Ian Hodson | 2ee91b4 | 2012-05-14 12:29:36 +0100 | [diff] [blame] | 1 | // Copyright 2006 The RE2 Authors. All Rights Reserved. |
| 2 | // Use of this source code is governed by a BSD-style |
| 3 | // license that can be found in the LICENSE file. |
| 4 | |
| 5 | // Regular expression representation. |
| 6 | // Tested by parse_test.cc |
| 7 | |
| 8 | #include "util/util.h" |
| 9 | #include "re2/regexp.h" |
| 10 | #include "re2/stringpiece.h" |
| 11 | #include "re2/walker-inl.h" |
| 12 | |
| 13 | namespace re2 { |
| 14 | |
| 15 | // Constructor. Allocates vectors as appropriate for operator. |
| 16 | Regexp::Regexp(RegexpOp op, ParseFlags parse_flags) |
| 17 | : op_(op), |
| 18 | simple_(false), |
| 19 | parse_flags_(static_cast<uint16>(parse_flags)), |
| 20 | ref_(1), |
| 21 | nsub_(0), |
| 22 | down_(NULL) { |
| 23 | subone_ = NULL; |
| 24 | memset(the_union_, 0, sizeof the_union_); |
| 25 | } |
| 26 | |
| 27 | // Destructor. Assumes already cleaned up children. |
| 28 | // Private: use Decref() instead of delete to destroy Regexps. |
| 29 | // Can't call Decref on the sub-Regexps here because |
| 30 | // that could cause arbitrarily deep recursion, so |
| 31 | // required Decref() to have handled them for us. |
| 32 | Regexp::~Regexp() { |
| 33 | if (nsub_ > 0) |
| 34 | LOG(DFATAL) << "Regexp not destroyed."; |
| 35 | |
| 36 | switch (op_) { |
| 37 | default: |
| 38 | break; |
| 39 | case kRegexpCapture: |
| 40 | delete name_; |
| 41 | break; |
| 42 | case kRegexpLiteralString: |
| 43 | delete[] runes_; |
| 44 | break; |
| 45 | case kRegexpCharClass: |
| 46 | cc_->Delete(); |
| 47 | delete ccb_; |
| 48 | break; |
| 49 | } |
| 50 | } |
| 51 | |
| 52 | // If it's possible to destroy this regexp without recurring, |
| 53 | // do so and return true. Else return false. |
| 54 | bool Regexp::QuickDestroy() { |
| 55 | if (nsub_ == 0) { |
| 56 | delete this; |
| 57 | return true; |
| 58 | } |
| 59 | return false; |
| 60 | } |
| 61 | |
Alexander Gutkin | 0d4c523 | 2013-02-28 13:47:27 +0000 | [diff] [blame] | 62 | static map<Regexp*, int> *ref_map; |
| 63 | GLOBAL_MUTEX(ref_mutex); |
Ian Hodson | 2ee91b4 | 2012-05-14 12:29:36 +0100 | [diff] [blame] | 64 | |
| 65 | int Regexp::Ref() { |
| 66 | if (ref_ < kMaxRef) |
| 67 | return ref_; |
| 68 | |
Alexander Gutkin | 0d4c523 | 2013-02-28 13:47:27 +0000 | [diff] [blame] | 69 | GLOBAL_MUTEX_LOCK(ref_mutex); |
| 70 | int r = 0; |
| 71 | if (ref_map != NULL) { |
| 72 | r = (*ref_map)[this]; |
| 73 | } |
| 74 | GLOBAL_MUTEX_UNLOCK(ref_mutex); |
| 75 | return r; |
Ian Hodson | 2ee91b4 | 2012-05-14 12:29:36 +0100 | [diff] [blame] | 76 | } |
| 77 | |
| 78 | // Increments reference count, returns object as convenience. |
| 79 | Regexp* Regexp::Incref() { |
| 80 | if (ref_ >= kMaxRef-1) { |
| 81 | // Store ref count in overflow map. |
Alexander Gutkin | 0d4c523 | 2013-02-28 13:47:27 +0000 | [diff] [blame] | 82 | GLOBAL_MUTEX_LOCK(ref_mutex); |
| 83 | if (ref_map == NULL) { |
| 84 | ref_map = new map<Regexp*, int>; |
Ian Hodson | 2ee91b4 | 2012-05-14 12:29:36 +0100 | [diff] [blame] | 85 | } |
Alexander Gutkin | 0d4c523 | 2013-02-28 13:47:27 +0000 | [diff] [blame] | 86 | if (ref_ == kMaxRef) { |
| 87 | // already overflowed |
| 88 | (*ref_map)[this]++; |
| 89 | } else { |
| 90 | // overflowing now |
| 91 | (*ref_map)[this] = kMaxRef; |
| 92 | ref_ = kMaxRef; |
| 93 | } |
| 94 | GLOBAL_MUTEX_UNLOCK(ref_mutex); |
Ian Hodson | 2ee91b4 | 2012-05-14 12:29:36 +0100 | [diff] [blame] | 95 | return this; |
| 96 | } |
| 97 | |
| 98 | ref_++; |
| 99 | return this; |
| 100 | } |
| 101 | |
| 102 | // Decrements reference count and deletes this object if count reaches 0. |
| 103 | void Regexp::Decref() { |
| 104 | if (ref_ == kMaxRef) { |
| 105 | // Ref count is stored in overflow map. |
Alexander Gutkin | 0d4c523 | 2013-02-28 13:47:27 +0000 | [diff] [blame] | 106 | GLOBAL_MUTEX_LOCK(ref_mutex); |
| 107 | int r = (*ref_map)[this] - 1; |
Ian Hodson | 2ee91b4 | 2012-05-14 12:29:36 +0100 | [diff] [blame] | 108 | if (r < kMaxRef) { |
| 109 | ref_ = r; |
Alexander Gutkin | 0d4c523 | 2013-02-28 13:47:27 +0000 | [diff] [blame] | 110 | ref_map->erase(this); |
Ian Hodson | 2ee91b4 | 2012-05-14 12:29:36 +0100 | [diff] [blame] | 111 | } else { |
Alexander Gutkin | 0d4c523 | 2013-02-28 13:47:27 +0000 | [diff] [blame] | 112 | (*ref_map)[this] = r; |
Ian Hodson | 2ee91b4 | 2012-05-14 12:29:36 +0100 | [diff] [blame] | 113 | } |
Alexander Gutkin | 0d4c523 | 2013-02-28 13:47:27 +0000 | [diff] [blame] | 114 | GLOBAL_MUTEX_UNLOCK(ref_mutex); |
Ian Hodson | 2ee91b4 | 2012-05-14 12:29:36 +0100 | [diff] [blame] | 115 | return; |
| 116 | } |
| 117 | ref_--; |
| 118 | if (ref_ == 0) |
| 119 | Destroy(); |
| 120 | } |
| 121 | |
| 122 | // Deletes this object; ref count has count reached 0. |
| 123 | void Regexp::Destroy() { |
| 124 | if (QuickDestroy()) |
| 125 | return; |
| 126 | |
| 127 | // Handle recursive Destroy with explicit stack |
| 128 | // to avoid arbitrarily deep recursion on process stack [sigh]. |
| 129 | down_ = NULL; |
| 130 | Regexp* stack = this; |
| 131 | while (stack != NULL) { |
| 132 | Regexp* re = stack; |
| 133 | stack = re->down_; |
| 134 | if (re->ref_ != 0) |
| 135 | LOG(DFATAL) << "Bad reference count " << re->ref_; |
| 136 | if (re->nsub_ > 0) { |
| 137 | Regexp** subs = re->sub(); |
| 138 | for (int i = 0; i < re->nsub_; i++) { |
| 139 | Regexp* sub = subs[i]; |
| 140 | if (sub == NULL) |
| 141 | continue; |
| 142 | if (sub->ref_ == kMaxRef) |
| 143 | sub->Decref(); |
| 144 | else |
| 145 | --sub->ref_; |
| 146 | if (sub->ref_ == 0 && !sub->QuickDestroy()) { |
| 147 | sub->down_ = stack; |
| 148 | stack = sub; |
| 149 | } |
| 150 | } |
| 151 | if (re->nsub_ > 1) |
| 152 | delete[] subs; |
| 153 | re->nsub_ = 0; |
| 154 | } |
| 155 | delete re; |
| 156 | } |
| 157 | } |
| 158 | |
| 159 | void Regexp::AddRuneToString(Rune r) { |
| 160 | DCHECK(op_ == kRegexpLiteralString); |
| 161 | if (nrunes_ == 0) { |
| 162 | // start with 8 |
| 163 | runes_ = new Rune[8]; |
| 164 | } else if (nrunes_ >= 8 && (nrunes_ & (nrunes_ - 1)) == 0) { |
| 165 | // double on powers of two |
| 166 | Rune *old = runes_; |
| 167 | runes_ = new Rune[nrunes_ * 2]; |
| 168 | for (int i = 0; i < nrunes_; i++) |
| 169 | runes_[i] = old[i]; |
| 170 | delete[] old; |
| 171 | } |
| 172 | |
| 173 | runes_[nrunes_++] = r; |
| 174 | } |
| 175 | |
| 176 | Regexp* Regexp::HaveMatch(int match_id, ParseFlags flags) { |
| 177 | Regexp* re = new Regexp(kRegexpHaveMatch, flags); |
| 178 | re->match_id_ = match_id; |
| 179 | return re; |
| 180 | } |
| 181 | |
| 182 | Regexp* Regexp::Plus(Regexp* sub, ParseFlags flags) { |
| 183 | if (sub->op() == kRegexpPlus && sub->parse_flags() == flags) |
| 184 | return sub; |
| 185 | Regexp* re = new Regexp(kRegexpPlus, flags); |
| 186 | re->AllocSub(1); |
| 187 | re->sub()[0] = sub; |
| 188 | return re; |
| 189 | } |
| 190 | |
| 191 | Regexp* Regexp::Star(Regexp* sub, ParseFlags flags) { |
| 192 | if (sub->op() == kRegexpStar && sub->parse_flags() == flags) |
| 193 | return sub; |
| 194 | Regexp* re = new Regexp(kRegexpStar, flags); |
| 195 | re->AllocSub(1); |
| 196 | re->sub()[0] = sub; |
| 197 | return re; |
| 198 | } |
| 199 | |
| 200 | Regexp* Regexp::Quest(Regexp* sub, ParseFlags flags) { |
| 201 | if (sub->op() == kRegexpQuest && sub->parse_flags() == flags) |
| 202 | return sub; |
| 203 | Regexp* re = new Regexp(kRegexpQuest, flags); |
| 204 | re->AllocSub(1); |
| 205 | re->sub()[0] = sub; |
| 206 | return re; |
| 207 | } |
| 208 | |
| 209 | Regexp* Regexp::ConcatOrAlternate(RegexpOp op, Regexp** sub, int nsub, |
| 210 | ParseFlags flags, bool can_factor) { |
| 211 | if (nsub == 1) |
| 212 | return sub[0]; |
| 213 | |
| 214 | Regexp** subcopy = NULL; |
| 215 | if (op == kRegexpAlternate && can_factor) { |
| 216 | // Going to edit sub; make a copy so we don't step on caller. |
| 217 | subcopy = new Regexp*[nsub]; |
| 218 | memmove(subcopy, sub, nsub * sizeof sub[0]); |
| 219 | sub = subcopy; |
| 220 | nsub = FactorAlternation(sub, nsub, flags); |
| 221 | if (nsub == 1) { |
| 222 | Regexp* re = sub[0]; |
| 223 | delete[] subcopy; |
| 224 | return re; |
| 225 | } |
| 226 | } |
| 227 | |
| 228 | if (nsub > kMaxNsub) { |
| 229 | // Too many subexpressions to fit in a single Regexp. |
| 230 | // Make a two-level tree. Two levels gets us to 65535^2. |
| 231 | int nbigsub = (nsub+kMaxNsub-1)/kMaxNsub; |
| 232 | Regexp* re = new Regexp(op, flags); |
| 233 | re->AllocSub(nbigsub); |
| 234 | Regexp** subs = re->sub(); |
| 235 | for (int i = 0; i < nbigsub - 1; i++) |
| 236 | subs[i] = ConcatOrAlternate(op, sub+i*kMaxNsub, kMaxNsub, flags, false); |
| 237 | subs[nbigsub - 1] = ConcatOrAlternate(op, sub+(nbigsub-1)*kMaxNsub, |
| 238 | nsub - (nbigsub-1)*kMaxNsub, flags, |
| 239 | false); |
| 240 | delete[] subcopy; |
| 241 | return re; |
| 242 | } |
| 243 | |
| 244 | Regexp* re = new Regexp(op, flags); |
| 245 | re->AllocSub(nsub); |
| 246 | Regexp** subs = re->sub(); |
| 247 | for (int i = 0; i < nsub; i++) |
| 248 | subs[i] = sub[i]; |
| 249 | |
| 250 | delete[] subcopy; |
| 251 | return re; |
| 252 | } |
| 253 | |
| 254 | Regexp* Regexp::Concat(Regexp** sub, int nsub, ParseFlags flags) { |
| 255 | return ConcatOrAlternate(kRegexpConcat, sub, nsub, flags, false); |
| 256 | } |
| 257 | |
| 258 | Regexp* Regexp::Alternate(Regexp** sub, int nsub, ParseFlags flags) { |
| 259 | return ConcatOrAlternate(kRegexpAlternate, sub, nsub, flags, true); |
| 260 | } |
| 261 | |
| 262 | Regexp* Regexp::AlternateNoFactor(Regexp** sub, int nsub, ParseFlags flags) { |
| 263 | return ConcatOrAlternate(kRegexpAlternate, sub, nsub, flags, false); |
| 264 | } |
| 265 | |
| 266 | Regexp* Regexp::Capture(Regexp* sub, ParseFlags flags, int cap) { |
| 267 | Regexp* re = new Regexp(kRegexpCapture, flags); |
| 268 | re->AllocSub(1); |
| 269 | re->sub()[0] = sub; |
| 270 | re->cap_ = cap; |
| 271 | return re; |
| 272 | } |
| 273 | |
| 274 | Regexp* Regexp::Repeat(Regexp* sub, ParseFlags flags, int min, int max) { |
| 275 | Regexp* re = new Regexp(kRegexpRepeat, flags); |
| 276 | re->AllocSub(1); |
| 277 | re->sub()[0] = sub; |
| 278 | re->min_ = min; |
| 279 | re->max_ = max; |
| 280 | return re; |
| 281 | } |
| 282 | |
| 283 | Regexp* Regexp::NewLiteral(Rune rune, ParseFlags flags) { |
| 284 | Regexp* re = new Regexp(kRegexpLiteral, flags); |
| 285 | re->rune_ = rune; |
| 286 | return re; |
| 287 | } |
| 288 | |
| 289 | Regexp* Regexp::LiteralString(Rune* runes, int nrunes, ParseFlags flags) { |
| 290 | if (nrunes <= 0) |
| 291 | return new Regexp(kRegexpEmptyMatch, flags); |
| 292 | if (nrunes == 1) |
| 293 | return NewLiteral(runes[0], flags); |
| 294 | Regexp* re = new Regexp(kRegexpLiteralString, flags); |
| 295 | for (int i = 0; i < nrunes; i++) |
| 296 | re->AddRuneToString(runes[i]); |
| 297 | return re; |
| 298 | } |
| 299 | |
| 300 | Regexp* Regexp::NewCharClass(CharClass* cc, ParseFlags flags) { |
| 301 | Regexp* re = new Regexp(kRegexpCharClass, flags); |
| 302 | re->cc_ = cc; |
| 303 | return re; |
| 304 | } |
| 305 | |
| 306 | // Swaps this and that in place. |
| 307 | void Regexp::Swap(Regexp* that) { |
| 308 | // Can use memmove because Regexp is just a struct (no vtable). |
| 309 | char tmp[sizeof *this]; |
| 310 | memmove(tmp, this, sizeof tmp); |
| 311 | memmove(this, that, sizeof tmp); |
| 312 | memmove(that, tmp, sizeof tmp); |
| 313 | } |
| 314 | |
| 315 | // Tests equality of all top-level structure but not subregexps. |
| 316 | static bool TopEqual(Regexp* a, Regexp* b) { |
| 317 | if (a->op() != b->op()) |
| 318 | return false; |
| 319 | |
| 320 | switch (a->op()) { |
| 321 | case kRegexpNoMatch: |
| 322 | case kRegexpEmptyMatch: |
| 323 | case kRegexpAnyChar: |
| 324 | case kRegexpAnyByte: |
| 325 | case kRegexpBeginLine: |
| 326 | case kRegexpEndLine: |
| 327 | case kRegexpWordBoundary: |
| 328 | case kRegexpNoWordBoundary: |
| 329 | case kRegexpBeginText: |
| 330 | return true; |
| 331 | |
| 332 | case kRegexpEndText: |
| 333 | // The parse flags remember whether it's \z or (?-m:$), |
| 334 | // which matters when testing against PCRE. |
| 335 | return ((a->parse_flags() ^ b->parse_flags()) & Regexp::WasDollar) == 0; |
| 336 | |
| 337 | case kRegexpLiteral: |
| 338 | return a->rune() == b->rune() && |
| 339 | ((a->parse_flags() ^ b->parse_flags()) & Regexp::FoldCase) == 0; |
| 340 | |
| 341 | case kRegexpLiteralString: |
| 342 | return a->nrunes() == b->nrunes() && |
| 343 | ((a->parse_flags() ^ b->parse_flags()) & Regexp::FoldCase) == 0 && |
| 344 | memcmp(a->runes(), b->runes(), |
| 345 | a->nrunes() * sizeof a->runes()[0]) == 0; |
| 346 | |
| 347 | case kRegexpAlternate: |
| 348 | case kRegexpConcat: |
| 349 | return a->nsub() == b->nsub(); |
| 350 | |
| 351 | case kRegexpStar: |
| 352 | case kRegexpPlus: |
| 353 | case kRegexpQuest: |
| 354 | return ((a->parse_flags() ^ b->parse_flags()) & Regexp::NonGreedy) == 0; |
| 355 | |
| 356 | case kRegexpRepeat: |
| 357 | return ((a->parse_flags() ^ b->parse_flags()) & Regexp::NonGreedy) == 0 && |
| 358 | a->min() == b->min() && |
| 359 | a->max() == b->max(); |
| 360 | |
| 361 | case kRegexpCapture: |
| 362 | return a->cap() == b->cap() && a->name() == b->name(); |
| 363 | |
| 364 | case kRegexpHaveMatch: |
| 365 | return a->match_id() == b->match_id(); |
| 366 | |
| 367 | case kRegexpCharClass: { |
| 368 | CharClass* acc = a->cc(); |
| 369 | CharClass* bcc = b->cc(); |
| 370 | return acc->size() == bcc->size() && |
| 371 | acc->end() - acc->begin() == bcc->end() - bcc->begin() && |
| 372 | memcmp(acc->begin(), bcc->begin(), |
| 373 | (acc->end() - acc->begin()) * sizeof acc->begin()[0]) == 0; |
| 374 | } |
| 375 | } |
| 376 | |
| 377 | LOG(DFATAL) << "Unexpected op in Regexp::Equal: " << a->op(); |
| 378 | return 0; |
| 379 | } |
| 380 | |
| 381 | bool Regexp::Equal(Regexp* a, Regexp* b) { |
| 382 | if (a == NULL || b == NULL) |
| 383 | return a == b; |
| 384 | |
| 385 | if (!TopEqual(a, b)) |
| 386 | return false; |
| 387 | |
| 388 | // Fast path: |
| 389 | // return without allocating vector if there are no subregexps. |
| 390 | switch (a->op()) { |
| 391 | case kRegexpAlternate: |
| 392 | case kRegexpConcat: |
| 393 | case kRegexpStar: |
| 394 | case kRegexpPlus: |
| 395 | case kRegexpQuest: |
| 396 | case kRegexpRepeat: |
| 397 | case kRegexpCapture: |
| 398 | break; |
| 399 | |
| 400 | default: |
| 401 | return true; |
| 402 | } |
| 403 | |
| 404 | // Committed to doing real work. |
| 405 | // The stack (vector) has pairs of regexps waiting to |
| 406 | // be compared. The regexps are only equal if |
| 407 | // all the pairs end up being equal. |
| 408 | vector<Regexp*> stk; |
| 409 | |
| 410 | for (;;) { |
| 411 | // Invariant: TopEqual(a, b) == true. |
| 412 | Regexp* a2; |
| 413 | Regexp* b2; |
| 414 | switch (a->op()) { |
| 415 | default: |
| 416 | break; |
| 417 | case kRegexpAlternate: |
| 418 | case kRegexpConcat: |
| 419 | for (int i = 0; i < a->nsub(); i++) { |
| 420 | a2 = a->sub()[i]; |
| 421 | b2 = b->sub()[i]; |
| 422 | if (!TopEqual(a2, b2)) |
| 423 | return false; |
| 424 | stk.push_back(a2); |
| 425 | stk.push_back(b2); |
| 426 | } |
| 427 | break; |
| 428 | |
| 429 | case kRegexpStar: |
| 430 | case kRegexpPlus: |
| 431 | case kRegexpQuest: |
| 432 | case kRegexpRepeat: |
| 433 | case kRegexpCapture: |
| 434 | a2 = a->sub()[0]; |
| 435 | b2 = b->sub()[0]; |
| 436 | if (!TopEqual(a2, b2)) |
| 437 | return false; |
| 438 | // Really: |
| 439 | // stk.push_back(a2); |
| 440 | // stk.push_back(b2); |
| 441 | // break; |
| 442 | // but faster to assign directly and loop. |
| 443 | a = a2; |
| 444 | b = b2; |
| 445 | continue; |
| 446 | } |
| 447 | |
| 448 | int n = stk.size(); |
| 449 | if (n == 0) |
| 450 | break; |
| 451 | |
| 452 | a = stk[n-2]; |
| 453 | b = stk[n-1]; |
| 454 | stk.resize(n-2); |
| 455 | } |
| 456 | |
| 457 | return true; |
| 458 | } |
| 459 | |
| 460 | // Keep in sync with enum RegexpStatusCode in regexp.h |
Alexander Gutkin | 0d4c523 | 2013-02-28 13:47:27 +0000 | [diff] [blame] | 461 | static const char *kErrorStrings[] = { |
Ian Hodson | 2ee91b4 | 2012-05-14 12:29:36 +0100 | [diff] [blame] | 462 | "no error", |
| 463 | "unexpected error", |
| 464 | "invalid escape sequence", |
| 465 | "invalid character class", |
| 466 | "invalid character class range", |
| 467 | "missing ]", |
| 468 | "missing )", |
| 469 | "trailing \\", |
| 470 | "no argument for repetition operator", |
| 471 | "invalid repetition size", |
| 472 | "bad repetition operator", |
| 473 | "invalid perl operator", |
| 474 | "invalid UTF-8", |
| 475 | "invalid named capture group", |
| 476 | }; |
| 477 | |
Alexander Gutkin | 0d4c523 | 2013-02-28 13:47:27 +0000 | [diff] [blame] | 478 | string RegexpStatus::CodeText(enum RegexpStatusCode code) { |
Ian Hodson | 2ee91b4 | 2012-05-14 12:29:36 +0100 | [diff] [blame] | 479 | if (code < 0 || code >= arraysize(kErrorStrings)) |
| 480 | code = kRegexpInternalError; |
| 481 | return kErrorStrings[code]; |
| 482 | } |
| 483 | |
| 484 | string RegexpStatus::Text() const { |
| 485 | if (error_arg_.empty()) |
| 486 | return CodeText(code_); |
| 487 | string s; |
| 488 | s.append(CodeText(code_)); |
| 489 | s.append(": "); |
| 490 | s.append(error_arg_.data(), error_arg_.size()); |
| 491 | return s; |
| 492 | } |
| 493 | |
| 494 | void RegexpStatus::Copy(const RegexpStatus& status) { |
| 495 | code_ = status.code_; |
| 496 | error_arg_ = status.error_arg_; |
| 497 | } |
| 498 | |
| 499 | typedef int Ignored; // Walker<void> doesn't exist |
| 500 | |
| 501 | // Walker subclass to count capturing parens in regexp. |
| 502 | class NumCapturesWalker : public Regexp::Walker<Ignored> { |
| 503 | public: |
| 504 | NumCapturesWalker() : ncapture_(0) {} |
| 505 | int ncapture() { return ncapture_; } |
| 506 | |
| 507 | virtual Ignored PreVisit(Regexp* re, Ignored ignored, bool* stop) { |
| 508 | if (re->op() == kRegexpCapture) |
| 509 | ncapture_++; |
| 510 | return ignored; |
| 511 | } |
| 512 | virtual Ignored ShortVisit(Regexp* re, Ignored ignored) { |
| 513 | // Should never be called: we use Walk not WalkExponential. |
| 514 | LOG(DFATAL) << "NumCapturesWalker::ShortVisit called"; |
| 515 | return ignored; |
| 516 | } |
| 517 | |
| 518 | private: |
| 519 | int ncapture_; |
| 520 | DISALLOW_EVIL_CONSTRUCTORS(NumCapturesWalker); |
| 521 | }; |
| 522 | |
| 523 | int Regexp::NumCaptures() { |
| 524 | NumCapturesWalker w; |
| 525 | w.Walk(this, 0); |
| 526 | return w.ncapture(); |
| 527 | } |
| 528 | |
| 529 | // Walker class to build map of named capture groups and their indices. |
| 530 | class NamedCapturesWalker : public Regexp::Walker<Ignored> { |
| 531 | public: |
| 532 | NamedCapturesWalker() : map_(NULL) {} |
| 533 | ~NamedCapturesWalker() { delete map_; } |
| 534 | |
| 535 | map<string, int>* TakeMap() { |
| 536 | map<string, int>* m = map_; |
| 537 | map_ = NULL; |
| 538 | return m; |
| 539 | } |
| 540 | |
| 541 | Ignored PreVisit(Regexp* re, Ignored ignored, bool* stop) { |
| 542 | if (re->op() == kRegexpCapture && re->name() != NULL) { |
| 543 | // Allocate map once we find a name. |
| 544 | if (map_ == NULL) |
| 545 | map_ = new map<string, int>; |
| 546 | |
| 547 | // Record first occurrence of each name. |
| 548 | // (The rule is that if you have the same name |
| 549 | // multiple times, only the leftmost one counts.) |
| 550 | if (map_->find(*re->name()) == map_->end()) |
| 551 | (*map_)[*re->name()] = re->cap(); |
| 552 | } |
| 553 | return ignored; |
| 554 | } |
| 555 | |
| 556 | virtual Ignored ShortVisit(Regexp* re, Ignored ignored) { |
| 557 | // Should never be called: we use Walk not WalkExponential. |
| 558 | LOG(DFATAL) << "NamedCapturesWalker::ShortVisit called"; |
| 559 | return ignored; |
| 560 | } |
| 561 | |
| 562 | private: |
| 563 | map<string, int>* map_; |
| 564 | DISALLOW_EVIL_CONSTRUCTORS(NamedCapturesWalker); |
| 565 | }; |
| 566 | |
| 567 | map<string, int>* Regexp::NamedCaptures() { |
| 568 | NamedCapturesWalker w; |
| 569 | w.Walk(this, 0); |
| 570 | return w.TakeMap(); |
| 571 | } |
| 572 | |
| 573 | // Walker class to build map from capture group indices to their names. |
| 574 | class CaptureNamesWalker : public Regexp::Walker<Ignored> { |
| 575 | public: |
| 576 | CaptureNamesWalker() : map_(NULL) {} |
| 577 | ~CaptureNamesWalker() { delete map_; } |
| 578 | |
| 579 | map<int, string>* TakeMap() { |
| 580 | map<int, string>* m = map_; |
| 581 | map_ = NULL; |
| 582 | return m; |
| 583 | } |
| 584 | |
| 585 | Ignored PreVisit(Regexp* re, Ignored ignored, bool* stop) { |
| 586 | if (re->op() == kRegexpCapture && re->name() != NULL) { |
| 587 | // Allocate map once we find a name. |
| 588 | if (map_ == NULL) |
| 589 | map_ = new map<int, string>; |
| 590 | |
| 591 | (*map_)[re->cap()] = *re->name(); |
| 592 | } |
| 593 | return ignored; |
| 594 | } |
| 595 | |
| 596 | virtual Ignored ShortVisit(Regexp* re, Ignored ignored) { |
| 597 | // Should never be called: we use Walk not WalkExponential. |
| 598 | LOG(DFATAL) << "CaptureNamesWalker::ShortVisit called"; |
| 599 | return ignored; |
| 600 | } |
| 601 | |
| 602 | private: |
| 603 | map<int, string>* map_; |
| 604 | DISALLOW_EVIL_CONSTRUCTORS(CaptureNamesWalker); |
| 605 | }; |
| 606 | |
| 607 | map<int, string>* Regexp::CaptureNames() { |
| 608 | CaptureNamesWalker w; |
| 609 | w.Walk(this, 0); |
| 610 | return w.TakeMap(); |
| 611 | } |
| 612 | |
| 613 | // Determines whether regexp matches must be anchored |
| 614 | // with a fixed string prefix. If so, returns the prefix and |
| 615 | // the regexp that remains after the prefix. The prefix might |
| 616 | // be ASCII case-insensitive. |
| 617 | bool Regexp::RequiredPrefix(string *prefix, bool *foldcase, Regexp** suffix) { |
| 618 | // No need for a walker: the regexp must be of the form |
| 619 | // 1. some number of ^ anchors |
| 620 | // 2. a literal char or string |
| 621 | // 3. the rest |
| 622 | prefix->clear(); |
| 623 | *foldcase = false; |
| 624 | *suffix = NULL; |
| 625 | if (op_ != kRegexpConcat) |
| 626 | return false; |
| 627 | |
| 628 | // Some number of anchors, then a literal or concatenation. |
| 629 | int i = 0; |
| 630 | Regexp** sub = this->sub(); |
| 631 | while (i < nsub_ && sub[i]->op_ == kRegexpBeginText) |
| 632 | i++; |
| 633 | if (i == 0 || i >= nsub_) |
| 634 | return false; |
| 635 | |
| 636 | Regexp* re = sub[i]; |
| 637 | switch (re->op_) { |
| 638 | default: |
| 639 | return false; |
| 640 | |
| 641 | case kRegexpLiteralString: |
| 642 | // Convert to string in proper encoding. |
| 643 | if (re->parse_flags() & Latin1) { |
| 644 | prefix->resize(re->nrunes_); |
| 645 | for (int j = 0; j < re->nrunes_; j++) |
| 646 | (*prefix)[j] = re->runes_[j]; |
| 647 | } else { |
| 648 | // Convert to UTF-8 in place. |
| 649 | // Assume worst-case space and then trim. |
| 650 | prefix->resize(re->nrunes_ * UTFmax); |
| 651 | char *p = &(*prefix)[0]; |
| 652 | for (int j = 0; j < re->nrunes_; j++) { |
| 653 | Rune r = re->runes_[j]; |
| 654 | if (r < Runeself) |
| 655 | *p++ = r; |
| 656 | else |
| 657 | p += runetochar(p, &r); |
| 658 | } |
| 659 | prefix->resize(p - &(*prefix)[0]); |
| 660 | } |
| 661 | break; |
| 662 | |
| 663 | case kRegexpLiteral: |
| 664 | if ((re->parse_flags() & Latin1) || re->rune_ < Runeself) { |
| 665 | prefix->append(1, re->rune_); |
| 666 | } else { |
| 667 | char buf[UTFmax]; |
| 668 | prefix->append(buf, runetochar(buf, &re->rune_)); |
| 669 | } |
| 670 | break; |
| 671 | } |
| 672 | *foldcase = (sub[i]->parse_flags() & FoldCase); |
| 673 | i++; |
| 674 | |
| 675 | // The rest. |
| 676 | if (i < nsub_) { |
| 677 | for (int j = i; j < nsub_; j++) |
| 678 | sub[j]->Incref(); |
| 679 | re = Concat(sub + i, nsub_ - i, parse_flags()); |
| 680 | } else { |
| 681 | re = new Regexp(kRegexpEmptyMatch, parse_flags()); |
| 682 | } |
| 683 | *suffix = re; |
| 684 | return true; |
| 685 | } |
| 686 | |
| 687 | // Character class builder is a balanced binary tree (STL set) |
| 688 | // containing non-overlapping, non-abutting RuneRanges. |
| 689 | // The less-than operator used in the tree treats two |
| 690 | // ranges as equal if they overlap at all, so that |
| 691 | // lookups for a particular Rune are possible. |
| 692 | |
| 693 | CharClassBuilder::CharClassBuilder() { |
| 694 | nrunes_ = 0; |
| 695 | upper_ = 0; |
| 696 | lower_ = 0; |
| 697 | } |
| 698 | |
| 699 | // Add lo-hi to the class; return whether class got bigger. |
| 700 | bool CharClassBuilder::AddRange(Rune lo, Rune hi) { |
| 701 | if (hi < lo) |
| 702 | return false; |
| 703 | |
| 704 | if (lo <= 'z' && hi >= 'A') { |
| 705 | // Overlaps some alpha, maybe not all. |
| 706 | // Update bitmaps telling which ASCII letters are in the set. |
| 707 | Rune lo1 = max<Rune>(lo, 'A'); |
| 708 | Rune hi1 = min<Rune>(hi, 'Z'); |
| 709 | if (lo1 <= hi1) |
| 710 | upper_ |= ((1 << (hi1 - lo1 + 1)) - 1) << (lo1 - 'A'); |
| 711 | |
| 712 | lo1 = max<Rune>(lo, 'a'); |
| 713 | hi1 = min<Rune>(hi, 'z'); |
| 714 | if (lo1 <= hi1) |
| 715 | lower_ |= ((1 << (hi1 - lo1 + 1)) - 1) << (lo1 - 'a'); |
| 716 | } |
| 717 | |
| 718 | { // Check whether lo, hi is already in the class. |
| 719 | iterator it = ranges_.find(RuneRange(lo, lo)); |
| 720 | if (it != end() && it->lo <= lo && hi <= it->hi) |
| 721 | return false; |
| 722 | } |
| 723 | |
| 724 | // Look for a range abutting lo on the left. |
| 725 | // If it exists, take it out and increase our range. |
| 726 | if (lo > 0) { |
| 727 | iterator it = ranges_.find(RuneRange(lo-1, lo-1)); |
| 728 | if (it != end()) { |
| 729 | lo = it->lo; |
| 730 | if (it->hi > hi) |
| 731 | hi = it->hi; |
| 732 | nrunes_ -= it->hi - it->lo + 1; |
| 733 | ranges_.erase(it); |
| 734 | } |
| 735 | } |
| 736 | |
| 737 | // Look for a range abutting hi on the right. |
| 738 | // If it exists, take it out and increase our range. |
| 739 | if (hi < Runemax) { |
| 740 | iterator it = ranges_.find(RuneRange(hi+1, hi+1)); |
| 741 | if (it != end()) { |
| 742 | hi = it->hi; |
| 743 | nrunes_ -= it->hi - it->lo + 1; |
| 744 | ranges_.erase(it); |
| 745 | } |
| 746 | } |
| 747 | |
| 748 | // Look for ranges between lo and hi. Take them out. |
| 749 | // This is only safe because the set has no overlapping ranges. |
| 750 | // We've already removed any ranges abutting lo and hi, so |
| 751 | // any that overlap [lo, hi] must be contained within it. |
| 752 | for (;;) { |
| 753 | iterator it = ranges_.find(RuneRange(lo, hi)); |
| 754 | if (it == end()) |
| 755 | break; |
| 756 | nrunes_ -= it->hi - it->lo + 1; |
| 757 | ranges_.erase(it); |
| 758 | } |
| 759 | |
| 760 | // Finally, add [lo, hi]. |
| 761 | nrunes_ += hi - lo + 1; |
| 762 | ranges_.insert(RuneRange(lo, hi)); |
| 763 | return true; |
| 764 | } |
| 765 | |
| 766 | void CharClassBuilder::AddCharClass(CharClassBuilder *cc) { |
| 767 | for (iterator it = cc->begin(); it != cc->end(); ++it) |
| 768 | AddRange(it->lo, it->hi); |
| 769 | } |
| 770 | |
| 771 | bool CharClassBuilder::Contains(Rune r) { |
| 772 | return ranges_.find(RuneRange(r, r)) != end(); |
| 773 | } |
| 774 | |
| 775 | // Does the character class behave the same on A-Z as on a-z? |
| 776 | bool CharClassBuilder::FoldsASCII() { |
| 777 | return ((upper_ ^ lower_) & AlphaMask) == 0; |
| 778 | } |
| 779 | |
| 780 | CharClassBuilder* CharClassBuilder::Copy() { |
| 781 | CharClassBuilder* cc = new CharClassBuilder; |
| 782 | for (iterator it = begin(); it != end(); ++it) |
| 783 | cc->ranges_.insert(RuneRange(it->lo, it->hi)); |
| 784 | cc->upper_ = upper_; |
| 785 | cc->lower_ = lower_; |
| 786 | cc->nrunes_ = nrunes_; |
| 787 | return cc; |
| 788 | } |
| 789 | |
| 790 | |
| 791 | |
| 792 | void CharClassBuilder::RemoveAbove(Rune r) { |
| 793 | if (r >= Runemax) |
| 794 | return; |
| 795 | |
| 796 | if (r < 'z') { |
| 797 | if (r < 'a') |
| 798 | lower_ = 0; |
| 799 | else |
| 800 | lower_ &= AlphaMask >> ('z' - r); |
| 801 | } |
| 802 | |
| 803 | if (r < 'Z') { |
| 804 | if (r < 'A') |
| 805 | upper_ = 0; |
| 806 | else |
| 807 | upper_ &= AlphaMask >> ('Z' - r); |
| 808 | } |
| 809 | |
| 810 | for (;;) { |
| 811 | |
| 812 | iterator it = ranges_.find(RuneRange(r + 1, Runemax)); |
| 813 | if (it == end()) |
| 814 | break; |
| 815 | RuneRange rr = *it; |
| 816 | ranges_.erase(it); |
| 817 | nrunes_ -= rr.hi - rr.lo + 1; |
| 818 | if (rr.lo <= r) { |
| 819 | rr.hi = r; |
| 820 | ranges_.insert(rr); |
| 821 | nrunes_ += rr.hi - rr.lo + 1; |
| 822 | } |
| 823 | } |
| 824 | } |
| 825 | |
| 826 | void CharClassBuilder::Negate() { |
| 827 | // Build up negation and then copy in. |
| 828 | // Could edit ranges in place, but C++ won't let me. |
| 829 | vector<RuneRange> v; |
| 830 | v.reserve(ranges_.size() + 1); |
| 831 | |
| 832 | // In negation, first range begins at 0, unless |
| 833 | // the current class begins at 0. |
| 834 | iterator it = begin(); |
| 835 | if (it == end()) { |
| 836 | v.push_back(RuneRange(0, Runemax)); |
| 837 | } else { |
| 838 | int nextlo = 0; |
| 839 | if (it->lo == 0) { |
| 840 | nextlo = it->hi + 1; |
| 841 | ++it; |
| 842 | } |
| 843 | for (; it != end(); ++it) { |
| 844 | v.push_back(RuneRange(nextlo, it->lo - 1)); |
| 845 | nextlo = it->hi + 1; |
| 846 | } |
| 847 | if (nextlo <= Runemax) |
| 848 | v.push_back(RuneRange(nextlo, Runemax)); |
| 849 | } |
| 850 | |
| 851 | ranges_.clear(); |
| 852 | for (int i = 0; i < v.size(); i++) |
| 853 | ranges_.insert(v[i]); |
| 854 | |
| 855 | upper_ = AlphaMask & ~upper_; |
| 856 | lower_ = AlphaMask & ~lower_; |
| 857 | nrunes_ = Runemax+1 - nrunes_; |
| 858 | } |
| 859 | |
| 860 | // Character class is a sorted list of ranges. |
| 861 | // The ranges are allocated in the same block as the header, |
| 862 | // necessitating a special allocator and Delete method. |
| 863 | |
| 864 | CharClass* CharClass::New(int maxranges) { |
| 865 | CharClass* cc; |
| 866 | uint8* data = new uint8[sizeof *cc + maxranges*sizeof cc->ranges_[0]]; |
| 867 | cc = reinterpret_cast<CharClass*>(data); |
| 868 | cc->ranges_ = reinterpret_cast<RuneRange*>(data + sizeof *cc); |
| 869 | cc->nranges_ = 0; |
| 870 | cc->folds_ascii_ = false; |
| 871 | cc->nrunes_ = 0; |
| 872 | return cc; |
| 873 | } |
| 874 | |
| 875 | void CharClass::Delete() { |
| 876 | if (this == NULL) |
| 877 | return; |
| 878 | uint8 *data = reinterpret_cast<uint8*>(this); |
| 879 | delete[] data; |
| 880 | } |
| 881 | |
| 882 | CharClass* CharClass::Negate() { |
| 883 | CharClass* cc = CharClass::New(nranges_+1); |
| 884 | cc->folds_ascii_ = folds_ascii_; |
| 885 | cc->nrunes_ = Runemax + 1 - nrunes_; |
| 886 | int n = 0; |
| 887 | int nextlo = 0; |
| 888 | for (CharClass::iterator it = begin(); it != end(); ++it) { |
| 889 | if (it->lo == nextlo) { |
| 890 | nextlo = it->hi + 1; |
| 891 | } else { |
| 892 | cc->ranges_[n++] = RuneRange(nextlo, it->lo - 1); |
| 893 | nextlo = it->hi + 1; |
| 894 | } |
| 895 | } |
| 896 | if (nextlo <= Runemax) |
| 897 | cc->ranges_[n++] = RuneRange(nextlo, Runemax); |
| 898 | cc->nranges_ = n; |
| 899 | return cc; |
| 900 | } |
| 901 | |
| 902 | bool CharClass::Contains(Rune r) { |
| 903 | RuneRange* rr = ranges_; |
| 904 | int n = nranges_; |
| 905 | while (n > 0) { |
| 906 | int m = n/2; |
| 907 | if (rr[m].hi < r) { |
| 908 | rr += m+1; |
| 909 | n -= m+1; |
| 910 | } else if (r < rr[m].lo) { |
| 911 | n = m; |
| 912 | } else { // rr[m].lo <= r && r <= rr[m].hi |
| 913 | return true; |
| 914 | } |
| 915 | } |
| 916 | return false; |
| 917 | } |
| 918 | |
| 919 | CharClass* CharClassBuilder::GetCharClass() { |
| 920 | CharClass* cc = CharClass::New(ranges_.size()); |
| 921 | int n = 0; |
| 922 | for (iterator it = begin(); it != end(); ++it) |
| 923 | cc->ranges_[n++] = *it; |
| 924 | cc->nranges_ = n; |
| 925 | DCHECK_LE(n, ranges_.size()); |
| 926 | cc->nrunes_ = nrunes_; |
| 927 | cc->folds_ascii_ = FoldsASCII(); |
| 928 | return cc; |
| 929 | } |
| 930 | |
| 931 | } // namespace re2 |