contrib/less/prompt.c

   1 /*
   2  * Copyright (C) 1984-2015  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 int new_file;
  25 extern int sc_width;
  26 extern int so_s_width, so_e_width;
  27 extern int linenums;
  28 extern int hshift;
  29 extern int sc_height;
  30 extern int jump_sline;
  31 extern int less_is_more;
  32 extern IFILE curr_ifile;
  33 #if EDITOR
  34 extern char *editor;
  35 extern char *editproto;
  36 #endif
  37
  38 /*
  39  * Prototypes for the three flavors of prompts.
  40  * These strings are expanded by pr_expand().
  41  */
  42 static constant char s_proto[] =
  43   "?n?f%f .?m(%T %i of %m) ..?e(END) ?x- Next\\: %x..%t";
  44 static constant char m_proto[] =
  45   "?n?f%f .?m(%T %i of %m) ..?e(END) ?x- Next\\: %x.:?pB%pB\\%:byte %bB?s/%s...%t";
  46 static constant char M_proto[] =
  47   "?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";
  48 static constant char e_proto[] =
  49   "?f%f .?m(%T %i of %m) .?ltlines %lt-%lb?L/%L. .byte %bB?s/%s. ?e(END) :?pB%pB\\%..%t";
  50 static constant char h_proto[] =
  51   "HELP -- ?eEND -- Press g to see it again:Press RETURN for more., or q when done";
  52 static constant char w_proto[] =
  53   "Waiting for data";
  54 static constant char more_proto[] =
  55   "--More--(?eEND ?x- Next\\: %x.:?pB%pB\\%:byte %bB?s/%s...%t)";
  56
  57 public char *prproto[3];
  58 public char constant *eqproto = e_proto;
  59 public char constant *hproto = h_proto;
  60 public char constant *wproto = w_proto;
  61
  62 static char message[PROMPT_SIZE];
  63 static char *mp;
  64
  65 /*
  66  * Initialize the prompt prototype strings.
  67  */
  68         public void
  69 init_prompt()
  70 {
  71         prproto[0] = save(s_proto);
  72         prproto[1] = save(less_is_more ? more_proto : 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
  83 ap_str(s)
  84         char *s;
  85 {
  86         int len;
  87
  88         len = (int) strlen(s);
  89         if (mp + len >= message + PROMPT_SIZE)
  90                 len = (int) (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
 100 ap_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
 114 ap_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
 127 ap_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
 140 ap_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
 153 ap_quest()
 154 {
 155         ap_str("?");
 156 }
 157
 158 /*
 159  * Return the "current" byte offset in the file.
 160  */
 161         static POSITION
 162 curr_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
 182 cond(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 (eof_displayed());
 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
 246 protochar(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 'F':       /* Last component of file name */
 306                 ap_str(last_component(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                 *mp = '\0';
 369                 break;
 370         case 'T':       /* Type of list */
 371 #if TAGS
 372                 if (ntags())
 373                         ap_str("tag");
 374                 else
 375 #endif
 376                         ap_str("file");
 377                 break;
 378         case 'x':       /* Name of next file */
 379                 h = next_ifile(curr_ifile);
 380                 if (h != NULL_IFILE)
 381                         ap_str(get_filename(h));
 382                 else
 383                         ap_quest();
 384                 break;
 385         }
 386 }
 387
 388 /*
 389  * Skip a false conditional.
 390  * When a false condition is found (either a false IF or the ELSE part
 391  * of a true IF), this routine scans the prototype string to decide
 392  * where to resume parsing the string.
 393  * We must keep track of nested IFs and skip them properly.
 394  */
 395         static constant char *
 396 skipcond(p)
 397         register constant char *p;
 398 {
 399         register int iflevel;
 400
 401         /*
 402          * We came in here after processing a ? or :,
 403          * so we start nested one level deep.
 404          */
 405         iflevel = 1;
 406
 407         for (;;) switch (*++p)
 408         {
 409         case '?':
 410                 /*
 411                  * Start of a nested IF.
 412                  */
 413                 iflevel++;
 414                 break;
 415         case ':':
 416                 /*
 417                  * Else.
 418                  * If this matches the IF we came in here with,
 419                  * then we're done.
 420                  */
 421                 if (iflevel == 1)
 422                         return (p);
 423                 break;
 424         case '.':
 425                 /*
 426                  * Endif.
 427                  * If this matches the IF we came in here with,
 428                  * then we're done.
 429                  */
 430                 if (--iflevel == 0)
 431                         return (p);
 432                 break;
 433         case '\\':
 434                 /*
 435                  * Backslash escapes the next character.
 436                  */
 437                 ++p;
 438                 break;
 439         case '\0':
 440                 /*
 441                  * Whoops.  Hit end of string.
 442                  * This is a malformed conditional, but just treat it
 443                  * as if all active conditionals ends here.
 444                  */
 445                 return (p-1);
 446         }
 447         /*NOTREACHED*/
 448 }
 449
 450 /*
 451  * Decode a char that represents a position on the screen.
 452  */
 453         static constant char *
 454 wherechar(p, wp)
 455         char constant *p;
 456         int *wp;
 457 {
 458         switch (*p)
 459         {
 460         case 'b': case 'd': case 'l': case 'p': case 'P':
 461                 switch (*++p)
 462                 {
 463                 case 't':   *wp = TOP;                  break;
 464                 case 'm':   *wp = MIDDLE;               break;
 465                 case 'b':   *wp = BOTTOM;               break;
 466                 case 'B':   *wp = BOTTOM_PLUS_ONE;      break;
 467                 case 'j':   *wp = adjsline(jump_sline); break;
 468                 default:    *wp = TOP;  p--;            break;
 469                 }
 470         }
 471         return (p);
 472 }
 473
 474 /*
 475  * Construct a message based on a prototype string.
 476  */
 477         public char *
 478 pr_expand(proto, maxwidth)
 479         constant char *proto;
 480         int maxwidth;
 481 {
 482         register constant char *p;
 483         register int c;
 484         int where;
 485
 486         mp = message;
 487
 488         if (*proto == '\0')
 489                 return ("");
 490
 491         for (p = proto;  *p != '\0';  p++)
 492         {
 493                 switch (*p)
 494                 {
 495                 default:        /* Just put the character in the message */
 496                         ap_char(*p);
 497                         break;
 498                 case '\\':      /* Backslash escapes the next character */
 499                         p++;
 500                         ap_char(*p);
 501                         break;
 502                 case '?':       /* Conditional (IF) */
 503                         if ((c = *++p) == '\0')
 504                                 --p;
 505                         else
 506                         {
 507                                 where = 0;
 508                                 p = wherechar(p, &where);
 509                                 if (!cond(c, where))
 510                                         p = skipcond(p);
 511                         }
 512                         break;
 513                 case ':':       /* ELSE */
 514                         p = skipcond(p);
 515                         break;
 516                 case '.':       /* ENDIF */
 517                         break;
 518                 case '%':       /* Percent escape */
 519                         if ((c = *++p) == '\0')
 520                                 --p;
 521                         else
 522                         {
 523                                 where = 0;
 524                                 p = wherechar(p, &where);
 525                                 protochar(c, where,
 526 #if EDITOR
 527                                         (proto == editproto));
 528 #else
 529                                         0);
 530 #endif
 531
 532                         }
 533                         break;
 534                 }
 535         }
 536
 537         if (mp == message)
 538                 return ("");
 539         if (maxwidth > 0 && mp >= message + maxwidth)
 540         {
 541                 /*
 542                  * Message is too long.
 543                  * Return just the final portion of it.
 544                  */
 545                 return (mp - maxwidth);
 546         }
 547         return (message);
 548 }
 549
 550 /*
 551  * Return a message suitable for printing by the "=" command.
 552  */
 553         public char *
 554 eq_message()
 555 {
 556         return (pr_expand(eqproto, 0));
 557 }
 558
 559 /*
 560  * Return a prompt.
 561  * This depends on the prompt type (SHORT, MEDIUM, LONG), etc.
 562  * If we can't come up with an appropriate prompt, return NULL
 563  * and the caller will prompt with a colon.
 564  */
 565         public char *
 566 pr_string()
 567 {
 568         char *prompt;
 569         int type;
 570
 571         type = (!less_is_more) ? pr_type : pr_type ? 0 : 1;
 572         prompt = pr_expand((ch_getflags() & CH_HELPFILE) ?
 573                                 hproto : prproto[type],
 574                         sc_width-so_s_width-so_e_width-2);
 575         new_file = 0;
 576         return (prompt);
 577 }
 578
 579 /*
 580  * Return a message suitable for printing while waiting in the F command.
 581  */
 582         public char *
 583 wait_message()
 584 {
 585         return (pr_expand(wproto, sc_width-so_s_width-so_e_width-2));
 586 }