309 /* read_char():
310  *      Read a character from the tty.
311  */
312 private int
313 read_char(EditLine *el, Char *cp)
314 {
315         ssize_t num_read;
316         int tried = 0;
317         char cbuf[MB_LEN_MAX];
318         size_t cbp = 0;
319         int bytes = 0;
320
321  again:
322         el->el_signal->sig_no = 0;
323         while ((num_read = read(el->el_infd, cbuf + cbp, (size_t)1)) == -1) {
324                 int e = errno;
325                 switch (el->el_signal->sig_no) {
326                 case SIGCONT:
327                         FUN(el,set)(el, EL_REFRESH);
328                         /*FALLTHROUGH*/
329                 case SIGWINCH:
330                         sig_set(el);
331                         goto again;
332                 default:
333                         break;
334                 }
335                 if (!tried && read__fixio(el->el_infd, e) == 0)
336                         tried = 1;
337                 else {
338                         errno = e;
339                         *cp = '\0';
340                         return -1;
341                 }
342         }
343
344         /* Test for EOF */
345         if (num_read == 0) {
346                 errno = 0;
347                 *cp = '\0';
348                 return 0;
349         }
350
351 #ifdef WIDECHAR
352         if (el->el_flags & CHARSET_IS_UTF8) {
353                 if (!utf8_islead((unsigned char)cbuf[0]))
354                         goto again; /* discard the byte we read and try again */
355                 ++cbp;
356                 if ((bytes = ct_mbtowc(cp, cbuf, cbp)) == -1) {
357                         ct_mbtowc_reset;
358                         if (cbp >= MB_LEN_MAX) { /* "shouldn't happen" */
359                                 errno = EILSEQ;
360                                 *cp = '\0';
361                                 return -1;
362                         }
363                         goto again;
364                 }
365         } else if (isascii((unsigned char)cbuf[0]) ||
366                 /* we don't support other multibyte charsets */
367                 ++cbp != 1 ||
368                 /* Try non-ASCII characters in a 8-bit character set */
369                 (bytes = ct_mbtowc(cp, cbuf, cbp)) != 1)
370 #endif
371                 *cp = (unsigned char)cbuf[0];
372
373         if ((el->el_flags & IGNORE_EXTCHARS) && bytes > 1) {
374                 cbp = 0; /* skip this character */
375                 goto again;
376         }
377
378         return (int)num_read;
379 }
380
381 /* read_pop():
382  *      Pop a macro from the stack
383  */
384 private void
385 read_pop(c_macro_t *ma)
386 {
387         int i;
388
389         el_free(ma->macro[0]);
390         for (i = 0; i < ma->level; i++)
391                 ma->macro[i] = ma->macro[i + 1];
392         ma->level--;
393         ma->offset = 0;
394 }
395
396 /* el_getc():
397  *      Read a character
398  */
399 public int
400 FUN(el,getc)(EditLine *el, Char *cp)
401 {
402         int num_read;
403         c_macro_t *ma = &el->el_chared.c_macro;
404
405         terminal__flush(el);
406         for (;;) {
407                 if (ma->level < 0) {
408                         if (!read_preread(el))
409                                 break;
410                 }
411
412                 if (ma->level < 0)
413                         break;
414
415                 if (ma->macro[0][ma->offset] == '\0') {
416                         read_pop(ma);
417                         continue;
418                 }
419
420                 *cp = ma->macro[0][ma->offset++];
421
422                 if (ma->macro[0][ma->offset] == '\0') {
423                         /* Needed for QuoteMode On */
424                         read_pop(ma);
425                 }
426
427                 return 1;
428         }
429
430 #ifdef DEBUG_READ
431         (void) fprintf(el->el_errfile, "Turning raw mode on\n");
432 #endif /* DEBUG_READ */
433         if (tty_rawmode(el) < 0)/* make sure the tty is set up correctly */
434                 return 0;
435
436 #ifdef DEBUG_READ
437         (void) fprintf(el->el_errfile, "Reading a character\n");
438 #endif /* DEBUG_READ */
439         num_read = (*el->el_read.read_char)(el, cp);
440         if (num_read < 0)
441                 el->el_errno = errno;
442 #ifdef WIDECHAR
443         if (el->el_flags & NARROW_READ)
444                 *cp = *(char *)(void *)cp;
445 #endif
446 #ifdef DEBUG_READ
447         (void) fprintf(el->el_errfile, "Got it %c\n", *cp);
448 #endif /* DEBUG_READ */
449         return num_read;
450 }
451
452 protected void
453 read_prepare(EditLine *el)
454 {
455         if (el->el_flags & HANDLE_SIGNALS)
456                 sig_set(el);
457         if (el->el_flags & NO_TTY)
458                 return;
459         if ((el->el_flags & (UNBUFFERED|EDIT_DISABLED)) == UNBUFFERED)
460                 tty_rawmode(el);
461
462         /* This is relatively cheap, and things go terribly wrong if
463            we have the wrong size. */
464         el_resize(el);
465         re_clear_display(el);   /* reset the display stuff */
466         ch_reset(el, 0);
467         re_refresh(el);         /* print the prompt */
468
469         if (el->el_flags & UNBUFFERED)
470                 terminal__flush(el);
471 }
472
473 protected void
474 read_finish(EditLine *el)
475 {
476         if ((el->el_flags & UNBUFFERED) == 0)
477                 (void) tty_cookedmode(el);
478         if (el->el_flags & HANDLE_SIGNALS)
479                 sig_clr(el);
480 }
481
482 public const Char *
483 FUN(el,gets)(EditLine *el, int *nread)
484 {
485         int retval;
486         el_action_t cmdnum = 0;
487         int num;                /* how many chars we have read at NL */
488         Char ch, *cp;
489         int crlf = 0;
490         int nrb;
491 #ifdef FIONREAD
492         c_macro_t *ma = &el->el_chared.c_macro;
493 #endif /* FIONREAD */
494
495         if (nread == NULL)
496                 nread = &nrb;
497         *nread = 0;
498
499         if (el->el_flags & NO_TTY) {
500                 size_t idx;
501
502                 cp = el->el_line.buffer;
503                 while ((num = (*el->el_read.read_char)(el, cp)) == 1) {
504                         /* make sure there is space for next character */
505                         if (cp + 1 >= el->el_line.limit) {
506                                 idx = (size_t)(cp - el->el_line.buffer);
507                                 if (!ch_enlargebufs(el, (size_t)2))
508                                         break;
509                                 cp = &el->el_line.buffer[idx];
510                         }
511                         cp++;
512                         if (el->el_flags & UNBUFFERED)
513                                 break;
514                         if (cp[-1] == '\r' || cp[-1] == '\n')
515                                 break;
516                 }
517                 if (num == -1) {
518                         if (errno == EINTR)
519                                 cp = el->el_line.buffer;
520                         el->el_errno = errno;
521                 }
522
523                 goto noedit;
524         }
525
526
527 #ifdef FIONREAD
528         if (el->el_tty.t_mode == EX_IO && ma->level < 0) {
529                 long chrs = 0;
530
531                 (void) ioctl(el->el_infd, FIONREAD, &chrs);
532                 if (chrs == 0) {
533                         if (tty_rawmode(el) < 0) {
534                                 errno = 0;
535                                 *nread = 0;
536                                 return NULL;
537                         }
538                 }
539         }
540 #endif /* FIONREAD */
541
542         if ((el->el_flags & UNBUFFERED) == 0)
543                 read_prepare(el);
544
545         if (el->el_flags & EDIT_DISABLED) {
546                 size_t idx;
547
548                 if ((el->el_flags & UNBUFFERED) == 0)
549                         cp = el->el_line.buffer;
550                 else
551                         cp = el->el_line.lastchar;
552
553                 terminal__flush(el);
554
555                 while ((num = (*el->el_read.read_char)(el, cp)) == 1) {
556                         /* make sure there is space next character */
557                         if (cp + 1 >= el->el_line.limit) {
558                                 idx = (size_t)(cp - el->el_line.buffer);
559                                 if (!ch_enlargebufs(el, (size_t)2))
560                                         break;
561                                 cp = &el->el_line.buffer[idx];
562                         }
563                         cp++;
564                         crlf = cp[-1] == '\r' || cp[-1] == '\n';
565                         if (el->el_flags & UNBUFFERED)
566                                 break;
567                         if (crlf)
568                                 break;
569                 }
570
571                 if (num == -1) {
572                         if (errno == EINTR)
573                                 cp = el->el_line.buffer;
574                         el->el_errno = errno;
575                 }
576
577                 goto noedit;
578         }
579
580         for (num = OKCMD; num == OKCMD;) {      /* while still editing this
581                                                  * line */
582 #ifdef DEBUG_EDIT
583                 read_debug(el);
584 #endif /* DEBUG_EDIT */
585                 /* if EOF or error */
586                 if ((num = read_getcmd(el, &cmdnum, &ch)) != OKCMD) {
587                         num = -1;
588 #ifdef DEBUG_READ
589                         (void) fprintf(el->el_errfile,
590                             "Returning from el_gets %d\n", num);
591 #endif /* DEBUG_READ */
592                         break;
593                 }
594                 if (el->el_errno == EINTR) {
595                         el->el_line.buffer[0] = '\0';
596                         el->el_line.lastchar =
597                             el->el_line.cursor = el->el_line.buffer;
598                         break;
599                 }
600                 if ((size_t)cmdnum >= el->el_map.nfunc) {       /* BUG CHECK command */
601 #ifdef DEBUG_EDIT
602                         (void) fprintf(el->el_errfile,
603                             "ERROR: illegal command from key 0%o\r\n", ch);
604 #endif /* DEBUG_EDIT */
605                         continue;       /* try again */
606                 }
607                 /* now do the real command */
608 #ifdef DEBUG_READ
609                 {
610                         el_bindings_t *b;
611                         for (b = el->el_map.help; b->name; b++)
612                                 if (b->func == cmdnum)
613                                         break;
614                         if (b->name)
615                                 (void) fprintf(el->el_errfile,
616                                     "Executing %s\n", b->name);
617                         else
618                                 (void) fprintf(el->el_errfile,
619                                     "Error command = %d\n", cmdnum);
620                 }
621 #endif /* DEBUG_READ */
622                 /* vi redo needs these way down the levels... */
623                 el->el_state.thiscmd = cmdnum;
624                 el->el_state.thisch = ch;
625                 if (el->el_map.type == MAP_VI &&
626                     el->el_map.current == el->el_map.key &&
627                     el->el_chared.c_redo.pos < el->el_chared.c_redo.lim) {
628                         if (cmdnum == VI_DELETE_PREV_CHAR &&
629                             el->el_chared.c_redo.pos != el->el_chared.c_redo.buf
630                             && Isprint(el->el_chared.c_redo.pos[-1]))
631                                 el->el_chared.c_redo.pos--;
632                         else
633                                 *el->el_chared.c_redo.pos++ = ch;
634                 }
635                 retval = (*el->el_map.func[cmdnum]) (el, ch);
636 #ifdef DEBUG_READ
637                 (void) fprintf(el->el_errfile,
638                         "Returned state %d\n", retval );
639 #endif /* DEBUG_READ */
640
641                 /* save the last command here */
642                 el->el_state.lastcmd = cmdnum;
643
644                 /* use any return value */
645                 switch (retval) {
646                 case CC_CURSOR:
647                         re_refresh_cursor(el);
648                         break;
649
650                 case CC_REDISPLAY:
651                         re_clear_lines(el);
652                         re_clear_display(el);
653                         /* FALLTHROUGH */
654
655                 case CC_REFRESH:
656                         re_refresh(el);
657                         break;
658
659                 case CC_REFRESH_BEEP:
660                         re_refresh(el);
661                         terminal_beep(el);
662                         break;
663
664                 case CC_NORM:   /* normal char */
665                         break;
666
667                 case CC_ARGHACK:        /* Suggested by Rich Salz */
668                         /* <rsalz@pineapple.bbn.com> */
669                         continue;       /* keep going... */
670
671                 case CC_EOF:    /* end of file typed */
672                         if ((el->el_flags & UNBUFFERED) == 0)
673                                 num = 0;
674                         else if (num == -1) {
675                                 *el->el_line.lastchar++ = CONTROL('d');
676                                 el->el_line.cursor = el->el_line.lastchar;
677                                 num = 1;
678                         }
679                         break;
680
681                 case CC_NEWLINE:        /* normal end of line */
682                         num = (int)(el->el_line.lastchar - el->el_line.buffer);
683                         break;
684
685                 case CC_FATAL:  /* fatal error, reset to known state */
686 #ifdef DEBUG_READ
687                         (void) fprintf(el->el_errfile,
688                             "*** editor fatal ERROR ***\r\n\n");
689 #endif /* DEBUG_READ */
690                         /* put (real) cursor in a known place */
691                         re_clear_display(el);   /* reset the display stuff */
692                         ch_reset(el, 1);        /* reset the input pointers */
693                         re_refresh(el); /* print the prompt again */
694                         break;
695
696                 case CC_ERROR:
697                 default:        /* functions we don't know about */
698 #ifdef DEBUG_READ
699                         (void) fprintf(el->el_errfile,
700                             "*** editor ERROR ***\r\n\n");
701 #endif /* DEBUG_READ */
702                         terminal_beep(el);
703                         terminal__flush(el);
704                         break;
705                 }
706                 el->el_state.argument = 1;
707                 el->el_state.doingarg = 0;
708                 el->el_chared.c_vcmd.action = NOP;
709                 if (el->el_flags & UNBUFFERED)
710                         break;
711         }
712
713         terminal__flush(el);            /* flush any buffered output */
714         /* make sure the tty is set up correctly */
715         if ((el->el_flags & UNBUFFERED) == 0) {
716                 read_finish(el);
717                 *nread = num != -1 ? num : 0;
718         } else {
719                 *nread = (int)(el->el_line.lastchar - el->el_line.buffer);
720         }
721         goto done;
722 noedit:
723         el->el_line.cursor = el->el_line.lastchar = cp;
724         *cp = '\0';
725         *nread = (int)(el->el_line.cursor - el->el_line.buffer);
726 done:
727         if (*nread == 0) {
728                 if (num == -1) {
729                         *nread = -1;
730                         errno = el->el_errno;
731                 }
732                 return NULL;
733         } else
734                 return el->el_line.buffer;
735 }