prompt.c revision 170259 
1/* $FreeBSD: head/contrib/less/prompt.c 170259 2007-06-04 01:43:11Z delphij $ */
2/*
3 * Copyright (C) 1984-2007  Mark Nudelman
4 *
5 * You may distribute under the terms of either the GNU General Public
6 * License or the Less License, as specified in the README file.
7 *
8 * For more information about less, or for information on how to
9 * contact the author, see the README file.
10 */
11
12
13/*
14 * Prompting and other messages.
15 * There are three flavors of prompts, SHORT, MEDIUM and LONG,
16 * selected by the -m/-M options.
17 * There is also the "equals message", printed by the = command.
18 * A prompt is a message composed of various pieces, such as the
19 * name of the file being viewed, the percentage into the file, etc.
20 */
21
22#include "less.h"
23#include "position.h"
24
25extern int pr_type;
26extern int hit_eof;
27extern int new_file;
28extern int sc_width;
29extern int so_s_width, so_e_width;
30extern int linenums;
31extern int hshift;
32extern int sc_height;
33extern int jump_sline;
34extern int less_is_more;
35extern IFILE curr_ifile;
36#if EDITOR
37extern char *editor;
38extern char *editproto;
39#endif
40
41/*
42 * Prototypes for the three flavors of prompts.
43 * These strings are expanded by pr_expand().
44 */
45static constant char s_proto[] =
46  "?n?f%f .?m(%T %i of %m) ..?e(END) ?x- Next\\: %x..%t";
47static constant char m_proto[] =
48  "?n?f%f .?m(%T %i of %m) ..?e(END) ?x- Next\\: %x.:?pB%pB\\%:byte %bB?s/%s...%t";
49static constant char M_proto[] =
50  "?f%f .?n?m(%T %i of %m) ..?ltlines %lt-%lb?L/%L. :byte %bB?s/%s. .?e(END) ?x- Next\\: %x.:?pB%pB\\%..%t";
51static constant char e_proto[] =
52  "?f%f .?m(%T %i of %m) .?ltlines %lt-%lb?L/%L. .byte %bB?s/%s. ?e(END) :?pB%pB\\%..%t";
53static constant char h_proto[] =
54  "HELP -- ?eEND -- Press g to see it again:Press RETURN for more., or q when done";
55static constant char w_proto[] =
56  "Waiting for data";
57static constant char more_proto[] =
58  "--More--(?eEND ?x- Next\\: %x.:?pB%pB\\%:byte %bB?s/%s...%t)";
59
60public char *prproto[3];
61public char constant *eqproto = e_proto;
62public char constant *hproto = h_proto;
63public char constant *wproto = w_proto;
64
65static char message[PROMPT_SIZE];
66static char *mp;
67
68/*
69 * Initialize the prompt prototype strings.
70 */
71	public void
72init_prompt()
73{
74	prproto[0] = save(s_proto);
75	prproto[1] = save(less_is_more ? more_proto : m_proto);
76	prproto[2] = save(M_proto);
77	eqproto = save(e_proto);
78	hproto = save(h_proto);
79	wproto = save(w_proto);
80}
81
82/*
83 * Append a string to the end of the message.
84 */
85	static void
86ap_str(s)
87	char *s;
88{
89	int len;
90
91	len = strlen(s);
92	if (mp + len >= message + PROMPT_SIZE)
93		len = message + PROMPT_SIZE - mp - 1;
94	strncpy(mp, s, len);
95	mp += len;
96	*mp = '\0';
97}
98
99/*
100 * Append a character to the end of the message.
101 */
102	static void
103ap_char(c)
104	char c;
105{
106	char buf[2];
107
108	buf[0] = c;
109	buf[1] = '\0';
110	ap_str(buf);
111}
112
113/*
114 * Append a POSITION (as a decimal integer) to the end of the message.
115 */
116	static void
117ap_pos(pos)
118	POSITION pos;
119{
120	char buf[INT_STRLEN_BOUND(pos) + 2];
121
122	postoa(pos, buf);
123	ap_str(buf);
124}
125
126/*
127 * Append a line number to the end of the message.
128 */
129 	static void
130ap_linenum(linenum)
131	LINENUM linenum;
132{
133	char buf[INT_STRLEN_BOUND(linenum) + 2];
134
135	linenumtoa(linenum, buf);
136	ap_str(buf);
137}
138
139/*
140 * Append an integer to the end of the message.
141 */
142	static void
143ap_int(num)
144	int num;
145{
146	char buf[INT_STRLEN_BOUND(num) + 2];
147
148	inttoa(num, buf);
149	ap_str(buf);
150}
151
152/*
153 * Append a question mark to the end of the message.
154 */
155	static void
156ap_quest()
157{
158	ap_str("?");
159}
160
161/*
162 * Return the "current" byte offset in the file.
163 */
164	static POSITION
165curr_byte(where)
166	int where;
167{
168	POSITION pos;
169
170	pos = position(where);
171	while (pos == NULL_POSITION && where >= 0 && where < sc_height-1)
172		pos = position(++where);
173	if (pos == NULL_POSITION)
174		pos = ch_length();
175	return (pos);
176}
177
178/*
179 * Return the value of a prototype conditional.
180 * A prototype string may include conditionals which consist of a
181 * question mark followed by a single letter.
182 * Here we decode that letter and return the appropriate boolean value.
183 */
184	static int
185cond(c, where)
186	char c;
187	int where;
188{
189	POSITION len;
190
191	switch (c)
192	{
193	case 'a':	/* Anything in the message yet? */
194		return (mp > message);
195	case 'b':	/* Current byte offset known? */
196		return (curr_byte(where) != NULL_POSITION);
197	case 'c':
198		return (hshift != 0);
199	case 'e':	/* At end of file? */
200		return (hit_eof);
201	case 'f':	/* Filename known? */
202		return (strcmp(get_filename(curr_ifile), "-") != 0);
203	case 'l':	/* Line number known? */
204	case 'd':	/* Same as l */
205		return (linenums);
206	case 'L':	/* Final line number known? */
207	case 'D':	/* Final page number known? */
208		return (linenums && ch_length() != NULL_POSITION);
209	case 'm':	/* More than one file? */
210#if TAGS
211		return (ntags() ? (ntags() > 1) : (nifile() > 1));
212#else
213		return (nifile() > 1);
214#endif
215	case 'n':	/* First prompt in a new file? */
216#if TAGS
217		return (ntags() ? 1 : new_file);
218#else
219		return (new_file);
220#endif
221	case 'p':	/* Percent into file (bytes) known? */
222		return (curr_byte(where) != NULL_POSITION &&
223				ch_length() > 0);
224	case 'P':	/* Percent into file (lines) known? */
225		return (currline(where) != 0 &&
226				(len = ch_length()) > 0 &&
227				find_linenum(len) != 0);
228	case 's':	/* Size of file known? */
229	case 'B':
230		return (ch_length() != NULL_POSITION);
231	case 'x':	/* Is there a "next" file? */
232#if TAGS
233		if (ntags())
234			return (0);
235#endif
236		return (next_ifile(curr_ifile) != NULL_IFILE);
237	}
238	return (0);
239}
240
241/*
242 * Decode a "percent" prototype character.
243 * A prototype string may include various "percent" escapes;
244 * that is, a percent sign followed by a single letter.
245 * Here we decode that letter and take the appropriate action,
246 * usually by appending something to the message being built.
247 */
248	static void
249protochar(c, where, iseditproto)
250	int c;
251	int where;
252	int iseditproto;
253{
254	POSITION pos;
255	POSITION len;
256	int n;
257	LINENUM linenum;
258	LINENUM last_linenum;
259	IFILE h;
260
261#undef  PAGE_NUM
262#define PAGE_NUM(linenum)  ((((linenum) - 1) / (sc_height - 1)) + 1)
263
264	switch (c)
265	{
266	case 'b':	/* Current byte offset */
267		pos = curr_byte(where);
268		if (pos != NULL_POSITION)
269			ap_pos(pos);
270		else
271			ap_quest();
272		break;
273	case 'c':
274		ap_int(hshift);
275		break;
276	case 'd':	/* Current page number */
277		linenum = currline(where);
278		if (linenum > 0 && sc_height > 1)
279			ap_linenum(PAGE_NUM(linenum));
280		else
281			ap_quest();
282		break;
283	case 'D':	/* Final page number */
284		/* Find the page number of the last byte in the file (len-1). */
285		len = ch_length();
286		if (len == NULL_POSITION)
287			ap_quest();
288		else if (len == 0)
289			/* An empty file has no pages. */
290			ap_linenum(0);
291		else
292		{
293			linenum = find_linenum(len - 1);
294			if (linenum <= 0)
295				ap_quest();
296			else
297				ap_linenum(PAGE_NUM(linenum));
298		}
299		break;
300#if EDITOR
301	case 'E':	/* Editor name */
302		ap_str(editor);
303		break;
304#endif
305	case 'f':	/* File name */
306		ap_str(get_filename(curr_ifile));
307		break;
308	case 'i':	/* Index into list of files */
309#if TAGS
310		if (ntags())
311			ap_int(curr_tag());
312		else
313#endif
314			ap_int(get_index(curr_ifile));
315		break;
316	case 'l':	/* Current line number */
317		linenum = currline(where);
318		if (linenum != 0)
319			ap_linenum(linenum);
320		else
321			ap_quest();
322		break;
323	case 'L':	/* Final line number */
324		len = ch_length();
325		if (len == NULL_POSITION || len == ch_zero() ||
326		    (linenum = find_linenum(len)) <= 0)
327			ap_quest();
328		else
329			ap_linenum(linenum-1);
330		break;
331	case 'm':	/* Number of files */
332#if TAGS
333		n = ntags();
334		if (n)
335			ap_int(n);
336		else
337#endif
338			ap_int(nifile());
339		break;
340	case 'p':	/* Percent into file (bytes) */
341		pos = curr_byte(where);
342		len = ch_length();
343		if (pos != NULL_POSITION && len > 0)
344			ap_int(percentage(pos,len));
345		else
346			ap_quest();
347		break;
348	case 'P':	/* Percent into file (lines) */
349		linenum = currline(where);
350		if (linenum == 0 ||
351		    (len = ch_length()) == NULL_POSITION || len == ch_zero() ||
352		    (last_linenum = find_linenum(len)) <= 0)
353			ap_quest();
354		else
355			ap_int(percentage(linenum, last_linenum));
356		break;
357	case 's':	/* Size of file */
358	case 'B':
359		len = ch_length();
360		if (len != NULL_POSITION)
361			ap_pos(len);
362		else
363			ap_quest();
364		break;
365	case 't':	/* Truncate trailing spaces in the message */
366		while (mp > message && mp[-1] == ' ')
367			mp--;
368		break;
369	case 'T':	/* Type of list */
370#if TAGS
371		if (ntags())
372			ap_str("tag");
373		else
374#endif
375			ap_str("file");
376		break;
377	case 'x':	/* Name of next file */
378		h = next_ifile(curr_ifile);
379		if (h != NULL_IFILE)
380			ap_str(get_filename(h));
381		else
382			ap_quest();
383		break;
384	}
385}
386
387/*
388 * Skip a false conditional.
389 * When a false condition is found (either a false IF or the ELSE part
390 * of a true IF), this routine scans the prototype string to decide
391 * where to resume parsing the string.
392 * We must keep track of nested IFs and skip them properly.
393 */
394	static char *
395skipcond(p)
396	register char *p;
397{
398	register int iflevel;
399
400	/*
401	 * We came in here after processing a ? or :,
402	 * so we start nested one level deep.
403	 */
404	iflevel = 1;
405
406	for (;;) switch (*++p)
407	{
408	case '?':
409		/*
410		 * Start of a nested IF.
411		 */
412		iflevel++;
413		break;
414	case ':':
415		/*
416		 * Else.
417		 * If this matches the IF we came in here with,
418		 * then we're done.
419		 */
420		if (iflevel == 1)
421			return (p);
422		break;
423	case '.':
424		/*
425		 * Endif.
426		 * If this matches the IF we came in here with,
427		 * then we're done.
428		 */
429		if (--iflevel == 0)
430			return (p);
431		break;
432	case '\\':
433		/*
434		 * Backslash escapes the next character.
435		 */
436		++p;
437		break;
438	case '\0':
439		/*
440		 * Whoops.  Hit end of string.
441		 * This is a malformed conditional, but just treat it
442		 * as if all active conditionals ends here.
443		 */
444		return (p-1);
445	}
446	/*NOTREACHED*/
447}
448
449/*
450 * Decode a char that represents a position on the screen.
451 */
452	static char *
453wherechar(p, wp)
454	char *p;
455	int *wp;
456{
457	switch (*p)
458	{
459	case 'b': case 'd': case 'l': case 'p': case 'P':
460		switch (*++p)
461		{
462		case 't':   *wp = TOP;			break;
463		case 'm':   *wp = MIDDLE;		break;
464		case 'b':   *wp = BOTTOM;		break;
465		case 'B':   *wp = BOTTOM_PLUS_ONE;	break;
466		case 'j':   *wp = adjsline(jump_sline);	break;
467		default:    *wp = TOP;  p--;		break;
468		}
469	}
470	return (p);
471}
472
473/*
474 * Construct a message based on a prototype string.
475 */
476	public char *
477pr_expand(proto, maxwidth)
478	char *proto;
479	int maxwidth;
480{
481	register char *p;
482	register int c;
483	int where;
484
485	mp = message;
486
487	if (*proto == '\0')
488		return ("");
489
490	for (p = proto;  *p != '\0';  p++)
491	{
492		switch (*p)
493		{
494		default:	/* Just put the character in the message */
495			ap_char(*p);
496			break;
497		case '\\':	/* Backslash escapes the next character */
498			p++;
499			ap_char(*p);
500			break;
501		case '?':	/* Conditional (IF) */
502			if ((c = *++p) == '\0')
503				--p;
504			else
505			{
506				where = 0;
507				p = wherechar(p, &where);
508				if (!cond(c, where))
509					p = skipcond(p);
510			}
511			break;
512		case ':':	/* ELSE */
513			p = skipcond(p);
514			break;
515		case '.':	/* ENDIF */
516			break;
517		case '%':	/* Percent escape */
518			if ((c = *++p) == '\0')
519				--p;
520			else
521			{
522				where = 0;
523				p = wherechar(p, &where);
524				protochar(c, where,
525#if EDITOR
526					(proto == editproto));
527#else
528					0);
529#endif
530
531			}
532			break;
533		}
534	}
535
536	if (mp == message)
537		return ("");
538	if (maxwidth > 0 && mp >= message + maxwidth)
539	{
540		/*
541		 * Message is too long.
542		 * Return just the final portion of it.
543		 */
544		return (mp - maxwidth);
545	}
546	return (message);
547}
548
549/*
550 * Return a message suitable for printing by the "=" command.
551 */
552	public char *
553eq_message()
554{
555	return (pr_expand(eqproto, 0));
556}
557
558/*
559 * Return a prompt.
560 * This depends on the prompt type (SHORT, MEDIUM, LONG), etc.
561 * If we can't come up with an appropriate prompt, return NULL
562 * and the caller will prompt with a colon.
563 */
564	public char *
565pr_string()
566{
567	char *prompt;
568	int type;
569
570	type = (!less_is_more) ? pr_type : pr_type ? 0 : 1;
571	prompt = pr_expand((ch_getflags() & CH_HELPFILE) ?
572				hproto : prproto[type],
573			sc_width-so_s_width-so_e_width-2);
574	new_file = 0;
575	return (prompt);
576}
577
578/*
579 * Return a message suitable for printing while waiting in the F command.
580 */
581	public char *
582wait_message()
583{
584	return (pr_expand(wproto, sc_width-so_s_width-so_e_width-2));
585}
586