lib/libcr/stdio/vfscanf.c

   1 /*-
   2  * Copyright (c) 1990, 1993
   3  *      The Regents of the University of California.  All rights reserved.
   4  *
   5  * This code is derived from software contributed to Berkeley by
   6  * Chris Torek.
   7  *
   8  * Redistribution and use in source and binary forms, with or without
   9  * modification, are permitted provided that the following conditions
  10  * are met:
  11  * 1. Redistributions of source code must retain the above copyright
  12  *    notice, this list of conditions and the following disclaimer.
  13  * 2. Redistributions in binary form must reproduce the above copyright
  14  *    notice, this list of conditions and the following disclaimer in the
  15  *    documentation and/or other materials provided with the distribution.
  16  * 3. All advertising materials mentioning features or use of this software
  17  *    must display the following acknowledgement:
  18  *      This product includes software developed by the University of
  19  *      California, Berkeley and its contributors.
  20  * 4. Neither the name of the University nor the names of its contributors
  21  *    may be used to endorse or promote products derived from this software
  22  *    without specific prior written permission.
  23  *
  24  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  25  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  26  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  27  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  28  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  29  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  30  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  31  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  32  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  33  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  34  * SUCH DAMAGE.
  35  */
  36
  37 #if defined(LIBC_SCCS) && !defined(lint)
  38 #if 0
  39 static char sccsid[] = "@(#)vfscanf.c   8.1 (Berkeley) 6/4/93";
  40 #endif
  41 static const char rcsid[] =
  42   "$FreeBSD: src/lib/libc/stdio/vfscanf.c,v 1.14.2.2 2002/04/17 14:58:23 ache Exp $";
  43 #endif /* LIBC_SCCS and not lint */
  44
  45 #include <stdio.h>
  46 #include <stdlib.h>
  47 #include <ctype.h>
  48 #if __STDC__
  49 #include <stdarg.h>
  50 #else
  51 #include <varargs.h>
  52 #endif
  53 #include <string.h>
  54
  55 #include "collate.h"
  56 #include "local.h"
  57
  58 #define FLOATING_POINT
  59
  60 #ifdef FLOATING_POINT
  61 #include <locale.h>
  62 #include "floatio.h"
  63 #endif
  64
  65 #define BUF             513     /* Maximum length of numeric string. */
  66
  67 /*
  68  * Flags used during conversion.
  69  */
  70 #define LONG            0x01    /* l: long or double */
  71 #define LONGDBL         0x02    /* L: long double */
  72 #define SHORT           0x04    /* h: short */
  73 #define SUPPRESS        0x08    /* suppress assignment */
  74 #define POINTER         0x10    /* weird %p pointer (`fake hex') */
  75 #define NOSKIP          0x20    /* do not skip blanks */
  76 #define QUAD            0x400
  77
  78 /*
  79  * The following are used in numeric conversions only:
  80  * SIGNOK, NDIGITS, DPTOK, and EXPOK are for floating point;
  81  * SIGNOK, NDIGITS, PFXOK, and NZDIGITS are for integral.
  82  */
  83 #define SIGNOK          0x40    /* +/- is (still) legal */
  84 #define NDIGITS         0x80    /* no digits detected */
  85
  86 #define DPTOK           0x100   /* (float) decimal point is still legal */
  87 #define EXPOK           0x200   /* (float) exponent (e+3, etc) still legal */
  88
  89 #define PFXOK           0x100   /* 0x prefix is (still) legal */
  90 #define NZDIGITS        0x200   /* no zero digits detected */
  91
  92 /*
  93  * Conversion types.
  94  */
  95 #define CT_CHAR         0       /* %c conversion */
  96 #define CT_CCL          1       /* %[...] conversion */
  97 #define CT_STRING       2       /* %s conversion */
  98 #define CT_INT          3       /* integer, i.e., strtoq or strtouq */
  99 #define CT_FLOAT        4       /* floating, i.e., strtod */
 100
 101 #define u_char unsigned char
 102 #define u_long unsigned long
 103
 104 static u_char *__sccl(char *, u_char *);
 105
 106 /*
 107  * vfscanf
 108  */
 109 int
 110 __svfscanf(FILE *fp, char const *fmt0, va_list ap)
 111 {
 112         u_char *fmt = (u_char *)fmt0;
 113         int c;                  /* character from format, or conversion */
 114         size_t width;           /* field width, or 0 */
 115         char *p;                /* points into all kinds of strings */
 116         int n;                  /* handy integer */
 117         int flags;              /* flags as defined above */
 118         char *p0;               /* saves original value of p when necessary */
 119         int nassigned;          /* number of fields assigned */
 120         int nconversions;       /* number of conversions */
 121         int nread;              /* number of characters consumed from fp */
 122         int base;               /* base argument to strtoq/strtouq */
 123         u_quad_t(*ccfn)();      /* conversion function (strtoq/strtouq) */
 124         char ccltab[256];       /* character class table for %[...] */
 125         char buf[BUF];          /* buffer for numeric conversions */
 126
 127         /* `basefix' is used to avoid `if' tests in the integer scanner */
 128         static short basefix[17] =
 129                 { 10, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16 };
 130 #ifdef FLOATING_POINT
 131         char decimal_point = localeconv()->decimal_point[0];
 132 #endif
 133
 134         nassigned = 0;
 135         nconversions = 0;
 136         nread = 0;
 137         base = 0;               /* XXX just to keep gcc happy */
 138         ccfn = NULL;            /* XXX just to keep gcc happy */
 139         for (;;) {
 140                 c = *fmt++;
 141                 if (c == 0)
 142                         return (nassigned);
 143                 if (isspace(c)) {
 144                         while ((fp->_r > 0 || __srefill(fp) == 0) && isspace(*fp->_p))
 145                                 nread++, fp->_r--, fp->_p++;
 146                         continue;
 147                 }
 148                 if (c != '%')
 149                         goto literal;
 150                 width = 0;
 151                 flags = 0;
 152                 /*
 153                  * switch on the format.  continue if done;
 154                  * break once format type is derived.
 155                  */
 156 again:          c = *fmt++;
 157                 switch (c) {
 158                 case '%':
 159 literal:
 160                         if (fp->_r <= 0 && __srefill(fp))
 161                                 goto input_failure;
 162                         if (*fp->_p != c)
 163                                 goto match_failure;
 164                         fp->_r--, fp->_p++;
 165                         nread++;
 166                         continue;
 167
 168                 case '*':
 169                         flags |= SUPPRESS;
 170                         goto again;
 171                 case 'l':
 172                         flags |= LONG;
 173                         goto again;
 174                 case 'q':
 175                         flags |= QUAD;
 176                         goto again;
 177                 case 'L':
 178                         flags |= LONGDBL;
 179                         goto again;
 180                 case 'h':
 181                         flags |= SHORT;
 182                         goto again;
 183
 184                 case '0': case '1': case '2': case '3': case '4':
 185                 case '5': case '6': case '7': case '8': case '9':
 186                         width = width * 10 + c - '0';
 187                         goto again;
 188
 189                 /*
 190                  * Conversions.
 191                  * Those marked `compat' are for 4.[123]BSD compatibility.
 192                  *
 193                  * (According to ANSI, E and X formats are supposed
 194                  * to the same as e and x.  Sorry about that.)
 195                  */
 196                 case 'D':       /* compat */
 197                         flags |= LONG;
 198                         /* FALLTHROUGH */
 199                 case 'd':
 200                         c = CT_INT;
 201                         ccfn = (u_quad_t (*)())strtoq;
 202                         base = 10;
 203                         break;
 204
 205                 case 'i':
 206                         c = CT_INT;
 207                         ccfn = (u_quad_t (*)())strtoq;
 208                         base = 0;
 209                         break;
 210
 211                 case 'O':       /* compat */
 212                         flags |= LONG;
 213                         /* FALLTHROUGH */
 214                 case 'o':
 215                         c = CT_INT;
 216                         ccfn = strtouq;
 217                         base = 8;
 218                         break;
 219
 220                 case 'u':
 221                         c = CT_INT;
 222                         ccfn = strtouq;
 223                         base = 10;
 224                         break;
 225
 226                 case 'X':       /* compat   XXX */
 227                         flags |= LONG;
 228                         /* FALLTHROUGH */
 229                 case 'x':
 230                         flags |= PFXOK; /* enable 0x prefixing */
 231                         c = CT_INT;
 232                         ccfn = strtouq;
 233                         base = 16;
 234                         break;
 235
 236 #ifdef FLOATING_POINT
 237                 case 'E':       /* compat   XXX */
 238                 case 'F':       /* compat */
 239                         flags |= LONG;
 240                         /* FALLTHROUGH */
 241                 case 'e': case 'f': case 'g':
 242                         c = CT_FLOAT;
 243                         break;
 244 #endif
 245
 246                 case 's':
 247                         c = CT_STRING;
 248                         break;
 249
 250                 case '[':
 251                         fmt = __sccl(ccltab, fmt);
 252                         flags |= NOSKIP;
 253                         c = CT_CCL;
 254                         break;
 255
 256                 case 'c':
 257                         flags |= NOSKIP;
 258                         c = CT_CHAR;
 259                         break;
 260
 261                 case 'p':       /* pointer format is like hex */
 262                         flags |= POINTER | PFXOK;
 263                         c = CT_INT;
 264                         ccfn = strtouq;
 265                         base = 16;
 266                         break;
 267
 268                 case 'n':
 269                         nconversions++;
 270                         if (flags & SUPPRESS)   /* ??? */
 271                                 continue;
 272                         if (flags & SHORT)
 273                                 *va_arg(ap, short *) = nread;
 274                         else if (flags & LONG)
 275                                 *va_arg(ap, long *) = nread;
 276                         else if (flags & QUAD)
 277                                 *va_arg(ap, quad_t *) = nread;
 278                         else
 279                                 *va_arg(ap, int *) = nread;
 280                         continue;
 281
 282                 /*
 283                  * Disgusting backwards compatibility hacks.    XXX
 284                  */
 285                 case '\0':      /* compat */
 286                         return (EOF);
 287
 288                 default:        /* compat */
 289                         if (isupper(c))
 290                                 flags |= LONG;
 291                         c = CT_INT;
 292                         ccfn = (u_quad_t (*)())strtoq;
 293                         base = 10;
 294                         break;
 295                 }
 296
 297                 /*
 298                  * We have a conversion that requires input.
 299                  */
 300                 if (fp->_r <= 0 && __srefill(fp))
 301                         goto input_failure;
 302
 303                 /*
 304                  * Consume leading white space, except for formats
 305                  * that suppress this.
 306                  */
 307                 if ((flags & NOSKIP) == 0) {
 308                         while (isspace(*fp->_p)) {
 309                                 nread++;
 310                                 if (--fp->_r > 0)
 311                                         fp->_p++;
 312                                 else if (__srefill(fp))
 313                                         goto input_failure;
 314                         }
 315                         /*
 316                          * Note that there is at least one character in
 317                          * the buffer, so conversions that do not set NOSKIP
 318                          * ca no longer result in an input failure.
 319                          */
 320                 }
 321
 322                 /*
 323                  * Do the conversion.
 324                  */
 325                 switch (c) {
 326
 327                 case CT_CHAR:
 328                         /* scan arbitrary characters (sets NOSKIP) */
 329                         if (width == 0)
 330                                 width = 1;
 331                         if (flags & SUPPRESS) {
 332                                 size_t sum = 0;
 333                                 for (;;) {
 334                                         if ((n = fp->_r) < width) {
 335                                                 sum += n;
 336                                                 width -= n;
 337                                                 fp->_p += n;
 338                                                 if (__srefill(fp)) {
 339                                                         if (sum == 0)
 340                                                             goto input_failure;
 341                                                         break;
 342                                                 }
 343                                         } else {
 344                                                 sum += width;
 345                                                 fp->_r -= width;
 346                                                 fp->_p += width;
 347                                                 break;
 348                                         }
 349                                 }
 350                                 nread += sum;
 351                         } else {
 352                                 size_t r = fread((void *)va_arg(ap, char *), 1,
 353                                     width, fp);
 354
 355                                 if (r == 0)
 356                                         goto input_failure;
 357                                 nread += r;
 358                                 nassigned++;
 359                         }
 360                         nconversions++;
 361                         break;
 362
 363                 case CT_CCL:
 364                         /* scan a (nonempty) character class (sets NOSKIP) */
 365                         if (width == 0)
 366                                 width = (size_t)~0;     /* `infinity' */
 367                         /* take only those things in the class */
 368                         if (flags & SUPPRESS) {
 369                                 n = 0;
 370                                 while (ccltab[*fp->_p]) {
 371                                         n++, fp->_r--, fp->_p++;
 372                                         if (--width == 0)
 373                                                 break;
 374                                         if (fp->_r <= 0 && __srefill(fp)) {
 375                                                 if (n == 0)
 376                                                         goto input_failure;
 377                                                 break;
 378                                         }
 379                                 }
 380                                 if (n == 0)
 381                                         goto match_failure;
 382                         } else {
 383                                 p0 = p = va_arg(ap, char *);
 384                                 while (ccltab[*fp->_p]) {
 385                                         fp->_r--;
 386                                         *p++ = *fp->_p++;
 387                                         if (--width == 0)
 388                                                 break;
 389                                         if (fp->_r <= 0 && __srefill(fp)) {
 390                                                 if (p == p0)
 391                                                         goto input_failure;
 392                                                 break;
 393                                         }
 394                                 }
 395                                 n = p - p0;
 396                                 if (n == 0)
 397                                         goto match_failure;
 398                                 *p = 0;
 399                                 nassigned++;
 400                         }
 401                         nread += n;
 402                         nconversions++;
 403                         break;
 404
 405                 case CT_STRING:
 406                         /* like CCL, but zero-length string OK, & no NOSKIP */
 407                         if (width == 0)
 408                                 width = (size_t)~0;
 409                         if (flags & SUPPRESS) {
 410                                 n = 0;
 411                                 while (!isspace(*fp->_p)) {
 412                                         n++, fp->_r--, fp->_p++;
 413                                         if (--width == 0)
 414                                                 break;
 415                                         if (fp->_r <= 0 && __srefill(fp))
 416                                                 break;
 417                                 }
 418                                 nread += n;
 419                         } else {
 420                                 p0 = p = va_arg(ap, char *);
 421                                 while (!isspace(*fp->_p)) {
 422                                         fp->_r--;
 423                                         *p++ = *fp->_p++;
 424                                         if (--width == 0)
 425                                                 break;
 426                                         if (fp->_r <= 0 && __srefill(fp))
 427                                                 break;
 428                                 }
 429                                 *p = 0;
 430                                 nread += p - p0;
 431                                 nassigned++;
 432                         }
 433                         nconversions++;
 434                         continue;
 435
 436                 case CT_INT:
 437                         /* scan an integer as if by strtoq/strtouq */
 438 #ifdef hardway
 439                         if (width == 0 || width > sizeof(buf) - 1)
 440                                 width = sizeof(buf) - 1;
 441 #else
 442                         /* size_t is unsigned, hence this optimisation */
 443                         if (--width > sizeof(buf) - 2)
 444                                 width = sizeof(buf) - 2;
 445                         width++;
 446 #endif
 447                         flags |= SIGNOK | NDIGITS | NZDIGITS;
 448                         for (p = buf; width; width--) {
 449                                 c = *fp->_p;
 450                                 /*
 451                                  * Switch on the character; `goto ok'
 452                                  * if we accept it as a part of number.
 453                                  */
 454                                 switch (c) {
 455
 456                                 /*
 457                                  * The digit 0 is always legal, but is
 458                                  * special.  For %i conversions, if no
 459                                  * digits (zero or nonzero) have been
 460                                  * scanned (only signs), we will have
 461                                  * base==0.  In that case, we should set
 462                                  * it to 8 and enable 0x prefixing.
 463                                  * Also, if we have not scanned zero digits
 464                                  * before this, do not turn off prefixing
 465                                  * (someone else will turn it off if we
 466                                  * have scanned any nonzero digits).
 467                                  */
 468                                 case '0':
 469                                         if (base == 0) {
 470                                                 base = 8;
 471                                                 flags |= PFXOK;
 472                                         }
 473                                         if (flags & NZDIGITS)
 474                                             flags &= ~(SIGNOK|NZDIGITS|NDIGITS);
 475                                         else
 476                                             flags &= ~(SIGNOK|PFXOK|NDIGITS);
 477                                         goto ok;
 478
 479                                 /* 1 through 7 always legal */
 480                                 case '1': case '2': case '3':
 481                                 case '4': case '5': case '6': case '7':
 482                                         base = basefix[base];
 483                                         flags &= ~(SIGNOK | PFXOK | NDIGITS);
 484                                         goto ok;
 485
 486                                 /* digits 8 and 9 ok iff decimal or hex */
 487                                 case '8': case '9':
 488                                         base = basefix[base];
 489                                         if (base <= 8)
 490                                                 break;  /* not legal here */
 491                                         flags &= ~(SIGNOK | PFXOK | NDIGITS);
 492                                         goto ok;
 493
 494                                 /* letters ok iff hex */
 495                                 case 'A': case 'B': case 'C':
 496                                 case 'D': case 'E': case 'F':
 497                                 case 'a': case 'b': case 'c':
 498                                 case 'd': case 'e': case 'f':
 499                                         /* no need to fix base here */
 500                                         if (base <= 10)
 501                                                 break;  /* not legal here */
 502                                         flags &= ~(SIGNOK | PFXOK | NDIGITS);
 503                                         goto ok;
 504
 505                                 /* sign ok only as first character */
 506                                 case '+': case '-':
 507                                         if (flags & SIGNOK) {
 508                                                 flags &= ~SIGNOK;
 509                                                 goto ok;
 510                                         }
 511                                         break;
 512
 513                                 /* x ok iff flag still set & 2nd char */
 514                                 case 'x': case 'X':
 515                                         if (flags & PFXOK && p == buf + 1) {
 516                                                 base = 16;      /* if %i */
 517                                                 flags &= ~PFXOK;
 518                                                 goto ok;
 519                                         }
 520                                         break;
 521                                 }
 522
 523                                 /*
 524                                  * If we got here, c is not a legal character
 525                                  * for a number.  Stop accumulating digits.
 526                                  */
 527                                 break;
 528                 ok:
 529                                 /*
 530                                  * c is legal: store it and look at the next.
 531                                  */
 532                                 *p++ = c;
 533                                 if (--fp->_r > 0)
 534                                         fp->_p++;
 535                                 else if (__srefill(fp))
 536                                         break;          /* EOF */
 537                         }
 538                         /*
 539                          * If we had only a sign, it is no good; push
 540                          * back the sign.  If the number ends in `x',
 541                          * it was [sign] '0' 'x', so push back the x
 542                          * and treat it as [sign] '0'.
 543                          */
 544                         if (flags & NDIGITS) {
 545                                 if (p > buf)
 546                                         (void) ungetc(*(u_char *)--p, fp);
 547                                 goto match_failure;
 548                         }
 549                         c = ((u_char *)p)[-1];
 550                         if (c == 'x' || c == 'X') {
 551                                 --p;
 552                                 (void) ungetc(c, fp);
 553                         }
 554                         if ((flags & SUPPRESS) == 0) {
 555                                 u_quad_t res;
 556
 557                                 *p = 0;
 558                                 res = (*ccfn)(buf, (char **)NULL, base);
 559                                 if (flags & POINTER)
 560                                         *va_arg(ap, void **) =
 561                                                 (void *)(u_long)res;
 562                                 else if (flags & SHORT)
 563                                         *va_arg(ap, short *) = res;
 564                                 else if (flags & LONG)
 565                                         *va_arg(ap, long *) = res;
 566                                 else if (flags & QUAD)
 567                                         *va_arg(ap, quad_t *) = res;
 568                                 else
 569                                         *va_arg(ap, int *) = res;
 570                                 nassigned++;
 571                         }
 572                         nread += p - buf;
 573                         nconversions++;
 574                         break;
 575
 576 #ifdef FLOATING_POINT
 577                 case CT_FLOAT:
 578                         /* scan a floating point number as if by strtod */
 579 #ifdef hardway
 580                         if (width == 0 || width > sizeof(buf) - 1)
 581                                 width = sizeof(buf) - 1;
 582 #else
 583                         /* size_t is unsigned, hence this optimisation */
 584                         if (--width > sizeof(buf) - 2)
 585                                 width = sizeof(buf) - 2;
 586                         width++;
 587 #endif
 588                         flags |= SIGNOK | NDIGITS | DPTOK | EXPOK;
 589                         for (p = buf; width; width--) {
 590                                 c = *fp->_p;
 591                                 /*
 592                                  * This code mimicks the integer conversion
 593                                  * code, but is much simpler.
 594                                  */
 595                                 switch (c) {
 596
 597                                 case '0': case '1': case '2': case '3':
 598                                 case '4': case '5': case '6': case '7':
 599                                 case '8': case '9':
 600                                         flags &= ~(SIGNOK | NDIGITS);
 601                                         goto fok;
 602
 603                                 case '+': case '-':
 604                                         if (flags & SIGNOK) {
 605                                                 flags &= ~SIGNOK;
 606                                                 goto fok;
 607                                         }
 608                                         break;
 609                                 case 'e': case 'E':
 610                                         /* no exponent without some digits */
 611                                         if ((flags&(NDIGITS|EXPOK)) == EXPOK) {
 612                                                 flags =
 613                                                     (flags & ~(EXPOK|DPTOK)) |
 614                                                     SIGNOK | NDIGITS;
 615                                                 goto fok;
 616                                         }
 617                                         break;
 618                                 default:
 619                                         if ((char)c == decimal_point &&
 620                                             (flags & DPTOK)) {
 621                                                 flags &= ~(SIGNOK | DPTOK);
 622                                                 goto fok;
 623                                         }
 624                                         break;
 625                                 }
 626                                 break;
 627                 fok:
 628                                 *p++ = c;
 629                                 if (--fp->_r > 0)
 630                                         fp->_p++;
 631                                 else if (__srefill(fp))
 632                                         break;  /* EOF */
 633                         }
 634                         /*
 635                          * If no digits, might be missing exponent digits
 636                          * (just give back the exponent) or might be missing
 637                          * regular digits, but had sign and/or decimal point.
 638                          */
 639                         if (flags & NDIGITS) {
 640                                 if (flags & EXPOK) {
 641                                         /* no digits at all */
 642                                         while (p > buf)
 643                                                 ungetc(*(u_char *)--p, fp);
 644                                         goto match_failure;
 645                                 }
 646                                 /* just a bad exponent (e and maybe sign) */
 647                                 c = *(u_char *)--p;
 648                                 if (c != 'e' && c != 'E') {
 649                                         (void) ungetc(c, fp);/* sign */
 650                                         c = *(u_char *)--p;
 651                                 }
 652                                 (void) ungetc(c, fp);
 653                         }
 654                         if ((flags & SUPPRESS) == 0) {
 655                                 double res;
 656
 657                                 *p = 0;
 658                                 /* XXX this loses precision for long doubles. */
 659                                 res = strtod(buf, (char **) NULL);
 660                                 if (flags & LONGDBL)
 661                                         *va_arg(ap, long double *) = res;
 662                                 else if (flags & LONG)
 663                                         *va_arg(ap, double *) = res;
 664                                 else
 665                                         *va_arg(ap, float *) = res;
 666                                 nassigned++;
 667                         }
 668                         nread += p - buf;
 669                         nconversions++;
 670                         break;
 671 #endif /* FLOATING_POINT */
 672                 }
 673         }
 674 input_failure:
 675         return (nconversions != 0 ? nassigned : EOF);
 676 match_failure:
 677         return (nassigned);
 678 }
 679
 680 /*
 681  * Fill in the given table from the scanset at the given format
 682  * (just after `[').  Return a pointer to the character past the
 683  * closing `]'.  The table has a 1 wherever characters should be
 684  * considered part of the scanset.
 685  */
 686 static u_char *
 687 __sccl(tab, fmt)
 688         char *tab;
 689         u_char *fmt;
 690 {
 691         int c, n, v, i;
 692
 693         /* first `clear' the whole table */
 694         c = *fmt++;             /* first char hat => negated scanset */
 695         if (c == '^') {
 696                 v = 1;          /* default => accept */
 697                 c = *fmt++;     /* get new first char */
 698         } else
 699                 v = 0;          /* default => reject */
 700
 701         /* XXX: Will not work if sizeof(tab*) > sizeof(char) */
 702         (void) memset(tab, v, 256);
 703
 704         if (c == 0)
 705                 return (fmt - 1);/* format ended before closing ] */
 706
 707         /*
 708          * Now set the entries corresponding to the actual scanset
 709          * to the opposite of the above.
 710          *
 711          * The first character may be ']' (or '-') without being special;
 712          * the last character may be '-'.
 713          */
 714         v = 1 - v;
 715         for (;;) {
 716                 tab[c] = v;             /* take character c */
 717 doswitch:
 718                 n = *fmt++;             /* and examine the next */
 719                 switch (n) {
 720
 721                 case 0:                 /* format ended too soon */
 722                         return (fmt - 1);
 723
 724                 case '-':
 725                         /*
 726                          * A scanset of the form
 727                          *      [01+-]
 728                          * is defined as `the digit 0, the digit 1,
 729                          * the character +, the character -', but
 730                          * the effect of a scanset such as
 731                          *      [a-zA-Z0-9]
 732                          * is implementation defined.  The V7 Unix
 733                          * scanf treats `a-z' as `the letters a through
 734                          * z', but treats `a-a' as `the letter a, the
 735                          * character -, and the letter a'.
 736                          *
 737                          * For compatibility, the `-' is not considerd
 738                          * to define a range if the character following
 739                          * it is either a close bracket (required by ANSI)
 740                          * or is not numerically greater than the character
 741                          * we just stored in the table (c).
 742                          */
 743                         n = *fmt;
 744                         if (n == ']'
 745                             || (__collate_load_error ? n < c :
 746                                 __collate_range_cmp (n, c) < 0
 747                                )
 748                            ) {
 749                                 c = '-';
 750                                 break;  /* resume the for(;;) */
 751                         }
 752                         fmt++;
 753                         /* fill in the range */
 754                         if (__collate_load_error) {
 755                                 do {
 756                                         tab[++c] = v;
 757                                 } while (c < n);
 758                         } else {
 759                                 for (i = 0; i < 256; i ++)
 760                                         if (   __collate_range_cmp (c, i) < 0
 761                                             && __collate_range_cmp (i, n) <= 0
 762                                            )
 763                                                 tab[i] = v;
 764                         }
 765 #if 1   /* XXX another disgusting compatibility hack */
 766                         c = n;
 767                         /*
 768                          * Alas, the V7 Unix scanf also treats formats
 769                          * such as [a-c-e] as `the letters a through e'.
 770                          * This too is permitted by the standard....
 771                          */
 772                         goto doswitch;
 773 #else
 774                         c = *fmt++;
 775                         if (c == 0)
 776                                 return (fmt - 1);
 777                         if (c == ']')
 778                                 return (fmt);
 779 #endif
 780                         break;
 781
 782                 case ']':               /* end of scanset */
 783                         return (fmt);
 784
 785                 default:                /* just another character */
 786                         c = n;
 787                         break;
 788                 }
 789         }
 790         /* NOTREACHED */
 791 }