vfscanf.c revision 1.33
1 /* $NetBSD: vfscanf.c,v 1.33 2003/01/18 11:29:59 thorpej Exp $ */ 2 3 /*- 4 * Copyright (c) 1990, 1993 5 * The Regents of the University of California. All rights reserved. 6 * 7 * This code is derived from software contributed to Berkeley by 8 * Chris Torek. 9 * 10 * Redistribution and use in source and binary forms, with or without 11 * modification, are permitted provided that the following conditions 12 * are met: 13 * 1. Redistributions of source code must retain the above copyright 14 * notice, this list of conditions and the following disclaimer. 15 * 2. Redistributions in binary form must reproduce the above copyright 16 * notice, this list of conditions and the following disclaimer in the 17 * documentation and/or other materials provided with the distribution. 18 * 3. All advertising materials mentioning features or use of this software 19 * must display the following acknowledgement: 20 * This product includes software developed by the University of 21 * California, Berkeley and its contributors. 22 * 4. Neither the name of the University nor the names of its contributors 23 * may be used to endorse or promote products derived from this software 24 * without specific prior written permission. 25 * 26 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 27 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 28 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 29 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 30 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 31 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 32 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 33 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 34 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 35 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 36 * SUCH DAMAGE. 37 */ 38 39 #include <sys/cdefs.h> 40 #if defined(LIBC_SCCS) && !defined(lint) 41 #if 0 42 static char sccsid[] = "@(#)vfscanf.c 8.1 (Berkeley) 6/4/93"; 43 #else 44 __RCSID("$NetBSD: vfscanf.c,v 1.33 2003/01/18 11:29:59 thorpej Exp $"); 45 #endif 46 #endif /* LIBC_SCCS and not lint */ 47 48 #include "namespace.h" 49 50 #include <assert.h> 51 #include <errno.h> 52 #include <inttypes.h> 53 #include <stdarg.h> 54 #include <stddef.h> 55 #include <stdio.h> 56 #include <stdlib.h> 57 #include <ctype.h> 58 59 #include "reentrant.h" 60 #include "local.h" 61 62 #ifdef FLOATING_POINT 63 #include "floatio.h" 64 #endif 65 66 /* 67 * Provide an external name for vfscanf. Note, we don't use the normal 68 * namespace.h method; stdio routines explicitly use the internal name 69 * __svfscanf. 70 */ 71 #ifdef __weak_alias 72 __weak_alias(vfscanf,__svfscanf) 73 #endif 74 75 #define BUF 513 /* Maximum length of numeric string. */ 76 77 /* 78 * Flags used during conversion. 79 */ 80 #define LONG 0x0001 /* l: long or double */ 81 #define LONGDBL 0x0002 /* L: long double; unimplemented */ 82 #define SHORT 0x0004 /* h: short */ 83 #define QUAD 0x0008 /* q: quad */ 84 #define LONGLONG 0x0010 /* ll: long long */ 85 #define MAXINT 0x0020 /* j: intmax_t */ 86 #define PTRINT 0x0040 /* t: ptrdiff_t */ 87 #define SIZEINT 0x0080 /* z: size_t */ 88 #define SUPPRESS 0x0100 /* suppress assignment */ 89 #define POINTER 0x0200 /* weird %p pointer (`fake hex') */ 90 #define NOSKIP 0x0400 /* do not skip blanks */ 91 92 /* 93 * The following are used in numeric conversions only: 94 * SIGNOK, NDIGITS, DPTOK, and EXPOK are for floating point; 95 * SIGNOK, NDIGITS, PFXOK, and NZDIGITS are for integral. 96 */ 97 #define SIGNOK 0x0800 /* +/- is (still) legal */ 98 #define NDIGITS 0x1000 /* no digits detected */ 99 100 #define DPTOK 0x2000 /* (float) decimal point is still legal */ 101 #define EXPOK 0x4000 /* (float) exponent (e+3, etc) still legal */ 102 103 #define PFXOK 0x2000 /* 0x prefix is (still) legal */ 104 #define NZDIGITS 0x4000 /* no zero digits detected */ 105 106 /* 107 * Conversion types. 108 */ 109 #define CT_CHAR 0 /* %c conversion */ 110 #define CT_CCL 1 /* %[...] conversion */ 111 #define CT_STRING 2 /* %s conversion */ 112 #define CT_INT 3 /* integer, i.e., strtoimax or strtoumax */ 113 #define CT_FLOAT 4 /* floating, i.e., strtod */ 114 115 #define u_char unsigned char 116 #define u_long unsigned long 117 118 static const u_char *__sccl __P((char *, const u_char *)); 119 120 int 121 __svfscanf(fp, fmt0, ap) 122 FILE *fp; 123 const char *fmt0; 124 _BSD_VA_LIST_ ap; 125 { 126 int ret; 127 128 FLOCKFILE(fp); 129 ret = __svfscanf_unlocked(fp, fmt0, ap); 130 FUNLOCKFILE(fp); 131 132 return ret; 133 } 134 135 /* 136 * vfscanf 137 */ 138 int 139 __svfscanf_unlocked(fp, fmt0, ap) 140 FILE *fp; 141 const char *fmt0; 142 _BSD_VA_LIST_ ap; 143 { 144 const u_char *fmt = (const u_char *)fmt0; 145 int c; /* character from format, or conversion */ 146 size_t width; /* field width, or 0 */ 147 char *p; /* points into all kinds of strings */ 148 int n; /* handy integer */ 149 int flags; /* flags as defined above */ 150 char *p0; /* saves original value of p when necessary */ 151 int nassigned; /* number of fields assigned */ 152 int nread; /* number of characters consumed from fp */ 153 int base; /* base argument to strtoimax/strtoumax */ 154 uintmax_t (*ccfn) __P((const char *, char **, int)); 155 /* conversion function (strtoimax/strtoumax) */ 156 char ccltab[256]; /* character class table for %[...] */ 157 char buf[BUF]; /* buffer for numeric conversions */ 158 159 /* `basefix' is used to avoid `if' tests in the integer scanner */ 160 static const short basefix[17] = 161 { 10, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16 }; 162 163 _DIAGASSERT(fp != NULL); 164 _DIAGASSERT(fmt0 != NULL); 165 166 _SET_ORIENTATION(fp, -1); 167 168 nassigned = 0; 169 nread = 0; 170 base = 0; /* XXX just to keep gcc happy */ 171 ccfn = NULL; /* XXX just to keep gcc happy */ 172 for (;;) { 173 c = *fmt++; 174 if (c == 0) { 175 return (nassigned); 176 } 177 if (isspace(c)) { 178 while ((fp->_r > 0 || __srefill(fp) == 0) && 179 isspace(*fp->_p)) 180 nread++, fp->_r--, fp->_p++; 181 continue; 182 } 183 if (c != '%') 184 goto literal; 185 width = 0; 186 flags = 0; 187 /* 188 * switch on the format. continue if done; 189 * break once format type is derived. 190 */ 191 again: c = *fmt++; 192 switch (c) { 193 case '%': 194 literal: 195 if (fp->_r <= 0 && __srefill(fp)) 196 goto input_failure; 197 if (*fp->_p != c) 198 goto match_failure; 199 fp->_r--, fp->_p++; 200 nread++; 201 continue; 202 203 case '*': 204 flags |= SUPPRESS; 205 goto again; 206 case 'L': 207 flags |= LONGDBL; 208 goto again; 209 case 'h': 210 flags |= SHORT; 211 goto again; 212 case 'j': 213 flags |= MAXINT; 214 goto again; 215 case 'l': 216 if (*fmt == 'l') { 217 fmt++; 218 flags |= LONGLONG; 219 } else { 220 flags |= LONG; 221 } 222 goto again; 223 case 'q': 224 flags |= QUAD; 225 goto again; 226 case 't': 227 flags |= PTRINT; 228 goto again; 229 case 'z': 230 flags |= SIZEINT; 231 goto again; 232 233 case '0': case '1': case '2': case '3': case '4': 234 case '5': case '6': case '7': case '8': case '9': 235 width = width * 10 + c - '0'; 236 goto again; 237 238 /* 239 * Conversions. 240 * Those marked `compat' are for 4.[123]BSD compatibility. 241 * 242 * (According to ANSI, E and X formats are supposed 243 * to the same as e and x. Sorry about that.) 244 */ 245 case 'D': /* compat */ 246 flags |= LONG; 247 /* FALLTHROUGH */ 248 case 'd': 249 c = CT_INT; 250 ccfn = (uintmax_t (*) __P((const char *, char **, int)))strtoimax; 251 base = 10; 252 break; 253 254 case 'i': 255 c = CT_INT; 256 ccfn = (uintmax_t (*) __P((const char *, char **, int)))strtoimax; 257 base = 0; 258 break; 259 260 case 'O': /* compat */ 261 flags |= LONG; 262 /* FALLTHROUGH */ 263 case 'o': 264 c = CT_INT; 265 ccfn = strtoumax; 266 base = 8; 267 break; 268 269 case 'u': 270 c = CT_INT; 271 ccfn = strtoumax; 272 base = 10; 273 break; 274 275 case 'X': 276 case 'x': 277 flags |= PFXOK; /* enable 0x prefixing */ 278 c = CT_INT; 279 ccfn = strtoumax; 280 base = 16; 281 break; 282 283 #ifdef FLOATING_POINT 284 case 'E': 285 case 'F': 286 case 'G': 287 case 'e': 288 case 'f': 289 case 'g': 290 c = CT_FLOAT; 291 break; 292 #endif 293 294 case 's': 295 c = CT_STRING; 296 break; 297 298 case '[': 299 fmt = __sccl(ccltab, fmt); 300 flags |= NOSKIP; 301 c = CT_CCL; 302 break; 303 304 case 'c': 305 flags |= NOSKIP; 306 c = CT_CHAR; 307 break; 308 309 case 'p': /* pointer format is like hex */ 310 flags |= POINTER | PFXOK; 311 c = CT_INT; 312 ccfn = strtoumax; 313 base = 16; 314 break; 315 316 case 'n': 317 if (flags & SUPPRESS) /* ??? */ 318 continue; 319 if (flags & SHORT) 320 *va_arg(ap, short *) = nread; 321 else if (flags & LONG) 322 *va_arg(ap, long *) = nread; 323 else if (flags & QUAD) 324 *va_arg(ap, quad_t *) = nread; 325 else if (flags & LONGLONG) 326 /* LONGLONG */ 327 *va_arg(ap, long long int *) = nread; 328 else if (flags & SIZEINT) 329 *va_arg(ap, ssize_t *) = nread; 330 else if (flags & PTRINT) 331 *va_arg(ap, ptrdiff_t *) = nread; 332 else if (flags & MAXINT) 333 *va_arg(ap, intmax_t *) = nread; 334 else 335 *va_arg(ap, int *) = nread; 336 continue; 337 338 /* 339 * Disgusting backwards compatibility hacks. XXX 340 */ 341 case '\0': /* compat */ 342 return (EOF); 343 344 default: /* compat */ 345 if (isupper(c)) 346 flags |= LONG; 347 c = CT_INT; 348 ccfn = (uintmax_t (*) __P((const char *, char **, int)))strtoimax; 349 base = 10; 350 break; 351 } 352 353 /* 354 * We have a conversion that requires input. 355 */ 356 if (fp->_r <= 0 && __srefill(fp)) 357 goto input_failure; 358 359 /* 360 * Consume leading white space, except for formats 361 * that suppress this. 362 */ 363 if ((flags & NOSKIP) == 0) { 364 while (isspace(*fp->_p)) { 365 nread++; 366 if (--fp->_r > 0) 367 fp->_p++; 368 else if (__srefill(fp)) 369 goto input_failure; 370 } 371 /* 372 * Note that there is at least one character in 373 * the buffer, so conversions that do not set NOSKIP 374 * ca no longer result in an input failure. 375 */ 376 } 377 378 /* 379 * Do the conversion. 380 */ 381 switch (c) { 382 383 case CT_CHAR: 384 /* scan arbitrary characters (sets NOSKIP) */ 385 if (width == 0) 386 width = 1; 387 if (flags & SUPPRESS) { 388 size_t sum = 0; 389 for (;;) { 390 if ((n = fp->_r) < width) { 391 sum += n; 392 width -= n; 393 fp->_p += n; 394 if (__srefill(fp)) { 395 if (sum == 0) 396 goto input_failure; 397 break; 398 } 399 } else { 400 sum += width; 401 fp->_r -= width; 402 fp->_p += width; 403 break; 404 } 405 } 406 nread += sum; 407 } else { 408 size_t r = fread((void *)va_arg(ap, char *), 1, 409 width, fp); 410 411 if (r == 0) 412 goto input_failure; 413 nread += r; 414 nassigned++; 415 } 416 break; 417 418 case CT_CCL: 419 /* scan a (nonempty) character class (sets NOSKIP) */ 420 if (width == 0) 421 width = ~0U; /* `infinity' */ 422 /* take only those things in the class */ 423 if (flags & SUPPRESS) { 424 n = 0; 425 while (ccltab[*fp->_p]) { 426 n++, fp->_r--, fp->_p++; 427 if (--width == 0) 428 break; 429 if (fp->_r <= 0 && __srefill(fp)) { 430 if (n == 0) 431 goto input_failure; 432 break; 433 } 434 } 435 if (n == 0) 436 goto match_failure; 437 } else { 438 p0 = p = va_arg(ap, char *); 439 while (ccltab[*fp->_p]) { 440 fp->_r--; 441 *p++ = *fp->_p++; 442 if (--width == 0) 443 break; 444 if (fp->_r <= 0 && __srefill(fp)) { 445 if (p == p0) 446 goto input_failure; 447 break; 448 } 449 } 450 n = p - p0; 451 if (n == 0) 452 goto match_failure; 453 *p = 0; 454 nassigned++; 455 } 456 nread += n; 457 break; 458 459 case CT_STRING: 460 /* like CCL, but zero-length string OK, & no NOSKIP */ 461 if (width == 0) 462 width = ~0U; 463 if (flags & SUPPRESS) { 464 n = 0; 465 while (!isspace(*fp->_p)) { 466 n++, fp->_r--, fp->_p++; 467 if (--width == 0) 468 break; 469 if (fp->_r <= 0 && __srefill(fp)) 470 break; 471 } 472 nread += n; 473 } else { 474 p0 = p = va_arg(ap, char *); 475 while (!isspace(*fp->_p)) { 476 fp->_r--; 477 *p++ = *fp->_p++; 478 if (--width == 0) 479 break; 480 if (fp->_r <= 0 && __srefill(fp)) 481 break; 482 } 483 *p = 0; 484 nread += p - p0; 485 nassigned++; 486 } 487 continue; 488 489 case CT_INT: 490 /* scan an integer as if by strtoimax/strtoumax */ 491 #ifdef hardway 492 if (width == 0 || width > sizeof(buf) - 1) 493 width = sizeof(buf) - 1; 494 #else 495 /* size_t is unsigned, hence this optimisation */ 496 if (--width > sizeof(buf) - 2) 497 width = sizeof(buf) - 2; 498 width++; 499 #endif 500 flags |= SIGNOK | NDIGITS | NZDIGITS; 501 for (p = buf; width; width--) { 502 c = *fp->_p; 503 /* 504 * Switch on the character; `goto ok' 505 * if we accept it as a part of number. 506 */ 507 switch (c) { 508 509 /* 510 * The digit 0 is always legal, but is 511 * special. For %i conversions, if no 512 * digits (zero or nonzero) have been 513 * scanned (only signs), we will have 514 * base==0. In that case, we should set 515 * it to 8 and enable 0x prefixing. 516 * Also, if we have not scanned zero digits 517 * before this, do not turn off prefixing 518 * (someone else will turn it off if we 519 * have scanned any nonzero digits). 520 */ 521 case '0': 522 if (base == 0) { 523 base = 8; 524 flags |= PFXOK; 525 } 526 if (flags & NZDIGITS) 527 flags &= ~(SIGNOK|NZDIGITS|NDIGITS); 528 else 529 flags &= ~(SIGNOK|PFXOK|NDIGITS); 530 goto ok; 531 532 /* 1 through 7 always legal */ 533 case '1': case '2': case '3': 534 case '4': case '5': case '6': case '7': 535 base = basefix[base]; 536 flags &= ~(SIGNOK | PFXOK | NDIGITS); 537 goto ok; 538 539 /* digits 8 and 9 ok iff decimal or hex */ 540 case '8': case '9': 541 base = basefix[base]; 542 if (base <= 8) 543 break; /* not legal here */ 544 flags &= ~(SIGNOK | PFXOK | NDIGITS); 545 goto ok; 546 547 /* letters ok iff hex */ 548 case 'A': case 'B': case 'C': 549 case 'D': case 'E': case 'F': 550 case 'a': case 'b': case 'c': 551 case 'd': case 'e': case 'f': 552 /* no need to fix base here */ 553 if (base <= 10) 554 break; /* not legal here */ 555 flags &= ~(SIGNOK | PFXOK | NDIGITS); 556 goto ok; 557 558 /* sign ok only as first character */ 559 case '+': case '-': 560 if (flags & SIGNOK) { 561 flags &= ~SIGNOK; 562 goto ok; 563 } 564 break; 565 566 /* x ok iff flag still set & 2nd char */ 567 case 'x': case 'X': 568 if (flags & PFXOK && p == buf + 1) { 569 base = 16; /* if %i */ 570 flags &= ~PFXOK; 571 goto ok; 572 } 573 break; 574 } 575 576 /* 577 * If we got here, c is not a legal character 578 * for a number. Stop accumulating digits. 579 */ 580 break; 581 ok: 582 /* 583 * c is legal: store it and look at the next. 584 */ 585 *p++ = c; 586 if (--fp->_r > 0) 587 fp->_p++; 588 else if (__srefill(fp)) 589 break; /* EOF */ 590 } 591 /* 592 * If we had only a sign, it is no good; push 593 * back the sign. If the number ends in `x', 594 * it was [sign] '0' 'x', so push back the x 595 * and treat it as [sign] '0'. 596 */ 597 if (flags & NDIGITS) { 598 if (p > buf) 599 (void) ungetc(*(u_char *)--p, fp); 600 goto match_failure; 601 } 602 c = ((u_char *)p)[-1]; 603 if (c == 'x' || c == 'X') { 604 --p; 605 (void) ungetc(c, fp); 606 } 607 if ((flags & SUPPRESS) == 0) { 608 uintmax_t res; 609 610 *p = 0; 611 res = (*ccfn)(buf, (char **)NULL, base); 612 if (flags & POINTER) 613 *va_arg(ap, void **) = 614 (void *)(long)res; 615 else if (flags & MAXINT) 616 *va_arg(ap, intmax_t *) = res; 617 else if (flags & PTRINT) 618 *va_arg(ap, ptrdiff_t *) = 619 (ptrdiff_t)res; 620 else if (flags & SIZEINT) 621 *va_arg(ap, ssize_t *) = (ssize_t)res; 622 else if (flags & LONGLONG) 623 /* LONGLONG */ 624 *va_arg(ap, long long int *) = res; 625 else if (flags & QUAD) 626 *va_arg(ap, quad_t *) = (quad_t)res; 627 else if (flags & LONG) 628 *va_arg(ap, long *) = (long)res; 629 else if (flags & SHORT) 630 *va_arg(ap, short *) = (short)res; 631 else 632 *va_arg(ap, int *) = (int)res; 633 nassigned++; 634 } 635 nread += p - buf; 636 break; 637 638 #ifdef FLOATING_POINT 639 case CT_FLOAT: 640 /* scan a floating point number as if by strtod */ 641 #ifdef hardway 642 if (width == 0 || width > sizeof(buf) - 1) 643 width = sizeof(buf) - 1; 644 #else 645 /* size_t is unsigned, hence this optimisation */ 646 if (--width > sizeof(buf) - 2) 647 width = sizeof(buf) - 2; 648 width++; 649 #endif 650 flags |= SIGNOK | NDIGITS | DPTOK | EXPOK; 651 for (p = buf; width; width--) { 652 c = *fp->_p; 653 /* 654 * This code mimicks the integer conversion 655 * code, but is much simpler. 656 */ 657 switch (c) { 658 659 case '0': case '1': case '2': case '3': 660 case '4': case '5': case '6': case '7': 661 case '8': case '9': 662 flags &= ~(SIGNOK | NDIGITS); 663 goto fok; 664 665 case '+': case '-': 666 if (flags & SIGNOK) { 667 flags &= ~SIGNOK; 668 goto fok; 669 } 670 break; 671 case '.': 672 if (flags & DPTOK) { 673 flags &= ~(SIGNOK | DPTOK); 674 goto fok; 675 } 676 break; 677 case 'e': case 'E': 678 /* no exponent without some digits */ 679 if ((flags&(NDIGITS|EXPOK)) == EXPOK) { 680 flags = 681 (flags & ~(EXPOK|DPTOK)) | 682 SIGNOK | NDIGITS; 683 goto fok; 684 } 685 break; 686 } 687 break; 688 fok: 689 *p++ = c; 690 if (--fp->_r > 0) 691 fp->_p++; 692 else if (__srefill(fp)) 693 break; /* EOF */ 694 } 695 /* 696 * If no digits, might be missing exponent digits 697 * (just give back the exponent) or might be missing 698 * regular digits, but had sign and/or decimal point. 699 */ 700 if (flags & NDIGITS) { 701 if (flags & EXPOK) { 702 /* no digits at all */ 703 while (p > buf) 704 ungetc(*(u_char *)--p, fp); 705 goto match_failure; 706 } 707 /* just a bad exponent (e and maybe sign) */ 708 c = *(u_char *)--p; 709 if (c != 'e' && c != 'E') { 710 (void) ungetc(c, fp);/* sign */ 711 c = *(u_char *)--p; 712 } 713 (void) ungetc(c, fp); 714 } 715 if ((flags & SUPPRESS) == 0) { 716 double res; 717 718 *p = 0; 719 res = strtod(buf, (char **) NULL); 720 if (flags & LONGDBL) 721 *va_arg(ap, long double *) = res; 722 else if (flags & LONG) 723 *va_arg(ap, double *) = res; 724 else 725 *va_arg(ap, float *) = res; 726 nassigned++; 727 } 728 nread += p - buf; 729 break; 730 #endif /* FLOATING_POINT */ 731 } 732 } 733 input_failure: 734 return (nassigned ? nassigned : EOF); 735 match_failure: 736 return (nassigned); 737 } 738 739 /* 740 * Fill in the given table from the scanset at the given format 741 * (just after `['). Return a pointer to the character past the 742 * closing `]'. The table has a 1 wherever characters should be 743 * considered part of the scanset. 744 */ 745 static const u_char * 746 __sccl(tab, fmt) 747 char *tab; 748 const u_char *fmt; 749 { 750 int c, n, v; 751 752 _DIAGASSERT(tab != NULL); 753 _DIAGASSERT(fmt != NULL); 754 755 /* first `clear' the whole table */ 756 c = *fmt++; /* first char hat => negated scanset */ 757 if (c == '^') { 758 v = 1; /* default => accept */ 759 c = *fmt++; /* get new first char */ 760 } else 761 v = 0; /* default => reject */ 762 /* should probably use memset here */ 763 for (n = 0; n < 256; n++) 764 tab[n] = v; 765 if (c == 0) 766 return (fmt - 1);/* format ended before closing ] */ 767 768 /* 769 * Now set the entries corresponding to the actual scanset 770 * to the opposite of the above. 771 * 772 * The first character may be ']' (or '-') without being special; 773 * the last character may be '-'. 774 */ 775 v = 1 - v; 776 for (;;) { 777 tab[c] = v; /* take character c */ 778 doswitch: 779 n = *fmt++; /* and examine the next */ 780 switch (n) { 781 782 case 0: /* format ended too soon */ 783 return (fmt - 1); 784 785 case '-': 786 /* 787 * A scanset of the form 788 * [01+-] 789 * is defined as `the digit 0, the digit 1, 790 * the character +, the character -', but 791 * the effect of a scanset such as 792 * [a-zA-Z0-9] 793 * is implementation defined. The V7 Unix 794 * scanf treats `a-z' as `the letters a through 795 * z', but treats `a-a' as `the letter a, the 796 * character -, and the letter a'. 797 * 798 * For compatibility, the `-' is not considerd 799 * to define a range if the character following 800 * it is either a close bracket (required by ANSI) 801 * or is not numerically greater than the character 802 * we just stored in the table (c). 803 */ 804 n = *fmt; 805 if (n == ']' || n < c) { 806 c = '-'; 807 break; /* resume the for(;;) */ 808 } 809 fmt++; 810 do { /* fill in the range */ 811 tab[++c] = v; 812 } while (c < n); 813 #if 1 /* XXX another disgusting compatibility hack */ 814 /* 815 * Alas, the V7 Unix scanf also treats formats 816 * such as [a-c-e] as `the letters a through e'. 817 * This too is permitted by the standard.... 818 */ 819 goto doswitch; 820 #else 821 c = *fmt++; 822 if (c == 0) 823 return (fmt - 1); 824 if (c == ']') 825 return (fmt); 826 break; 827 #endif 828 829 case ']': /* end of scanset */ 830 return (fmt); 831 832 default: /* just another character */ 833 c = n; 834 break; 835 } 836 } 837 /* NOTREACHED */ 838 } 839
Indexes created Sat Sep 27 22:09:54 GMT 2025