summaryrefslogtreecommitdiffstats
path: root/contrib/less/decode.c
blob: 46ac21bcd5f8aba7265d52b9bb8fc8a3bf6db123 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
/*
 * Copyright (C) 1984-2000  Mark Nudelman
 *
 * You may distribute under the terms of either the GNU General Public
 * License or the Less License, as specified in the README file.
 *
 * For more information about less, or for information on how to 
 * contact the author, see the README file.
 */


/*
 * Routines to decode user commands.
 *
 * This is all table driven.
 * A command table is a sequence of command descriptors.
 * Each command descriptor is a sequence of bytes with the following format:
 *	<c1><c2>...<cN><0><action>
 * The characters c1,c2,...,cN are the command string; that is,
 * the characters which the user must type.
 * It is terminated by a null <0> byte.
 * The byte after the null byte is the action code associated
 * with the command string.
 * If an action byte is OR-ed with A_EXTRA, this indicates
 * that the option byte is followed by an extra string.
 *
 * There may be many command tables.
 * The first (default) table is built-in.
 * Other tables are read in from "lesskey" files.
 * All the tables are linked together and are searched in order.
 */

#include "less.h"
#include "cmd.h"
#include "lesskey.h"

extern int erase_char, kill_char;
extern int secure;

#define SK(k) \
	SK_SPECIAL_KEY, (k), 6, 1, 1, 1
/*
 * Command table is ordered roughly according to expected
 * frequency of use, so the common commands are near the beginning.
 */

static unsigned char cmdtable[] =
{
	'\r',0,				A_F_LINE,
	'\n',0,				A_F_LINE,
	'e',0,				A_F_LINE,
	'j',0,				A_F_LINE,
	SK(SK_DOWN_ARROW),0,		A_F_LINE,
	CONTROL('E'),0,			A_F_LINE,
	CONTROL('N'),0,			A_F_LINE,
	'k',0,				A_B_LINE,
	'y',0,				A_B_LINE,
	CONTROL('Y'),0,			A_B_LINE,
	SK(SK_CONTROL_K),0,		A_B_LINE,
	CONTROL('P'),0,			A_B_LINE,
	SK(SK_UP_ARROW),0,		A_B_LINE,
	'J',0,				A_FF_LINE,
	'K',0,				A_BF_LINE,
	'Y',0,				A_BF_LINE,
	'd',0,				A_F_SCROLL,
	CONTROL('D'),0,			A_F_SCROLL,
	'u',0,				A_B_SCROLL,
	CONTROL('U'),0,			A_B_SCROLL,
	' ',0,				A_F_SCREEN,
	'f',0,				A_F_SCREEN,
	CONTROL('F'),0,			A_F_SCREEN,
	CONTROL('V'),0,			A_F_SCREEN,
	SK(SK_PAGE_DOWN),0,		A_F_SCREEN,
	'b',0,				A_B_SCREEN,
	CONTROL('B'),0,			A_B_SCREEN,
	ESC,'v',0,			A_B_SCREEN,
	SK(SK_PAGE_UP),0,		A_B_SCREEN,
	'z',0,				A_F_WINDOW,
	'w',0,				A_B_WINDOW,
	ESC,' ',0,			A_FF_SCREEN,
	'F',0,				A_F_FOREVER,
	'R',0,				A_FREPAINT,
	'r',0,				A_REPAINT,
	CONTROL('R'),0,			A_REPAINT,
	CONTROL('L'),0,			A_REPAINT,
	ESC,'u',0,			A_UNDO_SEARCH,
	'g',0,				A_GOLINE,
	SK(SK_HOME),0,			A_GOLINE,
	'<',0,				A_GOLINE,
	ESC,'<',0,			A_GOLINE,
	'p',0,				A_PERCENT,
	'%',0,				A_PERCENT,
	ESC,'[',0,			A_LSHIFT,
	ESC,']',0,			A_RSHIFT,
	ESC,'(',0,			A_LSHIFT,
	ESC,')',0,			A_RSHIFT,
	SK(SK_RIGHT_ARROW),0,		A_RSHIFT,
	SK(SK_LEFT_ARROW),0,		A_LSHIFT,
	'{',0,				A_F_BRACKET|A_EXTRA,	'{','}',0,
	'}',0,				A_B_BRACKET|A_EXTRA,	'{','}',0,
	'(',0,				A_F_BRACKET|A_EXTRA,	'(',')',0,
	')',0,				A_B_BRACKET|A_EXTRA,	'(',')',0,
	'[',0,				A_F_BRACKET|A_EXTRA,	'[',']',0,
	']',0,				A_B_BRACKET|A_EXTRA,	'[',']',0,
	ESC,CONTROL('F'),0,		A_F_BRACKET,
	ESC,CONTROL('B'),0,		A_B_BRACKET,
	'G',0,				A_GOEND,
	ESC,'>',0,			A_GOEND,
	'>',0,				A_GOEND,
	SK(SK_END),0,			A_GOEND,
	'P',0,				A_GOPOS,

	'0',0,				A_DIGIT,
	'1',0,				A_DIGIT,
	'2',0,				A_DIGIT,
	'3',0,				A_DIGIT,
	'4',0,				A_DIGIT,
	'5',0,				A_DIGIT,
	'6',0,				A_DIGIT,
	'7',0,				A_DIGIT,
	'8',0,				A_DIGIT,
	'9',0,				A_DIGIT,

	'=',0,				A_STAT,
	CONTROL('G'),0,			A_STAT,
	':','f',0,			A_STAT,
	'/',0,				A_F_SEARCH,
	'?',0,				A_B_SEARCH,
	ESC,'/',0,			A_F_SEARCH|A_EXTRA,	'*',0,
	ESC,'?',0,			A_B_SEARCH|A_EXTRA,	'*',0,
	'n',0,				A_AGAIN_SEARCH,
	ESC,'n',0,			A_T_AGAIN_SEARCH,
	'N',0,				A_REVERSE_SEARCH,
	ESC,'N',0,			A_T_REVERSE_SEARCH,
	'm',0,				A_SETMARK,
	'\'',0,				A_GOMARK,
	CONTROL('X'),CONTROL('X'),0,	A_GOMARK,
	'E',0,				A_EXAMINE,
	':','e',0,			A_EXAMINE,
	CONTROL('X'),CONTROL('V'),0,	A_EXAMINE,
	':','n',0,			A_NEXT_FILE,
	':','p',0,			A_PREV_FILE,
	':','x',0,			A_INDEX_FILE,
	':','d',0,			A_REMOVE_FILE,
	'-',0,				A_OPT_TOGGLE,
	':','t',0,			A_OPT_TOGGLE|A_EXTRA,	't',0,
	's',0,				A_OPT_TOGGLE|A_EXTRA,	'o',0,
	'_',0,				A_DISP_OPTION,
	'|',0,				A_PIPE,
	'v',0,				A_VISUAL,
	'!',0,				A_SHELL,
	'+',0,				A_FIRSTCMD,

	'H',0,				A_HELP,
	'h',0,				A_HELP,
	SK(SK_F1),0,			A_HELP,
	'V',0,				A_VERSION,
	'q',0,				A_QUIT,
	'Q',0,				A_QUIT,
	':','q',0,			A_QUIT,
	':','Q',0,			A_QUIT,
	'Z','Z',0,			A_QUIT
};

static unsigned char edittable[] =
{
	'\t',0,	    			EC_F_COMPLETE,	/* TAB */
	'\17',0,			EC_B_COMPLETE,	/* BACKTAB */
	SK(SK_BACKTAB),0,		EC_B_COMPLETE,	/* BACKTAB */
	ESC,'\t',0,			EC_B_COMPLETE,	/* ESC TAB */
	CONTROL('L'),0,			EC_EXPAND,	/* CTRL-L */
	CONTROL('V'),0,			EC_LITERAL,	/* BACKSLASH */
	CONTROL('A'),0,			EC_LITERAL,	/* BACKSLASH */
   	ESC,'l',0,			EC_RIGHT,	/* ESC l */
	SK(SK_RIGHT_ARROW),0,		EC_RIGHT,	/* RIGHTARROW */
	ESC,'h',0,			EC_LEFT,	/* ESC h */
	SK(SK_LEFT_ARROW),0,		EC_LEFT,	/* LEFTARROW */
	ESC,'b',0,			EC_W_LEFT,	/* ESC b */
	ESC,SK(SK_LEFT_ARROW),0,	EC_W_LEFT,	/* ESC LEFTARROW */
	SK(SK_CTL_LEFT_ARROW),0,	EC_W_LEFT,	/* CTRL-LEFTARROW */
	ESC,'w',0,			EC_W_RIGHT,	/* ESC w */
	ESC,SK(SK_RIGHT_ARROW),0,	EC_W_RIGHT,	/* ESC RIGHTARROW */
	SK(SK_CTL_RIGHT_ARROW),0,	EC_W_RIGHT,	/* CTRL-RIGHTARROW */
	ESC,'i',0,			EC_INSERT,	/* ESC i */
	SK(SK_INSERT),0,		EC_INSERT,	/* INSERT */
	ESC,'x',0,			EC_DELETE,	/* ESC x */
	SK(SK_DELETE),0,		EC_DELETE,	/* DELETE */
	ESC,'X',0,			EC_W_DELETE,	/* ESC X */
	ESC,SK(SK_DELETE),0,		EC_W_DELETE,	/* ESC DELETE */
	SK(SK_CTL_DELETE),0,		EC_W_DELETE,	/* CTRL-DELETE */
	SK(SK_CTL_BACKSPACE),0,		EC_W_BACKSPACE, /* CTRL-BACKSPACE */
	ESC,'\b',0,			EC_W_BACKSPACE,	/* ESC BACKSPACE */
	ESC,'0',0,			EC_HOME,	/* ESC 0 */
	SK(SK_HOME),0,			EC_HOME,	/* HOME */
	ESC,'$',0,			EC_END,		/* ESC $ */
	SK(SK_END),0,			EC_END,		/* END */
	ESC,'k',0,			EC_UP,		/* ESC k */
	SK(SK_UP_ARROW),0,		EC_UP,		/* UPARROW */
	ESC,'j',0,			EC_DOWN,	/* ESC j */
	SK(SK_DOWN_ARROW),0,		EC_DOWN,	/* DOWNARROW */
};

/*
 * Structure to support a list of command tables.
 */
struct tablelist
{
	struct tablelist *t_next;
	char *t_start;
	char *t_end;
};

/*
 * List of command tables and list of line-edit tables.
 */
static struct tablelist *list_fcmd_tables = NULL;
static struct tablelist *list_ecmd_tables = NULL;
static struct tablelist *list_var_tables = NULL;
static struct tablelist *list_sysvar_tables = NULL;


/*
 * Expand special key abbreviations in a command table.
 */
	static void
expand_special_keys(table, len)
	char *table;
	int len;
{
	register char *fm;
	register char *to;
	register int a;
	char *repl;
	int klen;

	for (fm = table;  fm < table + len; )
	{
		/*
		 * Rewrite each command in the table with any
		 * special key abbreviations expanded.
		 */
		for (to = fm;  *fm != '\0'; )
		{
			if (*fm != SK_SPECIAL_KEY)
			{
				*to++ = *fm++;
				continue;
			}
			/*
			 * After SK_SPECIAL_KEY, next byte is the type
			 * of special key (one of the SK_* contants),
			 * and the byte after that is the number of bytes,
			 * N, reserved by the abbreviation (including the
			 * SK_SPECIAL_KEY and key type bytes).
			 * Replace all N bytes with the actual bytes
			 * output by the special key on this terminal.
			 */
			repl = special_key_str(fm[1]);
			klen = fm[2] & 0377;
			fm += klen;
			if (repl == NULL || strlen(repl) > klen)
				repl = "\377";
			while (*repl != '\0')
				*to++ = *repl++;
		}
		*to++ = '\0';
		/*
		 * Fill any unused bytes between end of command and 
		 * the action byte with A_SKIP.
		 */
		while (to <= fm)
			*to++ = A_SKIP;
		fm++;
		a = *fm++ & 0377;
		if (a & A_EXTRA)
		{
			while (*fm++ != '\0')
				continue;
		}
	}
}

/*
 * Initialize the command lists.
 */
	public void
init_cmds()
{
	/*
	 * Add the default command tables.
	 */
	add_fcmd_table((char*)cmdtable, sizeof(cmdtable));
	add_ecmd_table((char*)edittable, sizeof(edittable));
#if USERFILE
	/*
	 * Try to add the tables in the system lesskey file.
	 */
	add_hometable("LESSKEY_SYSTEM", LESSKEYFILE_SYS, 1);
	/*
	 * Try to add the tables in the standard lesskey file "$HOME/.less".
	 */
	add_hometable("LESSKEY", LESSKEYFILE, 0);
#endif
}

/*
 * Add a command table.
 */
	static int
add_cmd_table(tlist, buf, len)
	struct tablelist **tlist;
	char *buf;
	int len;
{
	register struct tablelist *t;

	if (len == 0)
		return (0);
	/*
	 * Allocate a tablelist structure, initialize it, 
	 * and link it into the list of tables.
	 */
	if ((t = (struct tablelist *) 
			calloc(1, sizeof(struct tablelist))) == NULL)
	{
		return (-1);
	}
	expand_special_keys(buf, len);
	t->t_start = buf;
	t->t_end = buf + len;
	t->t_next = *tlist;
	*tlist = t;
	return (0);
}

/*
 * Add a command table.
 */
	public void
add_fcmd_table(buf, len)
	char *buf;
	int len;
{
	if (add_cmd_table(&list_fcmd_tables, buf, len) < 0)
		error("Warning: some commands disabled", NULL_PARG);
}

/*
 * Add an editing command table.
 */
	public void
add_ecmd_table(buf, len)
	char *buf;
	int len;
{
	if (add_cmd_table(&list_ecmd_tables, buf, len) < 0)
		error("Warning: some edit commands disabled", NULL_PARG);
}

/*
 * Add an environment variable table.
 */
	static void
add_var_table(tlist, buf, len)
	struct tablelist **tlist;
	char *buf;
	int len;
{
	if (add_cmd_table(tlist, buf, len) < 0)
		error("Warning: environment variables from lesskey file unavailable", NULL_PARG);
}

/*
 * Search a single command table for the command string in cmd.
 */
	static int
cmd_search(cmd, table, endtable, sp)
	char *cmd;
	char *table;
	char *endtable;
	char **sp;
{
	register char *p;
	register char *q;
	register int a;

	*sp = NULL;
	for (p = table, q = cmd;  p < endtable;  p++, q++)
	{
		if (*p == *q)
		{
			/*
			 * Current characters match.
			 * If we're at the end of the string, we've found it.
			 * Return the action code, which is the character
			 * after the null at the end of the string
			 * in the command table.
			 */
			if (*p == '\0')
			{
				a = *++p & 0377;
				while (a == A_SKIP)
					a = *++p & 0377;
				if (a == A_END_LIST)
				{
					/*
					 * We get here only if the original
					 * cmd string passed in was empty ("").
					 * I don't think that can happen,
					 * but just in case ...
					 */
					return (A_UINVALID);
				}
				/*
				 * Check for an "extra" string.
				 */
				if (a & A_EXTRA)
				{
					*sp = ++p;
					a &= ~A_EXTRA;
				}
				return (a);
			}
		} else if (*q == '\0')
		{
			/*
			 * Hit the end of the user's command,
			 * but not the end of the string in the command table.
			 * The user's command is incomplete.
			 */
			return (A_PREFIX);
		} else
		{
			/*
			 * Not a match.
			 * Skip ahead to the next command in the
			 * command table, and reset the pointer
			 * to the beginning of the user's command.
			 */
			if (*p == '\0' && p[1] == A_END_LIST)
			{
				/*
				 * A_END_LIST is a special marker that tells 
				 * us to abort the cmd search.
				 */
				return (A_UINVALID);
			}
			while (*p++ != '\0')
				continue;
			while (*p == A_SKIP)
				p++;
			if (*p & A_EXTRA)
				while (*++p != '\0')
					continue;
			q = cmd-1;
		}
	}
	/*
	 * No match found in the entire command table.
	 */
	return (A_INVALID);
}

/*
 * Decode a command character and return the associated action.
 * The "extra" string, if any, is returned in sp.
 */
	static int
cmd_decode(tlist, cmd, sp)
	struct tablelist *tlist;
	char *cmd;
	char **sp;
{
	register struct tablelist *t;
	register int action = A_INVALID;

	/*
	 * Search thru all the command tables.
	 * Stop when we find an action which is not A_INVALID.
	 */
	for (t = tlist;  t != NULL;  t = t->t_next)
	{
		action = cmd_search(cmd, t->t_start, t->t_end, sp);
		if (action != A_INVALID)
			break;
	}
	if (action == A_UINVALID)
		action = A_INVALID;
	return (action);
}

/*
 * Decode a command from the cmdtables list.
 */
	public int
fcmd_decode(cmd, sp)
	char *cmd;
	char **sp;
{
	return (cmd_decode(list_fcmd_tables, cmd, sp));
}

/*
 * Decode a command from the edittables list.
 */
	public int
ecmd_decode(cmd, sp)
	char *cmd;
	char **sp;
{
	return (cmd_decode(list_ecmd_tables, cmd, sp));
}

/*
 * Get the value of an environment variable.
 * Looks first in the lesskey file, then in the real environment.
 */
	public char *
lgetenv(var)
	char *var;
{
	int a;
	char *s;

	a = cmd_decode(list_var_tables, var, &s);
	if (a == EV_OK)
		return (s);
	s = getenv(var);
	if (s != NULL && *s != '\0')
		return (s);
	a = cmd_decode(list_sysvar_tables, var, &s);
	if (a == EV_OK)
		return (s);
	return (NULL);
}

#if USERFILE
/*
 * Get an "integer" from a lesskey file.
 * Integers are stored in a funny format: 
 * two bytes, low order first, in radix KRADIX.
 */
	static int
gint(sp)
	char **sp;
{
	int n;

	n = *(*sp)++;
	n += *(*sp)++ * KRADIX;
	return (n);
}

/*
 * Process an old (pre-v241) lesskey file.
 */
	static int
old_lesskey(buf, len)
	char *buf;
	int len;
{
	/*
	 * Old-style lesskey file.
	 * The file must end with either 
	 *     ...,cmd,0,action
	 * or  ...,cmd,0,action|A_EXTRA,string,0
	 * So the last byte or the second to last byte must be zero.
	 */
	if (buf[len-1] != '\0' && buf[len-2] != '\0')
		return (-1);
	add_fcmd_table(buf, len);
	return (0);
}

/* 
 * Process a new (post-v241) lesskey file.
 */
	static int
new_lesskey(buf, len, sysvar)
	char *buf;
	int len;
	int sysvar;
{
	char *p;
	register int c;
	register int n;

	/*
	 * New-style lesskey file.
	 * Extract the pieces.
	 */
	if (buf[len-3] != C0_END_LESSKEY_MAGIC ||
	    buf[len-2] != C1_END_LESSKEY_MAGIC ||
	    buf[len-1] != C2_END_LESSKEY_MAGIC)
		return (-1);
	p = buf + 4;
	for (;;)
	{
		c = *p++;
		switch (c)
		{
		case CMD_SECTION:
			n = gint(&p);
			add_fcmd_table(p, n);
			p += n;
			break;
		case EDIT_SECTION:
			n = gint(&p);
			add_ecmd_table(p, n);
			p += n;
			break;
		case VAR_SECTION:
			n = gint(&p);
			add_var_table((sysvar) ? 
				&list_sysvar_tables : &list_var_tables, p, n);
			p += n;
			break;
		case END_SECTION:
			return (0);
		default:
			/*
			 * Unrecognized section type.
			 */
			return (-1);
		}
	}
}

/*
 * Set up a user command table, based on a "lesskey" file.
 */
	public int
lesskey(filename, sysvar)
	char *filename;
	int sysvar;
{
	register char *buf;
	register POSITION len;
	register long n;
	register int f;

	if (secure)
		return (1);
	/*
	 * Try to open the lesskey file.
	 */
	filename = unquote_file(filename);
	f = open(filename, OPEN_READ);
	free(filename);
	if (f < 0)
		return (1);

	/*
	 * Read the file into a buffer.
	 * We first figure out the size of the file and allocate space for it.
	 * {{ Minimal error checking is done here.
	 *    A garbage .less file will produce strange results.
	 *    To avoid a large amount of error checking code here, we
	 *    rely on the lesskey program to generate a good .less file. }}
	 */
	len = filesize(f);
	if (len == NULL_POSITION || len < 3)
	{
		/*
		 * Bad file (valid file must have at least 3 chars).
		 */
		close(f);
		return (-1);
	}
	if ((buf = (char *) calloc((int)len, sizeof(char))) == NULL)
	{
		close(f);
		return (-1);
	}
	if (lseek(f, (off_t)0, 0) == BAD_LSEEK)
	{
		free(buf);
		close(f);
		return (-1);
	}
	n = read(f, buf, (unsigned int) len);
	close(f);
	if (n != len)
	{
		free(buf);
		return (-1);
	}

	/*
	 * Figure out if this is an old-style (before version 241)
	 * or new-style lesskey file format.
	 */
	if (buf[0] != C0_LESSKEY_MAGIC || buf[1] != C1_LESSKEY_MAGIC ||
	    buf[2] != C2_LESSKEY_MAGIC || buf[3] != C3_LESSKEY_MAGIC)
		return (old_lesskey(buf, (int)len));
	return (new_lesskey(buf, (int)len, sysvar));
}

/*
 * Add the standard lesskey file "$HOME/.less"
 */
	public void
add_hometable(envname, def_filename, sysvar)
	char *envname;
	char *def_filename;
	int sysvar;
{
	char *filename;
	PARG parg;

	if ((filename = lgetenv(envname)) != NULL)
		filename = save(filename);
	else if (sysvar)
		filename = save(def_filename);
	else
		filename = homefile(def_filename);
	if (filename == NULL)
		return;
	if (lesskey(filename, sysvar) < 0)
	{
		parg.p_string = filename;
		error("Cannot use lesskey file \"%s\"", &parg);
	}
	free(filename);
}
#endif

/*
 * See if a char is a special line-editing command.
 */
	public int
editchar(c, flags)
	int c;
	int flags;
{
	int action;
	int nch;
	char *s;
	char usercmd[MAX_CMDLEN+1];
	
	/*
	 * An editing character could actually be a sequence of characters;
	 * for example, an escape sequence sent by pressing the uparrow key.
	 * To match the editing string, we use the command decoder
	 * but give it the edit-commands command table
	 * This table is constructed to match the user's keyboard.
	 */
	if (c == erase_char)
		return (EC_BACKSPACE);
	if (c == kill_char)
		return (EC_LINEKILL);
		
	/*
	 * Collect characters in a buffer.
	 * Start with the one we have, and get more if we need them.
	 */
	nch = 0;
	do {
	  	if (nch > 0)
			c = getcc();
		usercmd[nch] = c;
		usercmd[nch+1] = '\0';
		nch++;
		action = ecmd_decode(usercmd, &s);
	} while (action == A_PREFIX);
	
#if CMD_HISTORY
	if (flags & EC_NOHISTORY) 
	{
		/*
		 * The caller says there is no history list.
		 * Reject any history-manipulation action.
		 */
		switch (action)
		{
		case EC_UP:
		case EC_DOWN:
			action = A_INVALID;
			break;
		}
	}
#endif
#if TAB_COMPLETE_FILENAME
	if (flags & EC_NOCOMPLETE) 
	{
		/*
		 * The caller says we don't want any filename completion cmds.
		 * Reject them.
		 */
		switch (action)
		{
		case EC_F_COMPLETE:
		case EC_B_COMPLETE:
		case EC_EXPAND:
			action = A_INVALID;
			break;
		}
	}
#endif
	if ((flags & EC_PEEK) || action == A_INVALID)
	{
		/*
		 * We're just peeking, or we didn't understand the command.
		 * Unget all the characters we read in the loop above.
		 * This does NOT include the original character that was 
		 * passed in as a parameter.
		 */
		while (nch > 1) 
		{
			ungetcc(usercmd[--nch]);
		}
	} else
	{
		if (s != NULL)
			ungetsc(s);
	}
	return action;
}

OpenPOWER on IntegriCloud