contrib/less/prompt.c

   1 /*
   2  * Copyright (C) 1984-2009  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 new_file;
  26 extern int sc_width;
  27 extern int so_s_width, so_e_width;
  28 extern int linenums;
  29 extern int hshift;
  30 extern int sc_height;
  31 extern int jump_sline;
  32 extern int less_is_more;
  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 static constant char more_proto[] =
  56   "--More--(?eEND ?x- Next\\: %x.:?pB%pB\\%:byte %bB?s/%s...%t)";
  57
  58 public char *prproto[3];
  59 public char constant *eqproto = e_proto;
  60 public char constant *hproto = h_proto;
  61 public char constant *wproto = w_proto;
  62
  63 static char message[PROMPT_SIZE];
  64 static char *mp;
  65
  66 /*
  67  * Initialize the prompt prototype strings.
  68  */
  69         public void
  70 init_prompt()
  71 {
  72         prproto[0] = save(s_proto);
  73         prproto[1] = save(less_is_more ? more_proto : m_proto);
  74         prproto[2] = save(M_proto);
  75         eqproto = save(e_proto);
  76         hproto = save(h_proto);
  77         wproto = save(w_proto);
  78 }
  79
  80 /*
  81  * Append a string to the end of the message.
  82  */
  83         static void
  84 ap_str(s)
  85         char *s;
  86 {
  87         int len;
  88
  89         len = strlen(s);
  90         if (mp + len >= message + PROMPT_SIZE)
  91                 len = message + PROMPT_SIZE - mp - 1;
  92         strncpy(mp, s, len);
  93         mp += len;
  94         *mp = '\0';
  95 }
  96
  97 /*
  98  * Append a character to the end of the message.
  99  */
 100         static void
 101 ap_char(c)
 102         char c;
 103 {
 104         char buf[2];
 105
 106         buf[0] = c;
 107         buf[1] = '\0';
 108         ap_str(buf);
 109 }
 110
 111 /*
 112  * Append a POSITION (as a decimal integer) to the end of the message.
 113  */
 114         static void
 115 ap_pos(pos)
 116         POSITION pos;
 117 {
 118         char buf[INT_STRLEN_BOUND(pos) + 2];
 119
 120         postoa(pos, buf);
 121         ap_str(buf);
 122 }
 123
 124 /*
 125  * Append a line number to the end of the message.
 126  */
 127         static void
 128 ap_linenum(linenum)
 129         LINENUM linenum;
 130 {
 131         char buf[INT_STRLEN_BOUND(linenum) + 2];
 132
 133         linenumtoa(linenum, buf);
 134         ap_str(buf);
 135 }
 136
 137 /*
 138  * Append an integer to the end of the message.
 139  */
 140         static void
 141 ap_int(num)
 142         int num;
 143 {
 144         char buf[INT_STRLEN_BOUND(num) + 2];
 145
 146         inttoa(num, buf);
 147         ap_str(buf);
 148 }
 149
 150 /*
 151  * Append a question mark to the end of the message.
 152  */
 153         static void
 154 ap_quest()
 155 {
 156         ap_str("?");
 157 }
 158
 159 /*
 160  * Return the "current" byte offset in the file.
 161  */
 162         static POSITION
 163 curr_byte(where)
 164         int where;
 165 {
 166         POSITION pos;
 167
 168         pos = position(where);
 169         while (pos == NULL_POSITION && where >= 0 && where < sc_height-1)
 170                 pos = position(++where);
 171         if (pos == NULL_POSITION)
 172                 pos = ch_length();
 173         return (pos);
 174 }
 175
 176 /*
 177  * Return the value of a prototype conditional.
 178  * A prototype string may include conditionals which consist of a
 179  * question mark followed by a single letter.
 180  * Here we decode that letter and return the appropriate boolean value.
 181  */
 182         static int
 183 cond(c, where)
 184         char c;
 185         int where;
 186 {
 187         POSITION len;
 188
 189         switch (c)
 190         {
 191         case 'a':       /* Anything in the message yet? */
 192                 return (mp > message);
 193         case 'b':       /* Current byte offset known? */
 194                 return (curr_byte(where) != NULL_POSITION);
 195         case 'c':
 196                 return (hshift != 0);
 197         case 'e':       /* At end of file? */
 198                 return (eof_displayed());
 199         case 'f':       /* Filename known? */
 200                 return (strcmp(get_filename(curr_ifile), "-") != 0);
 201         case 'l':       /* Line number known? */
 202         case 'd':       /* Same as l */
 203                 return (linenums);
 204         case 'L':       /* Final line number known? */
 205         case 'D':       /* Final page number known? */
 206                 return (linenums && ch_length() != NULL_POSITION);
 207         case 'm':       /* More than one file? */
 208 #if TAGS
 209                 return (ntags() ? (ntags() > 1) : (nifile() > 1));
 210 #else
 211                 return (nifile() > 1);
 212 #endif
 213         case 'n':       /* First prompt in a new file? */
 214 #if TAGS
 215                 return (ntags() ? 1 : new_file);
 216 #else
 217                 return (new_file);
 218 #endif
 219         case 'p':       /* Percent into file (bytes) known? */
 220                 return (curr_byte(where) != NULL_POSITION &&
 221                                 ch_length() > 0);
 222         case 'P':       /* Percent into file (lines) known? */
 223                 return (currline(where) != 0 &&
 224                                 (len = ch_length()) > 0 &&
 225                                 find_linenum(len) != 0);
 226         case 's':       /* Size of file known? */
 227         case 'B':
 228                 return (ch_length() != NULL_POSITION);
 229         case 'x':       /* Is there a "next" file? */
 230 #if TAGS
 231                 if (ntags())
 232                         return (0);
 233 #endif
 234                 return (next_ifile(curr_ifile) != NULL_IFILE);
 235         }
 236         return (0);
 237 }
 238
 239 /*
 240  * Decode a "percent" prototype character.
 241  * A prototype string may include various "percent" escapes;
 242  * that is, a percent sign followed by a single letter.
 243  * Here we decode that letter and take the appropriate action,
 244  * usually by appending something to the message being built.
 245  */
 246         static void
 247 protochar(c, where, iseditproto)
 248         int c;
 249         int where;
 250         int iseditproto;
 251 {
 252         POSITION pos;
 253         POSITION len;
 254         int n;
 255         LINENUM linenum;
 256         LINENUM last_linenum;
 257         IFILE h;
 258
 259 #undef  PAGE_NUM
 260 #define PAGE_NUM(linenum)  ((((linenum) - 1) / (sc_height - 1)) + 1)
 261
 262         switch (c)
 263         {
 264         case 'b':       /* Current byte offset */
 265                 pos = curr_byte(where);
 266                 if (pos != NULL_POSITION)
 267                         ap_pos(pos);
 268                 else
 269                         ap_quest();
 270                 break;
 271         case 'c':
 272                 ap_int(hshift);
 273                 break;
 274         case 'd':       /* Current page number */
 275                 linenum = currline(where);
 276                 if (linenum > 0 && sc_height > 1)
 277                         ap_linenum(PAGE_NUM(linenum));
 278                 else
 279                         ap_quest();
 280                 break;
 281         case 'D':       /* Final page number */
 282                 /* Find the page number of the last byte in the file (len-1). */
 283                 len = ch_length();
 284                 if (len == NULL_POSITION)
 285                         ap_quest();
 286                 else if (len == 0)
 287                         /* An empty file has no pages. */
 288                         ap_linenum(0);
 289                 else
 290                 {
 291                         linenum = find_linenum(len - 1);
 292                         if (linenum <= 0)
 293                                 ap_quest();
 294                         else
 295                                 ap_linenum(PAGE_NUM(linenum));
 296                 }
 297                 break;
 298 #if EDITOR
 299         case 'E':       /* Editor name */
 300                 ap_str(editor);
 301                 break;
 302 #endif
 303         case 'f':       /* File name */
 304                 ap_str(get_filename(curr_ifile));
 305                 break;
 306         case 'i':       /* Index into list of files */
 307 #if TAGS
 308                 if (ntags())
 309                         ap_int(curr_tag());
 310                 else
 311 #endif
 312                         ap_int(get_index(curr_ifile));
 313                 break;
 314         case 'l':       /* Current line number */
 315                 linenum = currline(where);
 316                 if (linenum != 0)
 317                         ap_linenum(linenum);
 318                 else
 319                         ap_quest();
 320                 break;
 321         case 'L':       /* Final line number */
 322                 len = ch_length();
 323                 if (len == NULL_POSITION || len == ch_zero() ||
 324                     (linenum = find_linenum(len)) <= 0)
 325                         ap_quest();
 326                 else
 327                         ap_linenum(linenum-1);
 328                 break;
 329         case 'm':       /* Number of files */
 330 #if TAGS
 331                 n = ntags();
 332                 if (n)
 333                         ap_int(n);
 334                 else
 335 #endif
 336                         ap_int(nifile());
 337                 break;
 338         case 'p':       /* Percent into file (bytes) */
 339                 pos = curr_byte(where);
 340                 len = ch_length();
 341                 if (pos != NULL_POSITION && len > 0)
 342                         ap_int(percentage(pos,len));
 343                 else
 344                         ap_quest();
 345                 break;
 346         case 'P':       /* Percent into file (lines) */
 347                 linenum = currline(where);
 348                 if (linenum == 0 ||
 349                     (len = ch_length()) == NULL_POSITION || len == ch_zero() ||
 350                     (last_linenum = find_linenum(len)) <= 0)
 351                         ap_quest();
 352                 else
 353                         ap_int(percentage(linenum, last_linenum));
 354                 break;
 355         case 's':       /* Size of file */
 356         case 'B':
 357                 len = ch_length();
 358                 if (len != NULL_POSITION)
 359                         ap_pos(len);
 360                 else
 361                         ap_quest();
 362                 break;
 363         case 't':       /* Truncate trailing spaces in the message */
 364                 while (mp > message && mp[-1] == ' ')
 365                         mp--;
 366                 break;
 367         case 'T':       /* Type of list */
 368 #if TAGS
 369                 if (ntags())
 370                         ap_str("tag");
 371                 else
 372 #endif
 373                         ap_str("file");
 374                 break;
 375         case 'x':       /* Name of next file */
 376                 h = next_ifile(curr_ifile);
 377                 if (h != NULL_IFILE)
 378                         ap_str(get_filename(h));
 379                 else
 380                         ap_quest();
 381                 break;
 382         }
 383 }
 384
 385 /*
 386  * Skip a false conditional.
 387  * When a false condition is found (either a false IF or the ELSE part
 388  * of a true IF), this routine scans the prototype string to decide
 389  * where to resume parsing the string.
 390  * We must keep track of nested IFs and skip them properly.
 391  */
 392         static char *
 393 skipcond(p)
 394         register char *p;
 395 {
 396         register int iflevel;
 397
 398         /*
 399          * We came in here after processing a ? or :,
 400          * so we start nested one level deep.
 401          */
 402         iflevel = 1;
 403
 404         for (;;) switch (*++p)
 405         {
 406         case '?':
 407                 /*
 408                  * Start of a nested IF.
 409                  */
 410                 iflevel++;
 411                 break;
 412         case ':':
 413                 /*
 414                  * Else.
 415                  * If this matches the IF we came in here with,
 416                  * then we're done.
 417                  */
 418                 if (iflevel == 1)
 419                         return (p);
 420                 break;
 421         case '.':
 422                 /*
 423                  * Endif.
 424                  * If this matches the IF we came in here with,
 425                  * then we're done.
 426                  */
 427                 if (--iflevel == 0)
 428                         return (p);
 429                 break;
 430         case '\\':
 431                 /*
 432                  * Backslash escapes the next character.
 433                  */
 434                 ++p;
 435                 break;
 436         case '\0':
 437                 /*
 438                  * Whoops.  Hit end of string.
 439                  * This is a malformed conditional, but just treat it
 440                  * as if all active conditionals ends here.
 441                  */
 442                 return (p-1);
 443         }
 444         /*NOTREACHED*/
 445 }
 446
 447 /*
 448  * Decode a char that represents a position on the screen.
 449  */
 450         static char *
 451 wherechar(p, wp)
 452         char *p;
 453         int *wp;
 454 {
 455         switch (*p)
 456         {
 457         case 'b': case 'd': case 'l': case 'p': case 'P':
 458                 switch (*++p)
 459                 {
 460                 case 't':   *wp = TOP;                  break;
 461                 case 'm':   *wp = MIDDLE;               break;
 462                 case 'b':   *wp = BOTTOM;               break;
 463                 case 'B':   *wp = BOTTOM_PLUS_ONE;      break;
 464                 case 'j':   *wp = adjsline(jump_sline); break;
 465                 default:    *wp = TOP;  p--;            break;
 466                 }
 467         }
 468         return (p);
 469 }
 470
 471 /*
 472  * Construct a message based on a prototype string.
 473  */
 474         public char *
 475 pr_expand(proto, maxwidth)
 476         char *proto;
 477         int maxwidth;
 478 {
 479         register char *p;
 480         register int c;
 481         int where;
 482
 483         mp = message;
 484
 485         if (*proto == '\0')
 486                 return ("");
 487
 488         for (p = proto;  *p != '\0';  p++)
 489         {
 490                 switch (*p)
 491                 {
 492                 default:        /* Just put the character in the message */
 493                         ap_char(*p);
 494                         break;
 495                 case '\\':      /* Backslash escapes the next character */
 496                         p++;
 497                         ap_char(*p);
 498                         break;
 499                 case '?':       /* Conditional (IF) */
 500                         if ((c = *++p) == '\0')
 501                                 --p;
 502                         else
 503                         {
 504                                 where = 0;
 505                                 p = wherechar(p, &where);
 506                                 if (!cond(c, where))
 507                                         p = skipcond(p);
 508                         }
 509                         break;
 510                 case ':':       /* ELSE */
 511                         p = skipcond(p);
 512                         break;
 513                 case '.':       /* ENDIF */
 514                         break;
 515                 case '%':       /* Percent escape */
 516                         if ((c = *++p) == '\0')
 517                                 --p;
 518                         else
 519                         {
 520                                 where = 0;
 521                                 p = wherechar(p, &where);
 522                                 protochar(c, where,
 523 #if EDITOR
 524                                         (proto == editproto));
 525 #else
 526                                         0);
 527 #endif
 528
 529                         }
 530                         break;
 531                 }
 532         }
 533
 534         if (mp == message)
 535                 return ("");
 536         if (maxwidth > 0 && mp >= message + maxwidth)
 537         {
 538                 /*
 539                  * Message is too long.
 540                  * Return just the final portion of it.
 541                  */
 542                 return (mp - maxwidth);
 543         }
 544         return (message);
 545 }
 546
 547 /*
 548  * Return a message suitable for printing by the "=" command.
 549  */
 550         public char *
 551 eq_message()
 552 {
 553         return (pr_expand(eqproto, 0));
 554 }
 555
 556 /*
 557  * Return a prompt.
 558  * This depends on the prompt type (SHORT, MEDIUM, LONG), etc.
 559  * If we can't come up with an appropriate prompt, return NULL
 560  * and the caller will prompt with a colon.
 561  */
 562         public char *
 563 pr_string()
 564 {
 565         char *prompt;
 566         int type;
 567
 568         type = (!less_is_more) ? pr_type : pr_type ? 0 : 1;
 569         prompt = pr_expand((ch_getflags() & CH_HELPFILE) ?
 570                                 hproto : prproto[type],
 571                         sc_width-so_s_width-so_e_width-2);
 572         new_file = 0;
 573         return (prompt);
 574 }
 575
 576 /*
 577  * Return a message suitable for printing while waiting in the F command.
 578  */
 579         public char *
 580 wait_message()
 581 {
 582         return (pr_expand(wproto, sc_width-so_s_width-so_e_width-2));
 583 }