| 1 | /* regexp.c */ |
| 2 | |
| 3 | /* This file contains the code that compiles regular expressions and executes |
| 4 | * them. It supports the same syntax and features as vi's regular expression |
| 5 | * code. Specifically, the meta characters are: |
| 6 | * ^ matches the beginning of a line |
| 7 | * $ matches the end of a line |
| 8 | * \< matches the beginning of a word |
| 9 | * \> matches the end of a word |
| 10 | * . matches any single character |
| 11 | * [] matches any character in a character class |
| 12 | * \( delimits the start of a subexpression |
| 13 | * \) delimits the end of a subexpression |
| 14 | * * repeats the preceding 0 or more times |
| 15 | * NOTE: You cannot follow a \) with a *. |
| 16 | * |
| 17 | * The physical structure of a compiled RE is as follows: |
| 18 | * - First, there is a one-byte value that says how many character classes |
| 19 | * are used in this regular expression |
| 20 | * - Next, each character class is stored as a bitmap that is 256 bits |
| 21 | * (32 bytes) long. |
| 22 | * - A mixture of literal characters and compiled meta characters follows. |
| 23 | * This begins with M_BEGIN(0) and ends with M_END(0). All meta chars |
| 24 | * are stored as a \n followed by a one-byte code, so they take up two |
| 25 | * bytes apiece. Literal characters take up one byte apiece. \n can't |
| 26 | * be used as a literal character. |
| 27 | * |
| 28 | * If NO_MAGIC is defined, then a different set of functions is used instead. |
| 29 | * That right, this file contains TWO versions of the code. |
| 30 | */ |
| 31 | |
| 32 | #include <setjmp.h> |
| 33 | #include "config.h" |
| 34 | #include "ctype.h" |
| 35 | #include "vi.h" |
| 36 | #include "regexp.h" |
| 37 | |
| 38 | |
| 39 | |
| 40 | static char *previous; /* the previous regexp, used when null regexp is given */ |
| 41 | |
| 42 | |
| 43 | #ifndef NO_MAGIC |
| 44 | /* THE REAL REGEXP PACKAGE IS USED UNLESS "NO_MAGIC" IS DEFINED */ |
| 45 | |
| 46 | /* These are used to classify or recognize meta-characters */ |
| 47 | #define META '\0' |
| 48 | #define BASE_META(m) ((m) - 256) |
| 49 | #define INT_META(c) ((c) + 256) |
| 50 | #define IS_META(m) ((m) >= 256) |
| 51 | #define IS_CLASS(m) ((m) >= M_CLASS(0) && (m) <= M_CLASS(9)) |
| 52 | #define IS_START(m) ((m) >= M_START(0) && (m) <= M_START(9)) |
| 53 | #define IS_END(m) ((m) >= M_END(0) && (m) <= M_END(9)) |
| 54 | #define IS_CLOSURE(m) ((m) >= M_SPLAT && (m) <= M_RANGE) |
| 55 | #define ADD_META(s,m) (*(s)++ = META, *(s)++ = BASE_META(m)) |
| 56 | #define GET_META(s) (*(s) == META ? INT_META(*++(s)) : *s) |
| 57 | |
| 58 | /* These are the internal codes used for each type of meta-character */ |
| 59 | #define M_BEGLINE 256 /* internal code for ^ */ |
| 60 | #define M_ENDLINE 257 /* internal code for $ */ |
| 61 | #define M_BEGWORD 258 /* internal code for \< */ |
| 62 | #define M_ENDWORD 259 /* internal code for \> */ |
| 63 | #define M_ANY 260 /* internal code for . */ |
| 64 | #define M_SPLAT 261 /* internal code for * */ |
| 65 | #define M_PLUS 262 /* internal code for \+ */ |
| 66 | #define M_QMARK 263 /* internal code for \? */ |
| 67 | #define M_RANGE 264 /* internal code for \{ */ |
| 68 | #define M_CLASS(n) (265+(n)) /* internal code for [] */ |
| 69 | #define M_START(n) (275+(n)) /* internal code for \( */ |
| 70 | #define M_END(n) (285+(n)) /* internal code for \) */ |
| 71 | |
| 72 | /* These are used during compilation */ |
| 73 | static int class_cnt; /* used to assign class IDs */ |
| 74 | static int start_cnt; /* used to assign start IDs */ |
| 75 | static int end_stk[NSUBEXP];/* used to assign end IDs */ |
| 76 | static int end_sp; |
| 77 | static char *retext; /* points to the text being compiled */ |
| 78 | |
| 79 | /* error-handling stuff */ |
| 80 | jmp_buf errorhandler; |
| 81 | #define FAIL(why) regerror(why); longjmp(errorhandler, 1) |
| 82 | |
| 83 | |
| 84 | |
| 85 | |
| 86 | |
| 87 | /* This function builds a bitmap for a particular class */ |
| 88 | static char *makeclass(text, bmap) |
| 89 | REG char *text; /* start of the class */ |
| 90 | REG char *bmap; /* the bitmap */ |
| 91 | { |
| 92 | REG int i; |
| 93 | int complement = 0; |
| 94 | |
| 95 | |
| 96 | /* zero the bitmap */ |
| 97 | for (i = 0; bmap && i < 32; i++) |
| 98 | { |
| 99 | bmap[i] = 0; |
| 100 | } |
| 101 | |
| 102 | /* see if we're going to complement this class */ |
| 103 | if (*text == '^') |
| 104 | { |
| 105 | text++; |
| 106 | complement = 1; |
| 107 | } |
| 108 | |
| 109 | /* add in the characters */ |
| 110 | while (*text && *text != ']') |
| 111 | { |
| 112 | /* is this a span of characters? */ |
| 113 | if (text[1] == '-' && text[2]) |
| 114 | { |
| 115 | /* spans can't be backwards */ |
| 116 | if (text[0] > text[2]) |
| 117 | { |
| 118 | FAIL("Backwards span in []"); |
| 119 | } |
| 120 | |
| 121 | /* add each character in the span to the bitmap */ |
| 122 | for (i = text[0]; bmap && i <= text[2]; i++) |
| 123 | { |
| 124 | bmap[i >> 3] |= (1 << (i & 7)); |
| 125 | } |
| 126 | |
| 127 | /* move past this span */ |
| 128 | text += 3; |
| 129 | } |
| 130 | else |
| 131 | { |
| 132 | /* add this single character to the span */ |
| 133 | i = *text++; |
| 134 | if (bmap) |
| 135 | { |
| 136 | bmap[i >> 3] |= (1 << (i & 7)); |
| 137 | } |
| 138 | } |
| 139 | } |
| 140 | |
| 141 | /* make sure the closing ] is missing */ |
| 142 | if (*text++ != ']') |
| 143 | { |
| 144 | FAIL("] missing"); |
| 145 | } |
| 146 | |
| 147 | /* if we're supposed to complement this class, then do so */ |
| 148 | if (complement && bmap) |
| 149 | { |
| 150 | for (i = 0; i < 32; i++) |
| 151 | { |
| 152 | bmap[i] = ~bmap[i]; |
| 153 | } |
| 154 | } |
| 155 | |
| 156 | return text; |
| 157 | } |
| 158 | |
| 159 | |
| 160 | |
| 161 | |
| 162 | /* This function gets the next character or meta character from a string. |
| 163 | * The pointer is incremented by 1, or by 2 for \-quoted characters. For [], |
| 164 | * a bitmap is generated via makeclass() (if re is given), and the |
| 165 | * character-class text is skipped. |
| 166 | */ |
| 167 | static int gettoken(sptr, re) |
| 168 | char **sptr; |
| 169 | regexp *re; |
| 170 | { |
| 171 | int c; |
| 172 | |
| 173 | c = **sptr; |
| 174 | ++*sptr; |
| 175 | if (c == '\\') |
| 176 | { |
| 177 | c = **sptr; |
| 178 | ++*sptr; |
| 179 | switch (c) |
| 180 | { |
| 181 | case '<': |
| 182 | return M_BEGWORD; |
| 183 | |
| 184 | case '>': |
| 185 | return M_ENDWORD; |
| 186 | |
| 187 | case '(': |
| 188 | if (start_cnt >= NSUBEXP) |
| 189 | { |
| 190 | FAIL("Too many \\(s"); |
| 191 | } |
| 192 | end_stk[end_sp++] = start_cnt; |
| 193 | return M_START(start_cnt++); |
| 194 | |
| 195 | case ')': |
| 196 | if (end_sp <= 0) |
| 197 | { |
| 198 | FAIL("Mismatched \\)"); |
| 199 | } |
| 200 | return M_END(end_stk[--end_sp]); |
| 201 | |
| 202 | case '*': |
| 203 | return (*o_magic ? c : M_SPLAT); |
| 204 | |
| 205 | case '.': |
| 206 | return (*o_magic ? c : M_ANY); |
| 207 | |
| 208 | case '+': |
| 209 | return M_PLUS; |
| 210 | |
| 211 | case '?': |
| 212 | return M_QMARK; |
| 213 | #ifndef CRUNCH |
| 214 | case '{': |
| 215 | return M_RANGE; |
| 216 | #endif |
| 217 | default: |
| 218 | return c; |
| 219 | } |
| 220 | } |
| 221 | else if (*o_magic) |
| 222 | { |
| 223 | switch (c) |
| 224 | { |
| 225 | case '^': |
| 226 | if (*sptr == retext + 1) |
| 227 | { |
| 228 | return M_BEGLINE; |
| 229 | } |
| 230 | return c; |
| 231 | |
| 232 | case '$': |
| 233 | if (!**sptr) |
| 234 | { |
| 235 | return M_ENDLINE; |
| 236 | } |
| 237 | return c; |
| 238 | |
| 239 | case '.': |
| 240 | return M_ANY; |
| 241 | |
| 242 | case '*': |
| 243 | return M_SPLAT; |
| 244 | |
| 245 | case '[': |
| 246 | /* make sure we don't have too many classes */ |
| 247 | if (class_cnt >= 10) |
| 248 | { |
| 249 | FAIL("Too many []s"); |
| 250 | } |
| 251 | |
| 252 | /* process the character list for this class */ |
| 253 | if (re) |
| 254 | { |
| 255 | /* generate the bitmap for this class */ |
| 256 | *sptr = makeclass(*sptr, re->program + 1 + 32 * class_cnt); |
| 257 | } |
| 258 | else |
| 259 | { |
| 260 | /* skip to end of the class */ |
| 261 | *sptr = makeclass(*sptr, (char *)0); |
| 262 | } |
| 263 | return M_CLASS(class_cnt++); |
| 264 | |
| 265 | default: |
| 266 | return c; |
| 267 | } |
| 268 | } |
| 269 | else /* unquoted nomagic */ |
| 270 | { |
| 271 | switch (c) |
| 272 | { |
| 273 | case '^': |
| 274 | if (*sptr == retext + 1) |
| 275 | { |
| 276 | return M_BEGLINE; |
| 277 | } |
| 278 | return c; |
| 279 | |
| 280 | case '$': |
| 281 | if (!**sptr) |
| 282 | { |
| 283 | return M_ENDLINE; |
| 284 | } |
| 285 | return c; |
| 286 | |
| 287 | default: |
| 288 | return c; |
| 289 | } |
| 290 | } |
| 291 | /*NOTREACHED*/ |
| 292 | } |
| 293 | |
| 294 | |
| 295 | |
| 296 | |
| 297 | /* This function calculates the number of bytes that will be needed for a |
| 298 | * compiled RE. Its argument is the uncompiled version. It is not clever |
| 299 | * about catching syntax errors; that is done in a later pass. |
| 300 | */ |
| 301 | static unsigned calcsize(text) |
| 302 | char *text; |
| 303 | { |
| 304 | unsigned size; |
| 305 | int token; |
| 306 | |
| 307 | retext = text; |
| 308 | class_cnt = 0; |
| 309 | start_cnt = 1; |
| 310 | end_sp = 0; |
| 311 | size = 5; |
| 312 | while ((token = gettoken(&text, (regexp *)0)) != 0) |
| 313 | { |
| 314 | if (IS_CLASS(token)) |
| 315 | { |
| 316 | size += 34; |
| 317 | } |
| 318 | #ifndef CRUNCH |
| 319 | else if (token == M_RANGE) |
| 320 | { |
| 321 | size += 4; |
| 322 | while ((token = gettoken(&text, (regexp *)0)) != 0 |
| 323 | && token != '}') |
| 324 | { |
| 325 | } |
| 326 | if (!token) |
| 327 | { |
| 328 | return size; |
| 329 | } |
| 330 | } |
| 331 | #endif |
| 332 | else if (IS_META(token)) |
| 333 | { |
| 334 | size += 2; |
| 335 | } |
| 336 | else |
| 337 | { |
| 338 | size++; |
| 339 | } |
| 340 | } |
| 341 | |
| 342 | return size; |
| 343 | } |
| 344 | |
| 345 | |
| 346 | |
| 347 | /* This function compiles a regexp. */ |
| 348 | regexp *regcomp(exp) |
| 349 | char *exp; |
| 350 | { |
| 351 | int needfirst; |
| 352 | unsigned size; |
| 353 | int token; |
| 354 | int peek; |
| 355 | char *build; |
| 356 | regexp *re; |
| 357 | #ifndef CRUNCH |
| 358 | int from; |
| 359 | int to; |
| 360 | int digit; |
| 361 | #endif |
| 362 | |
| 363 | |
| 364 | /* prepare for error handling */ |
| 365 | re = (regexp *)0; |
| 366 | if (setjmp(errorhandler)) |
| 367 | { |
| 368 | if (re) |
| 369 | { |
| 370 | free(re); |
| 371 | } |
| 372 | return (regexp *)0; |
| 373 | } |
| 374 | |
| 375 | /* if an empty regexp string was given, use the previous one */ |
| 376 | if (*exp == 0) |
| 377 | { |
| 378 | if (!previous) |
| 379 | { |
| 380 | FAIL("No previous RE"); |
| 381 | } |
| 382 | exp = previous; |
| 383 | } |
| 384 | else /* non-empty regexp given, so remember it */ |
| 385 | { |
| 386 | if (previous) |
| 387 | free(previous); |
| 388 | previous = (char *)malloc((unsigned)(strlen(exp) + 1)); |
| 389 | if (previous) |
| 390 | strcpy(previous, exp); |
| 391 | } |
| 392 | |
| 393 | /* allocate memory */ |
| 394 | class_cnt = 0; |
| 395 | start_cnt = 1; |
| 396 | end_sp = 0; |
| 397 | retext = exp; |
| 398 | size = calcsize(exp) + sizeof(regexp) + 10; /* !!! 10 bytes for slop */ |
| 399 | #ifdef lint |
| 400 | re = ((regexp *)0) + size; |
| 401 | #else |
| 402 | re = (regexp *)malloc((unsigned)size); |
| 403 | #endif |
| 404 | if (!re) |
| 405 | { |
| 406 | FAIL("Not enough memory for this RE"); |
| 407 | } |
| 408 | |
| 409 | /* compile it */ |
| 410 | build = &re->program[1 + 32 * class_cnt]; |
| 411 | re->program[0] = class_cnt; |
| 412 | for (token = 0; token < NSUBEXP; token++) |
| 413 | { |
| 414 | re->startp[token] = re->endp[token] = (char *)0; |
| 415 | } |
| 416 | re->first = 0; |
| 417 | re->bol = 0; |
| 418 | re->minlen = 0; |
| 419 | needfirst = 1; |
| 420 | class_cnt = 0; |
| 421 | start_cnt = 1; |
| 422 | end_sp = 0; |
| 423 | retext = exp; |
| 424 | for (token = M_START(0), peek = gettoken(&exp, re); |
| 425 | token; |
| 426 | token = peek, peek = gettoken(&exp, re)) |
| 427 | { |
| 428 | /* special processing for the closure operator */ |
| 429 | if (IS_CLOSURE(peek)) |
| 430 | { |
| 431 | /* detect misuse of closure operator */ |
| 432 | if (IS_START(token)) |
| 433 | { |
| 434 | FAIL("Closure operator follows nothing"); |
| 435 | } |
| 436 | else if (IS_META(token) && token != M_ANY && !IS_CLASS(token)) |
| 437 | { |
| 438 | FAIL("Closure operators can only follow a normal character or . or []"); |
| 439 | } |
| 440 | |
| 441 | #ifndef CRUNCH |
| 442 | /* if \{ \} then read the range */ |
| 443 | if (peek == M_RANGE) |
| 444 | { |
| 445 | from = 0; |
| 446 | for (digit = gettoken(&exp, re); |
| 447 | !IS_META(digit) && isdigit(digit); |
| 448 | digit = gettoken(&exp, re)) |
| 449 | { |
| 450 | from = from * 10 + digit - '0'; |
| 451 | } |
| 452 | if (digit == '}') |
| 453 | { |
| 454 | to = from; |
| 455 | } |
| 456 | else if (digit == ',') |
| 457 | { |
| 458 | to = 0; |
| 459 | for (digit = gettoken(&exp, re); |
| 460 | !IS_META(digit) && isdigit(digit); |
| 461 | digit = gettoken(&exp, re)) |
| 462 | { |
| 463 | to = to * 10 + digit - '0'; |
| 464 | } |
| 465 | if (to == 0) |
| 466 | { |
| 467 | to = 255; |
| 468 | } |
| 469 | } |
| 470 | if (digit != '}') |
| 471 | { |
| 472 | FAIL("Bad characters after \\{"); |
| 473 | } |
| 474 | else if (to < from || to == 0 || from >= 255) |
| 475 | { |
| 476 | FAIL("Invalid range for \\{ \\}"); |
| 477 | } |
| 478 | re->minlen += from; |
| 479 | } |
| 480 | else |
| 481 | #endif |
| 482 | if (peek != M_SPLAT) |
| 483 | { |
| 484 | re->minlen++; |
| 485 | } |
| 486 | |
| 487 | /* it is okay -- make it prefix instead of postfix */ |
| 488 | ADD_META(build, peek); |
| 489 | #ifndef CRUNCH |
| 490 | if (peek == M_RANGE) |
| 491 | { |
| 492 | *build++ = from; |
| 493 | *build++ = (to < 255 ? to : 255); |
| 494 | } |
| 495 | #endif |
| 496 | |
| 497 | |
| 498 | /* take care of "needfirst" - is this the first char? */ |
| 499 | if (needfirst && peek == M_PLUS && !IS_META(token)) |
| 500 | { |
| 501 | re->first = token; |
| 502 | } |
| 503 | needfirst = 0; |
| 504 | |
| 505 | /* we used "peek" -- need to refill it */ |
| 506 | peek = gettoken(&exp, re); |
| 507 | if (IS_CLOSURE(peek)) |
| 508 | { |
| 509 | FAIL("* or \\+ or \\? doubled up"); |
| 510 | } |
| 511 | } |
| 512 | else if (!IS_META(token)) |
| 513 | { |
| 514 | /* normal char is NOT argument of closure */ |
| 515 | if (needfirst) |
| 516 | { |
| 517 | re->first = token; |
| 518 | needfirst = 0; |
| 519 | } |
| 520 | re->minlen++; |
| 521 | } |
| 522 | else if (token == M_ANY || IS_CLASS(token)) |
| 523 | { |
| 524 | /* . or [] is NOT argument of closure */ |
| 525 | needfirst = 0; |
| 526 | re->minlen++; |
| 527 | } |
| 528 | |
| 529 | /* the "token" character is not closure -- process it normally */ |
| 530 | if (token == M_BEGLINE) |
| 531 | { |
| 532 | /* set the BOL flag instead of storing M_BEGLINE */ |
| 533 | re->bol = 1; |
| 534 | } |
| 535 | else if (IS_META(token)) |
| 536 | { |
| 537 | ADD_META(build, token); |
| 538 | } |
| 539 | else |
| 540 | { |
| 541 | *build++ = token; |
| 542 | } |
| 543 | } |
| 544 | |
| 545 | /* end it with a \) which MUST MATCH the opening \( */ |
| 546 | ADD_META(build, M_END(0)); |
| 547 | if (end_sp > 0) |
| 548 | { |
| 549 | FAIL("Not enough \\)s"); |
| 550 | } |
| 551 | |
| 552 | return re; |
| 553 | } |
| 554 | |
| 555 | |
| 556 | |
| 557 | /*---------------------------------------------------------------------------*/ |
| 558 | |
| 559 | |
| 560 | /* This function checks for a match between a character and a token which is |
| 561 | * known to represent a single character. It returns 0 if they match, or |
| 562 | * 1 if they don't. |
| 563 | */ |
| 564 | int match1(re, ch, token) |
| 565 | regexp *re; |
| 566 | REG char ch; |
| 567 | REG int token; |
| 568 | { |
| 569 | if (!ch) |
| 570 | { |
| 571 | /* the end of a line can't match any RE of width 1 */ |
| 572 | return 1; |
| 573 | } |
| 574 | if (token == M_ANY) |
| 575 | { |
| 576 | return 0; |
| 577 | } |
| 578 | else if (IS_CLASS(token)) |
| 579 | { |
| 580 | if (re->program[1 + 32 * (token - M_CLASS(0)) + (ch >> 3)] & (1 << (ch & 7))) |
| 581 | return 0; |
| 582 | } |
| 583 | else if (ch == token || *o_ignorecase && tolower(ch) == tolower(token)) |
| 584 | { |
| 585 | return 0; |
| 586 | } |
| 587 | return 1; |
| 588 | } |
| 589 | |
| 590 | |
| 591 | |
| 592 | /* This function checks characters up to and including the next closure, at |
| 593 | * which point it does a recursive call to check the rest of it. This function |
| 594 | * returns 0 if everything matches, or 1 if something doesn't match. |
| 595 | */ |
| 596 | int match(re, str, prog, here) |
| 597 | regexp *re; /* the regular expression */ |
| 598 | char *str; /* the string */ |
| 599 | REG char *prog; /* a portion of re->program, an compiled RE */ |
| 600 | REG char *here; /* a portion of str, the string to compare it to */ |
| 601 | { |
| 602 | REG int token; /* the roken pointed to by prog */ |
| 603 | REG int nmatched;/* counter, used during closure matching */ |
| 604 | REG int closure;/* the token denoting the type of closure */ |
| 605 | int from; /* minimum number of matches in closure */ |
| 606 | int to; /* maximum number of matches in closure */ |
| 607 | |
| 608 | for (token = GET_META(prog); !IS_CLOSURE(token); prog++, token = GET_META(prog)) |
| 609 | { |
| 610 | switch (token) |
| 611 | { |
| 612 | /*case M_BEGLINE: can't happen; re->bol is used instead */ |
| 613 | case M_ENDLINE: |
| 614 | if (*here) |
| 615 | return 1; |
| 616 | break; |
| 617 | |
| 618 | case M_BEGWORD: |
| 619 | if (here != str && |
| 620 | (here[-1] == '_' || isalnum(here[-1]))) |
| 621 | return 1; |
| 622 | break; |
| 623 | |
| 624 | case M_ENDWORD: |
| 625 | if (here[0] == '_' || isalnum(here[0])) |
| 626 | return 1; |
| 627 | break; |
| 628 | |
| 629 | case M_START(0): |
| 630 | case M_START(1): |
| 631 | case M_START(2): |
| 632 | case M_START(3): |
| 633 | case M_START(4): |
| 634 | case M_START(5): |
| 635 | case M_START(6): |
| 636 | case M_START(7): |
| 637 | case M_START(8): |
| 638 | case M_START(9): |
| 639 | re->startp[token - M_START(0)] = (char *)here; |
| 640 | break; |
| 641 | |
| 642 | case M_END(0): |
| 643 | case M_END(1): |
| 644 | case M_END(2): |
| 645 | case M_END(3): |
| 646 | case M_END(4): |
| 647 | case M_END(5): |
| 648 | case M_END(6): |
| 649 | case M_END(7): |
| 650 | case M_END(8): |
| 651 | case M_END(9): |
| 652 | re->endp[token - M_END(0)] = (char *)here; |
| 653 | if (token == M_END(0)) |
| 654 | { |
| 655 | return 0; |
| 656 | } |
| 657 | break; |
| 658 | |
| 659 | default: /* literal, M_CLASS(n), or M_ANY */ |
| 660 | if (match1(re, *here, token) != 0) |
| 661 | return 1; |
| 662 | here++; |
| 663 | } |
| 664 | } |
| 665 | |
| 666 | /* C L O S U R E */ |
| 667 | |
| 668 | /* step 1: see what we have to match against, and move "prog" to point |
| 669 | * to the remainder of the compiled RE. |
| 670 | */ |
| 671 | closure = token; |
| 672 | prog++; |
| 673 | switch (closure) |
| 674 | { |
| 675 | case M_SPLAT: |
| 676 | from = 0; |
| 677 | to = strlen(str); /* infinity */ |
| 678 | break; |
| 679 | |
| 680 | case M_PLUS: |
| 681 | from = 1; |
| 682 | to = strlen(str); /* infinity */ |
| 683 | break; |
| 684 | |
| 685 | case M_QMARK: |
| 686 | from = 0; |
| 687 | to = 1; |
| 688 | break; |
| 689 | |
| 690 | #ifndef CRUNCH |
| 691 | case M_RANGE: |
| 692 | from = UCHAR(*prog++); |
| 693 | to = UCHAR(*prog++); |
| 694 | if (to == 255) |
| 695 | { |
| 696 | to = strlen(str); /* infinity */ |
| 697 | } |
| 698 | break; |
| 699 | #endif |
| 700 | } |
| 701 | token = GET_META(prog); |
| 702 | prog++; |
| 703 | |
| 704 | /* step 2: see how many times we can match that token against the string */ |
| 705 | for (nmatched = 0; |
| 706 | nmatched < to && *here && match1(re, *here, token) == 0; |
| 707 | nmatched++, here++) |
| 708 | { |
| 709 | } |
| 710 | |
| 711 | /* step 3: try to match the remainder, and back off if it doesn't */ |
| 712 | while (nmatched >= from && match(re, str, prog, here) != 0) |
| 713 | { |
| 714 | nmatched--; |
| 715 | here--; |
| 716 | } |
| 717 | |
| 718 | /* so how did it work out? */ |
| 719 | if (nmatched >= from) |
| 720 | return 0; |
| 721 | return 1; |
| 722 | } |
| 723 | |
| 724 | |
| 725 | |
| 726 | /* This function searches through a string for text that matches an RE. */ |
| 727 | int regexec(re, str, bol) |
| 728 | regexp *re; /* the compiled regexp to search for */ |
| 729 | char *str; /* the string to search through */ |
| 730 | int bol; /* boolean: does str start at the beginning of a line? */ |
| 731 | { |
| 732 | char *prog; /* the entry point of re->program */ |
| 733 | int len; /* length of the string */ |
| 734 | REG char *here; |
| 735 | |
| 736 | /* if must start at the beginning of a line, and this isn't, then fail */ |
| 737 | if (re->bol && !bol) |
| 738 | { |
| 739 | return 0; |
| 740 | } |
| 741 | |
| 742 | len = strlen(str); |
| 743 | prog = re->program + 1 + 32 * re->program[0]; |
| 744 | |
| 745 | /* search for the RE in the string */ |
| 746 | if (re->bol) |
| 747 | { |
| 748 | /* must occur at BOL */ |
| 749 | if ((re->first |
| 750 | && match1(re, *(char *)str, re->first))/* wrong first letter? */ |
| 751 | || len < re->minlen /* not long enough? */ |
| 752 | || match(re, (char *)str, prog, str)) /* doesn't match? */ |
| 753 | return 0; /* THEN FAIL! */ |
| 754 | } |
| 755 | #ifndef CRUNCH |
| 756 | else if (!*o_ignorecase) |
| 757 | { |
| 758 | /* can occur anywhere in the line, noignorecase */ |
| 759 | for (here = (char *)str; |
| 760 | (re->first && re->first != *here) |
| 761 | || match(re, (char *)str, prog, here); |
| 762 | here++, len--) |
| 763 | { |
| 764 | if (len < re->minlen) |
| 765 | return 0; |
| 766 | } |
| 767 | } |
| 768 | #endif |
| 769 | else |
| 770 | { |
| 771 | /* can occur anywhere in the line, ignorecase */ |
| 772 | for (here = (char *)str; |
| 773 | (re->first && match1(re, *here, (int)re->first)) |
| 774 | || match(re, (char *)str, prog, here); |
| 775 | here++, len--) |
| 776 | { |
| 777 | if (len < re->minlen) |
| 778 | return 0; |
| 779 | } |
| 780 | } |
| 781 | |
| 782 | /* if we didn't fail, then we must have succeeded */ |
| 783 | return 1; |
| 784 | } |
| 785 | |
| 786 | /*============================================================================*/ |
| 787 | #else /* NO_MAGIC */ |
| 788 | |
| 789 | regexp *regcomp(exp) |
| 790 | char *exp; |
| 791 | { |
| 792 | char *src; |
| 793 | char *dest; |
| 794 | regexp *re; |
| 795 | int i; |
| 796 | |
| 797 | /* allocate a big enough regexp structure */ |
| 798 | #ifdef lint |
| 799 | re = (regexp *)0; |
| 800 | #else |
| 801 | re = (regexp *)malloc((unsigned)(strlen(exp) + 1 + sizeof(struct regexp))); |
| 802 | #endif |
| 803 | if (!re) |
| 804 | { |
| 805 | regerror("Could not malloc a regexp structure"); |
| 806 | return (regexp *)0; |
| 807 | } |
| 808 | |
| 809 | /* initialize all fields of the structure */ |
| 810 | for (i = 0; i < NSUBEXP; i++) |
| 811 | { |
| 812 | re->startp[i] = re->endp[i] = (char *)0; |
| 813 | } |
| 814 | re->minlen = 0; |
| 815 | re->first = 0; |
| 816 | re->bol = 0; |
| 817 | |
| 818 | /* copy the string into it, translating ^ and $ as needed */ |
| 819 | for (src = exp, dest = re->program + 1; *src; src++) |
| 820 | { |
| 821 | switch (*src) |
| 822 | { |
| 823 | case '^': |
| 824 | if (src == exp) |
| 825 | { |
| 826 | re->bol += 1; |
| 827 | } |
| 828 | else |
| 829 | { |
| 830 | *dest++ = '^'; |
| 831 | re->minlen++; |
| 832 | } |
| 833 | break; |
| 834 | |
| 835 | case '$': |
| 836 | if (!src[1]) |
| 837 | { |
| 838 | re->bol += 2; |
| 839 | } |
| 840 | else |
| 841 | { |
| 842 | *dest++ = '$'; |
| 843 | re->minlen++; |
| 844 | } |
| 845 | break; |
| 846 | |
| 847 | case '\\': |
| 848 | if (src[1]) |
| 849 | { |
| 850 | *dest++ = *++src; |
| 851 | re->minlen++; |
| 852 | } |
| 853 | else |
| 854 | { |
| 855 | regerror("extra \\ at end of regular expression"); |
| 856 | } |
| 857 | break; |
| 858 | |
| 859 | default: |
| 860 | *dest++ = *src; |
| 861 | re->minlen++; |
| 862 | } |
| 863 | } |
| 864 | *dest = '\0'; |
| 865 | |
| 866 | return re; |
| 867 | } |
| 868 | |
| 869 | |
| 870 | /* This "helper" function checks for a match at a given location. It returns |
| 871 | * 1 if it matches, 0 if it doesn't match here but might match later on in the |
| 872 | * string, or -1 if it could not possibly match |
| 873 | */ |
| 874 | static int reghelp(prog, string, bolflag) |
| 875 | struct regexp *prog; |
| 876 | char *string; |
| 877 | int bolflag; |
| 878 | { |
| 879 | char *scan; |
| 880 | char *str; |
| 881 | |
| 882 | /* if ^, then require bolflag */ |
| 883 | if ((prog->bol & 1) && !bolflag) |
| 884 | { |
| 885 | return -1; |
| 886 | } |
| 887 | |
| 888 | /* if it matches, then it will start here */ |
| 889 | prog->startp[0] = string; |
| 890 | |
| 891 | /* compare, possibly ignoring case */ |
| 892 | if (*o_ignorecase) |
| 893 | { |
| 894 | for (scan = &prog->program[1]; *scan; scan++, string++) |
| 895 | if (tolower(*scan) != tolower(*string)) |
| 896 | return *string ? 0 : -1; |
| 897 | } |
| 898 | else |
| 899 | { |
| 900 | for (scan = &prog->program[1]; *scan; scan++, string++) |
| 901 | if (*scan != *string) |
| 902 | return *string ? 0 : -1; |
| 903 | } |
| 904 | |
| 905 | /* if $, then require string to end here, too */ |
| 906 | if ((prog->bol & 2) && *string) |
| 907 | { |
| 908 | return 0; |
| 909 | } |
| 910 | |
| 911 | /* if we get to here, it matches */ |
| 912 | prog->endp[0] = string; |
| 913 | return 1; |
| 914 | } |
| 915 | |
| 916 | |
| 917 | |
| 918 | int regexec(prog, string, bolflag) |
| 919 | struct regexp *prog; |
| 920 | char *string; |
| 921 | int bolflag; |
| 922 | { |
| 923 | int rc; |
| 924 | |
| 925 | /* keep trying to match it */ |
| 926 | for (rc = reghelp(prog, string, bolflag); rc == 0; rc = reghelp(prog, string, 0)) |
| 927 | { |
| 928 | string++; |
| 929 | } |
| 930 | |
| 931 | /* did we match? */ |
| 932 | return rc == 1; |
| 933 | } |
| 934 | #endif |