1 /* $NetBSD: vfscanf.c,v 1.28 2001/04/28 15:41:29 kleink 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 1.28 2001/04/28 15:41:29 kleink 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 "local.h" 64 #include "reentrant.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 /* 116 * vfscanf 117 */ 118 int 119 __svfscanf(fp, fmt0, ap) 120 FILE *fp; 121 const char *fmt0; 122 _BSD_VA_LIST_ ap; 123 { 124 const u_char *fmt = (const u_char *)fmt0; 125 int c; /* character from format, or conversion */ 126 size_t width; /* field width, or 0 */ 127 char *p; /* points into all kinds of strings */ 128 int n; /* handy integer */ 129 int flags; /* flags as defined above */ 130 char *p0; /* saves original value of p when necessary */ 131 int nassigned; /* number of fields assigned */ 132 int nread; /* number of characters consumed from fp */ 133 int base; /* base argument to strtoimax/strtoumax */ 134 uintmax_t (*ccfn) __P((const char *, char **, int)); 135 /* conversion function (strtoimax/strtoumax) */ 136 char ccltab[256]; /* character class table for %[...] */ 137 char buf[BUF]; /* buffer for numeric conversions */ 138 139 /* `basefix' is used to avoid `if' tests in the integer scanner */ 140 static const short basefix[17] = 141 { 10, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16 }; 142 143 _DIAGASSERT(fp != NULL); 144 _DIAGASSERT(fmt0 != NULL); 145 146 FLOCKFILE(fp); 147 148 nassigned = 0; 149 nread = 0; 150 base = 0; /* XXX just to keep gcc happy */ 151 ccfn = NULL; /* XXX just to keep gcc happy */ 152 for (;;) { 153 c = *fmt++; 154 if (c == 0) { 155 FUNLOCKFILE(fp); 156 return (nassigned); 157 } 158 if (isspace(c)) { 159 while ((fp->_r > 0 || __srefill(fp) == 0) && 160 isspace(*fp->_p)) 161 nread++, fp->_r--, fp->_p++; 162 continue; 163 } 164 if (c != '%') 165 goto literal; 166 width = 0; 167 flags = 0; 168 /* 169 * switch on the format. continue if done; 170 * break once format type is derived. 171 */ 172 again: c = *fmt++; 173 switch (c) { 174 case '%': 175 literal: 176 if (fp->_r <= 0 && __srefill(fp)) 177 goto input_failure; 178 if (*fp->_p != c) 179 goto match_failure; 180 fp->_r--, fp->_p++; 181 nread++; 182 continue; 183 184 case '*': 185 flags |= SUPPRESS; 186 goto again; 187 case 'L': 188 flags |= LONGDBL; 189 goto again; 190 case 'h': 191 flags |= SHORT; 192 goto again; 193 case 'j': 194 flags |= MAXINT; 195 goto again; 196 case 'l': 197 if (*fmt == 'l') { 198 fmt++; 199 flags |= LONGLONG; 200 } else { 201 flags |= LONG; 202 } 203 goto again; 204 case 'q': 205 flags |= QUAD; 206 goto again; 207 case 't': 208 flags |= PTRINT; 209 goto again; 210 case 'z': 211 flags |= SIZEINT; 212 goto again; 213 214 case '0': case '1': case '2': case '3': case '4': 215 case '5': case '6': case '7': case '8': case '9': 216 width = width * 10 + c - '0'; 217 goto again; 218 219 /* 220 * Conversions. 221 * Those marked `compat' are for 4.[123]BSD compatibility. 222 * 223 * (According to ANSI, E and X formats are supposed 224 * to the same as e and x. Sorry about that.) 225 */ 226 case 'D': /* compat */ 227 flags |= LONG; 228 /* FALLTHROUGH */ 229 case 'd': 230 c = CT_INT; 231 ccfn = (uintmax_t (*) __P((const char *, char **, int)))strtoimax; 232 base = 10; 233 break; 234 235 case 'i': 236 c = CT_INT; 237 ccfn = (uintmax_t (*) __P((const char *, char **, int)))strtoimax; 238 base = 0; 239 break; 240 241 case 'O': /* compat */ 242 flags |= LONG; 243 /* FALLTHROUGH */ 244 case 'o': 245 c = CT_INT; 246 ccfn = strtoumax; 247 base = 8; 248 break; 249 250 case 'u': 251 c = CT_INT; 252 ccfn = strtoumax; 253 base = 10; 254 break; 255 256 case 'X': 257 case 'x': 258 flags |= PFXOK; /* enable 0x prefixing */ 259 c = CT_INT; 260 ccfn = strtoumax; 261 base = 16; 262 break; 263 264 #ifdef FLOATING_POINT 265 case 'E': 266 case 'G': 267 case 'e': 268 case 'f': 269 case 'g': 270 c = CT_FLOAT; 271 break; 272 #endif 273 274 case 's': 275 c = CT_STRING; 276 break; 277 278 case '[': 279 fmt = __sccl(ccltab, fmt); 280 flags |= NOSKIP; 281 c = CT_CCL; 282 break; 283 284 case 'c': 285 flags |= NOSKIP; 286 c = CT_CHAR; 287 break; 288 289 case 'p': /* pointer format is like hex */ 290 flags |= POINTER | PFXOK; 291 c = CT_INT; 292 ccfn = strtoumax; 293 base = 16; 294 break; 295 296 case 'n': 297 if (flags & SUPPRESS) /* ??? */ 298 continue; 299 if (flags & SHORT) 300 *va_arg(ap, short *) = nread; 301 else if (flags & LONG) 302 *va_arg(ap, long *) = nread; 303 else if (flags & QUAD) 304 *va_arg(ap, quad_t *) = nread; 305 else if (flags & LONGLONG) 306 /* LONGLONG */ 307 *va_arg(ap, long long int *) = nread; 308 else if (flags & SIZEINT) 309 *va_arg(ap, ssize_t *) = nread; 310 else if (flags & PTRINT) 311 *va_arg(ap, ptrdiff_t *) = nread; 312 else if (flags & MAXINT) 313 *va_arg(ap, intmax_t *) = nread; 314 else 315 *va_arg(ap, int *) = nread; 316 continue; 317 318 /* 319 * Disgusting backwards compatibility hacks. XXX 320 */ 321 case '\0': /* compat */ 322 FUNLOCKFILE(fp); 323 return (EOF); 324 325 default: /* compat */ 326 if (isupper(c)) 327 flags |= LONG; 328 c = CT_INT; 329 ccfn = (uintmax_t (*) __P((const char *, char **, int)))strtoimax; 330 base = 10; 331 break; 332 } 333 334 /* 335 * We have a conversion that requires input. 336 */ 337 if (fp->_r <= 0 && __srefill(fp)) 338 goto input_failure; 339 340 /* 341 * Consume leading white space, except for formats 342 * that suppress this. 343 */ 344 if ((flags & NOSKIP) == 0) { 345 while (isspace(*fp->_p)) { 346 nread++; 347 if (--fp->_r > 0) 348 fp->_p++; 349 else if (__srefill(fp)) 350 goto input_failure; 351 } 352 /* 353 * Note that there is at least one character in 354 * the buffer, so conversions that do not set NOSKIP 355 * ca no longer result in an input failure. 356 */ 357 } 358 359 /* 360 * Do the conversion. 361 */ 362 switch (c) { 363 364 case CT_CHAR: 365 /* scan arbitrary characters (sets NOSKIP) */ 366 if (width == 0) 367 width = 1; 368 if (flags & SUPPRESS) { 369 size_t sum = 0; 370 for (;;) { 371 if ((n = fp->_r) < width) { 372 sum += n; 373 width -= n; 374 fp->_p += n; 375 if (__srefill(fp)) { 376 if (sum == 0) 377 goto input_failure; 378 break; 379 } 380 } else { 381 sum += width; 382 fp->_r -= width; 383 fp->_p += width; 384 break; 385 } 386 } 387 nread += sum; 388 } else { 389 size_t r = fread((void *)va_arg(ap, char *), 1, 390 width, fp); 391 392 if (r == 0) 393 goto input_failure; 394 nread += r; 395 nassigned++; 396 } 397 break; 398 399 case CT_CCL: 400 /* scan a (nonempty) character class (sets NOSKIP) */ 401 if (width == 0) 402 width = ~0U; /* `infinity' */ 403 /* take only those things in the class */ 404 if (flags & SUPPRESS) { 405 n = 0; 406 while (ccltab[*fp->_p]) { 407 n++, fp->_r--, fp->_p++; 408 if (--width == 0) 409 break; 410 if (fp->_r <= 0 && __srefill(fp)) { 411 if (n == 0) 412 goto input_failure; 413 break; 414 } 415 } 416 if (n == 0) 417 goto match_failure; 418 } else { 419 p0 = p = va_arg(ap, char *); 420 while (ccltab[*fp->_p]) { 421 fp->_r--; 422 *p++ = *fp->_p++; 423 if (--width == 0) 424 break; 425 if (fp->_r <= 0 && __srefill(fp)) { 426 if (p == p0) 427 goto input_failure; 428 break; 429 } 430 } 431 n = p - p0; 432 if (n == 0) 433 goto match_failure; 434 *p = 0; 435 nassigned++; 436 } 437 nread += n; 438 break; 439 440 case CT_STRING: 441 /* like CCL, but zero-length string OK, & no NOSKIP */ 442 if (width == 0) 443 width = ~0U; 444 if (flags & SUPPRESS) { 445 n = 0; 446 while (!isspace(*fp->_p)) { 447 n++, fp->_r--, fp->_p++; 448 if (--width == 0) 449 break; 450 if (fp->_r <= 0 && __srefill(fp)) 451 break; 452 } 453 nread += n; 454 } else { 455 p0 = p = va_arg(ap, char *); 456 while (!isspace(*fp->_p)) { 457 fp->_r--; 458 *p++ = *fp->_p++; 459 if (--width == 0) 460 break; 461 if (fp->_r <= 0 && __srefill(fp)) 462 break; 463 } 464 *p = 0; 465 nread += p - p0; 466 nassigned++; 467 } 468 continue; 469 470 case CT_INT: 471 /* scan an integer as if by strtoimax/strtoumax */ 472 #ifdef hardway 473 if (width == 0 || width > sizeof(buf) - 1) 474 width = sizeof(buf) - 1; 475 #else 476 /* size_t is unsigned, hence this optimisation */ 477 if (--width > sizeof(buf) - 2) 478 width = sizeof(buf) - 2; 479 width++; 480 #endif 481 flags |= SIGNOK | NDIGITS | NZDIGITS; 482 for (p = buf; width; width--) { 483 c = *fp->_p; 484 /* 485 * Switch on the character; `goto ok' 486 * if we accept it as a part of number. 487 */ 488 switch (c) { 489 490 /* 491 * The digit 0 is always legal, but is 492 * special. For %i conversions, if no 493 * digits (zero or nonzero) have been 494 * scanned (only signs), we will have 495 * base==0. In that case, we should set 496 * it to 8 and enable 0x prefixing. 497 * Also, if we have not scanned zero digits 498 * before this, do not turn off prefixing 499 * (someone else will turn it off if we 500 * have scanned any nonzero digits). 501 */ 502 case '0': 503 if (base == 0) { 504 base = 8; 505 flags |= PFXOK; 506 } 507 if (flags & NZDIGITS) 508 flags &= ~(SIGNOK|NZDIGITS|NDIGITS); 509 else 510 flags &= ~(SIGNOK|PFXOK|NDIGITS); 511 goto ok; 512 513 /* 1 through 7 always legal */ 514 case '1': case '2': case '3': 515 case '4': case '5': case '6': case '7': 516 base = basefix[base]; 517 flags &= ~(SIGNOK | PFXOK | NDIGITS); 518 goto ok; 519 520 /* digits 8 and 9 ok iff decimal or hex */ 521 case '8': case '9': 522 base = basefix[base]; 523 if (base <= 8) 524 break; /* not legal here */ 525 flags &= ~(SIGNOK | PFXOK | NDIGITS); 526 goto ok; 527 528 /* letters ok iff hex */ 529 case 'A': case 'B': case 'C': 530 case 'D': case 'E': case 'F': 531 case 'a': case 'b': case 'c': 532 case 'd': case 'e': case 'f': 533 /* no need to fix base here */ 534 if (base <= 10) 535 break; /* not legal here */ 536 flags &= ~(SIGNOK | PFXOK | NDIGITS); 537 goto ok; 538 539 /* sign ok only as first character */ 540 case '+': case '-': 541 if (flags & SIGNOK) { 542 flags &= ~SIGNOK; 543 goto ok; 544 } 545 break; 546 547 /* x ok iff flag still set & 2nd char */ 548 case 'x': case 'X': 549 if (flags & PFXOK && p == buf + 1) { 550 base = 16; /* if %i */ 551 flags &= ~PFXOK; 552 goto ok; 553 } 554 break; 555 } 556 557 /* 558 * If we got here, c is not a legal character 559 * for a number. Stop accumulating digits. 560 */ 561 break; 562 ok: 563 /* 564 * c is legal: store it and look at the next. 565 */ 566 *p++ = c; 567 if (--fp->_r > 0) 568 fp->_p++; 569 else if (__srefill(fp)) 570 break; /* EOF */ 571 } 572 /* 573 * If we had only a sign, it is no good; push 574 * back the sign. If the number ends in `x', 575 * it was [sign] '0' 'x', so push back the x 576 * and treat it as [sign] '0'. 577 */ 578 if (flags & NDIGITS) { 579 if (p > buf) 580 (void) ungetc(*(u_char *)--p, fp); 581 goto match_failure; 582 } 583 c = ((u_char *)p)[-1]; 584 if (c == 'x' || c == 'X') { 585 --p; 586 (void) ungetc(c, fp); 587 } 588 if ((flags & SUPPRESS) == 0) { 589 uintmax_t res; 590 591 *p = 0; 592 res = (*ccfn)(buf, (char **)NULL, base); 593 if (flags & POINTER) 594 *va_arg(ap, void **) = 595 (void *)(long)res; 596 else if (flags & MAXINT) 597 *va_arg(ap, intmax_t *) = res; 598 else if (flags & PTRINT) 599 *va_arg(ap, ptrdiff_t *) = 600 (ptrdiff_t)res; 601 else if (flags & SIZEINT) 602 *va_arg(ap, ssize_t *) = (ssize_t)res; 603 else if (flags & LONGLONG) 604 /* LONGLONG */ 605 *va_arg(ap, long long int *) = res; 606 else if (flags & QUAD) 607 *va_arg(ap, quad_t *) = (quad_t)res; 608 else if (flags & LONG) 609 *va_arg(ap, long *) = (long)res; 610 else if (flags & SHORT) 611 *va_arg(ap, short *) = (short)res; 612 else 613 *va_arg(ap, int *) = (int)res; 614 nassigned++; 615 } 616 nread += p - buf; 617 break; 618 619 #ifdef FLOATING_POINT 620 case CT_FLOAT: 621 /* scan a floating point number as if by strtod */ 622 #ifdef hardway 623 if (width == 0 || width > sizeof(buf) - 1) 624 width = sizeof(buf) - 1; 625 #else 626 /* size_t is unsigned, hence this optimisation */ 627 if (--width > sizeof(buf) - 2) 628 width = sizeof(buf) - 2; 629 width++; 630 #endif 631 flags |= SIGNOK | NDIGITS | DPTOK | EXPOK; 632 for (p = buf; width; width--) { 633 c = *fp->_p; 634 /* 635 * This code mimicks the integer conversion 636 * code, but is much simpler. 637 */ 638 switch (c) { 639 640 case '0': case '1': case '2': case '3': 641 case '4': case '5': case '6': case '7': 642 case '8': case '9': 643 flags &= ~(SIGNOK | NDIGITS); 644 goto fok; 645 646 case '+': case '-': 647 if (flags & SIGNOK) { 648 flags &= ~SIGNOK; 649 goto fok; 650 } 651 break; 652 case '.': 653 if (flags & DPTOK) { 654 flags &= ~(SIGNOK | DPTOK); 655 goto fok; 656 } 657 break; 658 case 'e': case 'E': 659 /* no exponent without some digits */ 660 if ((flags&(NDIGITS|EXPOK)) == EXPOK) { 661 flags = 662 (flags & ~(EXPOK|DPTOK)) | 663 SIGNOK | NDIGITS; 664 goto fok; 665 } 666 break; 667 } 668 break; 669 fok: 670 *p++ = c; 671 if (--fp->_r > 0) 672 fp->_p++; 673 else if (__srefill(fp)) 674 break; /* EOF */ 675 } 676 /* 677 * If no digits, might be missing exponent digits 678 * (just give back the exponent) or might be missing 679 * regular digits, but had sign and/or decimal point. 680 */ 681 if (flags & NDIGITS) { 682 if (flags & EXPOK) { 683 /* no digits at all */ 684 while (p > buf) 685 ungetc(*(u_char *)--p, fp); 686 goto match_failure; 687 } 688 /* just a bad exponent (e and maybe sign) */ 689 c = *(u_char *)--p; 690 if (c != 'e' && c != 'E') { 691 (void) ungetc(c, fp);/* sign */ 692 c = *(u_char *)--p; 693 } 694 (void) ungetc(c, fp); 695 } 696 if ((flags & SUPPRESS) == 0) { 697 double res; 698 699 *p = 0; 700 res = strtod(buf, (char **) NULL); 701 if (flags & LONGDBL) 702 *va_arg(ap, long double *) = res; 703 else if (flags & LONG) 704 *va_arg(ap, double *) = res; 705 else 706 *va_arg(ap, float *) = res; 707 nassigned++; 708 } 709 nread += p - buf; 710 break; 711 #endif /* FLOATING_POINT */ 712 } 713 } 714 input_failure: 715 FUNLOCKFILE(fp); 716 return (nassigned ? nassigned : EOF); 717 match_failure: 718 FUNLOCKFILE(fp); 719 return (nassigned); 720 } 721 722 /* 723 * Fill in the given table from the scanset at the given format 724 * (just after `['). Return a pointer to the character past the 725 * closing `]'. The table has a 1 wherever characters should be 726 * considered part of the scanset. 727 */ 728 static const u_char * 729 __sccl(tab, fmt) 730 char *tab; 731 const u_char *fmt; 732 { 733 int c, n, v; 734 735 _DIAGASSERT(tab != NULL); 736 _DIAGASSERT(fmt != NULL); 737 738 /* first `clear' the whole table */ 739 c = *fmt++; /* first char hat => negated scanset */ 740 if (c == '^') { 741 v = 1; /* default => accept */ 742 c = *fmt++; /* get new first char */ 743 } else 744 v = 0; /* default => reject */ 745 /* should probably use memset here */ 746 for (n = 0; n < 256; n++) 747 tab[n] = v; 748 if (c == 0) 749 return (fmt - 1);/* format ended before closing ] */ 750 751 /* 752 * Now set the entries corresponding to the actual scanset 753 * to the opposite of the above. 754 * 755 * The first character may be ']' (or '-') without being special; 756 * the last character may be '-'. 757 */ 758 v = 1 - v; 759 for (;;) { 760 tab[c] = v; /* take character c */ 761 doswitch: 762 n = *fmt++; /* and examine the next */ 763 switch (n) { 764 765 case 0: /* format ended too soon */ 766 return (fmt - 1); 767 768 case '-': 769 /* 770 * A scanset of the form 771 * [01+-] 772 * is defined as `the digit 0, the digit 1, 773 * the character +, the character -', but 774 * the effect of a scanset such as 775 * [a-zA-Z0-9] 776 * is implementation defined. The V7 Unix 777 * scanf treats `a-z' as `the letters a through 778 * z', but treats `a-a' as `the letter a, the 779 * character -, and the letter a'. 780 * 781 * For compatibility, the `-' is not considerd 782 * to define a range if the character following 783 * it is either a close bracket (required by ANSI) 784 * or is not numerically greater than the character 785 * we just stored in the table (c). 786 */ 787 n = *fmt; 788 if (n == ']' || n < c) { 789 c = '-'; 790 break; /* resume the for(;;) */ 791 } 792 fmt++; 793 do { /* fill in the range */ 794 tab[++c] = v; 795 } while (c < n); 796 #if 1 /* XXX another disgusting compatibility hack */ 797 /* 798 * Alas, the V7 Unix scanf also treats formats 799 * such as [a-c-e] as `the letters a through e'. 800 * This too is permitted by the standard.... 801 */ 802 goto doswitch; 803 #else 804 c = *fmt++; 805 if (c == 0) 806 return (fmt - 1); 807 if (c == ']') 808 return (fmt); 809 break; 810 #endif 811 812 case ']': /* end of scanset */ 813 return (fmt); 814 815 default: /* just another character */ 816 c = n; 817 break; 818 } 819 } 820 /* NOTREACHED */ 821 } 822