| 1 |
/* re-cmp.c |
| 2 |
* Pattern match a string, parsing some of the common RE-metacharacters. |
| 3 |
* |
| 4 |
* This code is public domain, but I would appreciate to hear of |
| 5 |
* improvements or even the fact that you use it in your program. |
| 6 |
* |
| 7 |
* Deliberate BUGS: |
| 8 |
* - These tokens are not supported: | ( ) |
| 9 |
* - You will get the longest expansion of the _first_ string which |
| 10 |
* matches the RE, not the longest string which would be the proper |
| 11 |
* behaviour for a RE-matcher. |
| 12 |
* |
| 13 |
* Author: Kjetil T. Homme <kjetilho@ifi.uio.no> May 1993 |
| 14 |
*/ |
| 15 |
|
| 16 |
#include <stdio.h> |
| 17 |
#include <stdlib.h> |
| 18 |
#include <memory.h> |
| 19 |
#include <limits.h> |
| 20 |
#include <re-cmp.h> |
| 21 |
#include <ctype.h> |
| 22 |
|
| 23 |
/* Get prototype functions to prevent warnings. */ |
| 24 |
#if defined (__sun__) && defined(StupidSunHeaders) |
| 25 |
# include <sys/types.h> |
| 26 |
# include <sys/time.h> |
| 27 |
# include "sunos.h" /* Prototypes for standard libraries, sunos lack those */ |
| 28 |
#endif |
| 29 |
|
| 30 |
|
| 31 |
/* P r o t o t y p e s |
| 32 |
*/ |
| 33 |
const char *re_cmp (const char *, const char *); |
| 34 |
static bool re_cmp_step (const char *, const char *, unsigned, int); |
| 35 |
static void re_init (void); |
| 36 |
static bool re_match_token (unsigned char, selection *); |
| 37 |
static const char *re_get_token (selection *, const char *); |
| 38 |
|
| 39 |
#ifdef DEBUG2 |
| 40 |
static void re_dump_sel (selection *); |
| 41 |
#endif |
| 42 |
|
| 43 |
/* G l o b a l v a r i a b l e s |
| 44 |
*/ |
| 45 |
static bool re_init_done = false; |
| 46 |
static selection *re_token[RE_TOKEN_MAX]; |
| 47 |
static const char *re_substr[RE_TOKEN_MAX]; |
| 48 |
static unsigned int re_token_depth; |
| 49 |
|
| 50 |
/* E x t e r n a l f u n c t i o n |
| 51 |
*/ |
| 52 |
|
| 53 |
/* re-cmp - get regular expression match. |
| 54 |
* Return values: NULL - no match or error in regexp. |
| 55 |
* pointer to beginning of matching string |
| 56 |
*/ |
| 57 |
const char * |
| 58 |
re_cmp (const char *str, const char *regexp) |
| 59 |
{ |
| 60 |
const char *next_regexp; |
| 61 |
bool once = false; |
| 62 |
bool matched; |
| 63 |
|
| 64 |
if (re_init_done == false) |
| 65 |
re_init (); |
| 66 |
|
| 67 |
#ifdef SAFE_CHECKS |
| 68 |
if (regexp == NULL || str == NULL) |
| 69 |
return NULL; |
| 70 |
#endif |
| 71 |
if (*regexp == '^') |
| 72 |
{ |
| 73 |
once = true; |
| 74 |
++regexp; |
| 75 |
} |
| 76 |
if (*regexp == 0) |
| 77 |
{ |
| 78 |
/* // or /^/ matches any string */ |
| 79 |
return str; |
| 80 |
} |
| 81 |
|
| 82 |
next_regexp = re_get_token (re_token[0], regexp); |
| 83 |
re_token_depth = 0; |
| 84 |
re_substr[0] = next_regexp; |
| 85 |
|
| 86 |
matched = false; |
| 87 |
while (*str != '\0' && !(matched = re_match_token (*str, re_token[0]))) |
| 88 |
str++; |
| 89 |
|
| 90 |
if (matched && *next_regexp == 0) |
| 91 |
return str; |
| 92 |
|
| 93 |
/* Apologies for the nearly duplicated code below, hopefully it |
| 94 |
* speeds things up. |
| 95 |
*/ |
| 96 |
if (once) |
| 97 |
{ |
| 98 |
switch (re_token[0]->repeat) |
| 99 |
{ |
| 100 |
case rep_once: |
| 101 |
if (matched == false) |
| 102 |
return NULL; |
| 103 |
break; |
| 104 |
case rep_once_or_more: |
| 105 |
if (matched == false) |
| 106 |
return NULL; |
| 107 |
|
| 108 |
if (re_cmp_step (str + 1, regexp, 0, 1)) |
| 109 |
return str; |
| 110 |
break; |
| 111 |
case rep_null_or_once: |
| 112 |
if (matched == false) |
| 113 |
return re_cmp_step (str, next_regexp, 1, 0) ? str : NULL; |
| 114 |
break; |
| 115 |
case rep_null_or_more: |
| 116 |
if (matched) |
| 117 |
{ |
| 118 |
if (re_cmp_step (str + 1, regexp, 0, 1)) |
| 119 |
return str; |
| 120 |
} |
| 121 |
else |
| 122 |
{ |
| 123 |
return re_cmp_step (str, next_regexp, 1, 0) ? str : NULL; |
| 124 |
} |
| 125 |
break; |
| 126 |
} |
| 127 |
return re_cmp_step (str + 1, next_regexp, 1, 0) ? str : NULL; |
| 128 |
} |
| 129 |
|
| 130 |
if (matched) |
| 131 |
{ |
| 132 |
switch (re_token[0]->repeat) |
| 133 |
{ |
| 134 |
case rep_once: |
| 135 |
case rep_null_or_once: |
| 136 |
break; |
| 137 |
case rep_once_or_more: |
| 138 |
case rep_null_or_more: |
| 139 |
if (re_cmp_step (str + 1, regexp, 0, 1)) |
| 140 |
return str; |
| 141 |
break; |
| 142 |
} |
| 143 |
/* The logic here is that re_match_token only sees |
| 144 |
* if the one letter matches. Thus, if the |
| 145 |
* regex is like '@match eureca', and the |
| 146 |
* the user enters anything with an e, re_match_token |
| 147 |
* returns true, but they really need to match the |
| 148 |
* entire regexp, which re_cmp_step will do. |
| 149 |
* However, what happens is that there can be a case |
| 150 |
* where the string being match is something like |
| 151 |
* 'where is eureca'. In this case, the re_match_token |
| 152 |
* matches that first e, but the re_cmp_step below, |
| 153 |
* fails because the next character (r) doesn't match |
| 154 |
* the u. So we call re_cmp with the string |
| 155 |
* after the first r, so that it should hopefully match |
| 156 |
* up properly. |
| 157 |
*/ |
| 158 |
if (re_cmp_step (str + 1, next_regexp, 1, 0)) |
| 159 |
return str; |
| 160 |
else if (*(str + 1) != 0) |
| 161 |
return re_cmp (str + 1, regexp); |
| 162 |
} |
| 163 |
return NULL; |
| 164 |
} |
| 165 |
|
| 166 |
/* A u x i l l i a r y f u n c t i o n s |
| 167 |
*/ |
| 168 |
|
| 169 |
static bool |
| 170 |
re_cmp_step (const char *str, const char *regexp, unsigned slot, int matches) |
| 171 |
{ |
| 172 |
/* str - string to match |
| 173 |
* regexp - pattern |
| 174 |
* slot - number of the token which under consideration |
| 175 |
* matches - how many times the token has matched |
| 176 |
*/ |
| 177 |
const char *next_regexp; |
| 178 |
bool matched; |
| 179 |
|
| 180 |
#ifdef DEBUG |
| 181 |
|
| 182 |
/* fprintf(stderr, "['%s', '%s', %u, %d]\n", str, regexp, slot, matches);*/ |
| 183 |
#endif |
| 184 |
|
| 185 |
if (*regexp == 0) |
| 186 |
{ |
| 187 |
/* When we reach the end of the regexp, the match is a success |
| 188 |
*/ |
| 189 |
return true; |
| 190 |
} |
| 191 |
|
| 192 |
/* This chunk of code makes sure that the regexp-tokenising happens |
| 193 |
* only once. We only tokenise as much as we need. |
| 194 |
*/ |
| 195 |
if (slot > re_token_depth) |
| 196 |
{ |
| 197 |
re_token_depth = slot; |
| 198 |
if (re_token[slot] == NULL) |
| 199 |
re_token[slot] = (selection *) malloc (sizeof (selection)); |
| 200 |
next_regexp = re_get_token (re_token[slot], regexp); |
| 201 |
if (next_regexp == NULL) |
| 202 |
{ |
| 203 |
/* Syntax error, what else can we do? */ |
| 204 |
return false; |
| 205 |
} |
| 206 |
re_substr[slot] = next_regexp; |
| 207 |
} |
| 208 |
else |
| 209 |
{ |
| 210 |
next_regexp = re_substr[slot]; |
| 211 |
} |
| 212 |
|
| 213 |
matched = re_match_token (*str, re_token[slot]); |
| 214 |
if (matched) |
| 215 |
++matches; |
| 216 |
|
| 217 |
if (*str == 0) |
| 218 |
return (*next_regexp == 0 || re_token[slot]->type == sel_end) && matched; |
| 219 |
|
| 220 |
switch (re_token[slot]->repeat) |
| 221 |
{ |
| 222 |
case rep_once: |
| 223 |
if (matches == 1) |
| 224 |
{ /* (matches == 1) => (matched == true) */ |
| 225 |
return re_cmp_step (str + 1, next_regexp, slot + 1, 0); |
| 226 |
} |
| 227 |
return false; |
| 228 |
case rep_once_or_more: |
| 229 |
if (matched) |
| 230 |
{ /* (matched == true) => (matches >= 1) */ |
| 231 |
/* First check if the current token repeats more */ |
| 232 |
if (re_cmp_step (str + 1, regexp, slot, matches)) |
| 233 |
return true; |
| 234 |
return re_cmp_step (str + 1, next_regexp, slot + 1, 0); |
| 235 |
} |
| 236 |
return false; |
| 237 |
case rep_null_or_once: |
| 238 |
/* We must go on to the next token, but should we advance str? */ |
| 239 |
if (matches == 0) |
| 240 |
{ |
| 241 |
return re_cmp_step (str, next_regexp, slot + 1, 0); |
| 242 |
} |
| 243 |
else if (matches == 1) |
| 244 |
{ |
| 245 |
return re_cmp_step (str + 1, next_regexp, slot + 1, 0); |
| 246 |
} |
| 247 |
return false; /* Not reached */ |
| 248 |
case rep_null_or_more: |
| 249 |
if (matched) |
| 250 |
{ |
| 251 |
/* Look for further repeats, advance str */ |
| 252 |
if (re_cmp_step (str + 1, regexp, slot, matches)) |
| 253 |
return true; |
| 254 |
return re_cmp_step (str, next_regexp, slot + 1, 0); |
| 255 |
} |
| 256 |
return re_cmp_step (str, next_regexp, slot + 1, 0); |
| 257 |
} |
| 258 |
return false; |
| 259 |
} |
| 260 |
|
| 261 |
static void |
| 262 |
re_init (void) |
| 263 |
{ |
| 264 |
int i; |
| 265 |
|
| 266 |
re_token[0] = (selection *) malloc (sizeof (selection)); |
| 267 |
for (i = 1; i < RE_TOKEN_MAX; i++) |
| 268 |
re_token[i] = NULL; |
| 269 |
|
| 270 |
re_init_done = true; |
| 271 |
} |
| 272 |
|
| 273 |
static bool |
| 274 |
re_match_token (unsigned char c, selection * sel) |
| 275 |
{ |
| 276 |
switch (sel->type) |
| 277 |
{ |
| 278 |
case sel_any: |
| 279 |
return true; |
| 280 |
case sel_end: |
| 281 |
return (c == 0); |
| 282 |
case sel_single: |
| 283 |
return (tolower (c) == tolower (sel->u.single)); |
| 284 |
case sel_range: |
| 285 |
return (c >= sel->u.range.low && c <= sel->u.range.high); |
| 286 |
case sel_array: |
| 287 |
return (sel->u.array[c]); |
| 288 |
case sel_not_single: |
| 289 |
return (tolower (c) != tolower (sel->u.single)); |
| 290 |
case sel_not_range: |
| 291 |
return (c < sel->u.range.low && c > sel->u.range.high); |
| 292 |
} |
| 293 |
return false; |
| 294 |
} |
| 295 |
|
| 296 |
/* re_get_token - get regular expression token |
| 297 |
* Returns the first token found in <regexp> in <sel> |
| 298 |
* Return values: NULL syntax error |
| 299 |
* pointer to first character past token. |
| 300 |
*/ |
| 301 |
static const char * |
| 302 |
re_get_token (selection * sel, const char *regexp) |
| 303 |
{ |
| 304 |
|
| 305 |
#ifdef SAFE_CHECKS |
| 306 |
# define exit_if_null if (*regexp == 0) return NULL |
| 307 |
#else |
| 308 |
# define exit_if_null |
| 309 |
#endif |
| 310 |
|
| 311 |
bool quoted = false; |
| 312 |
unsigned char looking_at; |
| 313 |
|
| 314 |
#ifdef SAFE_CHECKS |
| 315 |
if (sel == NULL || regexp == NULL || *regexp == 0) |
| 316 |
return NULL; |
| 317 |
#endif |
| 318 |
|
| 319 |
do |
| 320 |
{ |
| 321 |
looking_at = *regexp++; |
| 322 |
switch (looking_at) |
| 323 |
{ |
| 324 |
case '$': |
| 325 |
if (quoted) |
| 326 |
{ |
| 327 |
quoted = false; |
| 328 |
sel->type = sel_single; |
| 329 |
sel->u.single = looking_at; |
| 330 |
} |
| 331 |
else |
| 332 |
{ |
| 333 |
sel->type = sel_end; |
| 334 |
} |
| 335 |
break; |
| 336 |
case '.': |
| 337 |
if (quoted) |
| 338 |
{ |
| 339 |
quoted = false; |
| 340 |
sel->type = sel_single; |
| 341 |
sel->u.single = looking_at; |
| 342 |
} |
| 343 |
else |
| 344 |
{ |
| 345 |
sel->type = sel_any; |
| 346 |
} |
| 347 |
break; |
| 348 |
case '[': |
| 349 |
/* The fun stuff... perhaps a little obfuscated since I |
| 350 |
* don't trust the compiler to analyse liveness. |
| 351 |
*/ |
| 352 |
if (quoted) |
| 353 |
{ |
| 354 |
quoted = false; |
| 355 |
sel->type = sel_single; |
| 356 |
sel->u.single = looking_at; |
| 357 |
} |
| 358 |
else |
| 359 |
{ |
| 360 |
bool neg = false; |
| 361 |
unsigned char first, last = 0; |
| 362 |
|
| 363 |
exit_if_null; |
| 364 |
looking_at = *regexp++; |
| 365 |
|
| 366 |
if (looking_at == '^') |
| 367 |
{ |
| 368 |
neg = true; |
| 369 |
exit_if_null; |
| 370 |
looking_at = *regexp++; |
| 371 |
} |
| 372 |
first = looking_at; |
| 373 |
exit_if_null; |
| 374 |
looking_at = *regexp++; |
| 375 |
if (looking_at == ']') |
| 376 |
{ |
| 377 |
/* On the form [q] or [^q] */ |
| 378 |
sel->type = neg ? sel_not_single : sel_single; |
| 379 |
sel->u.single = first; |
| 380 |
break; |
| 381 |
} |
| 382 |
else if (looking_at == '-') |
| 383 |
{ |
| 384 |
exit_if_null; |
| 385 |
last = *regexp++; |
| 386 |
if (last == ']') |
| 387 |
{ |
| 388 |
/* On the form [A-] or [^A-]. Checking for |
| 389 |
* [,-] and making it a range is probably not |
| 390 |
* worth it :-) |
| 391 |
*/ |
| 392 |
sel->type = sel_array; |
| 393 |
memset (sel->u.array, neg, sizeof (sel->u.array)); |
| 394 |
sel->u.array[first] = sel->u.array['-'] = !neg; |
| 395 |
break; |
| 396 |
} |
| 397 |
else |
| 398 |
{ |
| 399 |
exit_if_null; |
| 400 |
looking_at = *regexp++; |
| 401 |
if (looking_at == ']') |
| 402 |
{ |
| 403 |
/* On the form [A-G] or [^A-G]. Note that [G-A] |
| 404 |
* is a syntax error. Fair enough, I think. |
| 405 |
*/ |
| 406 |
#ifdef SAFE_CHECK |
| 407 |
if (first > last) |
| 408 |
return NULL; |
| 409 |
#endif |
| 410 |
sel->type = neg ? sel_not_range : sel_range; |
| 411 |
sel->u.range.low = first; |
| 412 |
sel->u.range.high = last; |
| 413 |
break; |
| 414 |
} |
| 415 |
} |
| 416 |
} |
| 417 |
{ |
| 418 |
/* The datastructure can only represent a RE this |
| 419 |
* complex with an array. |
| 420 |
*/ |
| 421 |
int i; |
| 422 |
unsigned char previous; |
| 423 |
|
| 424 |
sel->type = sel_array; |
| 425 |
memset (sel->u.array, neg, sizeof (sel->u.array)); |
| 426 |
if (last) |
| 427 |
{ |
| 428 |
/* It starts with a range */ |
| 429 |
#ifdef SAFE_CHECK |
| 430 |
if (first > last) |
| 431 |
return NULL; |
| 432 |
#endif |
| 433 |
for (i = first; i <= last; i++) |
| 434 |
{ |
| 435 |
sel->u.array[i] = !neg; |
| 436 |
} |
| 437 |
} |
| 438 |
else |
| 439 |
{ |
| 440 |
/* It begins with a "random" character */ |
| 441 |
sel->u.array[first] = !neg; |
| 442 |
} |
| 443 |
sel->u.array[looking_at] = !neg; |
| 444 |
|
| 445 |
exit_if_null; |
| 446 |
previous = looking_at; |
| 447 |
looking_at = *regexp++; |
| 448 |
|
| 449 |
/* Add more characters to the array until we reach |
| 450 |
* ]. Quoting doesn't and shouldn't work in here. |
| 451 |
* ("]" should be put first, and "-" last if they |
| 452 |
* are needed inside this construct.) |
| 453 |
* Look for ranges as we go along. |
| 454 |
*/ |
| 455 |
while (looking_at != ']') |
| 456 |
{ |
| 457 |
if (looking_at == '-') |
| 458 |
{ |
| 459 |
exit_if_null; |
| 460 |
looking_at = *regexp++; |
| 461 |
if (looking_at != ']') |
| 462 |
{ |
| 463 |
#ifdef SAFE_CHECK |
| 464 |
if (previous > looking_at) |
| 465 |
return NULL; |
| 466 |
#endif |
| 467 |
for (i = previous + 1; i < looking_at; i++) |
| 468 |
{ |
| 469 |
/* previous has already been set and |
| 470 |
* looking_at is set below. |
| 471 |
*/ |
| 472 |
sel->u.array[i] = !neg; |
| 473 |
} |
| 474 |
exit_if_null; |
| 475 |
} |
| 476 |
else |
| 477 |
{ |
| 478 |
sel->u.array['-'] = !neg; |
| 479 |
break; |
| 480 |
} |
| 481 |
} |
| 482 |
sel->u.array[looking_at] = !neg; |
| 483 |
previous = looking_at; |
| 484 |
exit_if_null; |
| 485 |
looking_at = *regexp++; |
| 486 |
} |
| 487 |
} |
| 488 |
} |
| 489 |
break; |
| 490 |
case '\\': |
| 491 |
if (quoted) |
| 492 |
{ |
| 493 |
quoted = false; |
| 494 |
sel->type = sel_single; |
| 495 |
sel->u.single = looking_at; |
| 496 |
} |
| 497 |
else |
| 498 |
{ |
| 499 |
quoted = true; |
| 500 |
} |
| 501 |
break; |
| 502 |
default: |
| 503 |
quoted = false; |
| 504 |
sel->type = sel_single; |
| 505 |
sel->u.single = looking_at; |
| 506 |
break; |
| 507 |
} |
| 508 |
} |
| 509 |
while (quoted); |
| 510 |
|
| 511 |
if (*regexp == '*') |
| 512 |
{ |
| 513 |
sel->repeat = rep_null_or_more; |
| 514 |
++regexp; |
| 515 |
} |
| 516 |
else if (*regexp == '?') |
| 517 |
{ |
| 518 |
sel->repeat = rep_null_or_once; |
| 519 |
++regexp; |
| 520 |
} |
| 521 |
else if (*regexp == '+') |
| 522 |
{ |
| 523 |
sel->repeat = rep_once_or_more; |
| 524 |
++regexp; |
| 525 |
} |
| 526 |
else |
| 527 |
{ |
| 528 |
sel->repeat = rep_once; |
| 529 |
} |
| 530 |
|
| 531 |
return regexp; |
| 532 |
} |
| 533 |
|
| 534 |
/* D e b u g c o d e |
| 535 |
*/ |
| 536 |
#ifdef DEBUG2 /* compile all with DEBUG also ? hevi@lut.fi */ |
| 537 |
static void |
| 538 |
re_dump_sel (selection * sel) |
| 539 |
{ |
| 540 |
switch (sel->type) |
| 541 |
{ |
| 542 |
case sel_any: |
| 543 |
printf ("."); |
| 544 |
break; |
| 545 |
case sel_end: |
| 546 |
printf ("$"); |
| 547 |
break; |
| 548 |
case sel_single: |
| 549 |
printf ("<%c>", sel->u.single); |
| 550 |
break; |
| 551 |
case sel_range: |
| 552 |
printf ("[%c-%c]", sel->u.range.low, sel->u.range.high); |
| 553 |
break; |
| 554 |
case sel_array: |
| 555 |
{ |
| 556 |
int i; |
| 557 |
|
| 558 |
printf ("["); |
| 559 |
for (i = 0; i < uchar_MAX; i++) |
| 560 |
{ |
| 561 |
if (sel->u.array[i]) |
| 562 |
{ |
| 563 |
printf ("%c", i); |
| 564 |
} |
| 565 |
} |
| 566 |
printf ("]"); |
| 567 |
} |
| 568 |
break; |
| 569 |
case sel_not_single: |
| 570 |
printf ("[^%c]", sel->u.single); |
| 571 |
break; |
| 572 |
case sel_not_range: |
| 573 |
printf ("[^%c-%c]", sel->u.range.low, sel->u.range.high); |
| 574 |
break; |
| 575 |
default: |
| 576 |
printf ("<UNKNOWN TOKEN!>"); |
| 577 |
break; |
| 578 |
} |
| 579 |
switch (sel->repeat) |
| 580 |
{ |
| 581 |
case rep_once: |
| 582 |
break; |
| 583 |
case rep_null_or_once: |
| 584 |
printf ("?"); |
| 585 |
break; |
| 586 |
case rep_null_or_more: |
| 587 |
printf ("*"); |
| 588 |
break; |
| 589 |
case rep_once_or_more: |
| 590 |
printf ("+"); |
| 591 |
break; |
| 592 |
default: |
| 593 |
printf ("<UNKNOWN REP-TOKEN!>"); |
| 594 |
break; |
| 595 |
} |
| 596 |
} |
| 597 |
|
| 598 |
int |
| 599 |
main (int argc, char *argv[]) |
| 600 |
{ |
| 601 |
char *re, *m; |
| 602 |
selection sel; |
| 603 |
|
| 604 |
re = re_get_token (&sel, argv[1]); |
| 605 |
|
| 606 |
printf ("'%s' -> '%s'\n", argv[1], re); |
| 607 |
re_dump_sel (&sel); |
| 608 |
printf ("\n"); |
| 609 |
m = re_cmp (argv[2], argv[1]); |
| 610 |
if (m) |
| 611 |
printf ("MATCH! -> '%s'\n", m); |
| 612 |
return 0; |
| 613 |
} |
| 614 |
#endif |
