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}