contrib/less/option.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  * Process command line options.
  14  *
  15  * Each option is a single letter which controls a program variable.
  16  * The options have defaults which may be changed via
  17  * the command line option, toggled via the "-" command,
  18  * or queried via the "_" command.
  19  */
  20
  21 #include "less.h"
  22 #include "option.h"
  23
  24 static struct loption *pendopt;
  25 public int plusoption = FALSE;
  26
  27 static char *propt();
  28 static char *optstring();
  29 static int flip_triple();
  30
  31 extern int screen_trashed;
  32 extern int less_is_more;
  33 extern int quit_at_eof;
  34 extern char *every_first_cmd;
  35
  36 /*
  37  * Scan an argument (either from the command line or from the
  38  * LESS environment variable) and process it.
  39  */
  40         public void
  41 scan_option(s)
  42         char *s;
  43 {
  44         register struct loption *o;
  45         register int optc;
  46         char *optname;
  47         char *printopt;
  48         char *str;
  49         int set_default;
  50         int lc;
  51         int err;
  52         PARG parg;
  53
  54         if (s == NULL)
  55                 return;
  56
  57         /*
  58          * If we have a pending option which requires an argument,
  59          * handle it now.
  60          * This happens if the previous option was, for example, "-P"
  61          * without a following string.  In that case, the current
  62          * option is simply the argument for the previous option.
  63          */
  64         if (pendopt != NULL)
  65         {
  66                 switch (pendopt->otype & OTYPE)
  67                 {
  68                 case STRING:
  69                         (*pendopt->ofunc)(INIT, s);
  70                         break;
  71                 case NUMBER:
  72                         printopt = propt(pendopt->oletter);
  73                         *(pendopt->ovar) = getnum(&s, printopt, (int*)NULL);
  74                         break;
  75                 }
  76                 pendopt = NULL;
  77                 return;
  78         }
  79
  80         set_default = FALSE;
  81         optname = NULL;
  82
  83         while (*s != '\0')
  84         {
  85                 /*
  86                  * Check some special cases first.
  87                  */
  88                 switch (optc = *s++)
  89                 {
  90                 case ' ':
  91                 case '\t':
  92                 case END_OPTION_STRING:
  93                         continue;
  94                 case '-':
  95                         /*
  96                          * "--" indicates an option name instead of a letter.
  97                          */
  98                         if (*s == '-')
  99                         {
 100                                 optname = ++s;
 101                                 break;
 102                         }
 103                         /*
 104                          * "-+" means set these options back to their defaults.
 105                          * (They may have been set otherwise by previous
 106                          * options.)
 107                          */
 108                         set_default = (*s == '+');
 109                         if (set_default)
 110                                 s++;
 111                         continue;
 112                 case '+':
 113                         /*
 114                          * An option prefixed by a "+" is ungotten, so
 115                          * that it is interpreted as less commands
 116                          * processed at the start of the first input file.
 117                          * "++" means process the commands at the start of
 118                          * EVERY input file.
 119                          */
 120                         plusoption = TRUE;
 121                         s = optstring(s, &str, propt('+'), NULL);
 122                         if (*str == '+')
 123                                 every_first_cmd = save(++str);
 124                         else
 125                                 ungetsc(str);
 126                         continue;
 127                 case '0':  case '1':  case '2':  case '3':  case '4':
 128                 case '5':  case '6':  case '7':  case '8':  case '9':
 129                         /*
 130                          * Special "more" compatibility form "-<number>"
 131                          * instead of -z<number> to set the scrolling
 132                          * window size.
 133                          */
 134                         s--;
 135                         optc = 'z';
 136                         break;
 137                 case 'n':
 138                         if (less_is_more)
 139                                 optc = 'z';
 140                         break;
 141                 }
 142
 143                 /*
 144                  * Not a special case.
 145                  * Look up the option letter in the option table.
 146                  */
 147                 err = 0;
 148                 if (optname == NULL)
 149                 {
 150                         printopt = propt(optc);
 151                         lc = ASCII_IS_LOWER(optc);
 152                         o = findopt(optc);
 153                 } else
 154                 {
 155                         printopt = optname;
 156                         lc = ASCII_IS_LOWER(optname[0]);
 157                         o = findopt_name(&optname, NULL, &err);
 158                         s = optname;
 159                         optname = NULL;
 160                         if (*s == '\0' || *s == ' ')
 161                         {
 162                                 /*
 163                                  * The option name matches exactly.
 164                                  */
 165                                 ;
 166                         } else if (*s == '=')
 167                         {
 168                                 /*
 169                                  * The option name is followed by "=value".
 170                                  */
 171                                 if (o != NULL &&
 172                                     (o->otype & OTYPE) != STRING &&
 173                                     (o->otype & OTYPE) != NUMBER)
 174                                 {
 175                                         parg.p_string = printopt;
 176                                         error("The %s option should not be followed by =",
 177                                                 &parg);
 178                                         quit(QUIT_ERROR);
 179                                 }
 180                                 s++;
 181                         } else
 182                         {
 183                                 /*
 184                                  * The specified name is longer than the
 185                                  * real option name.
 186                                  */
 187                                 o = NULL;
 188                         }
 189                 }
 190                 if (o == NULL)
 191                 {
 192                         parg.p_string = printopt;
 193                         if (err == OPT_AMBIG)
 194                                 error("%s is an ambiguous abbreviation (\"less --help\" for help)",
 195                                         &parg);
 196                         else
 197                                 error("There is no %s option (\"less --help\" for help)",
 198                                         &parg);
 199                         quit(QUIT_ERROR);
 200                 }
 201
 202                 str = NULL;
 203                 switch (o->otype & OTYPE)
 204                 {
 205                 case BOOL:
 206                         if (set_default)
 207                                 *(o->ovar) = o->odefault;
 208                         else
 209                                 *(o->ovar) = ! o->odefault;
 210                         break;
 211                 case TRIPLE:
 212                         if (set_default)
 213                                 *(o->ovar) = o->odefault;
 214                         else
 215                                 *(o->ovar) = flip_triple(o->odefault, lc);
 216                         break;
 217                 case STRING:
 218                         if (*s == '\0')
 219                         {
 220                                 /*
 221                                  * Set pendopt and return.
 222                                  * We will get the string next time
 223                                  * scan_option is called.
 224                                  */
 225                                 pendopt = o;
 226                                 return;
 227                         }
 228                         /*
 229                          * Don't do anything here.
 230                          * All processing of STRING options is done by
 231                          * the handling function.
 232                          */
 233                         while (*s == ' ')
 234                                 s++;
 235                         s = optstring(s, &str, printopt, o->odesc[1]);
 236                         break;
 237                 case NUMBER:
 238                         if (*s == '\0')
 239                         {
 240                                 pendopt = o;
 241                                 return;
 242                         }
 243                         *(o->ovar) = getnum(&s, printopt, (int*)NULL);
 244                         break;
 245                 }
 246                 /*
 247                  * If the option has a handling function, call it.
 248                  */
 249                 if (o->ofunc != NULL)
 250                         (*o->ofunc)(INIT, str);
 251         }
 252 }
 253
 254 /*
 255  * Toggle command line flags from within the program.
 256  * Used by the "-" and "_" commands.
 257  * how_toggle may be:
 258  *      OPT_NO_TOGGLE   just report the current setting, without changing it.
 259  *      OPT_TOGGLE      invert the current setting
 260  *      OPT_UNSET       set to the default value
 261  *      OPT_SET         set to the inverse of the default value
 262  */
 263         public void
 264 toggle_option(c, s, how_toggle)
 265         int c;
 266         char *s;
 267         int how_toggle;
 268 {
 269         register struct loption *o;
 270         register int num;
 271         int no_prompt;
 272         int err;
 273         PARG parg;
 274
 275         no_prompt = (how_toggle & OPT_NO_PROMPT);
 276         how_toggle &= ~OPT_NO_PROMPT;
 277
 278         /*
 279          * Look up the option letter in the option table.
 280          */
 281         o = findopt(c);
 282         if (o == NULL)
 283         {
 284                 parg.p_string = propt(c);
 285                 error("There is no %s option", &parg);
 286                 return;
 287         }
 288
 289         if (how_toggle == OPT_TOGGLE && (o->otype & NO_TOGGLE))
 290         {
 291                 parg.p_string = propt(c);
 292                 error("Cannot change the %s option", &parg);
 293                 return;
 294         }
 295
 296         if (how_toggle == OPT_NO_TOGGLE && (o->otype & NO_QUERY))
 297         {
 298                 parg.p_string = propt(c);
 299                 error("Cannot query the %s option", &parg);
 300                 return;
 301         }
 302
 303         /*
 304          * Check for something which appears to be a do_toggle
 305          * (because the "-" command was used), but really is not.
 306          * This could be a string option with no string, or
 307          * a number option with no number.
 308          */
 309         switch (o->otype & OTYPE)
 310         {
 311         case STRING:
 312         case NUMBER:
 313                 if (how_toggle == OPT_TOGGLE && *s == '\0')
 314                         how_toggle = OPT_NO_TOGGLE;
 315                 break;
 316         }
 317
 318 #if HILITE_SEARCH
 319         if (how_toggle != OPT_NO_TOGGLE && (o->otype & HL_REPAINT))
 320                 repaint_hilite(0);
 321 #endif
 322
 323         /*
 324          * Now actually toggle (change) the variable.
 325          */
 326         if (how_toggle != OPT_NO_TOGGLE)
 327         {
 328                 switch (o->otype & OTYPE)
 329                 {
 330                 case BOOL:
 331                         /*
 332                          * Boolean.
 333                          */
 334                         switch (how_toggle)
 335                         {
 336                         case OPT_TOGGLE:
 337                                 *(o->ovar) = ! *(o->ovar);
 338                                 break;
 339                         case OPT_UNSET:
 340                                 *(o->ovar) = o->odefault;
 341                                 break;
 342                         case OPT_SET:
 343                                 *(o->ovar) = ! o->odefault;
 344                                 break;
 345                         }
 346                         break;
 347                 case TRIPLE:
 348                         /*
 349                          * Triple:
 350                          *      If user gave the lower case letter, then switch
 351                          *      to 1 unless already 1, in which case make it 0.
 352                          *      If user gave the upper case letter, then switch
 353                          *      to 2 unless already 2, in which case make it 0.
 354                          */
 355                         switch (how_toggle)
 356                         {
 357                         case OPT_TOGGLE:
 358                                 *(o->ovar) = flip_triple(*(o->ovar),
 359                                                 ASCII_IS_LOWER(c));
 360                                 break;
 361                         case OPT_UNSET:
 362                                 *(o->ovar) = o->odefault;
 363                                 break;
 364                         case OPT_SET:
 365                                 *(o->ovar) = flip_triple(o->odefault,
 366                                                 ASCII_IS_LOWER(c));
 367                                 break;
 368                         }
 369                         break;
 370                 case STRING:
 371                         /*
 372                          * String: don't do anything here.
 373                          *      The handling function will do everything.
 374                          */
 375                         switch (how_toggle)
 376                         {
 377                         case OPT_SET:
 378                         case OPT_UNSET:
 379                                 error("Cannot use \"-+\" or \"--\" for a string option",
 380                                         NULL_PARG);
 381                                 return;
 382                         }
 383                         break;
 384                 case NUMBER:
 385                         /*
 386                          * Number: set the variable to the given number.
 387                          */
 388                         switch (how_toggle)
 389                         {
 390                         case OPT_TOGGLE:
 391                                 num = getnum(&s, NULL, &err);
 392                                 if (!err)
 393                                         *(o->ovar) = num;
 394                                 break;
 395                         case OPT_UNSET:
 396                                 *(o->ovar) = o->odefault;
 397                                 break;
 398                         case OPT_SET:
 399                                 error("Can't use \"-!\" for a numeric option",
 400                                         NULL_PARG);
 401                                 return;
 402                         }
 403                         break;
 404                 }
 405         }
 406
 407         /*
 408          * Call the handling function for any special action
 409          * specific to this option.
 410          */
 411         if (o->ofunc != NULL)
 412                 (*o->ofunc)((how_toggle==OPT_NO_TOGGLE) ? QUERY : TOGGLE, s);
 413
 414 #if HILITE_SEARCH
 415         if (how_toggle != OPT_NO_TOGGLE && (o->otype & HL_REPAINT))
 416                 chg_hilite();
 417 #endif
 418
 419         if (!no_prompt)
 420         {
 421                 /*
 422                  * Print a message describing the new setting.
 423                  */
 424                 switch (o->otype & OTYPE)
 425                 {
 426                 case BOOL:
 427                 case TRIPLE:
 428                         /*
 429                          * Print the odesc message.
 430                          */
 431                         error(o->odesc[*(o->ovar)], NULL_PARG);
 432                         break;
 433                 case NUMBER:
 434                         /*
 435                          * The message is in odesc[1] and has a %d for
 436                          * the value of the variable.
 437                          */
 438                         parg.p_int = *(o->ovar);
 439                         error(o->odesc[1], &parg);
 440                         break;
 441                 case STRING:
 442                         /*
 443                          * Message was already printed by the handling function.
 444                          */
 445                         break;
 446                 }
 447         }
 448
 449         if (how_toggle != OPT_NO_TOGGLE && (o->otype & REPAINT))
 450                 screen_trashed = TRUE;
 451 }
 452
 453 /*
 454  * "Toggle" a triple-valued option.
 455  */
 456         static int
 457 flip_triple(val, lc)
 458         int val;
 459         int lc;
 460 {
 461         if (lc)
 462                 return ((val == OPT_ON) ? OPT_OFF : OPT_ON);
 463         else
 464                 return ((val == OPT_ONPLUS) ? OPT_OFF : OPT_ONPLUS);
 465 }
 466
 467 /*
 468  * Return a string suitable for printing as the "name" of an option.
 469  * For example, if the option letter is 'x', just return "-x".
 470  */
 471         static char *
 472 propt(c)
 473         int c;
 474 {
 475         static char buf[8];
 476
 477         sprintf(buf, "-%s", prchar(c));
 478         return (buf);
 479 }
 480
 481 /*
 482  * Determine if an option is a single character option (BOOL or TRIPLE),
 483  * or if it a multi-character option (NUMBER).
 484  */
 485         public int
 486 single_char_option(c)
 487         int c;
 488 {
 489         register struct loption *o;
 490
 491         o = findopt(c);
 492         if (o == NULL)
 493                 return (TRUE);
 494         return ((o->otype & (BOOL|TRIPLE|NOVAR|NO_TOGGLE)) != 0);
 495 }
 496
 497 /*
 498  * Return the prompt to be used for a given option letter.
 499  * Only string and number valued options have prompts.
 500  */
 501         public char *
 502 opt_prompt(c)
 503         int c;
 504 {
 505         register struct loption *o;
 506
 507         o = findopt(c);
 508         if (o == NULL || (o->otype & (STRING|NUMBER)) == 0)
 509                 return (NULL);
 510         return (o->odesc[0]);
 511 }
 512
 513 /*
 514  * Return whether or not there is a string option pending;
 515  * that is, if the previous option was a string-valued option letter
 516  * (like -P) without a following string.
 517  * In that case, the current option is taken to be the string for
 518  * the previous option.
 519  */
 520         public int
 521 isoptpending()
 522 {
 523         return (pendopt != NULL);
 524 }
 525
 526 /*
 527  * Print error message about missing string.
 528  */
 529         static void
 530 nostring(printopt)
 531         char *printopt;
 532 {
 533         PARG parg;
 534         parg.p_string = printopt;
 535         error("Value is required after %s", &parg);
 536 }
 537
 538 /*
 539  * Print error message if a STRING type option is not followed by a string.
 540  */
 541         public void
 542 nopendopt()
 543 {
 544         nostring(propt(pendopt->oletter));
 545 }
 546
 547 /*
 548  * Scan to end of string or to an END_OPTION_STRING character.
 549  * In the latter case, replace the char with a null char.
 550  * Return a pointer to the remainder of the string, if any.
 551  */
 552         static char *
 553 optstring(s, p_str, printopt, validchars)
 554         char *s;
 555         char **p_str;
 556         char *printopt;
 557         char *validchars;
 558 {
 559         register char *p;
 560
 561         if (*s == '\0')
 562         {
 563                 nostring(printopt);
 564                 quit(QUIT_ERROR);
 565         }
 566         *p_str = s;
 567         for (p = s;  *p != '\0';  p++)
 568         {
 569                 if (*p == END_OPTION_STRING ||
 570                     (validchars != NULL && strchr(validchars, *p) == NULL))
 571                 {
 572                         switch (*p)
 573                         {
 574                         case END_OPTION_STRING:
 575                         case ' ':  case '\t':  case '-':
 576                                 /* Replace the char with a null to terminate string. */
 577                                 *p++ = '\0';
 578                                 break;
 579                         default:
 580                                 /* Cannot replace char; make a copy of the string. */
 581                                 *p_str = (char *) ecalloc(p-s+1, sizeof(char));
 582                                 strncpy(*p_str, s, p-s);
 583                                 (*p_str)[p-s] = '\0';
 584                                 break;
 585                         }
 586                         break;
 587                 }
 588         }
 589         return (p);
 590 }
 591
 592 /*
 593  */
 594         static int
 595 num_error(printopt, errp)
 596         char *printopt;
 597         int *errp;
 598 {
 599         PARG parg;
 600
 601         if (errp != NULL)
 602         {
 603                 *errp = TRUE;
 604                 return (-1);
 605         }
 606         if (printopt != NULL)
 607         {
 608                 parg.p_string = printopt;
 609                 error("Number is required after %s", &parg);
 610         }
 611         quit(QUIT_ERROR);
 612         /* NOTREACHED */
 613         return (-1);
 614 }
 615
 616 /*
 617  * Translate a string into a number.
 618  * Like atoi(), but takes a pointer to a char *, and updates
 619  * the char * to point after the translated number.
 620  */
 621         public int
 622 getnum(sp, printopt, errp)
 623         char **sp;
 624         char *printopt;
 625         int *errp;
 626 {
 627         register char *s;
 628         register int n;
 629         register int neg;
 630
 631         s = skipsp(*sp);
 632         neg = FALSE;
 633         if (*s == '-')
 634         {
 635                 neg = TRUE;
 636                 s++;
 637         }
 638         if (*s < '0' || *s > '9')
 639                 return (num_error(printopt, errp));
 640
 641         n = 0;
 642         while (*s >= '0' && *s <= '9')
 643                 n = 10 * n + *s++ - '0';
 644         *sp = s;
 645         if (errp != NULL)
 646                 *errp = FALSE;
 647         if (neg)
 648                 n = -n;
 649         return (n);
 650 }
 651
 652 /*
 653  * Translate a string into a fraction, represented by the part of a
 654  * number which would follow a decimal point.
 655  * The value of the fraction is returned as parts per NUM_FRAC_DENOM.
 656  * That is, if "n" is returned, the fraction intended is n/NUM_FRAC_DENOM.
 657  */
 658         public long
 659 getfraction(sp, printopt, errp)
 660         char **sp;
 661         char *printopt;
 662         int *errp;
 663 {
 664         register char *s;
 665         long frac = 0;
 666         int fraclen = 0;
 667
 668         s = skipsp(*sp);
 669         if (*s < '0' || *s > '9')
 670                 return (num_error(printopt, errp));
 671
 672         for ( ;  *s >= '0' && *s <= '9';  s++)
 673         {
 674                 frac = (frac * 10) + (*s - '0');
 675                 fraclen++;
 676         }
 677         if (fraclen > NUM_LOG_FRAC_DENOM)
 678                 while (fraclen-- > NUM_LOG_FRAC_DENOM)
 679                         frac /= 10;
 680         else
 681                 while (fraclen++ < NUM_LOG_FRAC_DENOM)
 682                         frac *= 10;
 683         *sp = s;
 684         if (errp != NULL)
 685                 *errp = FALSE;
 686         return (frac);
 687 }
 688
 689
 690 /*
 691  * Get the value of the -e flag.
 692  */
 693         public int
 694 get_quit_at_eof()
 695 {
 696         if (!less_is_more)
 697                 return quit_at_eof;
 698         /* When less_is_more is set, the -e flag semantics are different. */
 699         return quit_at_eof ? OPT_ON : OPT_ONPLUS;
 700 }