contrib/less-381/prompt.c

   1 /*
   2  * Copyright (C) 1984-2002  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 about less, or for information on how to
   8  * contact the author, see the README file.
   9  */
  10
  11
  12 /*
  13  * Prompting and other messages.
  14  * There are three flavors of prompts, SHORT, MEDIUM and LONG,
  15  * selected by the -m/-M options.
  16  * There is also the "equals message", printed by the = command.
  17  * A prompt is a message composed of various pieces, such as the
  18  * name of the file being viewed, the percentage into the file, etc.
  19  */
  20
  21 #include "less.h"
  22 #include "position.h"
  23
  24 extern int pr_type;
  25 extern int hit_eof;
  26 extern int new_file;
  27 extern int sc_width;
  28 extern int so_s_width, so_e_width;
  29 extern int linenums;
  30 extern int hshift;
  31 extern int sc_height;
  32 extern int jump_sline;
  33 extern IFILE curr_ifile;
  34 #if EDITOR
  35 extern char *editor;
  36 extern char *editproto;
  37 #endif
  38
  39 /*
  40  * Prototypes for the three flavors of prompts.
  41  * These strings are expanded by pr_expand().
  42  */
  43 static constant char s_proto[] =
  44   "?n?f%f .?m(%T %i of %m) ..?e(END) ?x- Next\\: %x..%t";
  45 static constant char m_proto[] =
  46   "?n?f%f .?m(%T %i of %m) ..?e(END) ?x- Next\\: %x.:?pB%pB\\%:byte %bB?s/%s...%t";
  47 static constant char M_proto[] =
  48   "?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";
  49 static constant char e_proto[] =
  50   "?f%f .?m(%T %i of %m) .?ltlines %lt-%lb?L/%L. .byte %bB?s/%s. ?e(END) :?pB%pB\\%..%t";
  51 static constant char h_proto[] =
  52   "HELP -- ?eEND -- Press g to see it again:Press RETURN for more., or q when done";
  53 static constant char w_proto[] =
  54   "Waiting for data";
  55
  56 public char *prproto[3];
  57 public char constant *eqproto = e_proto;
  58 public char constant *hproto = h_proto;
  59 public char constant *wproto = w_proto;
  60
  61 static char message[PROMPT_SIZE];
  62 static char *mp;
  63
  64 /*
  65  * Initialize the prompt prototype strings.
  66  */
  67         public void
  68 init_prompt()
  69 {
  70         prproto[0] = save(s_proto);
  71         prproto[1] = save(m_proto);
  72         prproto[2] = save(M_proto);
  73         eqproto = save(e_proto);
  74         hproto = save(h_proto);
  75         wproto = save(w_proto);
  76 }
  77
  78 /*
  79  * Append a string to the end of the message.
  80  */
  81         static void
  82 ap_str(s)
  83         char *s;
  84 {
  85         int len;
  86
  87         len = strlen(s);
  88         if (mp + len >= message + PROMPT_SIZE)
  89                 len = message + PROMPT_SIZE - mp - 1;
  90         strncpy(mp, s, len);
  91         mp += len;
  92         *mp = '\0';
  93 }
  94
  95 /*
  96  * Append a character to the end of the message.
  97  */
  98         static void
  99 ap_char(c)
 100         char c;
 101 {
 102         char buf[2];
 103
 104         buf[0] = c;
 105         buf[1] = '\0';
 106         ap_str(buf);
 107 }
 108
 109 /*
 110  * Append a POSITION (as a decimal integer) to the end of the message.
 111  */
 112         static void
 113 ap_pos(pos)
 114         POSITION pos;
 115 {
 116         char buf[INT_STRLEN_BOUND(pos) + 2];
 117
 118         postoa(pos, buf);
 119         ap_str(buf);
 120 }
 121
 122 /*
 123  * Append a line number to the end of the message.
 124  */
 125         static void
 126 ap_linenum(linenum)
 127         LINENUM linenum;
 128 {
 129         char buf[INT_STRLEN_BOUND(linenum) + 2];
 130
 131         linenumtoa(linenum, buf);
 132         ap_str(buf);
 133 }
 134
 135 /*
 136  * Append an integer to the end of the message.
 137  */
 138         static void
 139 ap_int(num)
 140         int num;
 141 {
 142         char buf[INT_STRLEN_BOUND(num) + 2];
 143
 144         inttoa(num, buf);
 145         ap_str(buf);
 146 }
 147
 148 /*
 149  * Append a question mark to the end of the message.
 150  */
 151         static void
 152 ap_quest()
 153 {
 154         ap_str("?");
 155 }
 156
 157 /*
 158  * Return the "current" byte offset in the file.
 159  */
 160         static POSITION
 161 curr_byte(where)
 162         int where;
 163 {
 164         POSITION pos;
 165
 166         pos = position(where);
 167         while (pos == NULL_POSITION && where >= 0 && where < sc_height)
 168                 pos = position(++where);
 169         if (pos == NULL_POSITION)
 170                 pos = ch_length();
 171         return (pos);
 172 }
 173
 174 /*
 175  * Return the value of a prototype conditional.
 176  * A prototype string may include conditionals which consist of a
 177  * question mark followed by a single letter.
 178  * Here we decode that letter and return the appropriate boolean value.
 179  */
 180         static int
 181 cond(c, where)
 182         char c;
 183         int where;
 184 {
 185         POSITION len;
 186
 187         switch (c)
 188         {
 189         case 'a':       /* Anything in the message yet? */
 190                 return (mp > message);
 191         case 'b':       /* Current byte offset known? */
 192                 return (curr_byte(where) != NULL_POSITION);
 193         case 'c':
 194                 return (hshift != 0);
 195         case 'e':       /* At end of file? */
 196                 return (hit_eof);
 197         case 'f':       /* Filename known? */
 198                 return (strcmp(get_filename(curr_ifile), "-") != 0);
 199         case 'l':       /* Line number known? */
 200         case 'd':       /* Same as l */
 201                 return (linenums);
 202         case 'L':       /* Final line number known? */
 203         case 'D':       /* Same as L */
 204                 return (linenums && ch_length() != NULL_POSITION);
 205         case 'm':       /* More than one file? */
 206 #if TAGS
 207                 return (ntags() ? (ntags() > 1) : (nifile() > 1));
 208 #else
 209                 return (nifile() > 1);
 210 #endif
 211         case 'n':       /* First prompt in a new file? */
 212 #if TAGS
 213                 return (ntags() ? 1 : new_file);
 214 #else
 215                 return (new_file);
 216 #endif
 217         case 'p':       /* Percent into file (bytes) known? */
 218                 return (curr_byte(where) != NULL_POSITION &&
 219                                 ch_length() > 0);
 220         case 'P':       /* Percent into file (lines) known? */
 221                 return (currline(where) != 0 &&
 222                                 (len = ch_length()) > 0 &&
 223                                 find_linenum(len) != 0);
 224         case 's':       /* Size of file known? */
 225         case 'B':
 226                 return (ch_length() != NULL_POSITION);
 227         case 'x':       /* Is there a "next" file? */
 228 #if TAGS
 229                 if (ntags())
 230                         return (0);
 231 #endif
 232                 return (next_ifile(curr_ifile) != NULL_IFILE);
 233         }
 234         return (0);
 235 }
 236
 237 /*
 238  * Decode a "percent" prototype character.
 239  * A prototype string may include various "percent" escapes;
 240  * that is, a percent sign followed by a single letter.
 241  * Here we decode that letter and take the appropriate action,
 242  * usually by appending something to the message being built.
 243  */
 244         static void
 245 protochar(c, where, iseditproto)
 246         int c;
 247         int where;
 248         int iseditproto;
 249 {
 250         POSITION pos;
 251         POSITION len;
 252         int n;
 253         LINENUM linenum;
 254         LINENUM last_linenum;
 255         IFILE h;
 256
 257         switch (c)
 258         {
 259         case 'b':       /* Current byte offset */
 260                 pos = curr_byte(where);
 261                 if (pos != NULL_POSITION)
 262                         ap_pos(pos);
 263                 else
 264                         ap_quest();
 265                 break;
 266         case 'c':
 267                 ap_int(hshift);
 268                 break;
 269         case 'd':       /* Current page number */
 270                 linenum = currline(where);
 271                 if (linenum > 0 && sc_height > 1)
 272                         ap_linenum(((linenum - 1) / (sc_height - 1)) + 1);
 273                 else
 274                         ap_quest();
 275                 break;
 276         case 'D':       /* Last page number */
 277                 len = ch_length();
 278                 if (len == NULL_POSITION || len == ch_zero() ||
 279                     (linenum = find_linenum(len)) <= 0)
 280                         ap_quest();
 281                 else
 282                         ap_linenum(((linenum - 1) / (sc_height - 1)) + 1);
 283                 break;
 284 #if EDITOR
 285         case 'E':       /* Editor name */
 286                 ap_str(editor);
 287                 break;
 288 #endif
 289         case 'f':       /* File name */
 290                 ap_str(get_filename(curr_ifile));
 291                 break;
 292         case 'i':       /* Index into list of files */
 293 #if TAGS
 294                 if (ntags())
 295                         ap_int(curr_tag());
 296                 else
 297 #endif
 298                         ap_int(get_index(curr_ifile));
 299                 break;
 300         case 'l':       /* Current line number */
 301                 linenum = currline(where);
 302                 if (linenum != 0)
 303                         ap_linenum(linenum);
 304                 else
 305                         ap_quest();
 306                 break;
 307         case 'L':       /* Final line number */
 308                 len = ch_length();
 309                 if (len == NULL_POSITION || len == ch_zero() ||
 310                     (linenum = find_linenum(len)) <= 0)
 311                         ap_quest();
 312                 else
 313                         ap_linenum(linenum-1);
 314                 break;
 315         case 'm':       /* Number of files */
 316 #if TAGS
 317                 n = ntags();
 318                 if (n)
 319                         ap_int(n);
 320                 else
 321 #endif
 322                         ap_int(nifile());
 323                 break;
 324         case 'p':       /* Percent into file (bytes) */
 325                 pos = curr_byte(where);
 326                 len = ch_length();
 327                 if (pos != NULL_POSITION && len > 0)
 328                         ap_int(percentage(pos,len));
 329                 else
 330                         ap_quest();
 331                 break;
 332         case 'P':       /* Percent into file (lines) */
 333                 linenum = currline(where);
 334                 if (linenum == 0 ||
 335                     (len = ch_length()) == NULL_POSITION || len == ch_zero() ||
 336                     (last_linenum = find_linenum(len)) <= 0)
 337                         ap_quest();
 338                 else
 339                         ap_int(percentage(linenum, last_linenum));
 340                 break;
 341         case 's':       /* Size of file */
 342         case 'B':
 343                 len = ch_length();
 344                 if (len != NULL_POSITION)
 345                         ap_pos(len);
 346                 else
 347                         ap_quest();
 348                 break;
 349         case 't':       /* Truncate trailing spaces in the message */
 350                 while (mp > message && mp[-1] == ' ')
 351                         mp--;
 352                 break;
 353         case 'T':       /* Type of list */
 354 #if TAGS
 355                 if (ntags())
 356                         ap_str("tag");
 357                 else
 358 #endif
 359                         ap_str("file");
 360                 break;
 361         case 'x':       /* Name of next file */
 362                 h = next_ifile(curr_ifile);
 363                 if (h != NULL_IFILE)
 364                         ap_str(get_filename(h));
 365                 else
 366                         ap_quest();
 367                 break;
 368         }
 369 }
 370
 371 /*
 372  * Skip a false conditional.
 373  * When a false condition is found (either a false IF or the ELSE part
 374  * of a true IF), this routine scans the prototype string to decide
 375  * where to resume parsing the string.
 376  * We must keep track of nested IFs and skip them properly.
 377  */
 378         static char *
 379 skipcond(p)
 380         register char *p;
 381 {
 382         register int iflevel;
 383
 384         /*
 385          * We came in here after processing a ? or :,
 386          * so we start nested one level deep.
 387          */
 388         iflevel = 1;
 389
 390         for (;;) switch (*++p)
 391         {
 392         case '?':
 393                 /*
 394                  * Start of a nested IF.
 395                  */
 396                 iflevel++;
 397                 break;
 398         case ':':
 399                 /*
 400                  * Else.
 401                  * If this matches the IF we came in here with,
 402                  * then we're done.
 403                  */
 404                 if (iflevel == 1)
 405                         return (p);
 406                 break;
 407         case '.':
 408                 /*
 409                  * Endif.
 410                  * If this matches the IF we came in here with,
 411                  * then we're done.
 412                  */
 413                 if (--iflevel == 0)
 414                         return (p);
 415                 break;
 416         case '\\':
 417                 /*
 418                  * Backslash escapes the next character.
 419                  */
 420                 ++p;
 421                 break;
 422         case '\0':
 423                 /*
 424                  * Whoops.  Hit end of string.
 425                  * This is a malformed conditional, but just treat it
 426                  * as if all active conditionals ends here.
 427                  */
 428                 return (p-1);
 429         }
 430         /*NOTREACHED*/
 431 }
 432
 433 /*
 434  * Decode a char that represents a position on the screen.
 435  */
 436         static char *
 437 wherechar(p, wp)
 438         char *p;
 439         int *wp;
 440 {
 441         switch (*p)
 442         {
 443         case 'b': case 'd': case 'l': case 'p': case 'P':
 444                 switch (*++p)
 445                 {
 446                 case 't':   *wp = TOP;                  break;
 447                 case 'm':   *wp = MIDDLE;               break;
 448                 case 'b':   *wp = BOTTOM;               break;
 449                 case 'B':   *wp = BOTTOM_PLUS_ONE;      break;
 450                 case 'j':   *wp = adjsline(jump_sline); break;
 451                 default:    *wp = TOP;  p--;            break;
 452                 }
 453         }
 454         return (p);
 455 }
 456
 457 /*
 458  * Construct a message based on a prototype string.
 459  */
 460         public char *
 461 pr_expand(proto, maxwidth)
 462         char *proto;
 463         int maxwidth;
 464 {
 465         register char *p;
 466         register int c;
 467         int where;
 468
 469         mp = message;
 470
 471         if (*proto == '\0')
 472                 return ("");
 473
 474         for (p = proto;  *p != '\0';  p++)
 475         {
 476                 switch (*p)
 477                 {
 478                 default:        /* Just put the character in the message */
 479                         ap_char(*p);
 480                         break;
 481                 case '\\':      /* Backslash escapes the next character */
 482                         p++;
 483                         ap_char(*p);
 484                         break;
 485                 case '?':       /* Conditional (IF) */
 486                         if ((c = *++p) == '\0')
 487                                 --p;
 488                         else
 489                         {
 490                                 where = 0;
 491                                 p = wherechar(p, &where);
 492                                 if (!cond(c, where))
 493                                         p = skipcond(p);
 494                         }
 495                         break;
 496                 case ':':       /* ELSE */
 497                         p = skipcond(p);
 498                         break;
 499                 case '.':       /* ENDIF */
 500                         break;
 501                 case '%':       /* Percent escape */
 502                         if ((c = *++p) == '\0')
 503                                 --p;
 504                         else
 505                         {
 506                                 where = 0;
 507                                 p = wherechar(p, &where);
 508                                 protochar(c, where,
 509 #if EDITOR
 510                                         (proto == editproto));
 511 #else
 512                                         0);
 513 #endif
 514
 515                         }
 516                         break;
 517                 }
 518         }
 519
 520         if (mp == message)
 521                 return (NULL);
 522         if (maxwidth > 0 && mp >= message + maxwidth)
 523         {
 524                 /*
 525                  * Message is too long.
 526                  * Return just the final portion of it.
 527                  */
 528                 return (mp - maxwidth);
 529         }
 530         return (message);
 531 }
 532
 533 /*
 534  * Return a message suitable for printing by the "=" command.
 535  */
 536         public char *
 537 eq_message()
 538 {
 539         return (pr_expand(eqproto, 0));
 540 }
 541
 542 /*
 543  * Return a prompt.
 544  * This depends on the prompt type (SHORT, MEDIUM, LONG), etc.
 545  * If we can't come up with an appropriate prompt, return NULL
 546  * and the caller will prompt with a colon.
 547  */
 548         public char *
 549 pr_string()
 550 {
 551         char *prompt;
 552
 553         prompt = pr_expand((ch_getflags() & CH_HELPFILE) ?
 554                                 hproto : prproto[pr_type],
 555                         sc_width-so_s_width-so_e_width-2);
 556         new_file = 0;
 557         return (prompt);
 558 }
 559
 560 /*
 561  * Return a message suitable for printing while waiting in the F command.
 562  */
 563         public char *
 564 wait_message()
 565 {
 566         return (pr_expand(wproto, sc_width-so_s_width-so_e_width-2));
 567 }