1 /* $OpenBSD: vfscanf.c,v 1.21 2006/01/13 21:33:28 millert Exp $ */ 2 /*- 3 * Copyright (c) 1990, 1993 4 * The Regents of the University of California. All rights reserved. 5 * 6 * This code is derived from software contributed to Berkeley by 7 * Chris Torek. 8 * 9 * Redistribution and use in source and binary forms, with or without 10 * modification, are permitted provided that the following conditions 11 * are met: 12 * 1. Redistributions of source code must retain the above copyright 13 * notice, this list of conditions and the following disclaimer. 14 * 2. Redistributions in binary form must reproduce the above copyright 15 * notice, this list of conditions and the following disclaimer in the 16 * documentation and/or other materials provided with the distribution. 17 * 3. Neither the name of the University nor the names of its contributors 18 * may be used to endorse or promote products derived from this software 19 * without specific prior written permission. 20 * 21 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 22 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 23 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 24 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 25 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 26 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 27 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 28 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 29 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 30 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 31 * SUCH DAMAGE. 32 */ 33 34 #include <ctype.h> 35 #include <inttypes.h> 36 #include <stdarg.h> 37 #include <stddef.h> 38 #include <stdio.h> 39 #include <stdlib.h> 40 41 extern int __isthreaded; 42 43 #include "local.h" 44 45 #ifdef FLOATING_POINT 46 #include "floatio.h" 47 #endif 48 49 #define BUF 513 /* Maximum length of numeric string. */ 50 51 /* 52 * Flags used during conversion. 53 */ 54 #define LONG 0x00001 /* l: long or double */ 55 #define LONGDBL 0x00002 /* L: long double; unimplemented */ 56 #define SHORT 0x00004 /* h: short */ 57 #define SHORTSHORT 0x00008 /* hh: 8 bit integer */ 58 #define LLONG 0x00010 /* ll: long long (+ deprecated q: quad) */ 59 #define POINTER 0x00020 /* p: void * (as hex) */ 60 #define SIZEINT 0x00040 /* z: (signed) size_t */ 61 #define MAXINT 0x00080 /* j: intmax_t */ 62 #define PTRINT 0x00100 /* t: ptrdiff_t */ 63 #define NOSKIP 0x00200 /* [ or c: do not skip blanks */ 64 #define SUPPRESS 0x00400 /* *: suppress assignment */ 65 #define UNSIGNED 0x00800 /* %[oupxX] conversions */ 66 67 /* 68 * The following are used in numeric conversions only: 69 * SIGNOK, HAVESIGN, NDIGITS, DPTOK, and EXPOK are for floating point; 70 * SIGNOK, HAVESIGN, NDIGITS, PFXOK, and NZDIGITS are for integral. 71 */ 72 #define SIGNOK 0x01000 /* +/- is (still) legal */ 73 #define HAVESIGN 0x02000 /* sign detected */ 74 #define NDIGITS 0x04000 /* no digits detected */ 75 76 #define DPTOK 0x08000 /* (float) decimal point is still legal */ 77 #define EXPOK 0x10000 /* (float) exponent (e+3, etc) still legal */ 78 79 #define PFXOK 0x20000 /* 0x prefix is (still) legal */ 80 #define NZDIGITS 0x40000 /* no zero digits detected */ 81 82 /* 83 * Conversion types. 84 */ 85 #define CT_CHAR 0 /* %c conversion */ 86 #define CT_CCL 1 /* %[...] conversion */ 87 #define CT_STRING 2 /* %s conversion */ 88 #define CT_INT 3 /* integer, i.e., strtoimax or strtoumax */ 89 #define CT_FLOAT 4 /* floating, i.e., strtod */ 90 91 #define u_char unsigned char 92 #define u_long unsigned long 93 94 static u_char *__sccl(char *, u_char *); 95 96 #if !defined(VFSCANF) 97 #define VFSCANF vfscanf 98 #endif 99 100 /* 101 * vfscanf 102 */ 103 int 104 VFSCANF(FILE *fp, const char *fmt0, __va_list ap) 105 { 106 u_char *fmt = (u_char *)fmt0; 107 int c; /* character from format, or conversion */ 108 size_t width; /* field width, or 0 */ 109 char *p; /* points into all kinds of strings */ 110 int n; /* handy integer */ 111 int flags; /* flags as defined above */ 112 char *p0; /* saves original value of p when necessary */ 113 int nassigned; /* number of fields assigned */ 114 int nread; /* number of characters consumed from fp */ 115 int base; /* base argument to strtoimax/strtouimax */ 116 char ccltab[256]; /* character class table for %[...] */ 117 char buf[BUF]; /* buffer for numeric conversions */ 118 119 /* `basefix' is used to avoid `if' tests in the integer scanner */ 120 static short basefix[17] = 121 { 10, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16 }; 122 123 FLOCKFILE(fp); 124 _SET_ORIENTATION(fp, -1); 125 126 nassigned = 0; 127 nread = 0; 128 base = 0; /* XXX just to keep gcc happy */ 129 for (;;) { 130 c = *fmt++; 131 if (c == 0) { 132 FUNLOCKFILE(fp); 133 return (nassigned); 134 } 135 if (isspace(c)) { 136 while ((fp->_r > 0 || __srefill(fp) == 0) && 137 isspace(*fp->_p)) 138 nread++, fp->_r--, fp->_p++; 139 continue; 140 } 141 if (c != '%') 142 goto literal; 143 width = 0; 144 flags = 0; 145 /* 146 * switch on the format. continue if done; 147 * break once format type is derived. 148 */ 149 again: c = *fmt++; 150 switch (c) { 151 case '%': 152 literal: 153 if (fp->_r <= 0 && __srefill(fp)) 154 goto input_failure; 155 if (*fp->_p != c) 156 goto match_failure; 157 fp->_r--, fp->_p++; 158 nread++; 159 continue; 160 161 case '*': 162 flags |= SUPPRESS; 163 goto again; 164 case 'j': 165 flags |= MAXINT; 166 goto again; 167 case 'L': 168 flags |= 169 (*fmt == 'd') ? LLONG : 170 (*fmt == 'i') ? LLONG : 171 (*fmt == 'o') ? LLONG : 172 (*fmt == 'u') ? LLONG : 173 (*fmt == 'x') ? LLONG : 174 LONGDBL; 175 goto again; 176 case 'h': 177 if (*fmt == 'h') { 178 fmt++; 179 flags |= SHORTSHORT; 180 } else { 181 flags |= SHORT; 182 } 183 goto again; 184 case 'l': 185 if (*fmt == 'l') { 186 fmt++; 187 flags |= LLONG; 188 } else { 189 flags |= LONG; 190 } 191 goto again; 192 case 'q': 193 flags |= LLONG; /* deprecated */ 194 goto again; 195 case 't': 196 flags |= PTRINT; 197 goto again; 198 case 'z': 199 flags |= SIZEINT; 200 goto again; 201 202 case '0': case '1': case '2': case '3': case '4': 203 case '5': case '6': case '7': case '8': case '9': 204 width = width * 10 + c - '0'; 205 goto again; 206 207 /* 208 * Conversions. 209 * Those marked `compat' are for 4.[123]BSD compatibility. 210 * 211 * (According to ANSI, E and X formats are supposed 212 * to the same as e and x. Sorry about that.) 213 */ 214 case 'D': /* compat */ 215 flags |= LONG; 216 /* FALLTHROUGH */ 217 case 'd': 218 c = CT_INT; 219 base = 10; 220 break; 221 222 case 'i': 223 c = CT_INT; 224 base = 0; 225 break; 226 227 case 'O': /* compat */ 228 flags |= LONG; 229 /* FALLTHROUGH */ 230 case 'o': 231 c = CT_INT; 232 flags |= UNSIGNED; 233 base = 8; 234 break; 235 236 case 'u': 237 c = CT_INT; 238 flags |= UNSIGNED; 239 base = 10; 240 break; 241 242 case 'X': 243 case 'x': 244 flags |= PFXOK; /* enable 0x prefixing */ 245 c = CT_INT; 246 flags |= UNSIGNED; 247 base = 16; 248 break; 249 250 #ifdef FLOATING_POINT 251 case 'A': 252 case 'E': 253 case 'G': 254 case 'a': 255 case 'e': 256 case 'f': 257 case 'g': 258 c = CT_FLOAT; 259 break; 260 #endif 261 262 case 's': 263 c = CT_STRING; 264 break; 265 266 case '[': 267 fmt = __sccl(ccltab, fmt); 268 flags |= NOSKIP; 269 c = CT_CCL; 270 break; 271 272 case 'c': 273 flags |= NOSKIP; 274 c = CT_CHAR; 275 break; 276 277 case 'p': /* pointer format is like hex */ 278 flags |= POINTER | PFXOK; 279 c = CT_INT; 280 flags |= UNSIGNED; 281 base = 16; 282 break; 283 284 case 'n': 285 if (flags & SUPPRESS) 286 continue; 287 if (flags & SHORTSHORT) 288 *va_arg(ap, __signed char *) = nread; 289 else if (flags & SHORT) 290 *va_arg(ap, short *) = nread; 291 else if (flags & LONG) 292 *va_arg(ap, long *) = nread; 293 else if (flags & SIZEINT) 294 *va_arg(ap, ssize_t *) = nread; 295 else if (flags & PTRINT) 296 *va_arg(ap, ptrdiff_t *) = nread; 297 else if (flags & LLONG) 298 *va_arg(ap, long long *) = nread; 299 else if (flags & MAXINT) 300 *va_arg(ap, intmax_t *) = nread; 301 else 302 *va_arg(ap, int *) = nread; 303 continue; 304 305 /* 306 * Disgusting backwards compatibility hacks. XXX 307 */ 308 case '\0': /* compat */ 309 FUNLOCKFILE(fp); 310 return (EOF); 311 312 default: /* compat */ 313 if (isupper(c)) 314 flags |= LONG; 315 c = CT_INT; 316 base = 10; 317 break; 318 } 319 320 /* 321 * We have a conversion that requires input. 322 */ 323 if (fp->_r <= 0 && __srefill(fp)) 324 goto input_failure; 325 326 /* 327 * Consume leading white space, except for formats 328 * that suppress this. 329 */ 330 if ((flags & NOSKIP) == 0) { 331 while (isspace(*fp->_p)) { 332 nread++; 333 if (--fp->_r > 0) 334 fp->_p++; 335 else if (__srefill(fp)) 336 goto input_failure; 337 } 338 /* 339 * Note that there is at least one character in 340 * the buffer, so conversions that do not set NOSKIP 341 * ca no longer result in an input failure. 342 */ 343 } 344 345 /* 346 * Do the conversion. 347 */ 348 switch (c) { 349 350 case CT_CHAR: 351 /* scan arbitrary characters (sets NOSKIP) */ 352 if (width == 0) 353 width = 1; 354 if (flags & SUPPRESS) { 355 size_t sum = 0; 356 for (;;) { 357 if ((n = fp->_r) < (int)width) { 358 sum += n; 359 width -= n; 360 fp->_p += n; 361 if (__srefill(fp)) { 362 if (sum == 0) 363 goto input_failure; 364 break; 365 } 366 } else { 367 sum += width; 368 fp->_r -= width; 369 fp->_p += width; 370 break; 371 } 372 } 373 nread += sum; 374 } else { 375 size_t r = fread((void *)va_arg(ap, char *), 1, 376 width, fp); 377 378 if (r == 0) 379 goto input_failure; 380 nread += r; 381 nassigned++; 382 } 383 break; 384 385 case CT_CCL: 386 /* scan a (nonempty) character class (sets NOSKIP) */ 387 if (width == 0) 388 width = (size_t)~0; /* `infinity' */ 389 /* take only those things in the class */ 390 if (flags & SUPPRESS) { 391 n = 0; 392 while (ccltab[*fp->_p]) { 393 n++, fp->_r--, fp->_p++; 394 if (--width == 0) 395 break; 396 if (fp->_r <= 0 && __srefill(fp)) { 397 if (n == 0) 398 goto input_failure; 399 break; 400 } 401 } 402 if (n == 0) 403 goto match_failure; 404 } else { 405 p0 = p = va_arg(ap, char *); 406 while (ccltab[*fp->_p]) { 407 fp->_r--; 408 *p++ = *fp->_p++; 409 if (--width == 0) 410 break; 411 if (fp->_r <= 0 && __srefill(fp)) { 412 if (p == p0) 413 goto input_failure; 414 break; 415 } 416 } 417 n = p - p0; 418 if (n == 0) 419 goto match_failure; 420 *p = '\0'; 421 nassigned++; 422 } 423 nread += n; 424 break; 425 426 case CT_STRING: 427 /* like CCL, but zero-length string OK, & no NOSKIP */ 428 if (width == 0) 429 width = (size_t)~0; 430 if (flags & SUPPRESS) { 431 n = 0; 432 while (!isspace(*fp->_p)) { 433 n++, fp->_r--, fp->_p++; 434 if (--width == 0) 435 break; 436 if (fp->_r <= 0 && __srefill(fp)) 437 break; 438 } 439 nread += n; 440 } else { 441 p0 = p = va_arg(ap, char *); 442 while (!isspace(*fp->_p)) { 443 fp->_r--; 444 *p++ = *fp->_p++; 445 if (--width == 0) 446 break; 447 if (fp->_r <= 0 && __srefill(fp)) 448 break; 449 } 450 *p = '\0'; 451 nread += p - p0; 452 nassigned++; 453 } 454 continue; 455 456 case CT_INT: 457 /* scan an integer as if by strtoimax/strtoumax */ 458 #ifdef hardway 459 if (width == 0 || width > sizeof(buf) - 1) 460 width = sizeof(buf) - 1; 461 #else 462 /* size_t is unsigned, hence this optimisation */ 463 if (--width > sizeof(buf) - 2) 464 width = sizeof(buf) - 2; 465 width++; 466 #endif 467 flags |= SIGNOK | NDIGITS | NZDIGITS; 468 for (p = buf; width; width--) { 469 c = *fp->_p; 470 /* 471 * Switch on the character; `goto ok' 472 * if we accept it as a part of number. 473 */ 474 switch (c) { 475 476 /* 477 * The digit 0 is always legal, but is 478 * special. For %i conversions, if no 479 * digits (zero or nonzero) have been 480 * scanned (only signs), we will have 481 * base==0. In that case, we should set 482 * it to 8 and enable 0x prefixing. 483 * Also, if we have not scanned zero digits 484 * before this, do not turn off prefixing 485 * (someone else will turn it off if we 486 * have scanned any nonzero digits). 487 */ 488 case '0': 489 if (base == 0) { 490 base = 8; 491 flags |= PFXOK; 492 } 493 if (flags & NZDIGITS) 494 flags &= ~(SIGNOK|NZDIGITS|NDIGITS); 495 else 496 flags &= ~(SIGNOK|PFXOK|NDIGITS); 497 goto ok; 498 499 /* 1 through 7 always legal */ 500 case '1': case '2': case '3': 501 case '4': case '5': case '6': case '7': 502 base = basefix[base]; 503 flags &= ~(SIGNOK | PFXOK | NDIGITS); 504 goto ok; 505 506 /* digits 8 and 9 ok iff decimal or hex */ 507 case '8': case '9': 508 base = basefix[base]; 509 if (base <= 8) 510 break; /* not legal here */ 511 flags &= ~(SIGNOK | PFXOK | NDIGITS); 512 goto ok; 513 514 /* letters ok iff hex */ 515 case 'A': case 'B': case 'C': 516 case 'D': case 'E': case 'F': 517 case 'a': case 'b': case 'c': 518 case 'd': case 'e': case 'f': 519 /* no need to fix base here */ 520 if (base <= 10) 521 break; /* not legal here */ 522 flags &= ~(SIGNOK | PFXOK | NDIGITS); 523 goto ok; 524 525 /* sign ok only as first character */ 526 case '+': case '-': 527 if (flags & SIGNOK) { 528 flags &= ~SIGNOK; 529 flags |= HAVESIGN; 530 goto ok; 531 } 532 break; 533 534 /* 535 * x ok iff flag still set and 2nd char (or 536 * 3rd char if we have a sign). 537 */ 538 case 'x': case 'X': 539 if ((flags & PFXOK) && p == 540 buf + 1 + !!(flags & HAVESIGN)) { 541 base = 16; /* if %i */ 542 flags &= ~PFXOK; 543 goto ok; 544 } 545 break; 546 } 547 548 /* 549 * If we got here, c is not a legal character 550 * for a number. Stop accumulating digits. 551 */ 552 break; 553 ok: 554 /* 555 * c is legal: store it and look at the next. 556 */ 557 *p++ = c; 558 if (--fp->_r > 0) 559 fp->_p++; 560 else if (__srefill(fp)) 561 break; /* EOF */ 562 } 563 /* 564 * If we had only a sign, it is no good; push 565 * back the sign. If the number ends in `x', 566 * it was [sign] '0' 'x', so push back the x 567 * and treat it as [sign] '0'. 568 */ 569 if (flags & NDIGITS) { 570 if (p > buf) 571 (void) ungetc(*(u_char *)--p, fp); 572 goto match_failure; 573 } 574 c = ((u_char *)p)[-1]; 575 if (c == 'x' || c == 'X') { 576 --p; 577 (void) ungetc(c, fp); 578 } 579 if ((flags & SUPPRESS) == 0) { 580 uintmax_t res; 581 582 *p = '\0'; 583 if (flags & UNSIGNED) 584 res = strtoumax(buf, NULL, base); 585 else 586 res = strtoimax(buf, NULL, base); 587 if (flags & POINTER) 588 *va_arg(ap, void **) = 589 (void *)(uintptr_t)res; 590 else if (flags & MAXINT) 591 *va_arg(ap, intmax_t *) = res; 592 else if (flags & LLONG) 593 *va_arg(ap, long long *) = res; 594 else if (flags & SIZEINT) 595 *va_arg(ap, ssize_t *) = res; 596 else if (flags & PTRINT) 597 *va_arg(ap, ptrdiff_t *) = res; 598 else if (flags & LONG) 599 *va_arg(ap, long *) = res; 600 else if (flags & SHORT) 601 *va_arg(ap, short *) = res; 602 else if (flags & SHORTSHORT) 603 *va_arg(ap, __signed char *) = res; 604 else 605 *va_arg(ap, int *) = res; 606 nassigned++; 607 } 608 nread += p - buf; 609 break; 610 611 #ifdef FLOATING_POINT 612 case CT_FLOAT: 613 /* scan a floating point number as if by strtod */ 614 /* FIXME: Support INFINITY, NaN(...)? */ 615 #ifdef hardway 616 if (width == 0 || width > sizeof(buf) - 1) 617 width = sizeof(buf) - 1; 618 #else 619 /* size_t is unsigned, hence this optimisation */ 620 if (--width > sizeof(buf) - 2) 621 width = sizeof(buf) - 2; 622 width++; 623 #endif 624 flags |= SIGNOK | NDIGITS | DPTOK | EXPOK | NZDIGITS; 625 for (p = buf; width; width--) { 626 c = *fp->_p; 627 /* 628 * This code mimicks the integer conversion 629 * code, but is much simpler. 630 */ 631 switch (c) { 632 case '0': 633 if (flags & NZDIGITS) { 634 flags &= ~(SIGNOK|NZDIGITS|NDIGITS); 635 flags |= PFXOK; 636 } else { 637 flags &= ~(SIGNOK|PFXOK|NDIGITS); 638 } 639 goto fok; 640 case '1': case '2': case '3': 641 case '4': case '5': case '6': case '7': 642 case '8': case '9': 643 flags &= ~(SIGNOK | NDIGITS | PFXOK); 644 goto fok; 645 case '+': case '-': 646 if (flags & SIGNOK) { 647 flags &= ~SIGNOK; 648 flags |= HAVESIGN; 649 goto fok; 650 } 651 break; 652 /* 653 * x ok iff flag still set and 2nd char (or 654 * 3rd char if we have a sign). 655 */ 656 case 'x': case 'X': 657 if ((flags & PFXOK) && p == 658 buf + 1 + !!(flags & HAVESIGN)) { 659 base = 16; 660 flags &= ~PFXOK; 661 goto fok; 662 } 663 break; 664 case '.': 665 if (flags & DPTOK) { 666 flags &= ~(SIGNOK | DPTOK | PFXOK); 667 goto fok; 668 } 669 break; 670 case 'e': case 'E': 671 /* no exponent without some digits */ 672 if ((flags&(NDIGITS|EXPOK)) == EXPOK && base != 16) { 673 flags = 674 (flags & ~(EXPOK|DPTOK|PFXOK)) | 675 SIGNOK | NDIGITS; 676 goto fok; 677 } 678 break; 679 case 'p': case 'P': 680 /* no exponent without some digits */ 681 if ((flags&(NDIGITS|EXPOK)) == EXPOK && base == 16) { 682 flags = 683 (flags & ~(EXPOK|DPTOK|PFXOK)) | 684 SIGNOK | NDIGITS; 685 goto fok; 686 } 687 break; 688 } 689 break; 690 fok: 691 *p++ = c; 692 if (--fp->_r > 0) 693 fp->_p++; 694 else if (__srefill(fp)) 695 break; /* EOF */ 696 } 697 /* 698 * If no digits, might be missing exponent digits 699 * (just give back the exponent) or might be missing 700 * regular digits, but had sign and/or decimal point. 701 */ 702 if (flags & NDIGITS) { 703 if (flags & EXPOK) { 704 /* no digits at all */ 705 while (p > buf) 706 ungetc(*(u_char *)--p, fp); 707 goto match_failure; 708 } 709 /* just a bad exponent (e and maybe sign) */ 710 c = *(u_char *)--p; 711 if (c != 'e' && c != 'E') { 712 (void) ungetc(c, fp);/* sign */ 713 c = *(u_char *)--p; 714 } 715 (void) ungetc(c, fp); 716 } 717 if ((flags & SUPPRESS) == 0) { 718 double res; 719 720 *p = '\0'; 721 res = strtod(buf, (char **) NULL); 722 if (flags & LONGDBL) 723 *va_arg(ap, long double *) = res; 724 else if (flags & LONG) 725 *va_arg(ap, double *) = res; 726 else 727 *va_arg(ap, float *) = res; 728 nassigned++; 729 } 730 nread += p - buf; 731 break; 732 #endif /* FLOATING_POINT */ 733 } 734 } 735 input_failure: 736 if (nassigned == 0) 737 nassigned = -1; 738 match_failure: 739 FUNLOCKFILE(fp); 740 return (nassigned); 741 } 742 743 /* 744 * Fill in the given table from the scanset at the given format 745 * (just after `['). Return a pointer to the character past the 746 * closing `]'. The table has a 1 wherever characters should be 747 * considered part of the scanset. 748 */ 749 static u_char * 750 __sccl(char *tab, u_char *fmt) 751 { 752 int c, n, v; 753 754 /* first `clear' the whole table */ 755 c = *fmt++; /* first char hat => negated scanset */ 756 if (c == '^') { 757 v = 1; /* default => accept */ 758 c = *fmt++; /* get new first char */ 759 } else 760 v = 0; /* default => reject */ 761 /* should probably use memset here */ 762 for (n = 0; n < 256; n++) 763 tab[n] = v; 764 if (c == 0) 765 return (fmt - 1);/* format ended before closing ] */ 766 767 /* 768 * Now set the entries corresponding to the actual scanset 769 * to the opposite of the above. 770 * 771 * The first character may be ']' (or '-') without being special; 772 * the last character may be '-'. 773 */ 774 v = 1 - v; 775 for (;;) { 776 tab[c] = v; /* take character c */ 777 doswitch: 778 n = *fmt++; /* and examine the next */ 779 switch (n) { 780 781 case 0: /* format ended too soon */ 782 return (fmt - 1); 783 784 case '-': 785 /* 786 * A scanset of the form 787 * [01+-] 788 * is defined as `the digit 0, the digit 1, 789 * the character +, the character -', but 790 * the effect of a scanset such as 791 * [a-zA-Z0-9] 792 * is implementation defined. The V7 Unix 793 * scanf treats `a-z' as `the letters a through 794 * z', but treats `a-a' as `the letter a, the 795 * character -, and the letter a'. 796 * 797 * For compatibility, the `-' is not considerd 798 * to define a range if the character following 799 * it is either a close bracket (required by ANSI) 800 * or is not numerically greater than the character 801 * we just stored in the table (c). 802 */ 803 n = *fmt; 804 if (n == ']' || n < c) { 805 c = '-'; 806 break; /* resume the for(;;) */ 807 } 808 fmt++; 809 do { /* fill in the range */ 810 tab[++c] = v; 811 } while (c < n); 812 #if 1 /* XXX another disgusting compatibility hack */ 813 /* 814 * Alas, the V7 Unix scanf also treats formats 815 * such as [a-c-e] as `the letters a through e'. 816 * This too is permitted by the standard.... 817 */ 818 goto doswitch; 819 #else 820 c = *fmt++; 821 if (c == 0) 822 return (fmt - 1); 823 if (c == ']') 824 return (fmt); 825 #endif 826 break; 827 828 case ']': /* end of scanset */ 829 return (fmt); 830 831 default: /* just another character */ 832 c = n; 833 break; 834 } 835 } 836 /* NOTREACHED */ 837 } 838
