libkern/stdio/scanf.c

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