contrib/less-4/prompt.c

   1 /*
   2  * Copyright (C) 1984-2007  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 int less_is_more;
  34 extern IFILE curr_ifile;
  35 #if EDITOR
  36 extern char *editor;
  37 extern char *editproto;
  38 #endif
  39
  40 /*
  41  * Prototypes for the three flavors of prompts.
  42  * These strings are expanded by pr_expand().
  43  */
  44 static constant char s_proto[] =
  45   "?n?f%f .?m(%T %i of %m) ..?e(END) ?x- Next\\: %x..%t";
  46 static constant char m_proto[] =
  47   "?n?f%f .?m(%T %i of %m) ..?e(END) ?x- Next\\: %x.:?pB%pB\\%:byte %bB?s/%s...%t";
  48 static constant char M_proto[] =
  49   "?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";
  50 static constant char e_proto[] =
  51   "?f%f .?m(%T %i of %m) .?ltlines %lt-%lb?L/%L. .byte %bB?s/%s. ?e(END) :?pB%pB\\%..%t";
  52 static constant char h_proto[] =
  53   "HELP -- ?eEND -- Press g to see it again:Press RETURN for more., or q when done";
  54 static constant char w_proto[] =
  55   "Waiting for data";
  56 static constant char more_proto[] =
  57   "--More--(?eEND ?x- Next\\: %x.:?pB%pB\\%:byte %bB?s/%s...%t)";
  58
  59 public char *prproto[3];
  60 public char constant *eqproto = e_proto;
  61 public char constant *hproto = h_proto;
  62 public char constant *wproto = w_proto;
  63
  64 static char message[PROMPT_SIZE];
  65 static char *mp;
  66
  67 /*
  68  * Initialize the prompt prototype strings.
  69  */
  70         public void
  71 init_prompt()
  72 {
  73         prproto[0] = save(s_proto);
  74         prproto[1] = save(less_is_more ? more_proto : m_proto);
  75         prproto[2] = save(M_proto);
  76         eqproto = save(e_proto);
  77         hproto = save(h_proto);
  78         wproto = save(w_proto);
  79 }
  80
  81 /*
  82  * Append a string to the end of the message.
  83  */
  84         static void
  85 ap_str(s)
  86         char *s;
  87 {
  88         int len;
  89
  90         len = strlen(s);
  91         if (mp + len >= message + PROMPT_SIZE)
  92                 len = message + PROMPT_SIZE - mp - 1;
  93         strncpy(mp, s, len);
  94         mp += len;
  95         *mp = '\0';
  96 }
  97
  98 /*
  99  * Append a character to the end of the message.
 100  */
 101         static void
 102 ap_char(c)
 103         char c;
 104 {
 105         char buf[2];
 106
 107         buf[0] = c;
 108         buf[1] = '\0';
 109         ap_str(buf);
 110 }
 111
 112 /*
 113  * Append a POSITION (as a decimal integer) to the end of the message.
 114  */
 115         static void
 116 ap_pos(pos)
 117         POSITION pos;
 118 {
 119         char buf[INT_STRLEN_BOUND(pos) + 2];
 120
 121         postoa(pos, buf);
 122         ap_str(buf);
 123 }
 124
 125 /*
 126  * Append a line number to the end of the message.
 127  */
 128         static void
 129 ap_linenum(linenum)
 130         LINENUM linenum;
 131 {
 132         char buf[INT_STRLEN_BOUND(linenum) + 2];
 133
 134         linenumtoa(linenum, buf);
 135         ap_str(buf);
 136 }
 137
 138 /*
 139  * Append an integer to the end of the message.
 140  */
 141         static void
 142 ap_int(num)
 143         int num;
 144 {
 145         char buf[INT_STRLEN_BOUND(num) + 2];
 146
 147         inttoa(num, buf);
 148         ap_str(buf);
 149 }
 150
 151 /*
 152  * Append a question mark to the end of the message.
 153  */
 154         static void
 155 ap_quest()
 156 {
 157         ap_str("?");
 158 }
 159
 160 /*
 161  * Return the "current" byte offset in the file.
 162  */
 163         static POSITION
 164 curr_byte(where)
 165         int where;
 166 {
 167         POSITION pos;
 168
 169         pos = position(where);
 170         while (pos == NULL_POSITION && where >= 0 && where < sc_height-1)
 171                 pos = position(++where);
 172         if (pos == NULL_POSITION)
 173                 pos = ch_length();
 174         return (pos);
 175 }
 176
 177 /*
 178  * Return the value of a prototype conditional.
 179  * A prototype string may include conditionals which consist of a
 180  * question mark followed by a single letter.
 181  * Here we decode that letter and return the appropriate boolean value.
 182  */
 183         static int
 184 cond(c, where)
 185         char c;
 186         int where;
 187 {
 188         POSITION len;
 189
 190         switch (c)
 191         {
 192         case 'a':       /* Anything in the message yet? */
 193                 return (mp > message);
 194         case 'b':       /* Current byte offset known? */
 195                 return (curr_byte(where) != NULL_POSITION);
 196         case 'c':
 197                 return (hshift != 0);
 198         case 'e':       /* At end of file? */
 199                 return (hit_eof);
 200         case 'f':       /* Filename known? */
 201                 return (strcmp(get_filename(curr_ifile), "-") != 0);
 202         case 'l':       /* Line number known? */
 203         case 'd':       /* Same as l */
 204                 return (linenums);
 205         case 'L':       /* Final line number known? */
 206         case 'D':       /* Final page number known? */
 207                 return (linenums && ch_length() != NULL_POSITION);
 208         case 'm':       /* More than one file? */
 209 #if TAGS
 210                 return (ntags() ? (ntags() > 1) : (nifile() > 1));
 211 #else
 212                 return (nifile() > 1);
 213 #endif
 214         case 'n':       /* First prompt in a new file? */
 215 #if TAGS
 216                 return (ntags() ? 1 : new_file);
 217 #else
 218                 return (new_file);
 219 #endif
 220         case 'p':       /* Percent into file (bytes) known? */
 221                 return (curr_byte(where) != NULL_POSITION &&
 222                                 ch_length() > 0);
 223         case 'P':       /* Percent into file (lines) known? */
 224                 return (currline(where) != 0 &&
 225                                 (len = ch_length()) > 0 &&
 226                                 find_linenum(len) != 0);
 227         case 's':       /* Size of file known? */
 228         case 'B':
 229                 return (ch_length() != NULL_POSITION);
 230         case 'x':       /* Is there a "next" file? */
 231 #if TAGS
 232                 if (ntags())
 233                         return (0);
 234 #endif
 235                 return (next_ifile(curr_ifile) != NULL_IFILE);
 236         }
 237         return (0);
 238 }
 239
 240 /*
 241  * Decode a "percent" prototype character.
 242  * A prototype string may include various "percent" escapes;
 243  * that is, a percent sign followed by a single letter.
 244  * Here we decode that letter and take the appropriate action,
 245  * usually by appending something to the message being built.
 246  */
 247         static void
 248 protochar(c, where, iseditproto)
 249         int c;
 250         int where;
 251         int iseditproto;
 252 {
 253         POSITION pos;
 254         POSITION len;
 255         int n;
 256         LINENUM linenum;
 257         LINENUM last_linenum;
 258         IFILE h;
 259
 260 #undef  PAGE_NUM
 261 #define PAGE_NUM(linenum)  ((((linenum) - 1) / (sc_height - 1)) + 1)
 262
 263         switch (c)
 264         {
 265         case 'b':       /* Current byte offset */
 266                 pos = curr_byte(where);
 267                 if (pos != NULL_POSITION)
 268                         ap_pos(pos);
 269                 else
 270                         ap_quest();
 271                 break;
 272         case 'c':
 273                 ap_int(hshift);
 274                 break;
 275         case 'd':       /* Current page number */
 276                 linenum = currline(where);
 277                 if (linenum > 0 && sc_height > 1)
 278                         ap_linenum(PAGE_NUM(linenum));
 279                 else
 280                         ap_quest();
 281                 break;
 282         case 'D':       /* Final page number */
 283                 /* Find the page number of the last byte in the file (len-1). */
 284                 len = ch_length();
 285                 if (len == NULL_POSITION)
 286                         ap_quest();
 287                 else if (len == 0)
 288                         /* An empty file has no pages. */
 289                         ap_linenum(0);
 290                 else
 291                 {
 292                         linenum = find_linenum(len - 1);
 293                         if (linenum <= 0)
 294                                 ap_quest();
 295                         else
 296                                 ap_linenum(PAGE_NUM(linenum));
 297                 }
 298                 break;
 299 #if EDITOR
 300         case 'E':       /* Editor name */
 301                 ap_str(editor);
 302                 break;
 303 #endif
 304         case 'f':       /* File name */
 305                 ap_str(get_filename(curr_ifile));
 306                 break;
 307         case 'i':       /* Index into list of files */
 308 #if TAGS
 309                 if (ntags())
 310                         ap_int(curr_tag());
 311                 else
 312 #endif
 313                         ap_int(get_index(curr_ifile));
 314                 break;
 315         case 'l':       /* Current line number */
 316                 linenum = currline(where);
 317                 if (linenum != 0)
 318                         ap_linenum(linenum);
 319                 else
 320                         ap_quest();
 321                 break;
 322         case 'L':       /* Final line number */
 323                 len = ch_length();
 324                 if (len == NULL_POSITION || len == ch_zero() ||
 325                     (linenum = find_linenum(len)) <= 0)
 326                         ap_quest();
 327                 else
 328                         ap_linenum(linenum-1);
 329                 break;
 330         case 'm':       /* Number of files */
 331 #if TAGS
 332                 n = ntags();
 333                 if (n)
 334                         ap_int(n);
 335                 else
 336 #endif
 337                         ap_int(nifile());
 338                 break;
 339         case 'p':       /* Percent into file (bytes) */
 340                 pos = curr_byte(where);
 341                 len = ch_length();
 342                 if (pos != NULL_POSITION && len > 0)
 343                         ap_int(percentage(pos,len));
 344                 else
 345                         ap_quest();
 346                 break;
 347         case 'P':       /* Percent into file (lines) */
 348                 linenum = currline(where);
 349                 if (linenum == 0 ||
 350                     (len = ch_length()) == NULL_POSITION || len == ch_zero() ||
 351                     (last_linenum = find_linenum(len)) <= 0)
 352                         ap_quest();
 353                 else
 354                         ap_int(percentage(linenum, last_linenum));
 355                 break;
 356         case 's':       /* Size of file */
 357         case 'B':
 358                 len = ch_length();
 359                 if (len != NULL_POSITION)
 360                         ap_pos(len);
 361                 else
 362                         ap_quest();
 363                 break;
 364         case 't':       /* Truncate trailing spaces in the message */
 365                 while (mp > message && mp[-1] == ' ')
 366                         mp--;
 367                 break;
 368         case 'T':       /* Type of list */
 369 #if TAGS
 370                 if (ntags())
 371                         ap_str("tag");
 372                 else
 373 #endif
 374                         ap_str("file");
 375                 break;
 376         case 'x':       /* Name of next file */
 377                 h = next_ifile(curr_ifile);
 378                 if (h != NULL_IFILE)
 379                         ap_str(get_filename(h));
 380                 else
 381                         ap_quest();
 382                 break;
 383         }
 384 }
 385
 386 /*
 387  * Skip a false conditional.
 388  * When a false condition is found (either a false IF or the ELSE part
 389  * of a true IF), this routine scans the prototype string to decide
 390  * where to resume parsing the string.
 391  * We must keep track of nested IFs and skip them properly.
 392  */
 393         static char *
 394 skipcond(p)
 395         register char *p;
 396 {
 397         register int iflevel;
 398
 399         /*
 400          * We came in here after processing a ? or :,
 401          * so we start nested one level deep.
 402          */
 403         iflevel = 1;
 404
 405         for (;;) switch (*++p)
 406         {
 407         case '?':
 408                 /*
 409                  * Start of a nested IF.
 410                  */
 411                 iflevel++;
 412                 break;
 413         case ':':
 414                 /*
 415                  * Else.
 416                  * If this matches the IF we came in here with,
 417                  * then we're done.
 418                  */
 419                 if (iflevel == 1)
 420                         return (p);
 421                 break;
 422         case '.':
 423                 /*
 424                  * Endif.
 425                  * If this matches the IF we came in here with,
 426                  * then we're done.
 427                  */
 428                 if (--iflevel == 0)
 429                         return (p);
 430                 break;
 431         case '\\':
 432                 /*
 433                  * Backslash escapes the next character.
 434                  */
 435                 ++p;
 436                 break;
 437         case '\0':
 438                 /*
 439                  * Whoops.  Hit end of string.
 440                  * This is a malformed conditional, but just treat it
 441                  * as if all active conditionals ends here.
 442                  */
 443                 return (p-1);
 444         }
 445         /*NOTREACHED*/
 446 }
 447
 448 /*
 449  * Decode a char that represents a position on the screen.
 450  */
 451         static char *
 452 wherechar(p, wp)
 453         char *p;
 454         int *wp;
 455 {
 456         switch (*p)
 457         {
 458         case 'b': case 'd': case 'l': case 'p': case 'P':
 459                 switch (*++p)
 460                 {
 461                 case 't':   *wp = TOP;                  break;
 462                 case 'm':   *wp = MIDDLE;               break;
 463                 case 'b':   *wp = BOTTOM;               break;
 464                 case 'B':   *wp = BOTTOM_PLUS_ONE;      break;
 465                 case 'j':   *wp = adjsline(jump_sline); break;
 466                 default:    *wp = TOP;  p--;            break;
 467                 }
 468         }
 469         return (p);
 470 }
 471
 472 /*
 473  * Construct a message based on a prototype string.
 474  */
 475         public char *
 476 pr_expand(proto, maxwidth)
 477         char *proto;
 478         int maxwidth;
 479 {
 480         register char *p;
 481         register int c;
 482         int where;
 483
 484         mp = message;
 485
 486         if (*proto == '\0')
 487                 return ("");
 488
 489         for (p = proto;  *p != '\0';  p++)
 490         {
 491                 switch (*p)
 492                 {
 493                 default:        /* Just put the character in the message */
 494                         ap_char(*p);
 495                         break;
 496                 case '\\':      /* Backslash escapes the next character */
 497                         p++;
 498                         ap_char(*p);
 499                         break;
 500                 case '?':       /* Conditional (IF) */
 501                         if ((c = *++p) == '\0')
 502                                 --p;
 503                         else
 504                         {
 505                                 where = 0;
 506                                 p = wherechar(p, &where);
 507                                 if (!cond(c, where))
 508                                         p = skipcond(p);
 509                         }
 510                         break;
 511                 case ':':       /* ELSE */
 512                         p = skipcond(p);
 513                         break;
 514                 case '.':       /* ENDIF */
 515                         break;
 516                 case '%':       /* Percent escape */
 517                         if ((c = *++p) == '\0')
 518                                 --p;
 519                         else
 520                         {
 521                                 where = 0;
 522                                 p = wherechar(p, &where);
 523                                 protochar(c, where,
 524 #if EDITOR
 525                                         (proto == editproto));
 526 #else
 527                                         0);
 528 #endif
 529
 530                         }
 531                         break;
 532                 }
 533         }
 534
 535         if (mp == message)
 536                 return ("");
 537         if (maxwidth > 0 && mp >= message + maxwidth)
 538         {
 539                 /*
 540                  * Message is too long.
 541                  * Return just the final portion of it.
 542                  */
 543                 return (mp - maxwidth);
 544         }
 545         return (message);
 546 }
 547
 548 /*
 549  * Return a message suitable for printing by the "=" command.
 550  */
 551         public char *
 552 eq_message()
 553 {
 554         return (pr_expand(eqproto, 0));
 555 }
 556
 557 /*
 558  * Return a prompt.
 559  * This depends on the prompt type (SHORT, MEDIUM, LONG), etc.
 560  * If we can't come up with an appropriate prompt, return NULL
 561  * and the caller will prompt with a colon.
 562  */
 563         public char *
 564 pr_string()
 565 {
 566         char *prompt;
 567         int type;
 568
 569         type = (!less_is_more) ? pr_type : pr_type ? 0 : 1;
 570         prompt = pr_expand((ch_getflags() & CH_HELPFILE) ?
 571                                 hproto : prproto[type],
 572                         sc_width-so_s_width-so_e_width-2);
 573         new_file = 0;
 574         return (prompt);
 575 }
 576
 577 /*
 578  * Return a message suitable for printing while waiting in the F command.
 579  */
 580         public char *
 581 wait_message()
 582 {
 583         return (pr_expand(wproto, sc_width-so_s_width-so_e_width-2));
 584 }