prompt.c revision 161478 
1/* $FreeBSD: head/contrib/less/prompt.c 161478 2006-08-20 15:50:51Z delphij $ */
2/*
3 * Copyright (C) 1984-2004  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 IFILE curr_ifile;
35#if EDITOR
36extern char *editor;
37extern char *editproto;
38#endif
39
40/*
41 * Prototypes for the three flavors of prompts.
42 * These strings are expanded by pr_expand().
43 */
44static constant char s_proto[] =
45  "?n?f%f .?m(%T %i of %m) ..?e(END) ?x- Next\\: %x..%t";
46static constant char m_proto[] =
47  "?n?f%f .?m(%T %i of %m) ..?e(END) ?x- Next\\: %x.:?pB%pB\\%:byte %bB?s/%s...%t";
48static constant char M_proto[] =
49  "?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";
50static constant char e_proto[] =
51  "?f%f .?m(%T %i of %m) .?ltlines %lt-%lb?L/%L. .byte %bB?s/%s. ?e(END) :?pB%pB\\%..%t";
52static constant char h_proto[] =
53  "HELP -- ?eEND -- Press g to see it again:Press RETURN for more., or q when done";
54static constant char w_proto[] =
55  "Waiting for data";
56
57public char *prproto[3];
58public char constant *eqproto = e_proto;
59public char constant *hproto = h_proto;
60public char constant *wproto = w_proto;
61
62static char message[PROMPT_SIZE];
63static char *mp;
64
65/*
66 * Initialize the prompt prototype strings.
67 */
68	public void
69init_prompt()
70{
71	prproto[0] = save(s_proto);
72	prproto[1] = save(m_proto);
73	prproto[2] = save(M_proto);
74	eqproto = save(e_proto);
75	hproto = save(h_proto);
76	wproto = save(w_proto);
77}
78
79/*
80 * Append a string to the end of the message.
81 */
82	static void
83ap_str(s)
84	char *s;
85{
86	int len;
87
88	len = strlen(s);
89	if (mp + len >= message + PROMPT_SIZE)
90		len = message + PROMPT_SIZE - mp - 1;
91	strncpy(mp, s, len);
92	mp += len;
93	*mp = '\0';
94}
95
96/*
97 * Append a character to the end of the message.
98 */
99	static void
100ap_char(c)
101	char c;
102{
103	char buf[2];
104
105	buf[0] = c;
106	buf[1] = '\0';
107	ap_str(buf);
108}
109
110/*
111 * Append a POSITION (as a decimal integer) to the end of the message.
112 */
113	static void
114ap_pos(pos)
115	POSITION pos;
116{
117	char buf[INT_STRLEN_BOUND(pos) + 2];
118
119	postoa(pos, buf);
120	ap_str(buf);
121}
122
123/*
124 * Append a line number to the end of the message.
125 */
126 	static void
127ap_linenum(linenum)
128	LINENUM linenum;
129{
130	char buf[INT_STRLEN_BOUND(linenum) + 2];
131
132	linenumtoa(linenum, buf);
133	ap_str(buf);
134}
135
136/*
137 * Append an integer to the end of the message.
138 */
139	static void
140ap_int(num)
141	int num;
142{
143	char buf[INT_STRLEN_BOUND(num) + 2];
144
145	inttoa(num, buf);
146	ap_str(buf);
147}
148
149/*
150 * Append a question mark to the end of the message.
151 */
152	static void
153ap_quest()
154{
155	ap_str("?");
156}
157
158/*
159 * Return the "current" byte offset in the file.
160 */
161	static POSITION
162curr_byte(where)
163	int where;
164{
165	POSITION pos;
166
167	pos = position(where);
168	while (pos == NULL_POSITION && where >= 0 && where < sc_height-1)
169		pos = position(++where);
170	if (pos == NULL_POSITION)
171		pos = ch_length();
172	return (pos);
173}
174
175/*
176 * Return the value of a prototype conditional.
177 * A prototype string may include conditionals which consist of a
178 * question mark followed by a single letter.
179 * Here we decode that letter and return the appropriate boolean value.
180 */
181	static int
182cond(c, where)
183	char c;
184	int where;
185{
186	POSITION len;
187
188	switch (c)
189	{
190	case 'a':	/* Anything in the message yet? */
191		return (mp > message);
192	case 'b':	/* Current byte offset known? */
193		return (curr_byte(where) != NULL_POSITION);
194	case 'c':
195		return (hshift != 0);
196	case 'e':	/* At end of file? */
197		return (hit_eof);
198	case 'f':	/* Filename known? */
199		return (strcmp(get_filename(curr_ifile), "-") != 0);
200	case 'l':	/* Line number known? */
201	case 'd':	/* Same as l */
202		return (linenums);
203	case 'L':	/* Final line number known? */
204	case 'D':	/* Final page number known? */
205		return (linenums && ch_length() != NULL_POSITION);
206	case 'm':	/* More than one file? */
207#if TAGS
208		return (ntags() ? (ntags() > 1) : (nifile() > 1));
209#else
210		return (nifile() > 1);
211#endif
212	case 'n':	/* First prompt in a new file? */
213#if TAGS
214		return (ntags() ? 1 : new_file);
215#else
216		return (new_file);
217#endif
218	case 'p':	/* Percent into file (bytes) known? */
219		return (curr_byte(where) != NULL_POSITION &&
220				ch_length() > 0);
221	case 'P':	/* Percent into file (lines) known? */
222		return (currline(where) != 0 &&
223				(len = ch_length()) > 0 &&
224				find_linenum(len) != 0);
225	case 's':	/* Size of file known? */
226	case 'B':
227		return (ch_length() != NULL_POSITION);
228	case 'x':	/* Is there a "next" file? */
229#if TAGS
230		if (ntags())
231			return (0);
232#endif
233		return (next_ifile(curr_ifile) != NULL_IFILE);
234	}
235	return (0);
236}
237
238/*
239 * Decode a "percent" prototype character.
240 * A prototype string may include various "percent" escapes;
241 * that is, a percent sign followed by a single letter.
242 * Here we decode that letter and take the appropriate action,
243 * usually by appending something to the message being built.
244 */
245	static void
246protochar(c, where, iseditproto)
247	int c;
248	int where;
249	int iseditproto;
250{
251	POSITION pos;
252	POSITION len;
253	int n;
254	LINENUM linenum;
255	LINENUM last_linenum;
256	IFILE h;
257
258#undef  PAGE_NUM
259#define PAGE_NUM(linenum)  ((((linenum) - 1) / (sc_height - 1)) + 1)
260
261	switch (c)
262	{
263	case 'b':	/* Current byte offset */
264		pos = curr_byte(where);
265		if (pos != NULL_POSITION)
266			ap_pos(pos);
267		else
268			ap_quest();
269		break;
270	case 'c':
271		ap_int(hshift);
272		break;
273	case 'd':	/* Current page number */
274		linenum = currline(where);
275		if (linenum > 0 && sc_height > 1)
276			ap_linenum(PAGE_NUM(linenum));
277		else
278			ap_quest();
279		break;
280	case 'D':	/* Final page number */
281		/* Find the page number of the last byte in the file (len-1). */
282		len = ch_length();
283		if (len == NULL_POSITION)
284			ap_quest();
285		else if (len == 0)
286			/* An empty file has no pages. */
287			ap_linenum(0);
288		else
289		{
290			linenum = find_linenum(len - 1);
291			if (linenum <= 0)
292				ap_quest();
293			else
294				ap_linenum(PAGE_NUM(linenum));
295		}
296		break;
297#if EDITOR
298	case 'E':	/* Editor name */
299		ap_str(editor);
300		break;
301#endif
302	case 'f':	/* File name */
303		ap_str(get_filename(curr_ifile));
304		break;
305	case 'i':	/* Index into list of files */
306#if TAGS
307		if (ntags())
308			ap_int(curr_tag());
309		else
310#endif
311			ap_int(get_index(curr_ifile));
312		break;
313	case 'l':	/* Current line number */
314		linenum = currline(where);
315		if (linenum != 0)
316			ap_linenum(linenum);
317		else
318			ap_quest();
319		break;
320	case 'L':	/* Final line number */
321		len = ch_length();
322		if (len == NULL_POSITION || len == ch_zero() ||
323		    (linenum = find_linenum(len)) <= 0)
324			ap_quest();
325		else
326			ap_linenum(linenum-1);
327		break;
328	case 'm':	/* Number of files */
329#if TAGS
330		n = ntags();
331		if (n)
332			ap_int(n);
333		else
334#endif
335			ap_int(nifile());
336		break;
337	case 'p':	/* Percent into file (bytes) */
338		pos = curr_byte(where);
339		len = ch_length();
340		if (pos != NULL_POSITION && len > 0)
341			ap_int(percentage(pos,len));
342		else
343			ap_quest();
344		break;
345	case 'P':	/* Percent into file (lines) */
346		linenum = currline(where);
347		if (linenum == 0 ||
348		    (len = ch_length()) == NULL_POSITION || len == ch_zero() ||
349		    (last_linenum = find_linenum(len)) <= 0)
350			ap_quest();
351		else
352			ap_int(percentage(linenum, last_linenum));
353		break;
354	case 's':	/* Size of file */
355	case 'B':
356		len = ch_length();
357		if (len != NULL_POSITION)
358			ap_pos(len);
359		else
360			ap_quest();
361		break;
362	case 't':	/* Truncate trailing spaces in the message */
363		while (mp > message && mp[-1] == ' ')
364			mp--;
365		break;
366	case 'T':	/* Type of list */
367#if TAGS
368		if (ntags())
369			ap_str("tag");
370		else
371#endif
372			ap_str("file");
373		break;
374	case 'x':	/* Name of next file */
375		h = next_ifile(curr_ifile);
376		if (h != NULL_IFILE)
377			ap_str(get_filename(h));
378		else
379			ap_quest();
380		break;
381	}
382}
383
384/*
385 * Skip a false conditional.
386 * When a false condition is found (either a false IF or the ELSE part
387 * of a true IF), this routine scans the prototype string to decide
388 * where to resume parsing the string.
389 * We must keep track of nested IFs and skip them properly.
390 */
391	static char *
392skipcond(p)
393	register char *p;
394{
395	register int iflevel;
396
397	/*
398	 * We came in here after processing a ? or :,
399	 * so we start nested one level deep.
400	 */
401	iflevel = 1;
402
403	for (;;) switch (*++p)
404	{
405	case '?':
406		/*
407		 * Start of a nested IF.
408		 */
409		iflevel++;
410		break;
411	case ':':
412		/*
413		 * Else.
414		 * If this matches the IF we came in here with,
415		 * then we're done.
416		 */
417		if (iflevel == 1)
418			return (p);
419		break;
420	case '.':
421		/*
422		 * Endif.
423		 * If this matches the IF we came in here with,
424		 * then we're done.
425		 */
426		if (--iflevel == 0)
427			return (p);
428		break;
429	case '\\':
430		/*
431		 * Backslash escapes the next character.
432		 */
433		++p;
434		break;
435	case '\0':
436		/*
437		 * Whoops.  Hit end of string.
438		 * This is a malformed conditional, but just treat it
439		 * as if all active conditionals ends here.
440		 */
441		return (p-1);
442	}
443	/*NOTREACHED*/
444}
445
446/*
447 * Decode a char that represents a position on the screen.
448 */
449	static char *
450wherechar(p, wp)
451	char *p;
452	int *wp;
453{
454	switch (*p)
455	{
456	case 'b': case 'd': case 'l': case 'p': case 'P':
457		switch (*++p)
458		{
459		case 't':   *wp = TOP;			break;
460		case 'm':   *wp = MIDDLE;		break;
461		case 'b':   *wp = BOTTOM;		break;
462		case 'B':   *wp = BOTTOM_PLUS_ONE;	break;
463		case 'j':   *wp = adjsline(jump_sline);	break;
464		default:    *wp = TOP;  p--;		break;
465		}
466	}
467	return (p);
468}
469
470/*
471 * Construct a message based on a prototype string.
472 */
473	public char *
474pr_expand(proto, maxwidth)
475	char *proto;
476	int maxwidth;
477{
478	register char *p;
479	register int c;
480	int where;
481
482	mp = message;
483
484	if (*proto == '\0')
485		return ("");
486
487	for (p = proto;  *p != '\0';  p++)
488	{
489		switch (*p)
490		{
491		default:	/* Just put the character in the message */
492			ap_char(*p);
493			break;
494		case '\\':	/* Backslash escapes the next character */
495			p++;
496			ap_char(*p);
497			break;
498		case '?':	/* Conditional (IF) */
499			if ((c = *++p) == '\0')
500				--p;
501			else
502			{
503				where = 0;
504				p = wherechar(p, &where);
505				if (!cond(c, where))
506					p = skipcond(p);
507			}
508			break;
509		case ':':	/* ELSE */
510			p = skipcond(p);
511			break;
512		case '.':	/* ENDIF */
513			break;
514		case '%':	/* Percent escape */
515			if ((c = *++p) == '\0')
516				--p;
517			else
518			{
519				where = 0;
520				p = wherechar(p, &where);
521				protochar(c, where,
522#if EDITOR
523					(proto == editproto));
524#else
525					0);
526#endif
527
528			}
529			break;
530		}
531	}
532
533	if (mp == message)
534		return ("");
535	if (maxwidth > 0 && mp >= message + maxwidth)
536	{
537		/*
538		 * Message is too long.
539		 * Return just the final portion of it.
540		 */
541		return (mp - maxwidth);
542	}
543	return (message);
544}
545
546/*
547 * Return a message suitable for printing by the "=" command.
548 */
549	public char *
550eq_message()
551{
552	return (pr_expand(eqproto, 0));
553}
554
555/*
556 * Return a prompt.
557 * This depends on the prompt type (SHORT, MEDIUM, LONG), etc.
558 * If we can't come up with an appropriate prompt, return NULL
559 * and the caller will prompt with a colon.
560 */
561	public char *
562pr_string()
563{
564	char *prompt;
565
566	prompt = pr_expand((ch_getflags() & CH_HELPFILE) ?
567				hproto : prproto[pr_type],
568			sc_width-so_s_width-so_e_width-2);
569	new_file = 0;
570	return (prompt);
571}
572
573/*
574 * Return a message suitable for printing while waiting in the F command.
575 */
576	public char *
577wait_message()
578{
579	return (pr_expand(wproto, sc_width-so_s_width-so_e_width-2));
580}
581