vfscanf.c revision 1.27.6.4
1 /* $NetBSD: vfscanf.c,v 1.27.6.4 2002/05/02 17:04:55 nathanw 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 1.27.6.4 2002/05/02 17:04:55 nathanw 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 <stddef.h> 54 #include <stdio.h> 55 #include <stdlib.h> 56 #include <ctype.h> 57 #if __STDC__ 58 #include <stdarg.h> 59 #else 60 #include <varargs.h> 61 #endif 62 63 #include "reentrant.h" 64 #include "local.h" 65 66 #ifdef FLOATING_POINT 67 #include "floatio.h" 68 #endif 69 70 #define BUF 513 /* Maximum length of numeric string. */ 71 72 /* 73 * Flags used during conversion. 74 */ 75 #define LONG 0x0001 /* l: long or double */ 76 #define LONGDBL 0x0002 /* L: long double; unimplemented */ 77 #define SHORT 0x0004 /* h: short */ 78 #define QUAD 0x0008 /* q: quad */ 79 #define LONGLONG 0x0010 /* ll: long long */ 80 #define MAXINT 0x0020 /* j: intmax_t */ 81 #define PTRINT 0x0040 /* t: ptrdiff_t */ 82 #define SIZEINT 0x0080 /* z: size_t */ 83 #define SUPPRESS 0x0100 /* suppress assignment */ 84 #define POINTER 0x0200 /* weird %p pointer (`fake hex') */ 85 #define NOSKIP 0x0400 /* do not skip blanks */ 86 87 /* 88 * The following are used in numeric conversions only: 89 * SIGNOK, NDIGITS, DPTOK, and EXPOK are for floating point; 90 * SIGNOK, NDIGITS, PFXOK, and NZDIGITS are for integral. 91 */ 92 #define SIGNOK 0x0800 /* +/- is (still) legal */ 93 #define NDIGITS 0x1000 /* no digits detected */ 94 95 #define DPTOK 0x2000 /* (float) decimal point is still legal */ 96 #define EXPOK 0x4000 /* (float) exponent (e+3, etc) still legal */ 97 98 #define PFXOK 0x2000 /* 0x prefix is (still) legal */ 99 #define NZDIGITS 0x4000 /* no zero digits detected */ 100 101 /* 102 * Conversion types. 103 */ 104 #define CT_CHAR 0 /* %c conversion */ 105 #define CT_CCL 1 /* %[...] conversion */ 106 #define CT_STRING 2 /* %s conversion */ 107 #define CT_INT 3 /* integer, i.e., strtoimax or strtoumax */ 108 #define CT_FLOAT 4 /* floating, i.e., strtod */ 109 110 #define u_char unsigned char 111 #define u_long unsigned long 112 113 static const u_char *__sccl __P((char *, const u_char *)); 114 115 int 116 __svfscanf(fp, fmt0, ap) 117 FILE *fp; 118 const char *fmt0; 119 _BSD_VA_LIST_ ap; 120 { 121 int ret; 122 123 FLOCKFILE(fp); 124 ret = __svfscanf_unlocked(fp, fmt0, ap); 125 FUNLOCKFILE(fp); 126 127 return ret; 128 } 129 130 /* 131 * vfscanf 132 */ 133 int 134 __svfscanf_unlocked(fp, fmt0, ap) 135 FILE *fp; 136 const char *fmt0; 137 _BSD_VA_LIST_ ap; 138 { 139 const u_char *fmt = (const u_char *)fmt0; 140 int c; /* character from format, or conversion */ 141 size_t width; /* field width, or 0 */ 142 char *p; /* points into all kinds of strings */ 143 int n; /* handy integer */ 144 int flags; /* flags as defined above */ 145 char *p0; /* saves original value of p when necessary */ 146 int nassigned; /* number of fields assigned */ 147 int nread; /* number of characters consumed from fp */ 148 int base; /* base argument to strtoimax/strtoumax */ 149 uintmax_t (*ccfn) __P((const char *, char **, int)); 150 /* conversion function (strtoimax/strtoumax) */ 151 char ccltab[256]; /* character class table for %[...] */ 152 char buf[BUF]; /* buffer for numeric conversions */ 153 154 /* `basefix' is used to avoid `if' tests in the integer scanner */ 155 static const short basefix[17] = 156 { 10, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16 }; 157 158 _DIAGASSERT(fp != NULL); 159 _DIAGASSERT(fmt0 != NULL); 160 161 _SET_ORIENTATION(fp, -1); 162 163 nassigned = 0; 164 nread = 0; 165 base = 0; /* XXX just to keep gcc happy */ 166 ccfn = NULL; /* XXX just to keep gcc happy */ 167 for (;;) { 168 c = *fmt++; 169 if (c == 0) { 170 return (nassigned); 171 } 172 if (isspace(c)) { 173 while ((fp->_r > 0 || __srefill(fp) == 0) && 174 isspace(*fp->_p)) 175 nread++, fp->_r--, fp->_p++; 176 continue; 177 } 178 if (c != '%') 179 goto literal; 180 width = 0; 181 flags = 0; 182 /* 183 * switch on the format. continue if done; 184 * break once format type is derived. 185 */ 186 again: c = *fmt++; 187 switch (c) { 188 case '%': 189 literal: 190 if (fp->_r <= 0 && __srefill(fp)) 191 goto input_failure; 192 if (*fp->_p != c) 193 goto match_failure; 194 fp->_r--, fp->_p++; 195 nread++; 196 continue; 197 198 case '*': 199 flags |= SUPPRESS; 200 goto again; 201 case 'L': 202 flags |= LONGDBL; 203 goto again; 204 case 'h': 205 flags |= SHORT; 206 goto again; 207 case 'j': 208 flags |= MAXINT; 209 goto again; 210 case 'l': 211 if (*fmt == 'l') { 212 fmt++; 213 flags |= LONGLONG; 214 } else { 215 flags |= LONG; 216 } 217 goto again; 218 case 'q': 219 flags |= QUAD; 220 goto again; 221 case 't': 222 flags |= PTRINT; 223 goto again; 224 case 'z': 225 flags |= SIZEINT; 226 goto again; 227 228 case '0': case '1': case '2': case '3': case '4': 229 case '5': case '6': case '7': case '8': case '9': 230 width = width * 10 + c - '0'; 231 goto again; 232 233 /* 234 * Conversions. 235 * Those marked `compat' are for 4.[123]BSD compatibility. 236 * 237 * (According to ANSI, E and X formats are supposed 238 * to the same as e and x. Sorry about that.) 239 */ 240 case 'D': /* compat */ 241 flags |= LONG; 242 /* FALLTHROUGH */ 243 case 'd': 244 c = CT_INT; 245 ccfn = (uintmax_t (*) __P((const char *, char **, int)))strtoimax; 246 base = 10; 247 break; 248 249 case 'i': 250 c = CT_INT; 251 ccfn = (uintmax_t (*) __P((const char *, char **, int)))strtoimax; 252 base = 0; 253 break; 254 255 case 'O': /* compat */ 256 flags |= LONG; 257 /* FALLTHROUGH */ 258 case 'o': 259 c = CT_INT; 260 ccfn = strtoumax; 261 base = 8; 262 break; 263 264 case 'u': 265 c = CT_INT; 266 ccfn = strtoumax; 267 base = 10; 268 break; 269 270 case 'X': 271 case 'x': 272 flags |= PFXOK; /* enable 0x prefixing */ 273 c = CT_INT; 274 ccfn = strtoumax; 275 base = 16; 276 break; 277 278 #ifdef FLOATING_POINT 279 case 'E': 280 case 'F': 281 case 'G': 282 case 'e': 283 case 'f': 284 case 'g': 285 c = CT_FLOAT; 286 break; 287 #endif 288 289 case 's': 290 c = CT_STRING; 291 break; 292 293 case '[': 294 fmt = __sccl(ccltab, fmt); 295 flags |= NOSKIP; 296 c = CT_CCL; 297 break; 298 299 case 'c': 300 flags |= NOSKIP; 301 c = CT_CHAR; 302 break; 303 304 case 'p': /* pointer format is like hex */ 305 flags |= POINTER | PFXOK; 306 c = CT_INT; 307 ccfn = strtoumax; 308 base = 16; 309 break; 310 311 case 'n': 312 if (flags & SUPPRESS) /* ??? */ 313 continue; 314 if (flags & SHORT) 315 *va_arg(ap, short *) = nread; 316 else if (flags & LONG) 317 *va_arg(ap, long *) = nread; 318 else if (flags & QUAD) 319 *va_arg(ap, quad_t *) = nread; 320 else if (flags & LONGLONG) 321 /* LONGLONG */ 322 *va_arg(ap, long long int *) = nread; 323 else if (flags & SIZEINT) 324 *va_arg(ap, ssize_t *) = nread; 325 else if (flags & PTRINT) 326 *va_arg(ap, ptrdiff_t *) = nread; 327 else if (flags & MAXINT) 328 *va_arg(ap, intmax_t *) = nread; 329 else 330 *va_arg(ap, int *) = nread; 331 continue; 332 333 /* 334 * Disgusting backwards compatibility hacks. XXX 335 */ 336 case '\0': /* compat */ 337 return (EOF); 338 339 default: /* compat */ 340 if (isupper(c)) 341 flags |= LONG; 342 c = CT_INT; 343 ccfn = (uintmax_t (*) __P((const char *, char **, int)))strtoimax; 344 base = 10; 345 break; 346 } 347 348 /* 349 * We have a conversion that requires input. 350 */ 351 if (fp->_r <= 0 && __srefill(fp)) 352 goto input_failure; 353 354 /* 355 * Consume leading white space, except for formats 356 * that suppress this. 357 */ 358 if ((flags & NOSKIP) == 0) { 359 while (isspace(*fp->_p)) { 360 nread++; 361 if (--fp->_r > 0) 362 fp->_p++; 363 else if (__srefill(fp)) 364 goto input_failure; 365 } 366 /* 367 * Note that there is at least one character in 368 * the buffer, so conversions that do not set NOSKIP 369 * ca no longer result in an input failure. 370 */ 371 } 372 373 /* 374 * Do the conversion. 375 */ 376 switch (c) { 377 378 case CT_CHAR: 379 /* scan arbitrary characters (sets NOSKIP) */ 380 if (width == 0) 381 width = 1; 382 if (flags & SUPPRESS) { 383 size_t sum = 0; 384 for (;;) { 385 if ((n = fp->_r) < width) { 386 sum += n; 387 width -= n; 388 fp->_p += n; 389 if (__srefill(fp)) { 390 if (sum == 0) 391 goto input_failure; 392 break; 393 } 394 } else { 395 sum += width; 396 fp->_r -= width; 397 fp->_p += width; 398 break; 399 } 400 } 401 nread += sum; 402 } else { 403 size_t r = fread((void *)va_arg(ap, char *), 1, 404 width, fp); 405 406 if (r == 0) 407 goto input_failure; 408 nread += r; 409 nassigned++; 410 } 411 break; 412 413 case CT_CCL: 414 /* scan a (nonempty) character class (sets NOSKIP) */ 415 if (width == 0) 416 width = ~0U; /* `infinity' */ 417 /* take only those things in the class */ 418 if (flags & SUPPRESS) { 419 n = 0; 420 while (ccltab[*fp->_p]) { 421 n++, fp->_r--, fp->_p++; 422 if (--width == 0) 423 break; 424 if (fp->_r <= 0 && __srefill(fp)) { 425 if (n == 0) 426 goto input_failure; 427 break; 428 } 429 } 430 if (n == 0) 431 goto match_failure; 432 } else { 433 p0 = p = va_arg(ap, char *); 434 while (ccltab[*fp->_p]) { 435 fp->_r--; 436 *p++ = *fp->_p++; 437 if (--width == 0) 438 break; 439 if (fp->_r <= 0 && __srefill(fp)) { 440 if (p == p0) 441 goto input_failure; 442 break; 443 } 444 } 445 n = p - p0; 446 if (n == 0) 447 goto match_failure; 448 *p = 0; 449 nassigned++; 450 } 451 nread += n; 452 break; 453 454 case CT_STRING: 455 /* like CCL, but zero-length string OK, & no NOSKIP */ 456 if (width == 0) 457 width = ~0U; 458 if (flags & SUPPRESS) { 459 n = 0; 460 while (!isspace(*fp->_p)) { 461 n++, fp->_r--, fp->_p++; 462 if (--width == 0) 463 break; 464 if (fp->_r <= 0 && __srefill(fp)) 465 break; 466 } 467 nread += n; 468 } else { 469 p0 = p = va_arg(ap, char *); 470 while (!isspace(*fp->_p)) { 471 fp->_r--; 472 *p++ = *fp->_p++; 473 if (--width == 0) 474 break; 475 if (fp->_r <= 0 && __srefill(fp)) 476 break; 477 } 478 *p = 0; 479 nread += p - p0; 480 nassigned++; 481 } 482 continue; 483 484 case CT_INT: 485 /* scan an integer as if by strtoimax/strtoumax */ 486 #ifdef hardway 487 if (width == 0 || width > sizeof(buf) - 1) 488 width = sizeof(buf) - 1; 489 #else 490 /* size_t is unsigned, hence this optimisation */ 491 if (--width > sizeof(buf) - 2) 492 width = sizeof(buf) - 2; 493 width++; 494 #endif 495 flags |= SIGNOK | NDIGITS | NZDIGITS; 496 for (p = buf; width; width--) { 497 c = *fp->_p; 498 /* 499 * Switch on the character; `goto ok' 500 * if we accept it as a part of number. 501 */ 502 switch (c) { 503 504 /* 505 * The digit 0 is always legal, but is 506 * special. For %i conversions, if no 507 * digits (zero or nonzero) have been 508 * scanned (only signs), we will have 509 * base==0. In that case, we should set 510 * it to 8 and enable 0x prefixing. 511 * Also, if we have not scanned zero digits 512 * before this, do not turn off prefixing 513 * (someone else will turn it off if we 514 * have scanned any nonzero digits). 515 */ 516 case '0': 517 if (base == 0) { 518 base = 8; 519 flags |= PFXOK; 520 } 521 if (flags & NZDIGITS) 522 flags &= ~(SIGNOK|NZDIGITS|NDIGITS); 523 else 524 flags &= ~(SIGNOK|PFXOK|NDIGITS); 525 goto ok; 526 527 /* 1 through 7 always legal */ 528 case '1': case '2': case '3': 529 case '4': case '5': case '6': case '7': 530 base = basefix[base]; 531 flags &= ~(SIGNOK | PFXOK | NDIGITS); 532 goto ok; 533 534 /* digits 8 and 9 ok iff decimal or hex */ 535 case '8': case '9': 536 base = basefix[base]; 537 if (base <= 8) 538 break; /* not legal here */ 539 flags &= ~(SIGNOK | PFXOK | NDIGITS); 540 goto ok; 541 542 /* letters ok iff hex */ 543 case 'A': case 'B': case 'C': 544 case 'D': case 'E': case 'F': 545 case 'a': case 'b': case 'c': 546 case 'd': case 'e': case 'f': 547 /* no need to fix base here */ 548 if (base <= 10) 549 break; /* not legal here */ 550 flags &= ~(SIGNOK | PFXOK | NDIGITS); 551 goto ok; 552 553 /* sign ok only as first character */ 554 case '+': case '-': 555 if (flags & SIGNOK) { 556 flags &= ~SIGNOK; 557 goto ok; 558 } 559 break; 560 561 /* x ok iff flag still set & 2nd char */ 562 case 'x': case 'X': 563 if (flags & PFXOK && p == buf + 1) { 564 base = 16; /* if %i */ 565 flags &= ~PFXOK; 566 goto ok; 567 } 568 break; 569 } 570 571 /* 572 * If we got here, c is not a legal character 573 * for a number. Stop accumulating digits. 574 */ 575 break; 576 ok: 577 /* 578 * c is legal: store it and look at the next. 579 */ 580 *p++ = c; 581 if (--fp->_r > 0) 582 fp->_p++; 583 else if (__srefill(fp)) 584 break; /* EOF */ 585 } 586 /* 587 * If we had only a sign, it is no good; push 588 * back the sign. If the number ends in `x', 589 * it was [sign] '0' 'x', so push back the x 590 * and treat it as [sign] '0'. 591 */ 592 if (flags & NDIGITS) { 593 if (p > buf) 594 (void) ungetc(*(u_char *)--p, fp); 595 goto match_failure; 596 } 597 c = ((u_char *)p)[-1]; 598 if (c == 'x' || c == 'X') { 599 --p; 600 (void) ungetc(c, fp); 601 } 602 if ((flags & SUPPRESS) == 0) { 603 uintmax_t res; 604 605 *p = 0; 606 res = (*ccfn)(buf, (char **)NULL, base); 607 if (flags & POINTER) 608 *va_arg(ap, void **) = 609 (void *)(long)res; 610 else if (flags & MAXINT) 611 *va_arg(ap, intmax_t *) = res; 612 else if (flags & PTRINT) 613 *va_arg(ap, ptrdiff_t *) = 614 (ptrdiff_t)res; 615 else if (flags & SIZEINT) 616 *va_arg(ap, ssize_t *) = (ssize_t)res; 617 else if (flags & LONGLONG) 618 /* LONGLONG */ 619 *va_arg(ap, long long int *) = res; 620 else if (flags & QUAD) 621 *va_arg(ap, quad_t *) = (quad_t)res; 622 else if (flags & LONG) 623 *va_arg(ap, long *) = (long)res; 624 else if (flags & SHORT) 625 *va_arg(ap, short *) = (short)res; 626 else 627 *va_arg(ap, int *) = (int)res; 628 nassigned++; 629 } 630 nread += p - buf; 631 break; 632 633 #ifdef FLOATING_POINT 634 case CT_FLOAT: 635 /* scan a floating point number as if by strtod */ 636 #ifdef hardway 637 if (width == 0 || width > sizeof(buf) - 1) 638 width = sizeof(buf) - 1; 639 #else 640 /* size_t is unsigned, hence this optimisation */ 641 if (--width > sizeof(buf) - 2) 642 width = sizeof(buf) - 2; 643 width++; 644 #endif 645 flags |= SIGNOK | NDIGITS | DPTOK | EXPOK; 646 for (p = buf; width; width--) { 647 c = *fp->_p; 648 /* 649 * This code mimicks the integer conversion 650 * code, but is much simpler. 651 */ 652 switch (c) { 653 654 case '0': case '1': case '2': case '3': 655 case '4': case '5': case '6': case '7': 656 case '8': case '9': 657 flags &= ~(SIGNOK | NDIGITS); 658 goto fok; 659 660 case '+': case '-': 661 if (flags & SIGNOK) { 662 flags &= ~SIGNOK; 663 goto fok; 664 } 665 break; 666 case '.': 667 if (flags & DPTOK) { 668 flags &= ~(SIGNOK | DPTOK); 669 goto fok; 670 } 671 break; 672 case 'e': case 'E': 673 /* no exponent without some digits */ 674 if ((flags&(NDIGITS|EXPOK)) == EXPOK) { 675 flags = 676 (flags & ~(EXPOK|DPTOK)) | 677 SIGNOK | NDIGITS; 678 goto fok; 679 } 680 break; 681 } 682 break; 683 fok: 684 *p++ = c; 685 if (--fp->_r > 0) 686 fp->_p++; 687 else if (__srefill(fp)) 688 break; /* EOF */ 689 } 690 /* 691 * If no digits, might be missing exponent digits 692 * (just give back the exponent) or might be missing 693 * regular digits, but had sign and/or decimal point. 694 */ 695 if (flags & NDIGITS) { 696 if (flags & EXPOK) { 697 /* no digits at all */ 698 while (p > buf) 699 ungetc(*(u_char *)--p, fp); 700 goto match_failure; 701 } 702 /* just a bad exponent (e and maybe sign) */ 703 c = *(u_char *)--p; 704 if (c != 'e' && c != 'E') { 705 (void) ungetc(c, fp);/* sign */ 706 c = *(u_char *)--p; 707 } 708 (void) ungetc(c, fp); 709 } 710 if ((flags & SUPPRESS) == 0) { 711 double res; 712 713 *p = 0; 714 res = strtod(buf, (char **) NULL); 715 if (flags & LONGDBL) 716 *va_arg(ap, long double *) = res; 717 else if (flags & LONG) 718 *va_arg(ap, double *) = res; 719 else 720 *va_arg(ap, float *) = res; 721 nassigned++; 722 } 723 nread += p - buf; 724 break; 725 #endif /* FLOATING_POINT */ 726 } 727 } 728 input_failure: 729 return (nassigned ? nassigned : EOF); 730 match_failure: 731 return (nassigned); 732 } 733 734 /* 735 * Fill in the given table from the scanset at the given format 736 * (just after `['). Return a pointer to the character past the 737 * closing `]'. The table has a 1 wherever characters should be 738 * considered part of the scanset. 739 */ 740 static const u_char * 741 __sccl(tab, fmt) 742 char *tab; 743 const u_char *fmt; 744 { 745 int c, n, v; 746 747 _DIAGASSERT(tab != NULL); 748 _DIAGASSERT(fmt != NULL); 749 750 /* first `clear' the whole table */ 751 c = *fmt++; /* first char hat => negated scanset */ 752 if (c == '^') { 753 v = 1; /* default => accept */ 754 c = *fmt++; /* get new first char */ 755 } else 756 v = 0; /* default => reject */ 757 /* should probably use memset here */ 758 for (n = 0; n < 256; n++) 759 tab[n] = v; 760 if (c == 0) 761 return (fmt - 1);/* format ended before closing ] */ 762 763 /* 764 * Now set the entries corresponding to the actual scanset 765 * to the opposite of the above. 766 * 767 * The first character may be ']' (or '-') without being special; 768 * the last character may be '-'. 769 */ 770 v = 1 - v; 771 for (;;) { 772 tab[c] = v; /* take character c */ 773 doswitch: 774 n = *fmt++; /* and examine the next */ 775 switch (n) { 776 777 case 0: /* format ended too soon */ 778 return (fmt - 1); 779 780 case '-': 781 /* 782 * A scanset of the form 783 * [01+-] 784 * is defined as `the digit 0, the digit 1, 785 * the character +, the character -', but 786 * the effect of a scanset such as 787 * [a-zA-Z0-9] 788 * is implementation defined. The V7 Unix 789 * scanf treats `a-z' as `the letters a through 790 * z', but treats `a-a' as `the letter a, the 791 * character -, and the letter a'. 792 * 793 * For compatibility, the `-' is not considerd 794 * to define a range if the character following 795 * it is either a close bracket (required by ANSI) 796 * or is not numerically greater than the character 797 * we just stored in the table (c). 798 */ 799 n = *fmt; 800 if (n == ']' || n < c) { 801 c = '-'; 802 break; /* resume the for(;;) */ 803 } 804 fmt++; 805 do { /* fill in the range */ 806 tab[++c] = v; 807 } while (c < n); 808 #if 1 /* XXX another disgusting compatibility hack */ 809 /* 810 * Alas, the V7 Unix scanf also treats formats 811 * such as [a-c-e] as `the letters a through e'. 812 * This too is permitted by the standard.... 813 */ 814 goto doswitch; 815 #else 816 c = *fmt++; 817 if (c == 0) 818 return (fmt - 1); 819 if (c == ']') 820 return (fmt); 821 break; 822 #endif 823 824 case ']': /* end of scanset */ 825 return (fmt); 826 827 default: /* just another character */ 828 c = n; 829 break; 830 } 831 } 832 /* NOTREACHED */ 833 } 834
Indexes created Sat Sep 27 21:09:56 GMT 2025