libkern/stdio/scanf.c

   1 /*
   2  * Copyright (c) 2004 Apple Computer, Inc. All rights reserved.
   3  *
   4  * @APPLE_LICENSE_OSREFERENCE_HEADER_START@
   5  *
   6  * This file contains Original Code and/or Modifications of Original Code
   7  * as defined in and that are subject to the Apple Public Source License
   8  * Version 2.0 (the 'License'). You may not use this file except in
   9  * compliance with the License.  The rights granted to you under the
  10  * License may not be used to create, or enable the creation or
  11  * redistribution of, unlawful or unlicensed copies of an Apple operating
  12  * system, or to circumvent, violate, or enable the circumvention or
  13  * violation of, any terms of an Apple operating system software license
  14  * agreement.
  15  *
  16  * Please obtain a copy of the License at
  17  * http://www.opensource.apple.com/apsl/ and read it before using this
  18  * file.
  19  *
  20  * The Original Code and all software distributed under the License are
  21  * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
  22  * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
  23  * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
  24  * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
  25  * Please see the License for the specific language governing rights and
  26  * limitations under the License.
  27  *
  28  * @APPLE_LICENSE_OSREFERENCE_HEADER_END@
  29  */
  30 /*-
  31  * Copyright (c) 1990, 1993
  32  *      The Regents of the University of California.  All rights reserved.
  33  *
  34  * This code is derived from software contributed to Berkeley by
  35  * Chris Torek.
  36  *
  37  * Redistribution and use in source and binary forms, with or without
  38  * modification, are permitted provided that the following conditions
  39  * are met:
  40  * 1. Redistributions of source code must retain the above copyright
  41  *    notice, this list of conditions and the following disclaimer.
  42  * 2. Redistributions in binary form must reproduce the above copyright
  43  *    notice, this list of conditions and the following disclaimer in the
  44  *    documentation and/or other materials provided with the distribution.
  45  * 3. All advertising materials mentioning features or use of this software
  46  *    must display the following acknowledgement:
  47  *      This product includes software developed by the University of
  48  *      California, Berkeley and its contributors.
  49  * 4. Neither the name of the University nor the names of its contributors
  50  *    may be used to endorse or promote products derived from this software
  51  *    without specific prior written permission.
  52  *
  53  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  54  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  55  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  56  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  57  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  58  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  59  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  60  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  61  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  62  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  63  * SUCH DAMAGE.
  64  */
  65
  66 #include <sys/cdefs.h>
  67
  68 #if 0 /* XXX coming soon */
  69 #include <ctype.h>
  70 #else
  71 static inline int
  72 isspace(char c)
  73 {
  74         return (c == ' ' || c == '\t' || c == '\n' || c == '\12');
  75 }
  76 #endif
  77 #include <stdarg.h>
  78 #include <string.h>
  79 #include <sys/param.h>
  80 #include <sys/systm.h>
  81
  82 #define BUF             32      /* Maximum length of numeric string. */
  83
  84 /*
  85  * Flags used during conversion.
  86  */
  87 #define LONG            0x01    /* l: long or double */
  88 #define SHORT           0x04    /* h: short */
  89 #define SUPPRESS        0x08    /* *: suppress assignment */
  90 #define POINTER         0x10    /* p: void * (as hex) */
  91 #define NOSKIP          0x20    /* [ or c: do not skip blanks */
  92 #define LONGLONG        0x400   /* ll: long long (+ deprecated q: quad) */
  93 #define SHORTSHORT      0x4000  /* hh: char */
  94 #define UNSIGNED        0x8000  /* %[oupxX] conversions */
  95
  96 /*
  97  * The following are used in numeric conversions only:
  98  * SIGNOK, NDIGITS, DPTOK, and EXPOK are for floating point;
  99  * SIGNOK, NDIGITS, PFXOK, and NZDIGITS are for integral.
 100  */
 101 #define SIGNOK          0x40    /* +/- is (still) legal */
 102 #define NDIGITS         0x80    /* no digits detected */
 103
 104 #define DPTOK           0x100   /* (float) decimal point is still legal */
 105 #define EXPOK           0x200   /* (float) exponent (e+3, etc) still legal */
 106
 107 #define PFXOK           0x100   /* 0x prefix is (still) legal */
 108 #define NZDIGITS        0x200   /* no zero digits detected */
 109
 110 /*
 111  * Conversion types.
 112  */
 113 #define CT_CHAR         0       /* %c conversion */
 114 #define CT_CCL          1       /* %[...] conversion */
 115 #define CT_STRING       2       /* %s conversion */
 116 #define CT_INT          3       /* %[dioupxX] conversion */
 117
 118 static const u_char *__sccl(char *, const u_char *);
 119
 120 int
 121 sscanf(const char *ibuf, const char *fmt, ...)
 122 {
 123         va_list ap;
 124         int ret;
 125
 126         va_start(ap, fmt);
 127         ret = vsscanf(ibuf, fmt, ap);
 128         va_end(ap);
 129         return(ret);
 130 }
 131
 132 int
 133 vsscanf(const char *inp, char const *fmt0, va_list ap)
 134 {
 135         int inr;
 136         const u_char *fmt = (const u_char *)fmt0;
 137         int c;                  /* character from format, or conversion */
 138         size_t width;           /* field width, or 0 */
 139         char *p;                /* points into all kinds of strings */
 140         int n;                  /* handy integer */
 141         int flags;              /* flags as defined above */
 142         char *p0;               /* saves original value of p when necessary */
 143         int nassigned;          /* number of fields assigned */
 144         int nconversions;       /* number of conversions */
 145         int nread;              /* number of characters consumed from fp */
 146         int base;               /* base argument to conversion function */
 147         char ccltab[256];       /* character class table for %[...] */
 148         char buf[BUF];          /* buffer for numeric conversions */
 149
 150         /* `basefix' is used to avoid `if' tests in the integer scanner */
 151         static short basefix[17] =
 152                 { 10, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16 };
 153
 154         inr = strlen(inp);
 155
 156         nassigned = 0;
 157         nconversions = 0;
 158         nread = 0;
 159         base = 0;               /* XXX just to keep gcc happy */
 160         for (;;) {
 161                 c = *fmt++;
 162                 if (c == 0)
 163                         return (nassigned);
 164                 if (isspace(c)) {
 165                         while (inr > 0 && isspace(*inp))
 166                                 nread++, inr--, inp++;
 167                         continue;
 168                 }
 169                 if (c != '%')
 170                         goto literal;
 171                 width = 0;
 172                 flags = 0;
 173                 /*
 174                  * switch on the format.  continue if done;
 175                  * break once format type is derived.
 176                  */
 177 again:          c = *fmt++;
 178                 switch (c) {
 179                 case '%':
 180 literal:
 181                         if (inr <= 0)
 182                                 goto input_failure;
 183                         if (*inp != c)
 184                                 goto match_failure;
 185                         inr--, inp++;
 186                         nread++;
 187                         continue;
 188
 189                 case '*':
 190                         flags |= SUPPRESS;
 191                         goto again;
 192                 case 'l':
 193                         if (flags & LONG) {
 194                                 flags &= ~LONG;
 195                                 flags |= LONGLONG;
 196                         } else
 197                                 flags |= LONG;
 198                         goto again;
 199                 case 'q':
 200                         flags |= LONGLONG;      /* not quite */
 201                         goto again;
 202                 case 'h':
 203                         if (flags & SHORT) {
 204                                 flags &= ~SHORT;
 205                                 flags |= SHORTSHORT;
 206                         } else
 207                                 flags |= SHORT;
 208                         goto again;
 209
 210                 case '0': case '1': case '2': case '3': case '4':
 211                 case '5': case '6': case '7': case '8': case '9':
 212                         width = width * 10 + c - '0';
 213                         goto again;
 214
 215                 /*
 216                  * Conversions.
 217                  */
 218                 case 'd':
 219                         c = CT_INT;
 220                         base = 10;
 221                         break;
 222
 223                 case 'i':
 224                         c = CT_INT;
 225                         base = 0;
 226                         break;
 227
 228                 case 'o':
 229                         c = CT_INT;
 230                         flags |= UNSIGNED;
 231                         base = 8;
 232                         break;
 233
 234                 case 'u':
 235                         c = CT_INT;
 236                         flags |= UNSIGNED;
 237                         base = 10;
 238                         break;
 239
 240                 case 'X':
 241                 case 'x':
 242                         flags |= PFXOK; /* enable 0x prefixing */
 243                         c = CT_INT;
 244                         flags |= UNSIGNED;
 245                         base = 16;
 246                         break;
 247
 248                 case 's':
 249                         c = CT_STRING;
 250                         break;
 251
 252                 case '[':
 253                         fmt = __sccl(ccltab, fmt);
 254                         flags |= NOSKIP;
 255                         c = CT_CCL;
 256                         break;
 257
 258                 case 'c':
 259                         flags |= NOSKIP;
 260                         c = CT_CHAR;
 261                         break;
 262
 263                 case 'p':       /* pointer format is like hex */
 264                         flags |= POINTER | PFXOK;
 265                         c = CT_INT;
 266                         flags |= UNSIGNED;
 267                         base = 16;
 268                         break;
 269
 270                 case 'n':
 271                         nconversions++;
 272                         if (flags & SUPPRESS)   /* ??? */
 273                                 continue;
 274                         if (flags & SHORTSHORT)
 275                                 *va_arg(ap, char *) = nread;
 276                         else if (flags & SHORT)
 277                                 *va_arg(ap, short *) = nread;
 278                         else if (flags & LONG)
 279                                 *va_arg(ap, long *) = nread;
 280                         else if (flags & LONGLONG)
 281                                 *va_arg(ap, long long *) = nread;
 282                         else
 283                                 *va_arg(ap, int *) = nread;
 284                         continue;
 285                 }
 286
 287                 /*
 288                  * We have a conversion that requires input.
 289                  */
 290                 if (inr <= 0)
 291                         goto input_failure;
 292
 293                 /*
 294                  * Consume leading white space, except for formats
 295                  * that suppress this.
 296                  */
 297                 if ((flags & NOSKIP) == 0) {
 298                         while (isspace(*inp)) {
 299                                 nread++;
 300                                 if (--inr > 0)
 301                                         inp++;
 302                                 else
 303                                         goto input_failure;
 304                         }
 305                         /*
 306                          * Note that there is at least one character in
 307                          * the buffer, so conversions that do not set NOSKIP
 308                          * can no longer result in an input failure.
 309                          */
 310                 }
 311
 312                 /*
 313                  * Do the conversion.
 314                  */
 315                 switch (c) {
 316
 317                 case CT_CHAR:
 318                         /* scan arbitrary characters (sets NOSKIP) */
 319                         if (width == 0)
 320                                 width = 1;
 321                         if (flags & SUPPRESS) {
 322                                 size_t sum = 0;
 323                                 for (;;) {
 324                                         if ((n = inr) < (int)width) {
 325                                                 sum += n;
 326                                                 width -= n;
 327                                                 inp += n;
 328                                                 if (sum == 0)
 329                                                         goto input_failure;
 330                                                 break;
 331                                         } else {
 332                                                 sum += width;
 333                                                 inr -= width;
 334                                                 inp += width;
 335                                                 break;
 336                                         }
 337                                 }
 338                                 nread += sum;
 339                         } else {
 340                                 bcopy(inp, va_arg(ap, char *), width);
 341                                 inr -= width;
 342                                 inp += width;
 343                                 nread += width;
 344                                 nassigned++;
 345                         }
 346                         nconversions++;
 347                         break;
 348
 349                 case CT_CCL:
 350                         /* scan a (nonempty) character class (sets NOSKIP) */
 351                         if (width == 0)
 352                                 width = (size_t)~0;     /* `infinity' */
 353                         /* take only those things in the class */
 354                         if (flags & SUPPRESS) {
 355                                 n = 0;
 356                                 while (ccltab[(unsigned char)*inp]) {
 357                                         n++, inr--, inp++;
 358                                         if (--width == 0)
 359                                                 break;
 360                                         if (inr <= 0) {
 361                                                 if (n == 0)
 362                                                         goto input_failure;
 363                                                 break;
 364                                         }
 365                                 }
 366                                 if (n == 0)
 367                                         goto match_failure;
 368                         } else {
 369                                 p0 = p = va_arg(ap, char *);
 370                                 while (ccltab[(unsigned char)*inp]) {
 371                                         inr--;
 372                                         *p++ = *inp++;
 373                                         if (--width == 0)
 374                                                 break;
 375                                         if (inr <= 0) {
 376                                                 if (p == p0)
 377                                                         goto input_failure;
 378                                                 break;
 379                                         }
 380                                 }
 381                                 n = p - p0;
 382                                 if (n == 0)
 383                                         goto match_failure;
 384                                 *p = 0;
 385                                 nassigned++;
 386                         }
 387                         nread += n;
 388                         nconversions++;
 389                         break;
 390
 391                 case CT_STRING:
 392                         /* like CCL, but zero-length string OK, & no NOSKIP */
 393                         if (width == 0)
 394                                 width = (size_t)~0;
 395                         if (flags & SUPPRESS) {
 396                                 n = 0;
 397                                 while (!isspace(*inp)) {
 398                                         n++, inr--, inp++;
 399                                         if (--width == 0)
 400                                                 break;
 401                                         if (inr <= 0)
 402                                                 break;
 403                                 }
 404                                 nread += n;
 405                         } else {
 406                                 p0 = p = va_arg(ap, char *);
 407                                 while (!isspace(*inp)) {
 408                                         inr--;
 409                                         *p++ = *inp++;
 410                                         if (--width == 0)
 411                                                 break;
 412                                         if (inr <= 0)
 413                                                 break;
 414                                 }
 415                                 *p = 0;
 416                                 nread += p - p0;
 417                                 nassigned++;
 418                         }
 419                         nconversions++;
 420                         continue;
 421
 422                 case CT_INT:
 423                         /* scan an integer as if by the conversion function */
 424 #ifdef hardway
 425                         if (width == 0 || width > sizeof(buf) - 1)
 426                                 width = sizeof(buf) - 1;
 427 #else
 428                         /* size_t is unsigned, hence this optimisation */
 429                         if (--width > sizeof(buf) - 2)
 430                                 width = sizeof(buf) - 2;
 431                         width++;
 432 #endif
 433                         flags |= SIGNOK | NDIGITS | NZDIGITS;
 434                         for (p = buf; width; width--) {
 435                                 c = *inp;
 436                                 /*
 437                                  * Switch on the character; `goto ok'
 438                                  * if we accept it as a part of number.
 439                                  */
 440                                 switch (c) {
 441
 442                                 /*
 443                                  * The digit 0 is always legal, but is
 444                                  * special.  For %i conversions, if no
 445                                  * digits (zero or nonzero) have been
 446                                  * scanned (only signs), we will have
 447                                  * base==0.  In that case, we should set
 448                                  * it to 8 and enable 0x prefixing.
 449                                  * Also, if we have not scanned zero digits
 450                                  * before this, do not turn off prefixing
 451                                  * (someone else will turn it off if we
 452                                  * have scanned any nonzero digits).
 453                                  */
 454                                 case '0':
 455                                         if (base == 0) {
 456                                                 base = 8;
 457                                                 flags |= PFXOK;
 458                                         }
 459                                         if (flags & NZDIGITS)
 460                                             flags &= ~(SIGNOK|NZDIGITS|NDIGITS);
 461                                         else
 462                                             flags &= ~(SIGNOK|PFXOK|NDIGITS);
 463                                         goto ok;
 464
 465                                 /* 1 through 7 always legal */
 466                                 case '1': case '2': case '3':
 467                                 case '4': case '5': case '6': case '7':
 468                                         base = basefix[base];
 469                                         flags &= ~(SIGNOK | PFXOK | NDIGITS);
 470                                         goto ok;
 471
 472                                 /* digits 8 and 9 ok iff decimal or hex */
 473                                 case '8': case '9':
 474                                         base = basefix[base];
 475                                         if (base <= 8)
 476                                                 break;  /* not legal here */
 477                                         flags &= ~(SIGNOK | PFXOK | NDIGITS);
 478                                         goto ok;
 479
 480                                 /* letters ok iff hex */
 481                                 case 'A': case 'B': case 'C':
 482                                 case 'D': case 'E': case 'F':
 483                                 case 'a': case 'b': case 'c':
 484                                 case 'd': case 'e': case 'f':
 485                                         /* no need to fix base here */
 486                                         if (base <= 10)
 487                                                 break;  /* not legal here */
 488                                         flags &= ~(SIGNOK | PFXOK | NDIGITS);
 489                                         goto ok;
 490
 491                                 /* sign ok only as first character */
 492                                 case '+': case '-':
 493                                         if (flags & SIGNOK) {
 494                                                 flags &= ~SIGNOK;
 495                                                 goto ok;
 496                                         }
 497                                         break;
 498
 499                                 /* x ok iff flag still set & 2nd char */
 500                                 case 'x': case 'X':
 501                                         if (flags & PFXOK && p == buf + 1) {
 502                                                 base = 16;      /* if %i */
 503                                                 flags &= ~PFXOK;
 504                                                 goto ok;
 505                                         }
 506                                         break;
 507                                 }
 508
 509                                 /*
 510                                  * If we got here, c is not a legal character
 511                                  * for a number.  Stop accumulating digits.
 512                                  */
 513                                 break;
 514                 ok:
 515                                 /*
 516                                  * c is legal: store it and look at the next.
 517                                  */
 518                                 *p++ = c;
 519                                 if (--inr > 0)
 520                                         inp++;
 521                                 else
 522                                         break;          /* end of input */
 523                         }
 524                         /*
 525                          * If we had only a sign, it is no good; push
 526                          * back the sign.  If the number ends in `x',
 527                          * it was [sign] '0' 'x', so push back the x
 528                          * and treat it as [sign] '0'.
 529                          */
 530                         if (flags & NDIGITS) {
 531                                 if (p > buf) {
 532                                         inp--;
 533                                         inr++;
 534                                 }
 535                                 goto match_failure;
 536                         }
 537                         c = ((u_char *)p)[-1];
 538                         if (c == 'x' || c == 'X') {
 539                                 --p;
 540                                 inp--;
 541                                 inr++;
 542                         }
 543                         if ((flags & SUPPRESS) == 0) {
 544                                 u_quad_t res;
 545
 546                                 *p = 0;
 547                                 if ((flags & UNSIGNED) == 0)
 548                                     res = strtoq(buf, (char **)NULL, base);
 549                                 else
 550                                     res = strtouq(buf, (char **)NULL, base);
 551                                 if (flags & POINTER)
 552                                         *va_arg(ap, void **) =
 553                                                 (void *)(uintptr_t)res;
 554                                 else if (flags & SHORTSHORT)
 555                                         *va_arg(ap, char *) = res;
 556                                 else if (flags & SHORT)
 557                                         *va_arg(ap, short *) = res;
 558                                 else if (flags & LONG)
 559                                         *va_arg(ap, long *) = res;
 560                                 else if (flags & LONGLONG)
 561                                         *va_arg(ap, long long *) = res;
 562                                 else
 563                                         *va_arg(ap, int *) = res;
 564                                 nassigned++;
 565                         }
 566                         nread += p - buf;
 567                         nconversions++;
 568                         break;
 569
 570                 }
 571         }
 572 input_failure:
 573         return (nconversions != 0 ? nassigned : -1);
 574 match_failure:
 575         return (nassigned);
 576 }
 577
 578 /*
 579  * Fill in the given table from the scanset at the given format
 580  * (just after `[').  Return a pointer to the character past the
 581  * closing `]'.  The table has a 1 wherever characters should be
 582  * considered part of the scanset.
 583  */
 584 static const u_char *
 585 __sccl(char *tab, const u_char *fmt)
 586 {
 587         int c, n, v;
 588
 589         /* first `clear' the whole table */
 590         c = *fmt++;             /* first char hat => negated scanset */
 591         if (c == '^') {
 592                 v = 1;          /* default => accept */
 593                 c = *fmt++;     /* get new first char */
 594         } else
 595                 v = 0;          /* default => reject */
 596
 597         /* XXX: Will not work if sizeof(tab*) > sizeof(char) */
 598         (void) memset(tab, v, 256);
 599
 600         if (c == 0)
 601                 return (fmt - 1);/* format ended before closing ] */
 602
 603         /*
 604          * Now set the entries corresponding to the actual scanset
 605          * to the opposite of the above.
 606          *
 607          * The first character may be ']' (or '-') without being special;
 608          * the last character may be '-'.
 609          */
 610         v = 1 - v;
 611         for (;;) {
 612                 tab[c] = v;             /* take character c */
 613 doswitch:
 614                 n = *fmt++;             /* and examine the next */
 615                 switch (n) {
 616
 617                 case 0:                 /* format ended too soon */
 618                         return (fmt - 1);
 619
 620                 case '-':
 621                         /*
 622                          * A scanset of the form
 623                          *      [01+-]
 624                          * is defined as `the digit 0, the digit 1,
 625                          * the character +, the character -', but
 626                          * the effect of a scanset such as
 627                          *      [a-zA-Z0-9]
 628                          * is implementation defined.  The V7 Unix
 629                          * scanf treats `a-z' as `the letters a through
 630                          * z', but treats `a-a' as `the letter a, the
 631                          * character -, and the letter a'.
 632                          *
 633                          * For compatibility, the `-' is not considerd
 634                          * to define a range if the character following
 635                          * it is either a close bracket (required by ANSI)
 636                          * or is not numerically greater than the character
 637                          * we just stored in the table (c).
 638                          */
 639                         n = *fmt;
 640                         if (n == ']' || n < c) {
 641                                 c = '-';
 642                                 break;  /* resume the for(;;) */
 643                         }
 644                         fmt++;
 645                         /* fill in the range */
 646                         do {
 647                             tab[++c] = v;
 648                         } while (c < n);
 649                         c = n;
 650                         /*
 651                          * Alas, the V7 Unix scanf also treats formats
 652                          * such as [a-c-e] as `the letters a through e'.
 653                          * This too is permitted by the standard....
 654                          */
 655                         goto doswitch;
 656                         break;
 657
 658                 case ']':               /* end of scanset */
 659                         return (fmt);
 660
 661                 default:                /* just another character */
 662                         c = n;
 663                         break;
 664                 }
 665         }
 666         /* NOTREACHED */
 667 }