xref: /freebsd/contrib/less/decode.c (revision 6780ab54325a71e7e70112b11657973edde8655e)
1 /*
2  * Copyright (C) 1984-2000  Mark Nudelman
3  *
4  * You may distribute under the terms of either the GNU General Public
5  * License or the Less License, as specified in the README file.
6  *
7  * For more information about less, or for information on how to
8  * contact the author, see the README file.
9  */
10 
11 
12 /*
13  * Routines to decode user commands.
14  *
15  * This is all table driven.
16  * A command table is a sequence of command descriptors.
17  * Each command descriptor is a sequence of bytes with the following format:
18  *	<c1><c2>...<cN><0><action>
19  * The characters c1,c2,...,cN are the command string; that is,
20  * the characters which the user must type.
21  * It is terminated by a null <0> byte.
22  * The byte after the null byte is the action code associated
23  * with the command string.
24  * If an action byte is OR-ed with A_EXTRA, this indicates
25  * that the option byte is followed by an extra string.
26  *
27  * There may be many command tables.
28  * The first (default) table is built-in.
29  * Other tables are read in from "lesskey" files.
30  * All the tables are linked together and are searched in order.
31  */
32 
33 #include "less.h"
34 #include "cmd.h"
35 #include "lesskey.h"
36 
37 extern int erase_char, kill_char;
38 extern int secure;
39 
40 #define SK(k) \
41 	SK_SPECIAL_KEY, (k), 6, 1, 1, 1
42 /*
43  * Command table is ordered roughly according to expected
44  * frequency of use, so the common commands are near the beginning.
45  */
46 
47 static unsigned char cmdtable[] =
48 {
49 	'\r',0,				A_F_LINE,
50 	'\n',0,				A_F_LINE,
51 	'e',0,				A_F_LINE,
52 	'j',0,				A_F_LINE,
53 	SK(SK_DOWN_ARROW),0,		A_F_LINE,
54 	CONTROL('E'),0,			A_F_LINE,
55 	CONTROL('N'),0,			A_F_LINE,
56 	'k',0,				A_B_LINE,
57 	'y',0,				A_B_LINE,
58 	CONTROL('Y'),0,			A_B_LINE,
59 	SK(SK_CONTROL_K),0,		A_B_LINE,
60 	CONTROL('P'),0,			A_B_LINE,
61 	SK(SK_UP_ARROW),0,		A_B_LINE,
62 	'J',0,				A_FF_LINE,
63 	'K',0,				A_BF_LINE,
64 	'Y',0,				A_BF_LINE,
65 	'd',0,				A_F_SCROLL,
66 	CONTROL('D'),0,			A_F_SCROLL,
67 	'u',0,				A_B_SCROLL,
68 	CONTROL('U'),0,			A_B_SCROLL,
69 	' ',0,				A_F_SCREEN,
70 	'f',0,				A_F_SCREEN,
71 	CONTROL('F'),0,			A_F_SCREEN,
72 	CONTROL('V'),0,			A_F_SCREEN,
73 	SK(SK_PAGE_DOWN),0,		A_F_SCREEN,
74 	'b',0,				A_B_SCREEN,
75 	CONTROL('B'),0,			A_B_SCREEN,
76 	ESC,'v',0,			A_B_SCREEN,
77 	SK(SK_PAGE_UP),0,		A_B_SCREEN,
78 	'z',0,				A_F_WINDOW,
79 	'w',0,				A_B_WINDOW,
80 	ESC,' ',0,			A_FF_SCREEN,
81 	'F',0,				A_F_FOREVER,
82 	'R',0,				A_FREPAINT,
83 	'r',0,				A_REPAINT,
84 	CONTROL('R'),0,			A_REPAINT,
85 	CONTROL('L'),0,			A_REPAINT,
86 	ESC,'u',0,			A_UNDO_SEARCH,
87 	'g',0,				A_GOLINE,
88 	SK(SK_HOME),0,			A_GOLINE,
89 	'<',0,				A_GOLINE,
90 	ESC,'<',0,			A_GOLINE,
91 	'p',0,				A_PERCENT,
92 	'%',0,				A_PERCENT,
93 	ESC,'[',0,			A_LSHIFT,
94 	ESC,']',0,			A_RSHIFT,
95 	ESC,'(',0,			A_LSHIFT,
96 	ESC,')',0,			A_RSHIFT,
97 	SK(SK_RIGHT_ARROW),0,		A_RSHIFT,
98 	SK(SK_LEFT_ARROW),0,		A_LSHIFT,
99 	'{',0,				A_F_BRACKET|A_EXTRA,	'{','}',0,
100 	'}',0,				A_B_BRACKET|A_EXTRA,	'{','}',0,
101 	'(',0,				A_F_BRACKET|A_EXTRA,	'(',')',0,
102 	')',0,				A_B_BRACKET|A_EXTRA,	'(',')',0,
103 	'[',0,				A_F_BRACKET|A_EXTRA,	'[',']',0,
104 	']',0,				A_B_BRACKET|A_EXTRA,	'[',']',0,
105 	ESC,CONTROL('F'),0,		A_F_BRACKET,
106 	ESC,CONTROL('B'),0,		A_B_BRACKET,
107 	'G',0,				A_GOEND,
108 	ESC,'>',0,			A_GOEND,
109 	'>',0,				A_GOEND,
110 	SK(SK_END),0,			A_GOEND,
111 	'P',0,				A_GOPOS,
112 
113 	'0',0,				A_DIGIT,
114 	'1',0,				A_DIGIT,
115 	'2',0,				A_DIGIT,
116 	'3',0,				A_DIGIT,
117 	'4',0,				A_DIGIT,
118 	'5',0,				A_DIGIT,
119 	'6',0,				A_DIGIT,
120 	'7',0,				A_DIGIT,
121 	'8',0,				A_DIGIT,
122 	'9',0,				A_DIGIT,
123 
124 	'=',0,				A_STAT,
125 	CONTROL('G'),0,			A_STAT,
126 	':','f',0,			A_STAT,
127 	'/',0,				A_F_SEARCH,
128 	'?',0,				A_B_SEARCH,
129 	ESC,'/',0,			A_F_SEARCH|A_EXTRA,	'*',0,
130 	ESC,'?',0,			A_B_SEARCH|A_EXTRA,	'*',0,
131 	'n',0,				A_AGAIN_SEARCH,
132 	ESC,'n',0,			A_T_AGAIN_SEARCH,
133 	'N',0,				A_REVERSE_SEARCH,
134 	ESC,'N',0,			A_T_REVERSE_SEARCH,
135 	'm',0,				A_SETMARK,
136 	'\'',0,				A_GOMARK,
137 	CONTROL('X'),CONTROL('X'),0,	A_GOMARK,
138 	'E',0,				A_EXAMINE,
139 	':','e',0,			A_EXAMINE,
140 	CONTROL('X'),CONTROL('V'),0,	A_EXAMINE,
141 	':','n',0,			A_NEXT_FILE,
142 	':','p',0,			A_PREV_FILE,
143 	't',0,				A_NEXT_TAG,
144 	'T',0,				A_PREV_TAG,
145 	':','x',0,			A_INDEX_FILE,
146 	':','d',0,			A_REMOVE_FILE,
147 	'-',0,				A_OPT_TOGGLE,
148 	':','t',0,			A_OPT_TOGGLE|A_EXTRA,	't',0,
149 	's',0,				A_OPT_TOGGLE|A_EXTRA,	'o',0,
150 	'_',0,				A_DISP_OPTION,
151 	'|',0,				A_PIPE,
152 	'v',0,				A_VISUAL,
153 	'!',0,				A_SHELL,
154 	'+',0,				A_FIRSTCMD,
155 
156 	'H',0,				A_HELP,
157 	'h',0,				A_HELP,
158 	SK(SK_F1),0,			A_HELP,
159 	'V',0,				A_VERSION,
160 	'q',0,				A_QUIT,
161 	'Q',0,				A_QUIT,
162 	':','q',0,			A_QUIT,
163 	':','Q',0,			A_QUIT,
164 	'Z','Z',0,			A_QUIT
165 };
166 
167 static unsigned char edittable[] =
168 {
169 	'\t',0,	    			EC_F_COMPLETE,	/* TAB */
170 	'\17',0,			EC_B_COMPLETE,	/* BACKTAB */
171 	SK(SK_BACKTAB),0,		EC_B_COMPLETE,	/* BACKTAB */
172 	ESC,'\t',0,			EC_B_COMPLETE,	/* ESC TAB */
173 	CONTROL('L'),0,			EC_EXPAND,	/* CTRL-L */
174 	CONTROL('V'),0,			EC_LITERAL,	/* BACKSLASH */
175 	CONTROL('A'),0,			EC_LITERAL,	/* BACKSLASH */
176    	ESC,'l',0,			EC_RIGHT,	/* ESC l */
177 	SK(SK_RIGHT_ARROW),0,		EC_RIGHT,	/* RIGHTARROW */
178 	ESC,'h',0,			EC_LEFT,	/* ESC h */
179 	SK(SK_LEFT_ARROW),0,		EC_LEFT,	/* LEFTARROW */
180 	ESC,'b',0,			EC_W_LEFT,	/* ESC b */
181 	ESC,SK(SK_LEFT_ARROW),0,	EC_W_LEFT,	/* ESC LEFTARROW */
182 	SK(SK_CTL_LEFT_ARROW),0,	EC_W_LEFT,	/* CTRL-LEFTARROW */
183 	ESC,'w',0,			EC_W_RIGHT,	/* ESC w */
184 	ESC,SK(SK_RIGHT_ARROW),0,	EC_W_RIGHT,	/* ESC RIGHTARROW */
185 	SK(SK_CTL_RIGHT_ARROW),0,	EC_W_RIGHT,	/* CTRL-RIGHTARROW */
186 	ESC,'i',0,			EC_INSERT,	/* ESC i */
187 	SK(SK_INSERT),0,		EC_INSERT,	/* INSERT */
188 	ESC,'x',0,			EC_DELETE,	/* ESC x */
189 	SK(SK_DELETE),0,		EC_DELETE,	/* DELETE */
190 	ESC,'X',0,			EC_W_DELETE,	/* ESC X */
191 	ESC,SK(SK_DELETE),0,		EC_W_DELETE,	/* ESC DELETE */
192 	SK(SK_CTL_DELETE),0,		EC_W_DELETE,	/* CTRL-DELETE */
193 	SK(SK_CTL_BACKSPACE),0,		EC_W_BACKSPACE, /* CTRL-BACKSPACE */
194 	ESC,'\b',0,			EC_W_BACKSPACE,	/* ESC BACKSPACE */
195 	ESC,'0',0,			EC_HOME,	/* ESC 0 */
196 	SK(SK_HOME),0,			EC_HOME,	/* HOME */
197 	ESC,'$',0,			EC_END,		/* ESC $ */
198 	SK(SK_END),0,			EC_END,		/* END */
199 	ESC,'k',0,			EC_UP,		/* ESC k */
200 	SK(SK_UP_ARROW),0,		EC_UP,		/* UPARROW */
201 	ESC,'j',0,			EC_DOWN,	/* ESC j */
202 	SK(SK_DOWN_ARROW),0,		EC_DOWN,	/* DOWNARROW */
203 };
204 
205 /*
206  * Structure to support a list of command tables.
207  */
208 struct tablelist
209 {
210 	struct tablelist *t_next;
211 	char *t_start;
212 	char *t_end;
213 };
214 
215 /*
216  * List of command tables and list of line-edit tables.
217  */
218 static struct tablelist *list_fcmd_tables = NULL;
219 static struct tablelist *list_ecmd_tables = NULL;
220 static struct tablelist *list_var_tables = NULL;
221 static struct tablelist *list_sysvar_tables = NULL;
222 
223 
224 /*
225  * Expand special key abbreviations in a command table.
226  */
227 	static void
228 expand_special_keys(table, len)
229 	char *table;
230 	int len;
231 {
232 	register char *fm;
233 	register char *to;
234 	register int a;
235 	char *repl;
236 	int klen;
237 
238 	for (fm = table;  fm < table + len; )
239 	{
240 		/*
241 		 * Rewrite each command in the table with any
242 		 * special key abbreviations expanded.
243 		 */
244 		for (to = fm;  *fm != '\0'; )
245 		{
246 			if (*fm != SK_SPECIAL_KEY)
247 			{
248 				*to++ = *fm++;
249 				continue;
250 			}
251 			/*
252 			 * After SK_SPECIAL_KEY, next byte is the type
253 			 * of special key (one of the SK_* contants),
254 			 * and the byte after that is the number of bytes,
255 			 * N, reserved by the abbreviation (including the
256 			 * SK_SPECIAL_KEY and key type bytes).
257 			 * Replace all N bytes with the actual bytes
258 			 * output by the special key on this terminal.
259 			 */
260 			repl = special_key_str(fm[1]);
261 			klen = fm[2] & 0377;
262 			fm += klen;
263 			if (repl == NULL || strlen(repl) > klen)
264 				repl = "\377";
265 			while (*repl != '\0')
266 				*to++ = *repl++;
267 		}
268 		*to++ = '\0';
269 		/*
270 		 * Fill any unused bytes between end of command and
271 		 * the action byte with A_SKIP.
272 		 */
273 		while (to <= fm)
274 			*to++ = A_SKIP;
275 		fm++;
276 		a = *fm++ & 0377;
277 		if (a & A_EXTRA)
278 		{
279 			while (*fm++ != '\0')
280 				continue;
281 		}
282 	}
283 }
284 
285 /*
286  * Initialize the command lists.
287  */
288 	public void
289 init_cmds()
290 {
291 	/*
292 	 * Add the default command tables.
293 	 */
294 	add_fcmd_table((char*)cmdtable, sizeof(cmdtable));
295 	add_ecmd_table((char*)edittable, sizeof(edittable));
296 #if USERFILE
297 	/*
298 	 * For backwards compatibility,
299 	 * try to add tables in the OLD system lesskey file.
300 	 */
301 #ifdef BINDIR
302 	add_hometable(NULL, BINDIR "/.sysless", 1);
303 #endif
304 	/*
305 	 * Try to add the tables in the system lesskey file.
306 	 */
307 	add_hometable("LESSKEY_SYSTEM", LESSKEYFILE_SYS, 1);
308 	/*
309 	 * Try to add the tables in the standard lesskey file "$HOME/.less".
310 	 */
311 	add_hometable("LESSKEY", LESSKEYFILE, 0);
312 #endif
313 }
314 
315 /*
316  * Add a command table.
317  */
318 	static int
319 add_cmd_table(tlist, buf, len)
320 	struct tablelist **tlist;
321 	char *buf;
322 	int len;
323 {
324 	register struct tablelist *t;
325 
326 	if (len == 0)
327 		return (0);
328 	/*
329 	 * Allocate a tablelist structure, initialize it,
330 	 * and link it into the list of tables.
331 	 */
332 	if ((t = (struct tablelist *)
333 			calloc(1, sizeof(struct tablelist))) == NULL)
334 	{
335 		return (-1);
336 	}
337 	expand_special_keys(buf, len);
338 	t->t_start = buf;
339 	t->t_end = buf + len;
340 	t->t_next = *tlist;
341 	*tlist = t;
342 	return (0);
343 }
344 
345 /*
346  * Add a command table.
347  */
348 	public void
349 add_fcmd_table(buf, len)
350 	char *buf;
351 	int len;
352 {
353 	if (add_cmd_table(&list_fcmd_tables, buf, len) < 0)
354 		error("Warning: some commands disabled", NULL_PARG);
355 }
356 
357 /*
358  * Add an editing command table.
359  */
360 	public void
361 add_ecmd_table(buf, len)
362 	char *buf;
363 	int len;
364 {
365 	if (add_cmd_table(&list_ecmd_tables, buf, len) < 0)
366 		error("Warning: some edit commands disabled", NULL_PARG);
367 }
368 
369 /*
370  * Add an environment variable table.
371  */
372 	static void
373 add_var_table(tlist, buf, len)
374 	struct tablelist **tlist;
375 	char *buf;
376 	int len;
377 {
378 	if (add_cmd_table(tlist, buf, len) < 0)
379 		error("Warning: environment variables from lesskey file unavailable", NULL_PARG);
380 }
381 
382 /*
383  * Search a single command table for the command string in cmd.
384  */
385 	static int
386 cmd_search(cmd, table, endtable, sp)
387 	char *cmd;
388 	char *table;
389 	char *endtable;
390 	char **sp;
391 {
392 	register char *p;
393 	register char *q;
394 	register int a;
395 
396 	*sp = NULL;
397 	for (p = table, q = cmd;  p < endtable;  p++, q++)
398 	{
399 		if (*p == *q)
400 		{
401 			/*
402 			 * Current characters match.
403 			 * If we're at the end of the string, we've found it.
404 			 * Return the action code, which is the character
405 			 * after the null at the end of the string
406 			 * in the command table.
407 			 */
408 			if (*p == '\0')
409 			{
410 				a = *++p & 0377;
411 				while (a == A_SKIP)
412 					a = *++p & 0377;
413 				if (a == A_END_LIST)
414 				{
415 					/*
416 					 * We get here only if the original
417 					 * cmd string passed in was empty ("").
418 					 * I don't think that can happen,
419 					 * but just in case ...
420 					 */
421 					return (A_UINVALID);
422 				}
423 				/*
424 				 * Check for an "extra" string.
425 				 */
426 				if (a & A_EXTRA)
427 				{
428 					*sp = ++p;
429 					a &= ~A_EXTRA;
430 				}
431 				return (a);
432 			}
433 		} else if (*q == '\0')
434 		{
435 			/*
436 			 * Hit the end of the user's command,
437 			 * but not the end of the string in the command table.
438 			 * The user's command is incomplete.
439 			 */
440 			return (A_PREFIX);
441 		} else
442 		{
443 			/*
444 			 * Not a match.
445 			 * Skip ahead to the next command in the
446 			 * command table, and reset the pointer
447 			 * to the beginning of the user's command.
448 			 */
449 			if (*p == '\0' && p[1] == A_END_LIST)
450 			{
451 				/*
452 				 * A_END_LIST is a special marker that tells
453 				 * us to abort the cmd search.
454 				 */
455 				return (A_UINVALID);
456 			}
457 			while (*p++ != '\0')
458 				continue;
459 			while (*p == A_SKIP)
460 				p++;
461 			if (*p & A_EXTRA)
462 				while (*++p != '\0')
463 					continue;
464 			q = cmd-1;
465 		}
466 	}
467 	/*
468 	 * No match found in the entire command table.
469 	 */
470 	return (A_INVALID);
471 }
472 
473 /*
474  * Decode a command character and return the associated action.
475  * The "extra" string, if any, is returned in sp.
476  */
477 	static int
478 cmd_decode(tlist, cmd, sp)
479 	struct tablelist *tlist;
480 	char *cmd;
481 	char **sp;
482 {
483 	register struct tablelist *t;
484 	register int action = A_INVALID;
485 
486 	/*
487 	 * Search thru all the command tables.
488 	 * Stop when we find an action which is not A_INVALID.
489 	 */
490 	for (t = tlist;  t != NULL;  t = t->t_next)
491 	{
492 		action = cmd_search(cmd, t->t_start, t->t_end, sp);
493 		if (action != A_INVALID)
494 			break;
495 	}
496 	if (action == A_UINVALID)
497 		action = A_INVALID;
498 	return (action);
499 }
500 
501 /*
502  * Decode a command from the cmdtables list.
503  */
504 	public int
505 fcmd_decode(cmd, sp)
506 	char *cmd;
507 	char **sp;
508 {
509 	return (cmd_decode(list_fcmd_tables, cmd, sp));
510 }
511 
512 /*
513  * Decode a command from the edittables list.
514  */
515 	public int
516 ecmd_decode(cmd, sp)
517 	char *cmd;
518 	char **sp;
519 {
520 	return (cmd_decode(list_ecmd_tables, cmd, sp));
521 }
522 
523 /*
524  * Get the value of an environment variable.
525  * Looks first in the lesskey file, then in the real environment.
526  */
527 	public char *
528 lgetenv(var)
529 	char *var;
530 {
531 	int a;
532 	char *s;
533 
534 	a = cmd_decode(list_var_tables, var, &s);
535 	if (a == EV_OK)
536 		return (s);
537 	s = getenv(var);
538 	if (s != NULL && *s != '\0')
539 		return (s);
540 	a = cmd_decode(list_sysvar_tables, var, &s);
541 	if (a == EV_OK)
542 		return (s);
543 	return (NULL);
544 }
545 
546 #if USERFILE
547 /*
548  * Get an "integer" from a lesskey file.
549  * Integers are stored in a funny format:
550  * two bytes, low order first, in radix KRADIX.
551  */
552 	static int
553 gint(sp)
554 	char **sp;
555 {
556 	int n;
557 
558 	n = *(*sp)++;
559 	n += *(*sp)++ * KRADIX;
560 	return (n);
561 }
562 
563 /*
564  * Process an old (pre-v241) lesskey file.
565  */
566 	static int
567 old_lesskey(buf, len)
568 	char *buf;
569 	int len;
570 {
571 	/*
572 	 * Old-style lesskey file.
573 	 * The file must end with either
574 	 *     ...,cmd,0,action
575 	 * or  ...,cmd,0,action|A_EXTRA,string,0
576 	 * So the last byte or the second to last byte must be zero.
577 	 */
578 	if (buf[len-1] != '\0' && buf[len-2] != '\0')
579 		return (-1);
580 	add_fcmd_table(buf, len);
581 	return (0);
582 }
583 
584 /*
585  * Process a new (post-v241) lesskey file.
586  */
587 	static int
588 new_lesskey(buf, len, sysvar)
589 	char *buf;
590 	int len;
591 	int sysvar;
592 {
593 	char *p;
594 	register int c;
595 	register int n;
596 
597 	/*
598 	 * New-style lesskey file.
599 	 * Extract the pieces.
600 	 */
601 	if (buf[len-3] != C0_END_LESSKEY_MAGIC ||
602 	    buf[len-2] != C1_END_LESSKEY_MAGIC ||
603 	    buf[len-1] != C2_END_LESSKEY_MAGIC)
604 		return (-1);
605 	p = buf + 4;
606 	for (;;)
607 	{
608 		c = *p++;
609 		switch (c)
610 		{
611 		case CMD_SECTION:
612 			n = gint(&p);
613 			add_fcmd_table(p, n);
614 			p += n;
615 			break;
616 		case EDIT_SECTION:
617 			n = gint(&p);
618 			add_ecmd_table(p, n);
619 			p += n;
620 			break;
621 		case VAR_SECTION:
622 			n = gint(&p);
623 			add_var_table((sysvar) ?
624 				&list_sysvar_tables : &list_var_tables, p, n);
625 			p += n;
626 			break;
627 		case END_SECTION:
628 			return (0);
629 		default:
630 			/*
631 			 * Unrecognized section type.
632 			 */
633 			return (-1);
634 		}
635 	}
636 }
637 
638 /*
639  * Set up a user command table, based on a "lesskey" file.
640  */
641 	public int
642 lesskey(filename, sysvar)
643 	char *filename;
644 	int sysvar;
645 {
646 	register char *buf;
647 	register POSITION len;
648 	register long n;
649 	register int f;
650 
651 	if (secure)
652 		return (1);
653 	/*
654 	 * Try to open the lesskey file.
655 	 */
656 	filename = unquote_file(filename);
657 	f = open(filename, OPEN_READ);
658 	free(filename);
659 	if (f < 0)
660 		return (1);
661 
662 	/*
663 	 * Read the file into a buffer.
664 	 * We first figure out the size of the file and allocate space for it.
665 	 * {{ Minimal error checking is done here.
666 	 *    A garbage .less file will produce strange results.
667 	 *    To avoid a large amount of error checking code here, we
668 	 *    rely on the lesskey program to generate a good .less file. }}
669 	 */
670 	len = filesize(f);
671 	if (len == NULL_POSITION || len < 3)
672 	{
673 		/*
674 		 * Bad file (valid file must have at least 3 chars).
675 		 */
676 		close(f);
677 		return (-1);
678 	}
679 	if ((buf = (char *) calloc((int)len, sizeof(char))) == NULL)
680 	{
681 		close(f);
682 		return (-1);
683 	}
684 	if (lseek(f, (off_t)0, 0) == BAD_LSEEK)
685 	{
686 		free(buf);
687 		close(f);
688 		return (-1);
689 	}
690 	n = read(f, buf, (unsigned int) len);
691 	close(f);
692 	if (n != len)
693 	{
694 		free(buf);
695 		return (-1);
696 	}
697 
698 	/*
699 	 * Figure out if this is an old-style (before version 241)
700 	 * or new-style lesskey file format.
701 	 */
702 	if (buf[0] != C0_LESSKEY_MAGIC || buf[1] != C1_LESSKEY_MAGIC ||
703 	    buf[2] != C2_LESSKEY_MAGIC || buf[3] != C3_LESSKEY_MAGIC)
704 		return (old_lesskey(buf, (int)len));
705 	return (new_lesskey(buf, (int)len, sysvar));
706 }
707 
708 /*
709  * Add the standard lesskey file "$HOME/.less"
710  */
711 	public void
712 add_hometable(envname, def_filename, sysvar)
713 	char *envname;
714 	char *def_filename;
715 	int sysvar;
716 {
717 	char *filename;
718 	PARG parg;
719 
720 	if (envname != NULL && (filename = lgetenv(envname)) != NULL)
721 		filename = save(filename);
722 	else if (sysvar)
723 		filename = save(def_filename);
724 	else
725 		filename = homefile(def_filename);
726 	if (filename == NULL)
727 		return;
728 	if (lesskey(filename, sysvar) < 0)
729 	{
730 		parg.p_string = filename;
731 		error("Cannot use lesskey file \"%s\"", &parg);
732 	}
733 	free(filename);
734 }
735 #endif
736 
737 /*
738  * See if a char is a special line-editing command.
739  */
740 	public int
741 editchar(c, flags)
742 	int c;
743 	int flags;
744 {
745 	int action;
746 	int nch;
747 	char *s;
748 	char usercmd[MAX_CMDLEN+1];
749 
750 	/*
751 	 * An editing character could actually be a sequence of characters;
752 	 * for example, an escape sequence sent by pressing the uparrow key.
753 	 * To match the editing string, we use the command decoder
754 	 * but give it the edit-commands command table
755 	 * This table is constructed to match the user's keyboard.
756 	 */
757 	if (c == erase_char)
758 		return (EC_BACKSPACE);
759 	if (c == kill_char)
760 		return (EC_LINEKILL);
761 
762 	/*
763 	 * Collect characters in a buffer.
764 	 * Start with the one we have, and get more if we need them.
765 	 */
766 	nch = 0;
767 	do {
768 	  	if (nch > 0)
769 			c = getcc();
770 		usercmd[nch] = c;
771 		usercmd[nch+1] = '\0';
772 		nch++;
773 		action = ecmd_decode(usercmd, &s);
774 	} while (action == A_PREFIX);
775 
776 	if (flags & EC_NORIGHTLEFT)
777 	{
778 		switch (action)
779 		{
780 		case EC_RIGHT:
781 		case EC_LEFT:
782 			action = A_INVALID;
783 			break;
784 		}
785 	}
786 #if CMD_HISTORY
787 	if (flags & EC_NOHISTORY)
788 	{
789 		/*
790 		 * The caller says there is no history list.
791 		 * Reject any history-manipulation action.
792 		 */
793 		switch (action)
794 		{
795 		case EC_UP:
796 		case EC_DOWN:
797 			action = A_INVALID;
798 			break;
799 		}
800 	}
801 #endif
802 #if TAB_COMPLETE_FILENAME
803 	if (flags & EC_NOCOMPLETE)
804 	{
805 		/*
806 		 * The caller says we don't want any filename completion cmds.
807 		 * Reject them.
808 		 */
809 		switch (action)
810 		{
811 		case EC_F_COMPLETE:
812 		case EC_B_COMPLETE:
813 		case EC_EXPAND:
814 			action = A_INVALID;
815 			break;
816 		}
817 	}
818 #endif
819 	if ((flags & EC_PEEK) || action == A_INVALID)
820 	{
821 		/*
822 		 * We're just peeking, or we didn't understand the command.
823 		 * Unget all the characters we read in the loop above.
824 		 * This does NOT include the original character that was
825 		 * passed in as a parameter.
826 		 */
827 		while (nch > 1)
828 		{
829 			ungetcc(usercmd[--nch]);
830 		}
831 	} else
832 	{
833 		if (s != NULL)
834 			ungetsc(s);
835 	}
836 	return action;
837 }
838 
839