lib/libc/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  * @(#)vfscanf.c        8.1 (Berkeley) 6/4/93
  37  * $FreeBSD: /repoman/r/ncvs/src/lib/libc/stdio/vfscanf.c,v 1.35 2004/01/31 23:16:09 das Exp $
  38  * $DragonFly: src/lib/libc/stdio/vfscanf.c,v 1.5 2004/07/08 17:56:46 cpressey Exp $
  39  */
  40
  41 #include <stdio.h>
  42 #include <stdlib.h>
  43 #include <ctype.h>
  44 #include <stdarg.h>
  45 #include <string.h>
  46
  47 #include "collate.h"
  48 #include "local.h"
  49
  50 #define FLOATING_POINT
  51
  52 #ifdef FLOATING_POINT
  53 #include <locale.h>
  54 #include "floatio.h"
  55 #endif
  56
  57 #define BUF             513     /* Maximum length of numeric string. */
  58
  59 /*
  60  * Flags used during conversion.
  61  */
  62 #define LONG            0x01    /* l: long or double */
  63 #define LONGDBL         0x02    /* L: long double */
  64 #define SHORT           0x04    /* h: short */
  65 #define SUPPRESS        0x08    /* suppress assignment */
  66 #define POINTER         0x10    /* weird %p pointer (`fake hex') */
  67 #define NOSKIP          0x20    /* do not skip blanks */
  68 #define QUAD            0x400
  69
  70 /*
  71  * The following are used in numeric conversions only:
  72  * SIGNOK, NDIGITS, DPTOK, and EXPOK are for floating point;
  73  * SIGNOK, NDIGITS, PFXOK, and NZDIGITS are for integral.
  74  */
  75 #define SIGNOK          0x40    /* +/- is (still) legal */
  76 #define NDIGITS         0x80    /* no digits detected */
  77
  78 #define DPTOK           0x100   /* (float) decimal point is still legal */
  79 #define EXPOK           0x200   /* (float) exponent (e+3, etc) still legal */
  80
  81 #define PFXOK           0x100   /* 0x prefix is (still) legal */
  82 #define NZDIGITS        0x200   /* no zero digits detected */
  83 #define HAVESIGN        0x10000 /* sign detected */
  84
  85 /*
  86  * Conversion types.
  87  */
  88 #define CT_CHAR         0       /* %c conversion */
  89 #define CT_CCL          1       /* %[...] conversion */
  90 #define CT_STRING       2       /* %s conversion */
  91 #define CT_INT          3       /* integer, i.e., strtoq or strtouq */
  92 #define CT_FLOAT        4       /* floating, i.e., strtod */
  93
  94 #define u_char unsigned char
  95 #define u_long unsigned long
  96
  97 static u_char *__sccl(char *, u_char *);
  98
  99 /*
 100  * vfscanf
 101  */
 102 int
 103 __svfscanf(FILE *fp, char const *fmt0, va_list ap)
 104 {
 105         u_char *fmt = (u_char *)fmt0;
 106         int c;                  /* character from format, or conversion */
 107         size_t width;           /* field width, or 0 */
 108         char *p;                /* points into all kinds of strings */
 109         int n;                  /* handy integer */
 110         int flags;              /* flags as defined above */
 111         char *p0;               /* saves original value of p when necessary */
 112         int nassigned;          /* number of fields assigned */
 113         int nconversions;       /* number of conversions */
 114         int nread;              /* number of characters consumed from fp */
 115         int base;               /* base argument to strtoq/strtouq */
 116         u_quad_t(*ccfn)();      /* conversion function (strtoq/strtouq) */
 117         char ccltab[256];       /* character class table for %[...] */
 118         char buf[BUF];          /* buffer for numeric conversions */
 119
 120         /* `basefix' is used to avoid `if' tests in the integer scanner */
 121         static short basefix[17] =
 122                 { 10, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16 };
 123 #ifdef FLOATING_POINT
 124         char decimal_point = localeconv()->decimal_point[0];
 125 #endif
 126
 127         nassigned = 0;
 128         nconversions = 0;
 129         nread = 0;
 130         base = 0;               /* XXX just to keep gcc happy */
 131         ccfn = NULL;            /* XXX just to keep gcc happy */
 132         for (;;) {
 133                 c = *fmt++;
 134                 if (c == 0)
 135                         return (nassigned);
 136                 if (isspace(c)) {
 137                         while ((fp->_r > 0 || __srefill(fp) == 0) && isspace(*fp->_p))
 138                                 nread++, fp->_r--, fp->_p++;
 139                         continue;
 140                 }
 141                 if (c != '%')
 142                         goto literal;
 143                 width = 0;
 144                 flags = 0;
 145                 /*
 146                  * switch on the format.  continue if done;
 147                  * break once format type is derived.
 148                  */
 149 again:          c = *fmt++;
 150                 switch (c) {
 151                 case '%':
 152 literal:
 153                         if (fp->_r <= 0 && __srefill(fp))
 154                                 goto input_failure;
 155                         if (*fp->_p != c)
 156                                 goto match_failure;
 157                         fp->_r--, fp->_p++;
 158                         nread++;
 159                         continue;
 160
 161                 case '*':
 162                         flags |= SUPPRESS;
 163                         goto again;
 164                 case 'l':
 165                         flags |= LONG;
 166                         goto again;
 167                 case 'q':
 168                         flags |= QUAD;
 169                         goto again;
 170                 case 'L':
 171                         flags |= LONGDBL;
 172                         goto again;
 173                 case 'h':
 174                         flags |= SHORT;
 175                         goto again;
 176
 177                 case '0': case '1': case '2': case '3': case '4':
 178                 case '5': case '6': case '7': case '8': case '9':
 179                         width = width * 10 + c - '0';
 180                         goto again;
 181
 182                 /*
 183                  * Conversions.
 184                  * Those marked `compat' are for 4.[123]BSD compatibility.
 185                  *
 186                  * (According to ANSI, E and X formats are supposed
 187                  * to the same as e and x.  Sorry about that.)
 188                  */
 189                 case 'D':       /* compat */
 190                         flags |= LONG;
 191                         /* FALLTHROUGH */
 192                 case 'd':
 193                         c = CT_INT;
 194                         ccfn = (u_quad_t (*)())strtoq;
 195                         base = 10;
 196                         break;
 197
 198                 case 'i':
 199                         c = CT_INT;
 200                         ccfn = (u_quad_t (*)())strtoq;
 201                         base = 0;
 202                         break;
 203
 204                 case 'O':       /* compat */
 205                         flags |= LONG;
 206                         /* FALLTHROUGH */
 207                 case 'o':
 208                         c = CT_INT;
 209                         ccfn = strtouq;
 210                         base = 8;
 211                         break;
 212
 213                 case 'u':
 214                         c = CT_INT;
 215                         ccfn = strtouq;
 216                         base = 10;
 217                         break;
 218
 219                 case 'X':       /* compat   XXX */
 220                         flags |= LONG;
 221                         /* FALLTHROUGH */
 222                 case 'x':
 223                         flags |= PFXOK; /* enable 0x prefixing */
 224                         c = CT_INT;
 225                         ccfn = strtouq;
 226                         base = 16;
 227                         break;
 228
 229 #ifdef FLOATING_POINT
 230                 case 'E':       /* compat   XXX */
 231                 case 'F':       /* compat */
 232                         flags |= LONG;
 233                         /* FALLTHROUGH */
 234                 case 'e': case 'f': case 'g':
 235                         c = CT_FLOAT;
 236                         break;
 237 #endif
 238
 239                 case 's':
 240                         c = CT_STRING;
 241                         break;
 242
 243                 case '[':
 244                         fmt = __sccl(ccltab, fmt);
 245                         flags |= NOSKIP;
 246                         c = CT_CCL;
 247                         break;
 248
 249                 case 'c':
 250                         flags |= NOSKIP;
 251                         c = CT_CHAR;
 252                         break;
 253
 254                 case 'p':       /* pointer format is like hex */
 255                         flags |= POINTER | PFXOK;
 256                         c = CT_INT;
 257                         ccfn = strtouq;
 258                         base = 16;
 259                         break;
 260
 261                 case 'n':
 262                         nconversions++;
 263                         if (flags & SUPPRESS)   /* ??? */
 264                                 continue;
 265                         if (flags & SHORT)
 266                                 *va_arg(ap, short *) = nread;
 267                         else if (flags & LONG)
 268                                 *va_arg(ap, long *) = nread;
 269                         else if (flags & QUAD)
 270                                 *va_arg(ap, quad_t *) = nread;
 271                         else
 272                                 *va_arg(ap, int *) = nread;
 273                         continue;
 274
 275                 /*
 276                  * Disgusting backwards compatibility hacks.    XXX
 277                  */
 278                 case '\0':      /* compat */
 279                         return (EOF);
 280
 281                 default:        /* compat */
 282                         if (isupper(c))
 283                                 flags |= LONG;
 284                         c = CT_INT;
 285                         ccfn = (u_quad_t (*)())strtoq;
 286                         base = 10;
 287                         break;
 288                 }
 289
 290                 /*
 291                  * We have a conversion that requires input.
 292                  */
 293                 if (fp->_r <= 0 && __srefill(fp))
 294                         goto input_failure;
 295
 296                 /*
 297                  * Consume leading white space, except for formats
 298                  * that suppress this.
 299                  */
 300                 if ((flags & NOSKIP) == 0) {
 301                         while (isspace(*fp->_p)) {
 302                                 nread++;
 303                                 if (--fp->_r > 0)
 304                                         fp->_p++;
 305                                 else if (__srefill(fp))
 306                                         goto input_failure;
 307                         }
 308                         /*
 309                          * Note that there is at least one character in
 310                          * the buffer, so conversions that do not set NOSKIP
 311                          * ca no longer result in an input failure.
 312                          */
 313                 }
 314
 315                 /*
 316                  * Do the conversion.
 317                  */
 318                 switch (c) {
 319
 320                 case CT_CHAR:
 321                         /* scan arbitrary characters (sets NOSKIP) */
 322                         if (width == 0)
 323                                 width = 1;
 324                         if (flags & SUPPRESS) {
 325                                 size_t sum = 0;
 326                                 for (;;) {
 327                                         if ((n = fp->_r) < width) {
 328                                                 sum += n;
 329                                                 width -= n;
 330                                                 fp->_p += n;
 331                                                 if (__srefill(fp)) {
 332                                                         if (sum == 0)
 333                                                             goto input_failure;
 334                                                         break;
 335                                                 }
 336                                         } else {
 337                                                 sum += width;
 338                                                 fp->_r -= width;
 339                                                 fp->_p += width;
 340                                                 break;
 341                                         }
 342                                 }
 343                                 nread += sum;
 344                         } else {
 345                                 size_t r = fread((void *)va_arg(ap, char *), 1,
 346                                     width, fp);
 347
 348                                 if (r == 0)
 349                                         goto input_failure;
 350                                 nread += r;
 351                                 nassigned++;
 352                         }
 353                         nconversions++;
 354                         break;
 355
 356                 case CT_CCL:
 357                         /* scan a (nonempty) character class (sets NOSKIP) */
 358                         if (width == 0)
 359                                 width = (size_t)~0;     /* `infinity' */
 360                         /* take only those things in the class */
 361                         if (flags & SUPPRESS) {
 362                                 n = 0;
 363                                 while (ccltab[*fp->_p]) {
 364                                         n++, fp->_r--, fp->_p++;
 365                                         if (--width == 0)
 366                                                 break;
 367                                         if (fp->_r <= 0 && __srefill(fp)) {
 368                                                 if (n == 0)
 369                                                         goto input_failure;
 370                                                 break;
 371                                         }
 372                                 }
 373                                 if (n == 0)
 374                                         goto match_failure;
 375                         } else {
 376                                 p0 = p = va_arg(ap, char *);
 377                                 while (ccltab[*fp->_p]) {
 378                                         fp->_r--;
 379                                         *p++ = *fp->_p++;
 380                                         if (--width == 0)
 381                                                 break;
 382                                         if (fp->_r <= 0 && __srefill(fp)) {
 383                                                 if (p == p0)
 384                                                         goto input_failure;
 385                                                 break;
 386                                         }
 387                                 }
 388                                 n = p - p0;
 389                                 if (n == 0)
 390                                         goto match_failure;
 391                                 *p = 0;
 392                                 nassigned++;
 393                         }
 394                         nread += n;
 395                         nconversions++;
 396                         break;
 397
 398                 case CT_STRING:
 399                         /* like CCL, but zero-length string OK, & no NOSKIP */
 400                         if (width == 0)
 401                                 width = (size_t)~0;
 402                         if (flags & SUPPRESS) {
 403                                 n = 0;
 404                                 while (!isspace(*fp->_p)) {
 405                                         n++, fp->_r--, fp->_p++;
 406                                         if (--width == 0)
 407                                                 break;
 408                                         if (fp->_r <= 0 && __srefill(fp))
 409                                                 break;
 410                                 }
 411                                 nread += n;
 412                         } else {
 413                                 p0 = p = va_arg(ap, char *);
 414                                 while (!isspace(*fp->_p)) {
 415                                         fp->_r--;
 416                                         *p++ = *fp->_p++;
 417                                         if (--width == 0)
 418                                                 break;
 419                                         if (fp->_r <= 0 && __srefill(fp))
 420                                                 break;
 421                                 }
 422                                 *p = 0;
 423                                 nread += p - p0;
 424                                 nassigned++;
 425                         }
 426                         nconversions++;
 427                         continue;
 428
 429                 case CT_INT:
 430                         /* scan an integer as if by strtoq/strtouq */
 431 #ifdef hardway
 432                         if (width == 0 || width > sizeof(buf) - 1)
 433                                 width = sizeof(buf) - 1;
 434 #else
 435                         /* size_t is unsigned, hence this optimisation */
 436                         if (--width > sizeof(buf) - 2)
 437                                 width = sizeof(buf) - 2;
 438                         width++;
 439 #endif
 440                         flags |= SIGNOK | NDIGITS | NZDIGITS;
 441                         for (p = buf; width; width--) {
 442                                 c = *fp->_p;
 443                                 /*
 444                                  * Switch on the character; `goto ok'
 445                                  * if we accept it as a part of number.
 446                                  */
 447                                 switch (c) {
 448
 449                                 /*
 450                                  * The digit 0 is always legal, but is
 451                                  * special.  For %i conversions, if no
 452                                  * digits (zero or nonzero) have been
 453                                  * scanned (only signs), we will have
 454                                  * base==0.  In that case, we should set
 455                                  * it to 8 and enable 0x prefixing.
 456                                  * Also, if we have not scanned zero digits
 457                                  * before this, do not turn off prefixing
 458                                  * (someone else will turn it off if we
 459                                  * have scanned any nonzero digits).
 460                                  */
 461                                 case '0':
 462                                         if (base == 0) {
 463                                                 base = 8;
 464                                                 flags |= PFXOK;
 465                                         }
 466                                         if (flags & NZDIGITS)
 467                                             flags &= ~(SIGNOK|NZDIGITS|NDIGITS);
 468                                         else
 469                                             flags &= ~(SIGNOK|PFXOK|NDIGITS);
 470                                         goto ok;
 471
 472                                 /* 1 through 7 always legal */
 473                                 case '1': case '2': case '3':
 474                                 case '4': case '5': case '6': case '7':
 475                                         base = basefix[base];
 476                                         flags &= ~(SIGNOK | PFXOK | NDIGITS);
 477                                         goto ok;
 478
 479                                 /* digits 8 and 9 ok iff decimal or hex */
 480                                 case '8': case '9':
 481                                         base = basefix[base];
 482                                         if (base <= 8)
 483                                                 break;  /* not legal here */
 484                                         flags &= ~(SIGNOK | PFXOK | NDIGITS);
 485                                         goto ok;
 486
 487                                 /* letters ok iff hex */
 488                                 case 'A': case 'B': case 'C':
 489                                 case 'D': case 'E': case 'F':
 490                                 case 'a': case 'b': case 'c':
 491                                 case 'd': case 'e': case 'f':
 492                                         /* no need to fix base here */
 493                                         if (base <= 10)
 494                                                 break;  /* not legal here */
 495                                         flags &= ~(SIGNOK | PFXOK | NDIGITS);
 496                                         goto ok;
 497
 498                                 /* sign ok only as first character */
 499                                 case '+': case '-':
 500                                         if (flags & SIGNOK) {
 501                                                 flags &= ~SIGNOK;
 502                                                 flags |= HAVESIGN;
 503                                                 goto ok;
 504                                         }
 505                                         break;
 506
 507                                 /*
 508                                  * x ok iff flag still set & 2nd char (or
 509                                  * 3rd char if we have a sign).
 510                                  */
 511                                 case 'x': case 'X':
 512                                         if (flags & PFXOK && p ==
 513                                             buf + 1 + !!(flags & HAVESIGN)) {
 514                                                 base = 16;      /* if %i */
 515                                                 flags &= ~PFXOK;
 516                                                 goto ok;
 517                                         }
 518                                         break;
 519                                 }
 520
 521                                 /*
 522                                  * If we got here, c is not a legal character
 523                                  * for a number.  Stop accumulating digits.
 524                                  */
 525                                 break;
 526                 ok:
 527                                 /*
 528                                  * c is legal: store it and look at the next.
 529                                  */
 530                                 *p++ = c;
 531                                 if (--fp->_r > 0)
 532                                         fp->_p++;
 533                                 else if (__srefill(fp))
 534                                         break;          /* EOF */
 535                         }
 536                         /*
 537                          * If we had only a sign, it is no good; push
 538                          * back the sign.  If the number ends in `x',
 539                          * it was [sign] '0' 'x', so push back the x
 540                          * and treat it as [sign] '0'.
 541                          */
 542                         if (flags & NDIGITS) {
 543                                 if (p > buf)
 544                                         (void) ungetc(*(u_char *)--p, fp);
 545                                 goto match_failure;
 546                         }
 547                         c = ((u_char *)p)[-1];
 548                         if (c == 'x' || c == 'X') {
 549                                 --p;
 550                                 (void) ungetc(c, fp);
 551                         }
 552                         if ((flags & SUPPRESS) == 0) {
 553                                 u_quad_t res;
 554
 555                                 *p = 0;
 556                                 res = (*ccfn)(buf, (char **)NULL, base);
 557                                 if (flags & POINTER)
 558                                         *va_arg(ap, void **) =
 559                                                 (void *)(u_long)res;
 560                                 else if (flags & SHORT)
 561                                         *va_arg(ap, short *) = res;
 562                                 else if (flags & LONG)
 563                                         *va_arg(ap, long *) = res;
 564                                 else if (flags & QUAD)
 565                                         *va_arg(ap, quad_t *) = res;
 566                                 else
 567                                         *va_arg(ap, int *) = res;
 568                                 nassigned++;
 569                         }
 570                         nread += p - buf;
 571                         nconversions++;
 572                         break;
 573
 574 #ifdef FLOATING_POINT
 575                 case CT_FLOAT:
 576                         /* scan a floating point number as if by strtod */
 577 #ifdef hardway
 578                         if (width == 0 || width > sizeof(buf) - 1)
 579                                 width = sizeof(buf) - 1;
 580 #else
 581                         /* size_t is unsigned, hence this optimisation */
 582                         if (--width > sizeof(buf) - 2)
 583                                 width = sizeof(buf) - 2;
 584                         width++;
 585 #endif
 586                         flags |= SIGNOK | NDIGITS | DPTOK | EXPOK;
 587                         for (p = buf; width; width--) {
 588                                 c = *fp->_p;
 589                                 /*
 590                                  * This code mimicks the integer conversion
 591                                  * code, but is much simpler.
 592                                  */
 593                                 switch (c) {
 594
 595                                 case '0': case '1': case '2': case '3':
 596                                 case '4': case '5': case '6': case '7':
 597                                 case '8': case '9':
 598                                         flags &= ~(SIGNOK | NDIGITS);
 599                                         goto fok;
 600
 601                                 case '+': case '-':
 602                                         if (flags & SIGNOK) {
 603                                                 flags &= ~SIGNOK;
 604                                                 goto fok;
 605                                         }
 606                                         break;
 607                                 case 'e': case 'E':
 608                                         /* no exponent without some digits */
 609                                         if ((flags&(NDIGITS|EXPOK)) == EXPOK) {
 610                                                 flags =
 611                                                     (flags & ~(EXPOK|DPTOK)) |
 612                                                     SIGNOK | NDIGITS;
 613                                                 goto fok;
 614                                         }
 615                                         break;
 616                                 default:
 617                                         if ((char)c == decimal_point &&
 618                                             (flags & DPTOK)) {
 619                                                 flags &= ~(SIGNOK | DPTOK);
 620                                                 goto fok;
 621                                         }
 622                                         break;
 623                                 }
 624                                 break;
 625                 fok:
 626                                 *p++ = c;
 627                                 if (--fp->_r > 0)
 628                                         fp->_p++;
 629                                 else if (__srefill(fp))
 630                                         break;  /* EOF */
 631                         }
 632                         /*
 633                          * If no digits, might be missing exponent digits
 634                          * (just give back the exponent) or might be missing
 635                          * regular digits, but had sign and/or decimal point.
 636                          */
 637                         if (flags & NDIGITS) {
 638                                 if (flags & EXPOK) {
 639                                         /* no digits at all */
 640                                         while (p > buf)
 641                                                 ungetc(*(u_char *)--p, fp);
 642                                         goto match_failure;
 643                                 }
 644                                 /* just a bad exponent (e and maybe sign) */
 645                                 c = *(u_char *)--p;
 646                                 if (c != 'e' && c != 'E') {
 647                                         (void) ungetc(c, fp);/* sign */
 648                                         c = *(u_char *)--p;
 649                                 }
 650                                 (void) ungetc(c, fp);
 651                         }
 652                         if ((flags & SUPPRESS) == 0) {
 653                                 double res;
 654
 655                                 *p = 0;
 656                                 /* XXX this loses precision for long doubles. */
 657                                 res = strtod(buf, (char **) NULL);
 658                                 if (flags & LONGDBL)
 659                                         *va_arg(ap, long double *) = res;
 660                                 else if (flags & LONG)
 661                                         *va_arg(ap, double *) = res;
 662                                 else
 663                                         *va_arg(ap, float *) = res;
 664                                 nassigned++;
 665                         }
 666                         nread += p - buf;
 667                         nconversions++;
 668                         break;
 669 #endif /* FLOATING_POINT */
 670                 }
 671         }
 672 input_failure:
 673         return (nconversions != 0 ? nassigned : EOF);
 674 match_failure:
 675         return (nassigned);
 676 }
 677
 678 /*
 679  * Fill in the given table from the scanset at the given format
 680  * (just after `[').  Return a pointer to the character past the
 681  * closing `]'.  The table has a 1 wherever characters should be
 682  * considered part of the scanset.
 683  */
 684 static u_char *
 685 __sccl(tab, fmt)
 686         char *tab;
 687         u_char *fmt;
 688 {
 689         int c, n, v, i;
 690
 691         /* first `clear' the whole table */
 692         c = *fmt++;             /* first char hat => negated scanset */
 693         if (c == '^') {
 694                 v = 1;          /* default => accept */
 695                 c = *fmt++;     /* get new first char */
 696         } else
 697                 v = 0;          /* default => reject */
 698
 699         /* XXX: Will not work if sizeof(tab*) > sizeof(char) */
 700         (void) memset(tab, v, 256);
 701
 702         if (c == 0)
 703                 return (fmt - 1);/* format ended before closing ] */
 704
 705         /*
 706          * Now set the entries corresponding to the actual scanset
 707          * to the opposite of the above.
 708          *
 709          * The first character may be ']' (or '-') without being special;
 710          * the last character may be '-'.
 711          */
 712         v = 1 - v;
 713         for (;;) {
 714                 tab[c] = v;             /* take character c */
 715 doswitch:
 716                 n = *fmt++;             /* and examine the next */
 717                 switch (n) {
 718
 719                 case 0:                 /* format ended too soon */
 720                         return (fmt - 1);
 721
 722                 case '-':
 723                         /*
 724                          * A scanset of the form
 725                          *      [01+-]
 726                          * is defined as `the digit 0, the digit 1,
 727                          * the character +, the character -', but
 728                          * the effect of a scanset such as
 729                          *      [a-zA-Z0-9]
 730                          * is implementation defined.  The V7 Unix
 731                          * scanf treats `a-z' as `the letters a through
 732                          * z', but treats `a-a' as `the letter a, the
 733                          * character -, and the letter a'.
 734                          *
 735                          * For compatibility, the `-' is not considerd
 736                          * to define a range if the character following
 737                          * it is either a close bracket (required by ANSI)
 738                          * or is not numerically greater than the character
 739                          * we just stored in the table (c).
 740                          */
 741                         n = *fmt;
 742                         if (n == ']'
 743                             || (__collate_load_error ? n < c :
 744                                 __collate_range_cmp (n, c) < 0
 745                                )
 746                            ) {
 747                                 c = '-';
 748                                 break;  /* resume the for(;;) */
 749                         }
 750                         fmt++;
 751                         /* fill in the range */
 752                         if (__collate_load_error) {
 753                                 do {
 754                                         tab[++c] = v;
 755                                 } while (c < n);
 756                         } else {
 757                                 for (i = 0; i < 256; i ++)
 758                                         if (   __collate_range_cmp (c, i) < 0
 759                                             && __collate_range_cmp (i, n) <= 0
 760                                            )
 761                                                 tab[i] = v;
 762                         }
 763 #if 1   /* XXX another disgusting compatibility hack */
 764                         c = n;
 765                         /*
 766                          * Alas, the V7 Unix scanf also treats formats
 767                          * such as [a-c-e] as `the letters a through e'.
 768                          * This too is permitted by the standard....
 769                          */
 770                         goto doswitch;
 771 #else
 772                         c = *fmt++;
 773                         if (c == 0)
 774                                 return (fmt - 1);
 775                         if (c == ']')
 776                                 return (fmt);
 777 #endif
 778                         break;
 779
 780                 case ']':               /* end of scanset */
 781                         return (fmt);
 782
 783                 default:                /* just another character */
 784                         c = n;
 785                         break;
 786                 }
 787         }
 788         /* NOTREACHED */
 789 }