stdio.subproj/vfscanf.c

   1 /*
   2  * Copyright (c) 1999 Apple Computer, Inc. All rights reserved.
   3  *
   4  * @APPLE_LICENSE_HEADER_START@
   5  *
   6  * The contents of this file constitute Original Code as defined in and
   7  * are subject to the Apple Public Source License Version 1.1 (the
   8  * "License").  You may not use this file except in compliance with the
   9  * License.  Please obtain a copy of the License at
  10  * http://www.apple.com/publicsource and read it before using this file.
  11  *
  12  * This Original Code and all software distributed under the License are
  13  * distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY KIND, EITHER
  14  * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
  15  * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
  16  * FITNESS FOR A PARTICULAR PURPOSE OR NON-INFRINGEMENT.  Please see the
  17  * License for the specific language governing rights and limitations
  18  * under the License.
  19  *
  20  * @APPLE_LICENSE_HEADER_END@
  21  */
  22 /*
  23  * Copyright (c) 1990, 1993
  24  *      The Regents of the University of California.  All rights reserved.
  25  *
  26  * This code is derived from software contributed to Berkeley by
  27  * Chris Torek.
  28  *
  29  * Redistribution and use in source and binary forms, with or without
  30  * modification, are permitted provided that the following conditions
  31  * are met:
  32  * 1. Redistributions of source code must retain the above copyright
  33  *    notice, this list of conditions and the following disclaimer.
  34  * 2. Redistributions in binary form must reproduce the above copyright
  35  *    notice, this list of conditions and the following disclaimer in the
  36  *    documentation and/or other materials provided with the distribution.
  37  * 3. All advertising materials mentioning features or use of this software
  38  *    must display the following acknowledgement:
  39  *      This product includes software developed by the University of
  40  *      California, Berkeley and its contributors.
  41  * 4. Neither the name of the University nor the names of its contributors
  42  *    may be used to endorse or promote products derived from this software
  43  *    without specific prior written permission.
  44  *
  45  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  46  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  47  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  48  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  49  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  50  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  51  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  52  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  53  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  54  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  55  * SUCH DAMAGE.
  56  */
  57
  58
  59 #include <stdio.h>
  60 #include <stdlib.h>
  61 #include <ctype.h>
  62 #if __STDC__
  63 #include <stdarg.h>
  64 #else
  65 #include <varargs.h>
  66 #endif
  67 #include "local.h"
  68
  69 #define FLOATING_POINT
  70
  71 #include "floatio.h"
  72 #define BUF             513     /* Maximum length of numeric string. */
  73
  74 /*
  75  * Flags used during conversion.
  76  */
  77 #define LONG            0x01    /* l: long or double */
  78 #define LONGDBL         0x02    /* L: long double; unimplemented */
  79 #define SHORT           0x04    /* h: short */
  80 #define SUPPRESS        0x08    /* suppress assignment */
  81 #define POINTER         0x10    /* weird %p pointer (`fake hex') */
  82 #define NOSKIP          0x20    /* do not skip blanks */
  83 #define QUAD            0x400
  84
  85 /*
  86  * The following are used in numeric conversions only:
  87  * SIGNOK, NDIGITS, DPTOK, and EXPOK are for floating point;
  88  * SIGNOK, NDIGITS, PFXOK, and NZDIGITS are for integral.
  89  */
  90 #define SIGNOK          0x40    /* +/- is (still) legal */
  91 #define NDIGITS         0x80    /* no digits detected */
  92
  93 #define DPTOK           0x100   /* (float) decimal point is still legal */
  94 #define EXPOK           0x200   /* (float) exponent (e+3, etc) still legal */
  95
  96 #define PFXOK           0x100   /* 0x prefix is (still) legal */
  97 #define NZDIGITS        0x200   /* no zero digits detected */
  98
  99 /*
 100  * Conversion types.
 101  */
 102 #define CT_CHAR         0       /* %c conversion */
 103 #define CT_CCL          1       /* %[...] conversion */
 104 #define CT_STRING       2       /* %s conversion */
 105 #define CT_INT          3       /* integer, i.e., strtoq or strtouq */
 106 #define CT_FLOAT        4       /* floating, i.e., strtod */
 107
 108 #define u_char unsigned char
 109 #define u_long unsigned long
 110
 111 static u_char *__sccl(char *, u_char *);
 112
 113 /*
 114  * vfscanf
 115  */
 116 int
 117 __svfscanf(fp, fmt0, ap)
 118         register FILE *fp;
 119         char const *fmt0;
 120         va_list ap;
 121 {
 122         register u_char *fmt = (u_char *)fmt0;
 123         register int c;         /* character from format, or conversion */
 124         register size_t width;  /* field width, or 0 */
 125         register char *p;       /* points into all kinds of strings */
 126         register int n;         /* handy integer */
 127         register int flags;     /* flags as defined above */
 128         register char *p0;      /* saves original value of p when necessary */
 129         int nassigned;          /* number of fields assigned */
 130         int nread;              /* number of characters consumed from fp */
 131         int base;               /* base argument to strtoq/strtouq */
 132         u_quad_t (*ccfn)();     /* conversion function (strtoq/strtouq) */
 133         char ccltab[256];       /* character class table for %[...] */
 134         char buf[BUF];          /* buffer for numeric conversions */
 135
 136         /* `basefix' is used to avoid `if' tests in the integer scanner */
 137         static short basefix[17] =
 138                 { 10, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16 };
 139
 140         nassigned = 0;
 141         nread = 0;
 142         base = 0;               /* XXX just to keep gcc happy */
 143         ccfn = NULL;            /* XXX just to keep gcc happy */
 144         for (;;) {
 145                 c = *fmt++;
 146                 if (c == 0)
 147                         return (nassigned);
 148                 if (isspace(c)) {
 149                         for (;;) {
 150                                 if (fp->_r <= 0 && __srefill(fp))
 151                                         return (nassigned);
 152                                 if (!isspace(*fp->_p))
 153                                         break;
 154                                 nread++, fp->_r--, fp->_p++;
 155                         }
 156                         continue;
 157                 }
 158                 if (c != '%')
 159                         goto literal;
 160                 width = 0;
 161                 flags = 0;
 162                 /*
 163                  * switch on the format.  continue if done;
 164                  * break once format type is derived.
 165                  */
 166 again:          c = *fmt++;
 167                 switch (c) {
 168                 case '%':
 169 literal:
 170                         if (fp->_r <= 0 && __srefill(fp))
 171                                 goto input_failure;
 172                         if (*fp->_p != c)
 173                                 goto match_failure;
 174                         fp->_r--, fp->_p++;
 175                         nread++;
 176                         continue;
 177
 178                 case '*':
 179                         flags |= SUPPRESS;
 180                         goto again;
 181                 case 'l':
 182                         flags |= LONG;
 183                         goto again;
 184                 case 'q':
 185                         flags |= QUAD;
 186                         goto again;
 187                 case 'L':
 188                         flags |= LONGDBL;
 189                         goto again;
 190                 case 'h':
 191                         flags |= SHORT;
 192                         goto again;
 193
 194                 case '0': case '1': case '2': case '3': case '4':
 195                 case '5': case '6': case '7': case '8': case '9':
 196                         width = width * 10 + c - '0';
 197                         goto again;
 198
 199                 /*
 200                  * Conversions.
 201                  * Those marked `compat' are for 4.[123]BSD compatibility.
 202                  *
 203                  * (According to ANSI, E and X formats are supposed
 204                  * to the same as e and x.  Sorry about that.)
 205                  */
 206                 case 'D':       /* compat */
 207                         flags |= LONG;
 208                         /* FALLTHROUGH */
 209                 case 'd':
 210                         c = CT_INT;
 211                         ccfn = (u_quad_t (*)())strtoq;
 212                         base = 10;
 213                         break;
 214
 215                 case 'i':
 216                         c = CT_INT;
 217                         ccfn = (u_quad_t (*)())strtoq;
 218                         base = 0;
 219                         break;
 220
 221                 case 'O':       /* compat */
 222                         flags |= LONG;
 223                         /* FALLTHROUGH */
 224                 case 'o':
 225                         c = CT_INT;
 226                         ccfn = strtouq;
 227                         base = 8;
 228                         break;
 229
 230                 case 'u':
 231                         c = CT_INT;
 232                         ccfn = strtouq;
 233                         base = 10;
 234                         break;
 235
 236                 case 'X':       /* compat   XXX */
 237                         flags |= LONG;
 238                         /* FALLTHROUGH */
 239                 case 'x':
 240                         flags |= PFXOK; /* enable 0x prefixing */
 241                         c = CT_INT;
 242                         ccfn = strtouq;
 243                         base = 16;
 244                         break;
 245
 246 #ifdef FLOATING_POINT
 247                 case 'E':       /* compat   XXX */
 248                 case 'F':       /* compat */
 249                         flags |= LONG;
 250                         /* FALLTHROUGH */
 251                 case 'e': case 'f': case 'g':
 252                         c = CT_FLOAT;
 253                         break;
 254 #endif
 255
 256                 case 's':
 257                         c = CT_STRING;
 258                         break;
 259
 260                 case '[':
 261                         fmt = __sccl(ccltab, fmt);
 262                         flags |= NOSKIP;
 263                         c = CT_CCL;
 264                         break;
 265
 266                 case 'c':
 267                         flags |= NOSKIP;
 268                         c = CT_CHAR;
 269                         break;
 270
 271                 case 'p':       /* pointer format is like hex */
 272                         flags |= POINTER | PFXOK;
 273                         c = CT_INT;
 274                         ccfn = strtouq;
 275                         base = 16;
 276                         break;
 277
 278                 case 'n':
 279                         if (flags & SUPPRESS)   /* ??? */
 280                                 continue;
 281                         if (flags & SHORT)
 282                                 *va_arg(ap, short *) = nread;
 283                         else if (flags & LONG)
 284                                 *va_arg(ap, long *) = nread;
 285                         else if (flags & QUAD)
 286                                 *va_arg(ap, quad_t *) = nread;
 287                         else
 288                                 *va_arg(ap, int *) = nread;
 289                         continue;
 290
 291                 /*
 292                  * Disgusting backwards compatibility hacks.    XXX
 293                  */
 294                 case '\0':      /* compat */
 295                         return (EOF);
 296
 297                 default:        /* compat */
 298                         if (isupper(c))
 299                                 flags |= LONG;
 300                         c = CT_INT;
 301                         ccfn = (u_quad_t (*)())strtoq;
 302                         base = 10;
 303                         break;
 304                 }
 305
 306                 /*
 307                  * We have a conversion that requires input.
 308                  */
 309                 if (fp->_r <= 0 && __srefill(fp))
 310                         goto input_failure;
 311
 312                 /*
 313                  * Consume leading white space, except for formats
 314                  * that suppress this.
 315                  */
 316                 if ((flags & NOSKIP) == 0) {
 317                         while (isspace(*fp->_p)) {
 318                                 nread++;
 319                                 if (--fp->_r > 0)
 320                                         fp->_p++;
 321                                 else if (__srefill(fp))
 322                                         goto input_failure;
 323                         }
 324                         /*
 325                          * Note that there is at least one character in
 326                          * the buffer, so conversions that do not set NOSKIP
 327                          * ca no longer result in an input failure.
 328                          */
 329                 }
 330
 331                 /*
 332                  * Do the conversion.
 333                  */
 334                 switch (c) {
 335
 336                 case CT_CHAR:
 337                         /* scan arbitrary characters (sets NOSKIP) */
 338                         if (width == 0)
 339                                 width = 1;
 340                         if (flags & SUPPRESS) {
 341                                 size_t sum = 0;
 342                                 for (;;) {
 343                                         if ((n = fp->_r) < width) {
 344                                                 sum += n;
 345                                                 width -= n;
 346                                                 fp->_p += n;
 347                                                 if (__srefill(fp)) {
 348                                                         if (sum == 0)
 349                                                             goto input_failure;
 350                                                         break;
 351                                                 }
 352                                         } else {
 353                                                 sum += width;
 354                                                 fp->_r -= width;
 355                                                 fp->_p += width;
 356                                                 break;
 357                                         }
 358                                 }
 359                                 nread += sum;
 360                         } else {
 361                                 size_t r = fread((void *)va_arg(ap, char *), 1,
 362                                     width, fp);
 363
 364                                 if (r == 0)
 365                                         goto input_failure;
 366                                 nread += r;
 367                                 nassigned++;
 368                         }
 369                         break;
 370
 371                 case CT_CCL:
 372                         /* scan a (nonempty) character class (sets NOSKIP) */
 373                         if (width == 0)
 374                                 width = ~0;     /* `infinity' */
 375                         /* take only those things in the class */
 376                         if (flags & SUPPRESS) {
 377                                 n = 0;
 378                                 while (ccltab[*fp->_p]) {
 379                                         n++, fp->_r--, fp->_p++;
 380                                         if (--width == 0)
 381                                                 break;
 382                                         if (fp->_r <= 0 && __srefill(fp)) {
 383                                                 if (n == 0)
 384                                                         goto input_failure;
 385                                                 break;
 386                                         }
 387                                 }
 388                                 if (n == 0)
 389                                         goto match_failure;
 390                         } else {
 391                                 p0 = p = va_arg(ap, char *);
 392                                 while (ccltab[*fp->_p]) {
 393                                         fp->_r--;
 394                                         *p++ = *fp->_p++;
 395                                         if (--width == 0)
 396                                                 break;
 397                                         if (fp->_r <= 0 && __srefill(fp)) {
 398                                                 if (p == p0)
 399                                                         goto input_failure;
 400                                                 break;
 401                                         }
 402                                 }
 403                                 n = p - p0;
 404                                 if (n == 0)
 405                                         goto match_failure;
 406                                 *p = 0;
 407                                 nassigned++;
 408                         }
 409                         nread += n;
 410                         break;
 411
 412                 case CT_STRING:
 413                         /* like CCL, but zero-length string OK, & no NOSKIP */
 414                         if (width == 0)
 415                                 width = ~0;
 416                         if (flags & SUPPRESS) {
 417                                 n = 0;
 418                                 while (!isspace(*fp->_p)) {
 419                                         n++, fp->_r--, fp->_p++;
 420                                         if (--width == 0)
 421                                                 break;
 422                                         if (fp->_r <= 0 && __srefill(fp))
 423                                                 break;
 424                                 }
 425                                 nread += n;
 426                         } else {
 427                                 p0 = p = va_arg(ap, char *);
 428                                 while (!isspace(*fp->_p)) {
 429                                         fp->_r--;
 430                                         *p++ = *fp->_p++;
 431                                         if (--width == 0)
 432                                                 break;
 433                                         if (fp->_r <= 0 && __srefill(fp))
 434                                                 break;
 435                                 }
 436                                 *p = 0;
 437                                 nread += p - p0;
 438                                 nassigned++;
 439                         }
 440                         continue;
 441
 442                 case CT_INT:
 443                         /* scan an integer as if by strtoq/strtouq */
 444 #ifdef hardway
 445                         if (width == 0 || width > sizeof(buf) - 1)
 446                                 width = sizeof(buf) - 1;
 447 #else
 448                         /* size_t is unsigned, hence this optimisation */
 449                         if (--width > sizeof(buf) - 2)
 450                                 width = sizeof(buf) - 2;
 451                         width++;
 452 #endif
 453                         flags |= SIGNOK | NDIGITS | NZDIGITS;
 454                         for (p = buf; width; width--) {
 455                                 c = *fp->_p;
 456                                 /*
 457                                  * Switch on the character; `goto ok'
 458                                  * if we accept it as a part of number.
 459                                  */
 460                                 switch (c) {
 461
 462                                 /*
 463                                  * The digit 0 is always legal, but is
 464                                  * special.  For %i conversions, if no
 465                                  * digits (zero or nonzero) have been
 466                                  * scanned (only signs), we will have
 467                                  * base==0.  In that case, we should set
 468                                  * it to 8 and enable 0x prefixing.
 469                                  * Also, if we have not scanned zero digits
 470                                  * before this, do not turn off prefixing
 471                                  * (someone else will turn it off if we
 472                                  * have scanned any nonzero digits).
 473                                  */
 474                                 case '0':
 475                                         if (base == 0) {
 476                                                 base = 8;
 477                                                 flags |= PFXOK;
 478                                         }
 479                                         if (flags & NZDIGITS)
 480                                             flags &= ~(SIGNOK|NZDIGITS|NDIGITS);
 481                                         else
 482                                             flags &= ~(SIGNOK|PFXOK|NDIGITS);
 483                                         goto ok;
 484
 485                                 /* 1 through 7 always legal */
 486                                 case '1': case '2': case '3':
 487                                 case '4': case '5': case '6': case '7':
 488                                         base = basefix[base];
 489                                         flags &= ~(SIGNOK | PFXOK | NDIGITS);
 490                                         goto ok;
 491
 492                                 /* digits 8 and 9 ok iff decimal or hex */
 493                                 case '8': case '9':
 494                                         base = basefix[base];
 495                                         if (base <= 8)
 496                                                 break;  /* not legal here */
 497                                         flags &= ~(SIGNOK | PFXOK | NDIGITS);
 498                                         goto ok;
 499
 500                                 /* letters ok iff hex */
 501                                 case 'A': case 'B': case 'C':
 502                                 case 'D': case 'E': case 'F':
 503                                 case 'a': case 'b': case 'c':
 504                                 case 'd': case 'e': case 'f':
 505                                         /* no need to fix base here */
 506                                         if (base <= 10)
 507                                                 break;  /* not legal here */
 508                                         flags &= ~(SIGNOK | PFXOK | NDIGITS);
 509                                         goto ok;
 510
 511                                 /* sign ok only as first character */
 512                                 case '+': case '-':
 513                                         if (flags & SIGNOK) {
 514                                                 flags &= ~SIGNOK;
 515                                                 goto ok;
 516                                         }
 517                                         break;
 518
 519                                 /* x ok iff flag still set & 2nd char */
 520                                 case 'x': case 'X':
 521                                         if (flags & PFXOK && p == buf + 1) {
 522                                                 base = 16;      /* if %i */
 523                                                 flags &= ~PFXOK;
 524                                                 goto ok;
 525                                         }
 526                                         break;
 527                                 }
 528
 529                                 /*
 530                                  * If we got here, c is not a legal character
 531                                  * for a number.  Stop accumulating digits.
 532                                  */
 533                                 break;
 534                 ok:
 535                                 /*
 536                                  * c is legal: store it and look at the next.
 537                                  */
 538                                 *p++ = c;
 539                                 if (--fp->_r > 0)
 540                                         fp->_p++;
 541                                 else if (__srefill(fp))
 542                                         break;          /* EOF */
 543                         }
 544                         /*
 545                          * If we had only a sign, it is no good; push
 546                          * back the sign.  If the number ends in `x',
 547                          * it was [sign] '0' 'x', so push back the x
 548                          * and treat it as [sign] '0'.
 549                          */
 550                         if (flags & NDIGITS) {
 551                                 if (p > buf)
 552                                         (void) ungetc(*(u_char *)--p, fp);
 553                                 goto match_failure;
 554                         }
 555                         c = ((u_char *)p)[-1];
 556                         if (c == 'x' || c == 'X') {
 557                                 --p;
 558                                 (void) ungetc(c, fp);
 559                         }
 560                         if ((flags & SUPPRESS) == 0) {
 561                                 u_quad_t res;
 562
 563                                 *p = 0;
 564                                 res = (*ccfn)(buf, (char **)NULL, base);
 565                                 if (flags & POINTER)
 566                                         *va_arg(ap, void **) = (void *)res;
 567                                 else if (flags & SHORT)
 568                                         *va_arg(ap, short *) = res;
 569                                 else if (flags & LONG)
 570                                         *va_arg(ap, long *) = res;
 571                                 else if (flags & QUAD)
 572                                         *va_arg(ap, quad_t *) = res;
 573                                 else
 574                                         *va_arg(ap, int *) = res;
 575                                 nassigned++;
 576                         }
 577                         nread += p - buf;
 578                         break;
 579
 580 #ifdef FLOATING_POINT
 581                 case CT_FLOAT:
 582                         /* scan a floating point number as if by strtod */
 583 #ifdef hardway
 584                         if (width == 0 || width > sizeof(buf) - 1)
 585                                 width = sizeof(buf) - 1;
 586 #else
 587                         /* size_t is unsigned, hence this optimisation */
 588                         if (--width > sizeof(buf) - 2)
 589                                 width = sizeof(buf) - 2;
 590                         width++;
 591 #endif
 592                         flags |= SIGNOK | NDIGITS | DPTOK | EXPOK;
 593                         for (p = buf; width; width--) {
 594                                 c = *fp->_p;
 595                                 /*
 596                                  * This code mimicks the integer conversion
 597                                  * code, but is much simpler.
 598                                  */
 599                                 switch (c) {
 600
 601                                 case '0': case '1': case '2': case '3':
 602                                 case '4': case '5': case '6': case '7':
 603                                 case '8': case '9':
 604                                         flags &= ~(SIGNOK | NDIGITS);
 605                                         goto fok;
 606
 607                                 case '+': case '-':
 608                                         if (flags & SIGNOK) {
 609                                                 flags &= ~SIGNOK;
 610                                                 goto fok;
 611                                         }
 612                                         break;
 613                                 case '.':
 614                                         if (flags & DPTOK) {
 615                                                 flags &= ~(SIGNOK | DPTOK);
 616                                                 goto fok;
 617                                         }
 618                                         break;
 619                                 case 'e': case 'E':
 620                                         /* no exponent without some digits */
 621                                         if ((flags&(NDIGITS|EXPOK)) == EXPOK) {
 622                                                 flags =
 623                                                     (flags & ~(EXPOK|DPTOK)) |
 624                                                     SIGNOK | NDIGITS;
 625                                                 goto fok;
 626                                         }
 627                                         break;
 628                                 }
 629                                 break;
 630                 fok:
 631                                 *p++ = c;
 632                                 if (--fp->_r > 0)
 633                                         fp->_p++;
 634                                 else if (__srefill(fp))
 635                                         break;  /* EOF */
 636                         }
 637                         /*
 638                          * If no digits, might be missing exponent digits
 639                          * (just give back the exponent) or might be missing
 640                          * regular digits, but had sign and/or decimal point.
 641                          */
 642                         if (flags & NDIGITS) {
 643                                 if (flags & EXPOK) {
 644                                         /* no digits at all */
 645                                         while (p > buf)
 646                                                 ungetc(*(u_char *)--p, fp);
 647                                         goto match_failure;
 648                                 }
 649                                 /* just a bad exponent (e and maybe sign) */
 650                                 c = *(u_char *)--p;
 651                                 if (c != 'e' && c != 'E') {
 652                                         (void) ungetc(c, fp);/* sign */
 653                                         c = *(u_char *)--p;
 654                                 }
 655                                 (void) ungetc(c, fp);
 656                         }
 657                         if ((flags & SUPPRESS) == 0) {
 658                                 double res;
 659
 660                                 *p = 0;
 661                                 res = strtod(buf,(char **) NULL);
 662                                 if (flags & LONGDBL)
 663                                         *va_arg(ap, long double *) = res;
 664                                 else if (flags & LONG)
 665                                         *va_arg(ap, double *) = res;
 666                                 else
 667                                         *va_arg(ap, float *) = res;
 668                                 nassigned++;
 669                         }
 670                         nread += p - buf;
 671                         break;
 672 #endif /* FLOATING_POINT */
 673                 }
 674         }
 675 input_failure:
 676         return (nassigned ? nassigned : -1);
 677 match_failure:
 678         return (nassigned);
 679 }
 680
 681 /*
 682  * Fill in the given table from the scanset at the given format
 683  * (just after `[').  Return a pointer to the character past the
 684  * closing `]'.  The table has a 1 wherever characters should be
 685  * considered part of the scanset.
 686  */
 687 static u_char *
 688 __sccl(tab, fmt)
 689         register char *tab;
 690         register u_char *fmt;
 691 {
 692         register int c, n, v;
 693
 694         /* first `clear' the whole table */
 695         c = *fmt++;             /* first char hat => negated scanset */
 696         if (c == '^') {
 697                 v = 1;          /* default => accept */
 698                 c = *fmt++;     /* get new first char */
 699         } else
 700                 v = 0;          /* default => reject */
 701         /* should probably use memset here */
 702         for (n = 0; n < 256; n++)
 703                 tab[n] = v;
 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 == ']' || n < c) {
 745                                 c = '-';
 746                                 break;  /* resume the for(;;) */
 747                         }
 748                         fmt++;
 749                         do {            /* fill in the range */
 750                                 tab[++c] = v;
 751                         } while (c < n);
 752 #if 1   /* XXX another disgusting compatibility hack */
 753                         /*
 754                          * Alas, the V7 Unix scanf also treats formats
 755                          * such as [a-c-e] as `the letters a through e'.
 756                          * This too is permitted by the standard....
 757                          */
 758                         goto doswitch;
 759 #else
 760                         c = *fmt++;
 761                         if (c == 0)
 762                                 return (fmt - 1);
 763                         if (c == ']')
 764                                 return (fmt);
 765 #endif
 766                         break;
 767
 768                 case ']':               /* end of scanset */
 769                         return (fmt);
 770
 771                 default:                /* just another character */
 772                         c = n;
 773                         break;
 774                 }
 775         }
 776         /* NOTREACHED */
 777 }