libkern/stdio/scanf.c

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