1 /*
2 * Copyright (C) 1984-2026 Mark Nudelman
3 *
4 * You may distribute under the terms of either the GNU General Public
5 * License or the Less License, as specified in the README file.
6 *
7 * For more information, see the README file.
8 */
9
10
11 /*
12 * Prompting and other messages.
13 * There are three flavors of prompts, SHORT, MEDIUM and LONG,
14 * selected by the -m/-M options.
15 * There is also the "equals message", printed by the = command.
16 * A prompt is a message composed of various pieces, such as the
17 * name of the file being viewed, the percentage into the file, etc.
18 */
19
20 #include "less.h"
21 #include "position.h"
22
23 extern int pr_type;
24 extern lbool new_file;
25 extern int linenums;
26 extern int hshift;
27 extern int sc_width;
28 extern int sc_height;
29 extern int jump_sline;
30 extern int less_is_more;
31 extern int header_lines;
32 extern int utf_mode;
33 extern IFILE curr_ifile;
34 #if OSC8_LINK
35 extern POSITION osc8_linepos;
36 #endif
37 #if EDITOR
38 extern constant char *editor;
39 extern constant char *editproto;
40 #endif
41
42 /*
43 * Prototypes for the three flavors of prompts.
44 * These strings are expanded by pr_expand().
45 */
46 static constant char s_proto[] =
47 "?n?f%f .?m(%T %i of %m) ..?e(END) ?x- Next\\: %x..%t";
48 static constant char m_proto[] =
49 "?n?f%f .?m(%T %i of %m) ..?e(END) ?x- Next\\: %x.:?pB%pB\\%:byte %bB?s/%s...%t";
50 static constant char M_proto[] =
51 "?f%f .?n?m(%T %i of %m) ..?ltlines %lt-%lb?L/%L. :byte %bB?s/%s. .?e(END) ?x- Next\\: %x.:?pB%pB\\%..?c (column %c).%t";
52 static constant char e_proto[] =
53 "?f%f .?m(%T %i of %m) .?ltlines %lt-%lb?L/%L. .byte %bB?s/%s. ?e(END) :?pB%pB\\%..?c (column %c).%t";
54 static constant char h_proto[] =
55 "HELP -- ?eEND -- Press g to see it again:Press RETURN for more., or q when done";
56 static constant char w_proto[] =
57 "Waiting for data";
58 static constant char more_proto[] =
59 "--More--(?eEND ?x- Next\\: %x.:?pB%pB\\%:byte %bB?s/%s...%t)";
60
61 public char *prproto[3];
62 public char *eprproto[3];
63 public char constant *eqproto = e_proto;
64 public char constant *hproto = h_proto;
65 public char constant *wproto = w_proto;
66
67 static char message[PROMPT_SIZE];
68 static char *mp;
69 static int longest_line;
70
71 /*
72 * Initialize the prompt prototype strings.
73 */
init_prompt(void)74 public void init_prompt(void)
75 {
76 prproto[0] = save(s_proto);
77 prproto[1] = save(less_is_more ? more_proto : m_proto);
78 prproto[2] = save(M_proto);
79 eprproto[0] = eprproto[1] = eprproto[2] = NULL;
80 eqproto = save(e_proto);
81 hproto = save(h_proto);
82 wproto = save(w_proto);
83 }
84
85 /*
86 * Get width of longest line currently on screen.
87 * Calling longest_line_width() is expensive, so we cache its value here
88 * in case it is called more than once per prompt expansion.
89 */
pr_longest_line(void)90 static int pr_longest_line(void)
91 {
92 if (longest_line < 0)
93 longest_line = longest_line_width();
94 return longest_line;
95 }
96
97 /*
98 * Append a string to the end of the message.
99 * nprt means the character *may* be nonprintable
100 * and should be converted to printable form.
101 */
ap_estr(constant char * s,lbool nprt)102 static void ap_estr(constant char *s, lbool nprt)
103 {
104 constant char *es = s + strlen(s);
105 while (*s != '\0')
106 {
107 LWCHAR ch = step_charc(&s, +1, es);
108 constant char *ps;
109 char ubuf[MAX_UTF_CHAR_LEN+1];
110 size_t plen;
111
112 if (nprt)
113 {
114 ps = utf_mode ? prutfchar(ch) : prchar(ch);
115 } else
116 {
117 char *up = ubuf;
118 put_wchar(&up, ch);
119 *up = '\0';
120 ps = ubuf;
121 }
122 plen = strlen(ps);
123 if (mp + plen >= message + PROMPT_SIZE)
124 break;
125 strcpy(mp, ps);
126 mp += plen;
127 }
128 *mp = '\0';
129 }
130
ap_str(constant char * s)131 static void ap_str(constant char *s)
132 {
133 ap_estr(s, FALSE);
134 }
135
136 /*
137 * Append a character to the end of the message.
138 */
ap_char(char c)139 static void ap_char(char c)
140 {
141 if (mp + 1 >= message + PROMPT_SIZE)
142 return;
143 *mp++ = c;
144 *mp = '\0';
145 }
146
147 /*
148 * Append a POSITION (as a decimal integer) to the end of the message.
149 */
ap_pos(POSITION pos)150 static void ap_pos(POSITION pos)
151 {
152 char buf[INT_STRLEN_BOUND(pos) + 2];
153
154 postoa(pos, buf, 10);
155 ap_str(buf);
156 }
157
158 /*
159 * Append a line number to the end of the message.
160 */
ap_linenum(LINENUM linenum)161 static void ap_linenum(LINENUM linenum)
162 {
163 char buf[INT_STRLEN_BOUND(linenum) + 2];
164
165 linenumtoa(linenum, buf, 10);
166 ap_str(buf);
167 }
168
169 /*
170 * Append an integer to the end of the message.
171 */
ap_int(int num)172 static void ap_int(int num)
173 {
174 char buf[INT_STRLEN_BOUND(num) + 2];
175
176 inttoa(num, buf, 10);
177 ap_str(buf);
178 }
179
180 /*
181 * Append a question mark to the end of the message.
182 */
ap_quest(void)183 static void ap_quest(void)
184 {
185 ap_str("?");
186 }
187
188 /*
189 * Return the "current" byte offset in the file.
190 */
curr_byte(int where)191 static POSITION curr_byte(int where)
192 {
193 POSITION pos;
194
195 pos = position(where);
196 while (pos == NULL_POSITION && where >= 0 && where < sc_height-1)
197 pos = position(++where);
198 if (pos == NULL_POSITION)
199 pos = ch_length();
200 return (pos);
201 }
202
203 /*
204 * Return the value of a prototype conditional.
205 * A prototype string may include conditionals which consist of a
206 * question mark followed by a single letter.
207 * Here we decode that letter and return the appropriate boolean value.
208 */
cond(char c,int where)209 static lbool cond(char c, int where)
210 {
211 POSITION len;
212
213 switch (c)
214 {
215 case 'a': /* Anything in the message yet? */
216 return (mp > message);
217 case 'b': /* Current byte offset known? */
218 return (curr_byte(where) != NULL_POSITION);
219 case 'c':
220 return (hshift != 0);
221 case 'e': /* At end of file? */
222 return (eof_displayed(FALSE));
223 case 'f': /* Filename known? */
224 case 'g':
225 return (strcmp(get_filename(curr_ifile), "-") != 0);
226 case 'l': /* Line number known? */
227 case 'd': /* Same as l */
228 if (!linenums)
229 return FALSE;
230 return (currline(where) != 0);
231 case 'L': /* Final line number known? */
232 case 'D': /* Final page number known? */
233 return (linenums && ch_length() != NULL_POSITION);
234 case 'm': /* More than one file? */
235 #if TAGS
236 return (ntags() ? (ntags() > 1) : (nifile() > 1));
237 #else
238 return (nifile() > 1);
239 #endif
240 case 'n': /* First prompt in a new file? */
241 #if TAGS
242 return (ntags() ? TRUE : new_file ? TRUE : FALSE);
243 #else
244 return (new_file ? TRUE : FALSE);
245 #endif
246 case 'O': /* OSC 8 link selected? */
247 #if OSC8_LINK
248 return (osc8_linepos != NULL_POSITION);
249 #else
250 return FALSE;
251 #endif
252 case 'p': /* Percent into file (bytes) known? */
253 return (curr_byte(where) != NULL_POSITION && ch_length() > 0);
254 case 'P': /* Percent into file (lines) known? */
255 return (currline(where) != 0 &&
256 (len = ch_length()) > 0 &&
257 find_linenum(len) != 0);
258 case 'Q': /* Any on-screen line truncated? */
259 return (hshift + sc_width < pr_longest_line());
260 case 's': /* Size of file known? */
261 case 'B':
262 return (ch_length() != NULL_POSITION);
263 case 'x': /* Is there a "next" file? */
264 #if TAGS
265 if (ntags())
266 return (FALSE);
267 #endif
268 return (next_ifile(curr_ifile) != NULL_IFILE);
269 }
270 return (FALSE);
271 }
272
273 /*
274 * Decode a "percent" prototype character.
275 * A prototype string may include various "percent" escapes;
276 * that is, a percent sign followed by a single letter.
277 * Here we decode that letter and take the appropriate action,
278 * usually by appending something to the message being built.
279 */
protochar(char c,int where)280 static void protochar(char c, int where)
281 {
282 POSITION pos;
283 POSITION len;
284 LINENUM linenum;
285 LINENUM last_linenum;
286 IFILE h;
287 char *s;
288
289 #undef PAGE_NUM
290 #define PAGE_NUM(linenum) ((((linenum) - 1) / (sc_height - header_lines - 1)) + 1)
291
292 switch (c)
293 {
294 case 'b': /* Current byte offset */
295 pos = curr_byte(where);
296 if (pos != NULL_POSITION)
297 ap_pos(pos);
298 else
299 ap_quest();
300 break;
301 case 'c':
302 ap_int(hshift+1);
303 break;
304 case 'C':
305 ap_int(hshift + sc_width);
306 break;
307 case 'd': /* Current page number */
308 linenum = currline(where);
309 if (linenum > 0 && sc_height > header_lines + 1)
310 ap_linenum(PAGE_NUM(linenum));
311 else
312 ap_quest();
313 break;
314 case 'D': /* Final page number */
315 /* Find the page number of the last byte in the file (len-1). */
316 len = ch_length();
317 if (len == NULL_POSITION)
318 ap_quest();
319 else if (len == 0)
320 /* An empty file has no pages. */
321 ap_linenum(0);
322 else
323 {
324 linenum = find_linenum(len - 1);
325 if (linenum <= 0)
326 ap_quest();
327 else
328 ap_linenum(PAGE_NUM(linenum));
329 }
330 break;
331 #if EDITOR
332 case 'E': /* Editor name */
333 ap_str(editor);
334 break;
335 #endif
336 case 'f': /* File name */
337 ap_estr(get_filename(curr_ifile), TRUE);
338 break;
339 case 'F': /* Last component of file name */
340 ap_estr(last_component(get_filename(curr_ifile)), TRUE);
341 break;
342 case 'g': /* Shell-escaped file name */
343 s = shell_quote(get_filename(curr_ifile));
344 ap_str(s);
345 free(s);
346 break;
347 case 'i': /* Index into list of files */
348 #if TAGS
349 if (ntags())
350 ap_int(curr_tag());
351 else
352 #endif
353 ap_int(get_index(curr_ifile));
354 break;
355 case 'l': /* Current line number */
356 linenum = currline(where);
357 if (linenum != 0)
358 ap_linenum(vlinenum(linenum));
359 else
360 ap_quest();
361 break;
362 case 'L': /* Final line number */
363 len = ch_length();
364 if (len == NULL_POSITION || len == ch_zero() ||
365 (linenum = find_linenum(len)) <= 0)
366 ap_quest();
367 else
368 ap_linenum(vlinenum(linenum-1));
369 break;
370 case 'm': { /* Number of files */
371 #if TAGS
372 int n = ntags();
373 if (n)
374 ap_int(n);
375 else
376 #endif
377 ap_int(nifile());
378 break; }
379 case 'p': /* Percent into file (bytes) */
380 pos = curr_byte(where);
381 len = ch_length();
382 if (pos != NULL_POSITION && len > 0)
383 ap_int(percentage(pos,len));
384 else
385 ap_quest();
386 break;
387 case 'P': /* Percent into file (lines) */
388 linenum = currline(where);
389 if (linenum == 0 ||
390 (len = ch_length()) == NULL_POSITION || len == ch_zero() ||
391 (last_linenum = find_linenum(len)) <= 0)
392 ap_quest();
393 else
394 ap_int(percentage(linenum, last_linenum));
395 break;
396 case 'Q': /* Percent shifted horizontally */
397 ap_int(percentage(hshift + sc_width, pr_longest_line()));
398 break;
399 case 's': /* Size of file */
400 case 'B':
401 len = ch_length();
402 if (len != NULL_POSITION)
403 ap_pos(len);
404 else
405 ap_quest();
406 break;
407 case 't': /* Truncate trailing spaces in the message */
408 while (mp > message && mp[-1] == ' ')
409 mp--;
410 *mp = '\0';
411 break;
412 case 'T': /* Type of list */
413 #if TAGS
414 if (ntags())
415 ap_str("tag");
416 else
417 #endif
418 ap_str("file");
419 break;
420 case 'W': /* Width of longest line on screen */
421 ap_int(pr_longest_line());
422 break;
423 case 'x': /* Name of next file */
424 h = next_ifile(curr_ifile);
425 if (h != NULL_IFILE)
426 ap_str(get_filename(h));
427 else
428 ap_quest();
429 break;
430 }
431 }
432
433 /*
434 * Skip a false conditional.
435 * When a false condition is found (either a false IF or the ELSE part
436 * of a true IF), this routine scans the prototype string to decide
437 * where to resume parsing the string.
438 * We must keep track of nested IFs and skip them properly.
439 */
skipcond(constant char * p)440 static constant char * skipcond(constant char *p)
441 {
442 int iflevel;
443
444 /*
445 * We came in here after processing a ? or :,
446 * so we start nested one level deep.
447 */
448 iflevel = 1;
449
450 for (;;) switch (*++p)
451 {
452 case '?':
453 /*
454 * Start of a nested IF.
455 */
456 iflevel++;
457 break;
458 case ':':
459 /*
460 * Else.
461 * If this matches the IF we came in here with,
462 * then we're done.
463 */
464 if (iflevel == 1)
465 return (p);
466 break;
467 case '.':
468 /*
469 * Endif.
470 * If this matches the IF we came in here with,
471 * then we're done.
472 */
473 if (--iflevel == 0)
474 return (p);
475 break;
476 case '\\':
477 /*
478 * Backslash escapes the next character.
479 */
480 if (p[1] != '\0')
481 ++p;
482 break;
483 case '\0':
484 /*
485 * Whoops. Hit end of string.
486 * This is a malformed conditional, but just treat it
487 * as if all active conditionals ends here.
488 */
489 return (p-1);
490 }
491 /*NOTREACHED*/
492 }
493
494 /*
495 * Decode a char that represents a position on the screen.
496 */
wherechar(char constant * p,int * wp)497 static constant char * wherechar(char constant *p, int *wp)
498 {
499 switch (*p)
500 {
501 case 'b': case 'd': case 'l': case 'p': case 'P':
502 switch (*++p)
503 {
504 case 't': *wp = TOP; break;
505 case 'm': *wp = MIDDLE; break;
506 case 'b': *wp = BOTTOM; break;
507 case 'B': *wp = BOTTOM_PLUS_ONE; break;
508 case 'j': *wp = sindex_from_sline(jump_sline); break;
509 default: *wp = TOP; p--; break;
510 }
511 }
512 return (p);
513 }
514
515 /*
516 * Construct a message based on a prototype string.
517 */
pr_expand(constant char * proto)518 public constant char * pr_expand(constant char *proto)
519 {
520 constant char *p;
521 char c;
522 int where;
523
524 if (*proto == '\0')
525 return ("");
526
527 mp = message;
528 longest_line = -1;
529
530 for (p = proto; *p != '\0'; p++)
531 {
532 switch (*p)
533 {
534 default: /* Just put the character in the message */
535 ap_char(*p);
536 break;
537 case '\\': /* Backslash escapes the next character */
538 if (p[1] != '\0')
539 ap_char(*++p);
540 break;
541 case '?': /* Conditional (IF) */
542 if ((c = *++p) == '\0')
543 --p;
544 else
545 {
546 where = 0;
547 p = wherechar(p, &where);
548 if (!cond(c, where))
549 p = skipcond(p);
550 }
551 break;
552 case ':': /* ELSE */
553 p = skipcond(p);
554 break;
555 case '.': /* ENDIF */
556 break;
557 case '%': /* Percent escape */
558 if ((c = *++p) == '\0')
559 --p;
560 else
561 {
562 where = 0;
563 p = wherechar(p, &where);
564 protochar(c, where);
565 }
566 break;
567 }
568 }
569
570 if (mp == message)
571 return ("");
572 return (message);
573 }
574
575 /*
576 * Return a message suitable for printing by the "=" command.
577 */
eq_message(void)578 public constant char * eq_message(void)
579 {
580 return (pr_expand(eqproto));
581 }
582
583 /*
584 * Return a prompt.
585 * This depends on the prompt type (SHORT, MEDIUM, LONG), etc.
586 * If we can't come up with an appropriate prompt, return NULL
587 * and the caller will prompt with a colon.
588 */
pr_string(void)589 public constant char * pr_string(void)
590 {
591 constant char *prompt;
592 int type;
593
594 type = (!less_is_more) ? pr_type : pr_type ? 0 : 1;
595 prompt = pr_expand((ch_getflags() & CH_HELPFILE) ?
596 hproto : prproto[type]);
597 new_file = FALSE;
598 return (prompt);
599 }
600
601 /*
602 * Return the end prompt string.
603 */
end_pr_string(void)604 public constant char * end_pr_string(void)
605 {
606 int type;
607
608 if (ch_getflags() & CH_HELPFILE)
609 return NULL;
610 type = (!less_is_more) ? pr_type : pr_type ? 0 : 1;
611 if (eprproto[type] == NULL)
612 return NULL;
613 return pr_expand(eprproto[type]);
614 }
615
616 /*
617 * Return a message suitable for printing while waiting in the F command.
618 */
wait_message(void)619 public constant char * wait_message(void)
620 {
621 return (pr_expand(wproto));
622 }
623