1 /* $OpenBSD: vfscanf.c,v 1.31 2014/03/19 05:17:01 guenther 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 <inttypes.h> 35 #include <stdarg.h> 36 #include <stddef.h> 37 #include <stdio.h> 38 #include <stdlib.h> 39 #include <string.h> 40 #include <sys/param.h> 41 #include <wctype.h> 42 #include "local.h" 43 44 #include <private/bionic_ctype.h> 45 #include <private/bionic_fortify.h> 46 #include <private/bionic_mbstate.h> 47 48 #define BUF 513 /* Maximum length of numeric string. */ 49 50 // Flags used during conversion. 51 // Size/type: 52 #define LONG 0x00001 // l: long or double 53 #define LONGDBL 0x00002 // L: long double 54 #define SHORT 0x00004 // h: short 55 #define SHORTSHORT 0x00008 // hh: 8 bit integer 56 #define LLONG 0x00010 // ll: long long (+ deprecated q: quad) 57 #define POINTER 0x00020 // p: void* (as hex) 58 #define SIZEINT 0x00040 // z: (signed) size_t 59 #define MAXINT 0x00080 // j: intmax_t 60 #define PTRINT 0x00100 // t: ptrdiff_t 61 #define NOSKIP 0x00200 // [ or c: do not skip blanks 62 // Modifiers: 63 #define SUPPRESS 0x00400 // *: suppress assignment 64 #define UNSIGNED 0x00800 // %[oupxX] conversions 65 #define ALLOCATE 0x01000 // m: allocate a char* 66 // Internal use during integer parsing: 67 #define SIGNOK 0x02000 // +/- is (still) legal 68 #define HAVESIGN 0x04000 // Sign detected 69 #define NDIGITS 0x08000 // No digits detected 70 #define PFXOK 0x10000 // "0x" prefix is (still) legal 71 #define NZDIGITS 0x20000 // No zero digits detected 72 73 // Conversion types. 74 #define CT_CHAR 0 // %c conversion 75 #define CT_CCL 1 // %[...] conversion 76 #define CT_STRING 2 // %s conversion 77 #define CT_INT 3 // Integer: strtoimax/strtoumax 78 #define CT_FLOAT 4 // Float: strtod 79 80 static const unsigned char* __sccl(char*, const unsigned char*); 81 82 /* 83 * Internal, unlocked version of vfscanf 84 */ 85 int __svfscanf(FILE* fp, const char* fmt0, va_list ap) { 86 const unsigned char* fmt = reinterpret_cast<const unsigned char*>(fmt0); 87 int c; /* character from format, or conversion */ 88 size_t width; /* field width, or 0 */ 89 char* p; 90 wchar_t* wcp; 91 size_t n; 92 int flags; /* flags as defined above */ 93 int nassigned; /* number of fields assigned */ 94 int nread; /* number of characters consumed from fp */ 95 int base; /* base argument to strtoimax/strtouimax */ 96 char ccltab[256]; /* character class table for %[...] */ 97 char buf[BUF]; /* buffer for numeric conversions */ 98 size_t nconv; /* length of multibyte sequence converted */ 99 mbstate_t mbs; 100 void* allocation = NULL; // Allocated but unassigned result for %mc/%ms/%m[. 101 size_t capacity = 0; // Number of char/wchar_t units allocated in `allocation`. 102 103 /* `basefix' is used to avoid `if' tests in the integer scanner */ 104 static short basefix[17] = { 10, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16 }; 105 106 _SET_ORIENTATION(fp, -1); 107 108 nassigned = 0; 109 nread = 0; 110 for (;;) { 111 c = *fmt++; 112 if (c == 0) return nassigned; 113 if (IsSpace(c)) { 114 while ((fp->_r > 0 || __srefill(fp) == 0) && IsSpace(*fp->_p)) nread++, fp->_r--, fp->_p++; 115 continue; 116 } 117 if (c != '%') goto literal; 118 width = 0; 119 flags = 0; 120 /* 121 * switch on the format. continue if done; 122 * break once format type is derived. 123 */ 124 again: 125 c = *fmt++; 126 switch (c) { 127 case '%': 128 literal: 129 if (fp->_r <= 0 && __srefill(fp)) goto input_failure; 130 if (*fp->_p != c) goto match_failure; 131 fp->_r--, fp->_p++; 132 nread++; 133 continue; 134 135 case '*': 136 flags |= SUPPRESS; 137 goto again; 138 case 'j': 139 flags |= MAXINT; 140 goto again; 141 case 'L': 142 flags |= LONGDBL; 143 goto again; 144 case 'h': 145 if (*fmt == 'h') { 146 fmt++; 147 flags |= SHORTSHORT; 148 } else { 149 flags |= SHORT; 150 } 151 goto again; 152 case 'l': 153 if (*fmt == 'l') { 154 fmt++; 155 flags |= LLONG; 156 } else { 157 flags |= LONG; 158 } 159 goto again; 160 case 'm': 161 flags |= ALLOCATE; 162 goto again; 163 case 'q': 164 flags |= LLONG; /* deprecated */ 165 goto again; 166 case 't': 167 flags |= PTRINT; 168 goto again; 169 case 'z': 170 flags |= SIZEINT; 171 goto again; 172 173 case '0': 174 case '1': 175 case '2': 176 case '3': 177 case '4': 178 case '5': 179 case '6': 180 case '7': 181 case '8': 182 case '9': 183 width = width * 10 + c - '0'; 184 goto again; 185 186 /* 187 * Conversions. 188 * Those marked `compat' are for 4.[123]BSD compatibility. 189 */ 190 case 'D': /* compat */ 191 flags |= LONG; 192 /* FALLTHROUGH */ 193 case 'd': 194 c = CT_INT; 195 base = 10; 196 break; 197 198 case 'i': 199 c = CT_INT; 200 base = 0; 201 break; 202 203 case 'O': /* compat */ 204 flags |= LONG; 205 /* FALLTHROUGH */ 206 case 'o': 207 c = CT_INT; 208 flags |= UNSIGNED; 209 base = 8; 210 break; 211 212 case 'u': 213 c = CT_INT; 214 flags |= UNSIGNED; 215 base = 10; 216 break; 217 218 case 'X': 219 case 'x': 220 flags |= PFXOK; /* enable 0x prefixing */ 221 c = CT_INT; 222 flags |= UNSIGNED; 223 base = 16; 224 break; 225 226 case 'e': 227 case 'E': 228 case 'f': 229 case 'F': 230 case 'g': 231 case 'G': 232 case 'a': 233 case 'A': 234 c = CT_FLOAT; 235 break; 236 237 case 's': 238 memset(ccltab, 1, 256); 239 ccltab['\t'] = ccltab['\n'] = ccltab['\v'] = ccltab['\f'] = ccltab['\r'] = ccltab[' '] = 0; 240 c = CT_STRING; 241 break; 242 243 case '[': 244 fmt = __sccl(ccltab, fmt); 245 flags |= NOSKIP; 246 c = CT_CCL; 247 break; 248 249 case 'c': 250 flags |= NOSKIP; 251 c = CT_CHAR; 252 break; 253 254 case 'p': /* pointer format is like hex */ 255 flags |= POINTER | PFXOK; 256 c = CT_INT; 257 flags |= UNSIGNED; 258 base = 16; 259 break; 260 261 case 'n': 262 if (flags & SUPPRESS) continue; 263 if (flags & SHORTSHORT) { 264 *va_arg(ap, signed char*) = nread; 265 } else if (flags & SHORT) { 266 *va_arg(ap, short*) = nread; 267 } else if (flags & LONG) { 268 *va_arg(ap, long*) = nread; 269 } else if (flags & SIZEINT) { 270 *va_arg(ap, ssize_t*) = nread; 271 } else if (flags & PTRINT) { 272 *va_arg(ap, ptrdiff_t*) = nread; 273 } else if (flags & LLONG) { 274 *va_arg(ap, long long*) = nread; 275 } else if (flags & MAXINT) { 276 *va_arg(ap, intmax_t*) = nread; 277 } else { 278 *va_arg(ap, int*) = nread; 279 } 280 continue; 281 282 /* 283 * Disgusting backwards compatibility hacks. XXX 284 */ 285 case '\0': /* compat */ 286 return EOF; 287 288 default: /* compat */ 289 if (IsUpper(c)) flags |= LONG; 290 c = CT_INT; 291 base = 10; 292 break; 293 } 294 295 if ((flags & ALLOCATE) != 0 && c > CT_STRING) { 296 __fortify_fatal("scanf 'm' only works with %%c/%%s/%%["); 297 } 298 if ((flags & (ALLOCATE|SUPPRESS)) == (ALLOCATE|SUPPRESS)) { 299 __fortify_fatal("scanf 'm' makes no sense with '*'"); 300 } 301 302 /* 303 * We have a conversion that requires input. 304 */ 305 if (fp->_r <= 0 && __srefill(fp)) goto input_failure; 306 307 /* 308 * Consume leading white space, except for formats 309 * that suppress this. 310 */ 311 if ((flags & NOSKIP) == 0) { 312 while (IsSpace(*fp->_p)) { 313 nread++; 314 if (--fp->_r > 0) { 315 fp->_p++; 316 } else if (__srefill(fp)) { 317 goto input_failure; 318 } 319 } 320 /* 321 * Note that there is at least one character in 322 * the buffer, so conversions that do not set NOSKIP 323 * ca no longer result in an input failure. 324 */ 325 } 326 327 /* 328 * Do the conversion. 329 */ 330 switch (c) { 331 case CT_CHAR: 332 /* scan arbitrary characters (sets NOSKIP) */ 333 if (width == 0) width = 1; 334 if (flags & LONG) { 335 if (flags & ALLOCATE) { 336 allocation = wcp = reinterpret_cast<wchar_t*>(malloc(width * sizeof(wchar_t))); 337 if (allocation == NULL) goto allocation_failure; 338 } else if (flags & SUPPRESS) { 339 wcp = NULL; 340 } else { 341 wcp = va_arg(ap, wchar_t*); 342 } 343 size_t bytes = 0; 344 while (width != 0) { 345 if (bytes == MB_CUR_MAX) { 346 fp->_flags |= __SERR; 347 goto input_failure; 348 } 349 buf[bytes++] = *fp->_p; 350 fp->_p++; 351 fp->_r--; 352 memset(&mbs, 0, sizeof(mbs)); 353 nconv = mbrtowc(wcp, buf, bytes, &mbs); 354 if (nconv == __MB_ERR_ILLEGAL_SEQUENCE) { 355 fp->_flags |= __SERR; 356 goto input_failure; 357 } 358 if (nconv == 0 && !(flags & SUPPRESS)) *wcp = L'\0'; 359 if (nconv != __MB_ERR_INCOMPLETE_SEQUENCE) { 360 nread += bytes; 361 width--; 362 if (!(flags & SUPPRESS)) wcp++; 363 bytes = 0; 364 } 365 if (fp->_r <= 0 && __srefill(fp)) { 366 if (bytes != 0) { 367 fp->_flags |= __SERR; 368 goto input_failure; 369 } 370 break; 371 } 372 } 373 if (allocation != NULL) { 374 *va_arg(ap, wchar_t**) = reinterpret_cast<wchar_t*>(allocation); 375 allocation = NULL; 376 } 377 if (!(flags & SUPPRESS)) nassigned++; 378 } else if (flags & SUPPRESS) { 379 size_t sum = 0; 380 for (;;) { 381 if ((n = fp->_r) < width) { 382 sum += n; 383 width -= n; 384 fp->_p += n; 385 if (__srefill(fp)) { 386 if (sum == 0) goto input_failure; 387 break; 388 } 389 } else { 390 sum += width; 391 fp->_r -= width; 392 fp->_p += width; 393 break; 394 } 395 } 396 nread += sum; 397 } else { 398 if (flags & ALLOCATE) { 399 allocation = p = reinterpret_cast<char*>(malloc(width)); 400 if (allocation == NULL) goto allocation_failure; 401 } else { 402 p = va_arg(ap, char*); 403 } 404 size_t r = fread(p, 1, width, fp); 405 if (r == 0) goto input_failure; 406 if (allocation != NULL) { 407 *va_arg(ap, char**) = reinterpret_cast<char*>(allocation); 408 allocation = NULL; 409 } 410 nread += r; 411 nassigned++; 412 } 413 break; 414 415 case CT_CCL: 416 case CT_STRING: 417 // CT_CCL: scan a (nonempty) character class (sets NOSKIP). 418 // CT_STRING: like CCL, but zero-length string OK, & no NOSKIP. 419 if (width == 0) width = SIZE_MAX; 420 if (flags & LONG) { 421 // TODO: since no-one cares, replace this with a simple fgetwc loop? 422 n = 0; 423 if (flags & ALLOCATE) { 424 capacity = MIN(width, 32); 425 allocation = wcp = reinterpret_cast<wchar_t*>(malloc(sizeof(wchar_t) * capacity)); 426 if (allocation == NULL) goto allocation_failure; 427 } else if (flags & SUPPRESS) { 428 wcp = NULL; 429 } else { 430 wcp = va_arg(ap, wchar_t*); 431 } 432 size_t bytes = 0; 433 while ((c == CT_CCL || !IsSpace(*fp->_p)) && width != 0) { 434 if (bytes == MB_CUR_MAX) { 435 fp->_flags |= __SERR; 436 goto input_failure; 437 } 438 buf[bytes++] = *fp->_p; 439 fp->_p++; 440 fp->_r--; 441 wchar_t wc = L'\0'; 442 memset(&mbs, 0, sizeof(mbs)); 443 nconv = mbrtowc(&wc, buf, bytes, &mbs); 444 if (nconv == __MB_ERR_ILLEGAL_SEQUENCE) { 445 fp->_flags |= __SERR; 446 goto input_failure; 447 } 448 if (nconv != __MB_ERR_INCOMPLETE_SEQUENCE) { 449 if ((c == CT_CCL && wctob(wc) != EOF && !ccltab[wctob(wc)]) || (c == CT_STRING && iswspace(wc))) { 450 while (bytes != 0) { 451 bytes--; 452 ungetc(buf[bytes], fp); 453 } 454 break; 455 } 456 if (wcp) wcp[n] = wc; 457 n++; 458 if (allocation != NULL && n == capacity) { 459 capacity *= 2; 460 wchar_t* new_allocation = 461 reinterpret_cast<wchar_t*>(realloc(allocation, sizeof(wchar_t) * capacity)); 462 if (new_allocation == NULL) goto allocation_failure; 463 allocation = wcp = new_allocation; 464 } 465 nread += bytes; 466 width--; 467 bytes = 0; 468 } 469 if (fp->_r <= 0 && __srefill(fp)) { 470 if (bytes != 0) { 471 fp->_flags |= __SERR; 472 goto input_failure; 473 } 474 break; 475 } 476 } 477 if (c == CT_CCL && bytes != 0) { 478 fp->_flags |= __SERR; 479 goto input_failure; 480 } 481 if (allocation != NULL) { 482 *va_arg(ap, wchar_t**) = reinterpret_cast<wchar_t*>(allocation); 483 allocation = NULL; 484 } 485 } else if (flags & SUPPRESS) { 486 n = 0; 487 while (ccltab[*fp->_p]) { 488 n++, fp->_r--, fp->_p++; 489 if (--width == 0) break; 490 if (fp->_r <= 0 && __srefill(fp)) { 491 if (c == CT_CCL && n == 0) goto input_failure; 492 break; 493 } 494 } 495 nread += n; 496 } else { 497 if (flags & ALLOCATE) { 498 capacity = MIN(width, 32); 499 allocation = p = reinterpret_cast<char*>(malloc(capacity)); 500 if (allocation == NULL) goto allocation_failure; 501 } else { 502 p = va_arg(ap, char*); 503 } 504 n = 0; 505 while (ccltab[*fp->_p]) { 506 fp->_r--; 507 p[n++] = *fp->_p++; 508 if (allocation != NULL && n == capacity) { 509 capacity *= 2; 510 char* new_allocation = reinterpret_cast<char*>(realloc(allocation, capacity)); 511 if (new_allocation == NULL) goto allocation_failure; 512 allocation = p = new_allocation; 513 } 514 if (--width == 0) break; 515 if (fp->_r <= 0 && __srefill(fp)) { 516 if (c == CT_CCL && n == 0) goto input_failure; 517 break; 518 } 519 } 520 nread += n; 521 if (allocation != NULL) { 522 *va_arg(ap, char**) = reinterpret_cast<char*>(allocation); 523 allocation = NULL; 524 } 525 } 526 if (c == CT_CCL && n == 0) goto match_failure; 527 if (!(flags & SUPPRESS)) { 528 if (flags & LONG) { 529 wcp[n] = L'\0'; 530 } else { 531 p[n] = '\0'; 532 } 533 ++nassigned; 534 } 535 break; 536 537 case CT_INT: 538 /* scan an integer as if by strtoimax/strtoumax */ 539 #ifdef hardway 540 if (width == 0 || width > sizeof(buf) - 1) width = sizeof(buf) - 1; 541 #else 542 /* size_t is unsigned, hence this optimisation */ 543 if (--width > sizeof(buf) - 2) width = sizeof(buf) - 2; 544 width++; 545 #endif 546 flags |= SIGNOK | NDIGITS | NZDIGITS; 547 for (p = buf; width; width--) { 548 c = *fp->_p; 549 /* 550 * Switch on the character; `goto ok' 551 * if we accept it as a part of number. 552 */ 553 switch (c) { 554 /* 555 * The digit 0 is always legal, but is 556 * special. For %i conversions, if no 557 * digits (zero or nonzero) have been 558 * scanned (only signs), we will have 559 * base==0. In that case, we should set 560 * it to 8 and enable 0x prefixing. 561 * Also, if we have not scanned zero digits 562 * before this, do not turn off prefixing 563 * (someone else will turn it off if we 564 * have scanned any nonzero digits). 565 */ 566 case '0': 567 if (base == 0) { 568 base = 8; 569 flags |= PFXOK; 570 } 571 if (flags & NZDIGITS) 572 flags &= ~(SIGNOK | NZDIGITS | NDIGITS); 573 else 574 flags &= ~(SIGNOK | PFXOK | NDIGITS); 575 goto ok; 576 577 /* 1 through 7 always legal */ 578 case '1': 579 case '2': 580 case '3': 581 case '4': 582 case '5': 583 case '6': 584 case '7': 585 base = basefix[base]; 586 flags &= ~(SIGNOK | PFXOK | NDIGITS); 587 goto ok; 588 589 /* digits 8 and 9 ok iff decimal or hex */ 590 case '8': 591 case '9': 592 base = basefix[base]; 593 if (base <= 8) break; /* not legal here */ 594 flags &= ~(SIGNOK | PFXOK | NDIGITS); 595 goto ok; 596 597 /* letters ok iff hex */ 598 case 'A': 599 case 'B': 600 case 'C': 601 case 'D': 602 case 'E': 603 case 'F': 604 case 'a': 605 case 'b': 606 case 'c': 607 case 'd': 608 case 'e': 609 case 'f': 610 /* no need to fix base here */ 611 if (base <= 10) break; /* not legal here */ 612 flags &= ~(SIGNOK | PFXOK | NDIGITS); 613 goto ok; 614 615 /* sign ok only as first character */ 616 case '+': 617 case '-': 618 if (flags & SIGNOK) { 619 flags &= ~SIGNOK; 620 flags |= HAVESIGN; 621 goto ok; 622 } 623 break; 624 625 /* 626 * x ok iff flag still set and 2nd char (or 627 * 3rd char if we have a sign). 628 */ 629 case 'x': 630 case 'X': 631 if ((flags & PFXOK) && p == buf + 1 + !!(flags & HAVESIGN)) { 632 base = 16; /* if %i */ 633 flags &= ~PFXOK; 634 goto ok; 635 } 636 break; 637 } 638 639 /* 640 * If we got here, c is not a legal character 641 * for a number. Stop accumulating digits. 642 */ 643 break; 644 ok: 645 /* 646 * c is legal: store it and look at the next. 647 */ 648 *p++ = c; 649 if (--fp->_r > 0) 650 fp->_p++; 651 else if (__srefill(fp)) 652 break; /* EOF */ 653 } 654 /* 655 * If we had only a sign, it is no good; push 656 * back the sign. If the number ends in `x', 657 * it was [sign] '0' 'x', so push back the x 658 * and treat it as [sign] '0'. 659 */ 660 if (flags & NDIGITS) { 661 if (p > buf) (void)ungetc(*(u_char*)--p, fp); 662 goto match_failure; 663 } 664 c = ((u_char*)p)[-1]; 665 if (c == 'x' || c == 'X') { 666 --p; 667 (void)ungetc(c, fp); 668 } 669 if ((flags & SUPPRESS) == 0) { 670 uintmax_t res; 671 672 *p = '\0'; 673 if (flags & UNSIGNED) { 674 res = strtoumax(buf, NULL, base); 675 } else { 676 res = strtoimax(buf, NULL, base); 677 } 678 if (flags & POINTER) { 679 *va_arg(ap, void**) = (void*)(uintptr_t)res; 680 } else if (flags & MAXINT) { 681 *va_arg(ap, intmax_t*) = res; 682 } else if (flags & LLONG) { 683 *va_arg(ap, long long*) = res; 684 } else if (flags & SIZEINT) { 685 *va_arg(ap, ssize_t*) = res; 686 } else if (flags & PTRINT) { 687 *va_arg(ap, ptrdiff_t*) = res; 688 } else if (flags & LONG) { 689 *va_arg(ap, long*) = res; 690 } else if (flags & SHORT) { 691 *va_arg(ap, short*) = res; 692 } else if (flags & SHORTSHORT) { 693 *va_arg(ap, signed char*) = res; 694 } else { 695 *va_arg(ap, int*) = res; 696 } 697 nassigned++; 698 } 699 nread += p - buf; 700 break; 701 702 case CT_FLOAT: 703 /* scan a floating point number as if by strtod */ 704 if (width == 0 || width > sizeof(buf) - 1) width = sizeof(buf) - 1; 705 if ((width = parsefloat(fp, buf, buf + width)) == 0) goto match_failure; 706 if ((flags & SUPPRESS) == 0) { 707 if (flags & LONGDBL) { 708 long double res = strtold(buf, &p); 709 *va_arg(ap, long double*) = res; 710 } else if (flags & LONG) { 711 double res = strtod(buf, &p); 712 *va_arg(ap, double*) = res; 713 } else { 714 float res = strtof(buf, &p); 715 *va_arg(ap, float*) = res; 716 } 717 if ((size_t)(p - buf) != width) abort(); 718 nassigned++; 719 } 720 nread += width; 721 break; 722 } 723 } 724 allocation_failure: 725 input_failure: 726 free(allocation); 727 if (nassigned == 0) nassigned = -1; 728 match_failure: 729 return nassigned; 730 } 731 732 /* 733 * Fill in the given table from the scanset at the given format 734 * (just after `['). Return a pointer to the character past the 735 * closing `]'. The table has a 1 wherever characters should be 736 * considered part of the scanset. 737 */ 738 static const unsigned char* __sccl(char* tab, const unsigned char* fmt) { 739 int c, n, v; 740 741 /* first `clear' the whole table */ 742 c = *fmt++; /* first char hat => negated scanset */ 743 if (c == '^') { 744 v = 1; /* default => accept */ 745 c = *fmt++; /* get new first char */ 746 } else { 747 v = 0; /* default => reject */ 748 } 749 memset(tab, v, 256); 750 if (c == 0) return (fmt - 1); /* format ended before closing ] */ 751 752 /* 753 * Now set the entries corresponding to the actual scanset 754 * to the opposite of the above. 755 * 756 * The first character may be ']' (or '-') without being special; 757 * the last character may be '-'. 758 */ 759 v = 1 - v; 760 for (;;) { 761 tab[c] = v; /* take character c */ 762 doswitch: 763 n = *fmt++; /* and examine the next */ 764 switch (n) { 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) return (fmt - 1); 806 if (c == ']') return (fmt); 807 #endif 808 break; 809 810 case ']': /* end of scanset */ 811 return fmt; 812 813 default: /* just another character */ 814 c = n; 815 break; 816 } 817 } 818 /* NOTREACHED */ 819 } 820
