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lesskey.c revision 1.3.8.1
      1 /*	$NetBSD: lesskey.c,v 1.3.8.1 2014/08/19 23:46:50 tls Exp $	*/
      2 
      3 /*
      4  * Copyright (C) 1984-2012  Mark Nudelman
      5  *
      6  * You may distribute under the terms of either the GNU General Public
      7  * License or the Less License, as specified in the README file.
      8  *
      9  * For more information, see the README file.
     10  */
     11 
     12 
     13 /*
     14  *	lesskey [-o output] [input]
     15  *
     16  * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *
     17  *
     18  *	Make a .less file.
     19  *	If no input file is specified, standard input is used.
     20  *	If no output file is specified, $HOME/.less is used.
     21  *
     22  *	The .less file is used to specify (to "less") user-defined
     23  *	key bindings.  Basically any sequence of 1 to MAX_CMDLEN
     24  *	keystrokes may be bound to an existing less function.
     25  *
     26  * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *
     27  *
     28  *	The input file is an ascii file consisting of a
     29  *	sequence of lines of the form:
     30  *		string <whitespace> action [chars] <newline>
     31  *
     32  *	"string" is a sequence of command characters which form
     33  *		the new user-defined command.  The command
     34  *		characters may be:
     35  *		1. The actual character itself.
     36  *		2. A character preceded by ^ to specify a
     37  *		   control character (e.g. ^X means control-X).
     38  *		3. A backslash followed by one to three octal digits
     39  *		   to specify a character by its octal value.
     40  *		4. A backslash followed by b, e, n, r or t
     41  *		   to specify \b, ESC, \n, \r or \t, respectively.
     42  *		5. Any character (other than those mentioned above) preceded
     43  *		   by a \ to specify the character itself (characters which
     44  *		   must be preceded by \ include ^, \, and whitespace.
     45  *	"action" is the name of a "less" action, from the table below.
     46  *	"chars" is an optional sequence of characters which is treated
     47  *		as keyboard input after the command is executed.
     48  *
     49  *	Blank lines and lines which start with # are ignored,
     50  *	except for the special control lines:
     51  *		#command	Signals the beginning of the command
     52  *				keys section.
     53  *		#line-edit	Signals the beginning of the line-editing
     54  *				keys section.
     55  *		#env		Signals the beginning of the environment
     56  *				variable section.
     57  *		#stop		Stops command parsing in less;
     58  *				causes all default keys to be disabled.
     59  *
     60  * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *
     61  *
     62  *	The output file is a non-ascii file, consisting of a header,
     63  *	one or more sections, and a trailer.
     64  *	Each section begins with a section header, a section length word
     65  *	and the section data.  Normally there are three sections:
     66  *		CMD_SECTION	Definition of command keys.
     67  *		EDIT_SECTION	Definition of editing keys.
     68  *		END_SECTION	A special section header, with no
     69  *				length word or section data.
     70  *
     71  *	Section data consists of zero or more byte sequences of the form:
     72  *		string <0> <action>
     73  *	or
     74  *		string <0> <action|A_EXTRA> chars <0>
     75  *
     76  *	"string" is the command string.
     77  *	"<0>" is one null byte.
     78  *	"<action>" is one byte containing the action code (the A_xxx value).
     79  *	If action is ORed with A_EXTRA, the action byte is followed
     80  *		by the null-terminated "chars" string.
     81  *
     82  * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *
     83  */
     84 
     85 #include "less.h"
     86 #include "lesskey.h"
     87 #include "cmd.h"
     88 
     89 struct cmdname
     90 {
     91 	char *cn_name;
     92 	int cn_action;
     93 };
     94 
     95 struct cmdname cmdnames[] =
     96 {
     97 	{ "back-bracket",         A_B_BRACKET },
     98 	{ "back-line",            A_B_LINE },
     99 	{ "back-line-force",      A_BF_LINE },
    100 	{ "back-screen",          A_B_SCREEN },
    101 	{ "back-scroll",          A_B_SCROLL },
    102 	{ "back-search",          A_B_SEARCH },
    103 	{ "back-window",          A_B_WINDOW },
    104 	{ "debug",                A_DEBUG },
    105 	{ "digit",                A_DIGIT },
    106 	{ "display-flag",         A_DISP_OPTION },
    107 	{ "display-option",       A_DISP_OPTION },
    108 	{ "end",                  A_GOEND },
    109 	{ "examine",              A_EXAMINE },
    110 	{ "filter",               A_FILTER },
    111 	{ "first-cmd",            A_FIRSTCMD },
    112 	{ "firstcmd",             A_FIRSTCMD },
    113 	{ "flush-repaint",        A_FREPAINT },
    114 	{ "forw-bracket",         A_F_BRACKET },
    115 	{ "forw-forever",         A_F_FOREVER },
    116 	{ "forw-until-hilite",    A_F_UNTIL_HILITE },
    117 	{ "forw-line",            A_F_LINE },
    118 	{ "forw-line-force",      A_FF_LINE },
    119 	{ "forw-screen",          A_F_SCREEN },
    120 	{ "forw-screen-force",    A_FF_SCREEN },
    121 	{ "forw-scroll",          A_F_SCROLL },
    122 	{ "forw-search",          A_F_SEARCH },
    123 	{ "forw-window",          A_F_WINDOW },
    124 	{ "goto-end",             A_GOEND },
    125 	{ "goto-line",            A_GOLINE },
    126 	{ "goto-mark",            A_GOMARK },
    127 	{ "help",                 A_HELP },
    128 	{ "index-file",           A_INDEX_FILE },
    129 	{ "invalid",              A_UINVALID },
    130 	{ "left-scroll",          A_LSHIFT },
    131 	{ "next-file",            A_NEXT_FILE },
    132 	{ "next-tag",             A_NEXT_TAG },
    133 	{ "noaction",             A_NOACTION },
    134 	{ "percent",              A_PERCENT },
    135 	{ "pipe",                 A_PIPE },
    136 	{ "prev-file",            A_PREV_FILE },
    137 	{ "prev-tag",             A_PREV_TAG },
    138 	{ "quit",                 A_QUIT },
    139 	{ "remove-file",          A_REMOVE_FILE },
    140 	{ "repaint",              A_REPAINT },
    141 	{ "repaint-flush",        A_FREPAINT },
    142 	{ "repeat-search",        A_AGAIN_SEARCH },
    143 	{ "repeat-search-all",    A_T_AGAIN_SEARCH },
    144 	{ "reverse-search",       A_REVERSE_SEARCH },
    145 	{ "reverse-search-all",   A_T_REVERSE_SEARCH },
    146 	{ "right-scroll",         A_RSHIFT },
    147 	{ "set-mark",             A_SETMARK },
    148 	{ "shell",                A_SHELL },
    149 	{ "status",               A_STAT },
    150 	{ "toggle-flag",          A_OPT_TOGGLE },
    151 	{ "toggle-option",        A_OPT_TOGGLE },
    152 	{ "undo-hilite",          A_UNDO_SEARCH },
    153 	{ "version",              A_VERSION },
    154 	{ "visual",               A_VISUAL },
    155 	{ NULL,   0 }
    156 };
    157 
    158 struct cmdname editnames[] =
    159 {
    160 	{ "back-complete",	EC_B_COMPLETE },
    161 	{ "backspace",		EC_BACKSPACE },
    162 	{ "delete",		EC_DELETE },
    163 	{ "down",		EC_DOWN },
    164 	{ "end",		EC_END },
    165 	{ "expand",		EC_EXPAND },
    166 	{ "forw-complete",	EC_F_COMPLETE },
    167 	{ "home",		EC_HOME },
    168 	{ "insert",		EC_INSERT },
    169 	{ "invalid",		EC_UINVALID },
    170 	{ "kill-line",		EC_LINEKILL },
    171 	{ "abort",		EC_ABORT },
    172 	{ "left",		EC_LEFT },
    173 	{ "literal",		EC_LITERAL },
    174 	{ "right",		EC_RIGHT },
    175 	{ "up",			EC_UP },
    176 	{ "word-backspace",	EC_W_BACKSPACE },
    177 	{ "word-delete",	EC_W_DELETE },
    178 	{ "word-left",		EC_W_LEFT },
    179 	{ "word-right",		EC_W_RIGHT },
    180 	{ NULL, 0 }
    181 };
    182 
    183 struct table
    184 {
    185 	struct cmdname *names;
    186 	char *pbuffer;
    187 	char buffer[MAX_USERCMD];
    188 };
    189 
    190 struct table cmdtable;
    191 struct table edittable;
    192 struct table vartable;
    193 struct table *currtable = &cmdtable;
    194 
    195 char fileheader[] = {
    196 	C0_LESSKEY_MAGIC,
    197 	C1_LESSKEY_MAGIC,
    198 	C2_LESSKEY_MAGIC,
    199 	C3_LESSKEY_MAGIC
    200 };
    201 char filetrailer[] = {
    202 	C0_END_LESSKEY_MAGIC,
    203 	C1_END_LESSKEY_MAGIC,
    204 	C2_END_LESSKEY_MAGIC
    205 };
    206 char cmdsection[1] =	{ CMD_SECTION };
    207 char editsection[1] =	{ EDIT_SECTION };
    208 char varsection[1] =	{ VAR_SECTION };
    209 char endsection[1] =	{ END_SECTION };
    210 
    211 char *infile = NULL;
    212 char *outfile = NULL ;
    213 
    214 int linenum;
    215 int errors;
    216 
    217 void terror(char *);
    218 
    219 extern char version[];
    220 
    221 	void
    222 usage()
    223 {
    224 	fprintf(stderr, "usage: lesskey [-o output] [input]\n");
    225 	exit(1);
    226 }
    227 
    228 	char *
    229 mkpathname(dirname, filename)
    230 	char *dirname;
    231 	char *filename;
    232 {
    233 	char *pathname;
    234 
    235 	pathname = calloc(strlen(dirname) + strlen(filename) + 2, sizeof(char));
    236 	strcpy(pathname, dirname);
    237 	strcat(pathname, PATHNAME_SEP);
    238 	strcat(pathname, filename);
    239 	return (pathname);
    240 }
    241 
    242 /*
    243  * Figure out the name of a default file (in the user's HOME directory).
    244  */
    245 	char *
    246 homefile(filename)
    247 	char *filename;
    248 {
    249 	char *p;
    250 	char *pathname;
    251 
    252 	if ((p = getenv("HOME")) != NULL && *p != '\0')
    253 		pathname = mkpathname(p, filename);
    254 #if OS2
    255 	else if ((p = getenv("INIT")) != NULL && *p != '\0')
    256 		pathname = mkpathname(p, filename);
    257 #endif
    258 	else
    259 	{
    260 		fprintf(stderr, "cannot find $HOME - using current directory\n");
    261 		pathname = mkpathname(".", filename);
    262 	}
    263 	return (pathname);
    264 }
    265 
    266 /*
    267  * Parse command line arguments.
    268  */
    269 	void
    270 parse_args(argc, argv)
    271 	int argc;
    272 	char **argv;
    273 {
    274 	char *arg;
    275 
    276 	outfile = NULL;
    277 	while (--argc > 0)
    278 	{
    279 		arg = *++argv;
    280 		if (arg[0] != '-')
    281 			/* Arg does not start with "-"; it's not an option. */
    282 			break;
    283 		if (arg[1] == '\0')
    284 			/* "-" means standard input. */
    285 			break;
    286 		if (arg[1] == '-' && arg[2] == '\0')
    287 		{
    288 			/* "--" means end of options. */
    289 			argc--;
    290 			argv++;
    291 			break;
    292 		}
    293 		switch (arg[1])
    294 		{
    295 		case '-':
    296 			if (strncmp(arg, "--output", 8) == 0)
    297 			{
    298 				if (arg[8] == '\0')
    299 					outfile = &arg[8];
    300 				else if (arg[8] == '=')
    301 					outfile = &arg[9];
    302 				else
    303 					usage();
    304 				goto opt_o;
    305 			}
    306 			if (strcmp(arg, "--version") == 0)
    307 			{
    308 				goto opt_V;
    309 			}
    310 			usage();
    311 			break;
    312 		case 'o':
    313 			outfile = &argv[0][2];
    314 		opt_o:
    315 			if (*outfile == '\0')
    316 			{
    317 				if (--argc <= 0)
    318 					usage();
    319 				outfile = *(++argv);
    320 			}
    321 			break;
    322 		case 'V':
    323 		opt_V:
    324 			printf("lesskey  version %s\n", version);
    325 			exit(0);
    326 		default:
    327 			usage();
    328 		}
    329 	}
    330 	if (argc > 1)
    331 		usage();
    332 	/*
    333 	 * Open the input file, or use DEF_LESSKEYINFILE if none specified.
    334 	 */
    335 	if (argc > 0)
    336 		infile = *argv;
    337 	else
    338 		infile = homefile(DEF_LESSKEYINFILE);
    339 }
    340 
    341 /*
    342  * Initialize data structures.
    343  */
    344 	void
    345 init_tables()
    346 {
    347 	cmdtable.names = cmdnames;
    348 	cmdtable.pbuffer = cmdtable.buffer;
    349 
    350 	edittable.names = editnames;
    351 	edittable.pbuffer = edittable.buffer;
    352 
    353 	vartable.names = NULL;
    354 	vartable.pbuffer = vartable.buffer;
    355 }
    356 
    357 /*
    358  * Parse one character of a string.
    359  */
    360 	char *
    361 tstr(pp, xlate)
    362 	char **pp;
    363 	int xlate;
    364 {
    365 	register char *p;
    366 	register char ch;
    367 	register int i;
    368 	static char buf[10];
    369 	static char tstr_control_k[] =
    370 		{ SK_SPECIAL_KEY, SK_CONTROL_K, 6, 1, 1, 1, '\0' };
    371 
    372 	p = *pp;
    373 	switch (*p)
    374 	{
    375 	case '\\':
    376 		++p;
    377 		switch (*p)
    378 		{
    379 		case '0': case '1': case '2': case '3':
    380 		case '4': case '5': case '6': case '7':
    381 			/*
    382 			 * Parse an octal number.
    383 			 */
    384 			ch = 0;
    385 			i = 0;
    386 			do
    387 				ch = 8*ch + (*p - '0');
    388 			while (*++p >= '0' && *p <= '7' && ++i < 3);
    389 			*pp = p;
    390 			if (xlate && ch == CONTROL('K'))
    391 				return tstr_control_k;
    392 			buf[0] = ch;
    393 			buf[1] = '\0';
    394 			return (buf);
    395 		case 'b':
    396 			*pp = p+1;
    397 			return ("\b");
    398 		case 'e':
    399 			*pp = p+1;
    400 			buf[0] = ESC;
    401 			buf[1] = '\0';
    402 			return (buf);
    403 		case 'n':
    404 			*pp = p+1;
    405 			return ("\n");
    406 		case 'r':
    407 			*pp = p+1;
    408 			return ("\r");
    409 		case 't':
    410 			*pp = p+1;
    411 			return ("\t");
    412 		case 'k':
    413 			if (xlate)
    414 			{
    415 				switch (*++p)
    416 				{
    417 				case 'u': ch = SK_UP_ARROW; break;
    418 				case 'd': ch = SK_DOWN_ARROW; break;
    419 				case 'r': ch = SK_RIGHT_ARROW; break;
    420 				case 'l': ch = SK_LEFT_ARROW; break;
    421 				case 'U': ch = SK_PAGE_UP; break;
    422 				case 'D': ch = SK_PAGE_DOWN; break;
    423 				case 'h': ch = SK_HOME; break;
    424 				case 'e': ch = SK_END; break;
    425 				case 'x': ch = SK_DELETE; break;
    426 				default:
    427 					terror("illegal char after \\k");
    428 					*pp = p+1;
    429 					return ("");
    430 				}
    431 				*pp = p+1;
    432 				buf[0] = SK_SPECIAL_KEY;
    433 				buf[1] = ch;
    434 				buf[2] = 6;
    435 				buf[3] = 1;
    436 				buf[4] = 1;
    437 				buf[5] = 1;
    438 				buf[6] = '\0';
    439 				return (buf);
    440 			}
    441 			/* FALLTHRU */
    442 		default:
    443 			/*
    444 			 * Backslash followed by any other char
    445 			 * just means that char.
    446 			 */
    447 			*pp = p+1;
    448 			buf[0] = *p;
    449 			buf[1] = '\0';
    450 			if (xlate && buf[0] == CONTROL('K'))
    451 				return tstr_control_k;
    452 			return (buf);
    453 		}
    454 	case '^':
    455 		/*
    456 		 * Caret means CONTROL.
    457 		 */
    458 		*pp = p+2;
    459 		buf[0] = CONTROL(p[1]);
    460 		buf[1] = '\0';
    461 		if (buf[0] == CONTROL('K'))
    462 			return tstr_control_k;
    463 		return (buf);
    464 	}
    465 	*pp = p+1;
    466 	buf[0] = *p;
    467 	buf[1] = '\0';
    468 	if (xlate && buf[0] == CONTROL('K'))
    469 		return tstr_control_k;
    470 	return (buf);
    471 }
    472 
    473 /*
    474  * Skip leading spaces in a string.
    475  */
    476 	public char *
    477 skipsp(s)
    478 	register char *s;
    479 {
    480 	while (*s == ' ' || *s == '\t')
    481 		s++;
    482 	return (s);
    483 }
    484 
    485 /*
    486  * Skip non-space characters in a string.
    487  */
    488 	public char *
    489 skipnsp(s)
    490 	register char *s;
    491 {
    492 	while (*s != '\0' && *s != ' ' && *s != '\t')
    493 		s++;
    494 	return (s);
    495 }
    496 
    497 /*
    498  * Clean up an input line:
    499  * strip off the trailing newline & any trailing # comment.
    500  */
    501 	char *
    502 clean_line(s)
    503 	char *s;
    504 {
    505 	register int i;
    506 
    507 	s = skipsp(s);
    508 	for (i = 0;  s[i] != '\n' && s[i] != '\r' && s[i] != '\0';  i++)
    509 		if (s[i] == '#' && (i == 0 || s[i-1] != '\\'))
    510 			break;
    511 	s[i] = '\0';
    512 	return (s);
    513 }
    514 
    515 /*
    516  * Add a byte to the output command table.
    517  */
    518 	void
    519 add_cmd_char(c)
    520 	int c;
    521 {
    522 	if (currtable->pbuffer >= currtable->buffer + MAX_USERCMD)
    523 	{
    524 		terror("too many commands");
    525 		exit(1);
    526 	}
    527 	*(currtable->pbuffer)++ = c;
    528 }
    529 
    530 /*
    531  * Add a string to the output command table.
    532  */
    533 	void
    534 add_cmd_str(s)
    535 	char *s;
    536 {
    537 	for ( ;  *s != '\0';  s++)
    538 		add_cmd_char(*s);
    539 }
    540 
    541 /*
    542  * See if we have a special "control" line.
    543  */
    544 	int
    545 control_line(s)
    546 	char *s;
    547 {
    548 #define	PREFIX(str,pat)	(strncmp(str,pat,strlen(pat)) == 0)
    549 
    550 	if (PREFIX(s, "#line-edit"))
    551 	{
    552 		currtable = &edittable;
    553 		return (1);
    554 	}
    555 	if (PREFIX(s, "#command"))
    556 	{
    557 		currtable = &cmdtable;
    558 		return (1);
    559 	}
    560 	if (PREFIX(s, "#env"))
    561 	{
    562 		currtable = &vartable;
    563 		return (1);
    564 	}
    565 	if (PREFIX(s, "#stop"))
    566 	{
    567 		add_cmd_char('\0');
    568 		add_cmd_char(A_END_LIST);
    569 		return (1);
    570 	}
    571 	return (0);
    572 }
    573 
    574 /*
    575  * Output some bytes.
    576  */
    577 	void
    578 fputbytes(fd, buf, len)
    579 	FILE *fd;
    580 	char *buf;
    581 	int len;
    582 {
    583 	while (len-- > 0)
    584 	{
    585 		fwrite(buf, sizeof(char), 1, fd);
    586 		buf++;
    587 	}
    588 }
    589 
    590 /*
    591  * Output an integer, in special KRADIX form.
    592  */
    593 	void
    594 fputint(fd, val)
    595 	FILE *fd;
    596 	unsigned int val;
    597 {
    598 	char c;
    599 
    600 	if (val >= KRADIX*KRADIX)
    601 	{
    602 		fprintf(stderr, "error: integer too big (%d > %d)\n",
    603 			val, KRADIX*KRADIX);
    604 		exit(1);
    605 	}
    606 	c = val % KRADIX;
    607 	fwrite(&c, sizeof(char), 1, fd);
    608 	c = val / KRADIX;
    609 	fwrite(&c, sizeof(char), 1, fd);
    610 }
    611 
    612 /*
    613  * Find an action, given the name of the action.
    614  */
    615 	int
    616 findaction(actname)
    617 	char *actname;
    618 {
    619 	int i;
    620 
    621 	for (i = 0;  currtable->names[i].cn_name != NULL;  i++)
    622 		if (strcmp(currtable->names[i].cn_name, actname) == 0)
    623 			return (currtable->names[i].cn_action);
    624 	terror("unknown action");
    625 	return (A_INVALID);
    626 }
    627 
    628 	void
    629 terror(s)
    630 	char *s;
    631 {
    632 	fprintf(stderr, "line %d: %s\n", linenum, s);
    633 	errors++;
    634 }
    635 
    636 
    637 	void
    638 parse_cmdline(p)
    639 	char *p;
    640 {
    641 	int cmdlen;
    642 	char *actname;
    643 	int action;
    644 	char *s;
    645 	char c;
    646 
    647 	/*
    648 	 * Parse the command string and store it in the current table.
    649 	 */
    650 	cmdlen = 0;
    651 	do
    652 	{
    653 		s = tstr(&p, 1);
    654 		cmdlen += strlen(s);
    655 		if (cmdlen > MAX_CMDLEN)
    656 			terror("command too long");
    657 		else
    658 			add_cmd_str(s);
    659 	} while (*p != ' ' && *p != '\t' && *p != '\0');
    660 	/*
    661 	 * Terminate the command string with a null byte.
    662 	 */
    663 	add_cmd_char('\0');
    664 
    665 	/*
    666 	 * Skip white space between the command string
    667 	 * and the action name.
    668 	 * Terminate the action name with a null byte.
    669 	 */
    670 	p = skipsp(p);
    671 	if (*p == '\0')
    672 	{
    673 		terror("missing action");
    674 		return;
    675 	}
    676 	actname = p;
    677 	p = skipnsp(p);
    678 	c = *p;
    679 	*p = '\0';
    680 
    681 	/*
    682 	 * Parse the action name and store it in the current table.
    683 	 */
    684 	action = findaction(actname);
    685 
    686 	/*
    687 	 * See if an extra string follows the action name.
    688 	 */
    689 	*p = c;
    690 	p = skipsp(p);
    691 	if (*p == '\0')
    692 	{
    693 		add_cmd_char(action);
    694 	} else
    695 	{
    696 		/*
    697 		 * OR the special value A_EXTRA into the action byte.
    698 		 * Put the extra string after the action byte.
    699 		 */
    700 		add_cmd_char(action | A_EXTRA);
    701 		while (*p != '\0')
    702 			add_cmd_str(tstr(&p, 0));
    703 		add_cmd_char('\0');
    704 	}
    705 }
    706 
    707 	void
    708 parse_varline(p)
    709 	char *p;
    710 {
    711 	char *s;
    712 
    713 	do
    714 	{
    715 		s = tstr(&p, 0);
    716 		add_cmd_str(s);
    717 	} while (*p != ' ' && *p != '\t' && *p != '=' && *p != '\0');
    718 	/*
    719 	 * Terminate the variable name with a null byte.
    720 	 */
    721 	add_cmd_char('\0');
    722 
    723 	p = skipsp(p);
    724 	if (*p++ != '=')
    725 	{
    726 		terror("missing =");
    727 		return;
    728 	}
    729 
    730 	add_cmd_char(EV_OK|A_EXTRA);
    731 
    732 	p = skipsp(p);
    733 	while (*p != '\0')
    734 	{
    735 		s = tstr(&p, 0);
    736 		add_cmd_str(s);
    737 	}
    738 	add_cmd_char('\0');
    739 }
    740 
    741 /*
    742  * Parse a line from the lesskey file.
    743  */
    744 	void
    745 parse_line(line)
    746 	char *line;
    747 {
    748 	char *p;
    749 
    750 	/*
    751 	 * See if it is a control line.
    752 	 */
    753 	if (control_line(line))
    754 		return;
    755 	/*
    756 	 * Skip leading white space.
    757 	 * Replace the final newline with a null byte.
    758 	 * Ignore blank lines and comments.
    759 	 */
    760 	p = clean_line(line);
    761 	if (*p == '\0')
    762 		return;
    763 
    764 	if (currtable == &vartable)
    765 		parse_varline(p);
    766 	else
    767 		parse_cmdline(p);
    768 }
    769 
    770 	int
    771 main(argc, argv)
    772 	int argc;
    773 	char *argv[];
    774 {
    775 	FILE *desc;
    776 	FILE *out;
    777 	char line[1024];
    778 
    779 #ifdef WIN32
    780 	if (getenv("HOME") == NULL)
    781 	{
    782 		/*
    783 		 * If there is no HOME environment variable,
    784 		 * try the concatenation of HOMEDRIVE + HOMEPATH.
    785 		 */
    786 		char *drive = getenv("HOMEDRIVE");
    787 		char *path  = getenv("HOMEPATH");
    788 		if (drive != NULL && path != NULL)
    789 		{
    790 			char *env = (char *) calloc(strlen(drive) +
    791 					strlen(path) + 6, sizeof(char));
    792 			strcpy(env, "HOME=");
    793 			strcat(env, drive);
    794 			strcat(env, path);
    795 			putenv(env);
    796 		}
    797 	}
    798 #endif /* WIN32 */
    799 
    800 	/*
    801 	 * Process command line arguments.
    802 	 */
    803 	parse_args(argc, argv);
    804 	init_tables();
    805 
    806 	/*
    807 	 * Open the input file.
    808 	 */
    809 	if (strcmp(infile, "-") == 0)
    810 		desc = stdin;
    811 	else if ((desc = fopen(infile, "r")) == NULL)
    812 	{
    813 #if HAVE_PERROR
    814 		perror(infile);
    815 #else
    816 		fprintf(stderr, "Cannot open %s\n", infile);
    817 #endif
    818 		usage();
    819 	}
    820 
    821 	/*
    822 	 * Read and parse the input file, one line at a time.
    823 	 */
    824 	errors = 0;
    825 	linenum = 0;
    826 	while (fgets(line, sizeof(line), desc) != NULL)
    827 	{
    828 		++linenum;
    829 		parse_line(line);
    830 	}
    831 
    832 	/*
    833 	 * Write the output file.
    834 	 * If no output file was specified, use "$HOME/.less"
    835 	 */
    836 	if (errors > 0)
    837 	{
    838 		fprintf(stderr, "%d errors; no output produced\n", errors);
    839 		exit(1);
    840 	}
    841 
    842 	if (outfile == NULL)
    843 		outfile = getenv("LESSKEY");
    844 	if (outfile == NULL)
    845 		outfile = homefile(LESSKEYFILE);
    846 	if ((out = fopen(outfile, "wb")) == NULL)
    847 	{
    848 #if HAVE_PERROR
    849 		perror(outfile);
    850 #else
    851 		fprintf(stderr, "Cannot open %s\n", outfile);
    852 #endif
    853 		exit(1);
    854 	}
    855 
    856 	/* File header */
    857 	fputbytes(out, fileheader, sizeof(fileheader));
    858 
    859 	/* Command key section */
    860 	fputbytes(out, cmdsection, sizeof(cmdsection));
    861 	fputint(out, cmdtable.pbuffer - cmdtable.buffer);
    862 	fputbytes(out, (char *)cmdtable.buffer, cmdtable.pbuffer-cmdtable.buffer);
    863 	/* Edit key section */
    864 	fputbytes(out, editsection, sizeof(editsection));
    865 	fputint(out, edittable.pbuffer - edittable.buffer);
    866 	fputbytes(out, (char *)edittable.buffer, edittable.pbuffer-edittable.buffer);
    867 
    868 	/* Environment variable section */
    869 	fputbytes(out, varsection, sizeof(varsection));
    870 	fputint(out, vartable.pbuffer - vartable.buffer);
    871 	fputbytes(out, (char *)vartable.buffer, vartable.pbuffer-vartable.buffer);
    872 
    873 	/* File trailer */
    874 	fputbytes(out, endsection, sizeof(endsection));
    875 	fputbytes(out, filetrailer, sizeof(filetrailer));
    876 	return (0);
    877 }
    878