Ian Hodson | 2ee91b4 | 2012-05-14 12:29:36 +0100 | [diff] [blame] | 1 | // Copyright 2007 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 | // Compile regular expression to Prog. |
| 6 | // |
| 7 | // Prog and Inst are defined in prog.h. |
| 8 | // This file's external interface is just Regexp::CompileToProg. |
| 9 | // The Compiler class defined in this file is private. |
| 10 | |
| 11 | #include "re2/prog.h" |
| 12 | #include "re2/re2.h" |
| 13 | #include "re2/regexp.h" |
| 14 | #include "re2/walker-inl.h" |
| 15 | |
| 16 | namespace re2 { |
| 17 | |
| 18 | // List of pointers to Inst* that need to be filled in (patched). |
| 19 | // Because the Inst* haven't been filled in yet, |
| 20 | // we can use the Inst* word to hold the list's "next" pointer. |
| 21 | // It's kind of sleazy, but it works well in practice. |
| 22 | // See http://swtch.com/~rsc/regexp/regexp1.html for inspiration. |
| 23 | // |
| 24 | // Because the out and out1 fields in Inst are no longer pointers, |
| 25 | // we can't use pointers directly here either. Instead, p refers |
| 26 | // to inst_[p>>1].out (p&1 == 0) or inst_[p>>1].out1 (p&1 == 1). |
| 27 | // p == 0 represents the NULL list. This is okay because instruction #0 |
| 28 | // is always the fail instruction, which never appears on a list. |
| 29 | |
| 30 | struct PatchList { |
| 31 | uint32 p; |
| 32 | |
| 33 | // Returns patch list containing just p. |
| 34 | static PatchList Mk(uint32 p); |
| 35 | |
| 36 | // Patches all the entries on l to have value v. |
| 37 | // Caller must not ever use patch list again. |
| 38 | static void Patch(Prog::Inst *inst0, PatchList l, uint32 v); |
| 39 | |
| 40 | // Deref returns the next pointer pointed at by p. |
| 41 | static PatchList Deref(Prog::Inst *inst0, PatchList l); |
| 42 | |
| 43 | // Appends two patch lists and returns result. |
| 44 | static PatchList Append(Prog::Inst *inst0, PatchList l1, PatchList l2); |
| 45 | }; |
| 46 | |
Alexander Gutkin | 0d4c523 | 2013-02-28 13:47:27 +0000 | [diff] [blame] | 47 | static PatchList nullPatchList; |
Ian Hodson | 2ee91b4 | 2012-05-14 12:29:36 +0100 | [diff] [blame] | 48 | |
| 49 | // Returns patch list containing just p. |
| 50 | PatchList PatchList::Mk(uint32 p) { |
| 51 | PatchList l; |
| 52 | l.p = p; |
| 53 | return l; |
| 54 | } |
| 55 | |
| 56 | // Returns the next pointer pointed at by l. |
| 57 | PatchList PatchList::Deref(Prog::Inst* inst0, PatchList l) { |
| 58 | Prog::Inst* ip = &inst0[l.p>>1]; |
| 59 | if (l.p&1) |
| 60 | l.p = ip->out1(); |
| 61 | else |
| 62 | l.p = ip->out(); |
| 63 | return l; |
| 64 | } |
| 65 | |
| 66 | // Patches all the entries on l to have value v. |
| 67 | void PatchList::Patch(Prog::Inst *inst0, PatchList l, uint32 val) { |
| 68 | while (l.p != 0) { |
| 69 | Prog::Inst* ip = &inst0[l.p>>1]; |
| 70 | if (l.p&1) { |
| 71 | l.p = ip->out1(); |
| 72 | ip->out1_ = val; |
| 73 | } else { |
| 74 | l.p = ip->out(); |
| 75 | ip->set_out(val); |
| 76 | } |
| 77 | } |
| 78 | } |
| 79 | |
| 80 | // Appends two patch lists and returns result. |
| 81 | PatchList PatchList::Append(Prog::Inst* inst0, PatchList l1, PatchList l2) { |
| 82 | if (l1.p == 0) |
| 83 | return l2; |
| 84 | if (l2.p == 0) |
| 85 | return l1; |
| 86 | |
| 87 | PatchList l = l1; |
| 88 | for (;;) { |
| 89 | PatchList next = PatchList::Deref(inst0, l); |
| 90 | if (next.p == 0) |
| 91 | break; |
| 92 | l = next; |
| 93 | } |
| 94 | |
| 95 | Prog::Inst* ip = &inst0[l.p>>1]; |
| 96 | if (l.p&1) |
| 97 | ip->out1_ = l2.p; |
| 98 | else |
| 99 | ip->set_out(l2.p); |
| 100 | |
| 101 | return l1; |
| 102 | } |
| 103 | |
| 104 | // Compiled program fragment. |
| 105 | struct Frag { |
| 106 | uint32 begin; |
| 107 | PatchList end; |
| 108 | |
Alexander Gutkin | 0d4c523 | 2013-02-28 13:47:27 +0000 | [diff] [blame] | 109 | explicit Frag(LinkerInitialized) {} |
Ian Hodson | 2ee91b4 | 2012-05-14 12:29:36 +0100 | [diff] [blame] | 110 | Frag() : begin(0) { end.p = 0; } // needed so Frag can go in vector |
| 111 | Frag(uint32 begin, PatchList end) : begin(begin), end(end) {} |
| 112 | }; |
| 113 | |
Alexander Gutkin | 0d4c523 | 2013-02-28 13:47:27 +0000 | [diff] [blame] | 114 | static Frag kNullFrag(LINKER_INITIALIZED); |
Ian Hodson | 2ee91b4 | 2012-05-14 12:29:36 +0100 | [diff] [blame] | 115 | |
| 116 | // Input encodings. |
| 117 | enum Encoding { |
| 118 | kEncodingUTF8 = 1, // UTF-8 (0-10FFFF) |
| 119 | kEncodingLatin1, // Latin1 (0-FF) |
| 120 | }; |
| 121 | |
| 122 | class Compiler : public Regexp::Walker<Frag> { |
| 123 | public: |
| 124 | explicit Compiler(); |
| 125 | ~Compiler(); |
| 126 | |
| 127 | // Compiles Regexp to a new Prog. |
| 128 | // Caller is responsible for deleting Prog when finished with it. |
| 129 | // If reversed is true, compiles for walking over the input |
| 130 | // string backward (reverses all concatenations). |
| 131 | static Prog *Compile(Regexp* re, bool reversed, int64 max_mem); |
| 132 | |
| 133 | // Compiles alternation of all the re to a new Prog. |
| 134 | // Each re has a match with an id equal to its index in the vector. |
| 135 | static Prog* CompileSet(const RE2::Options& options, RE2::Anchor anchor, |
| 136 | Regexp* re); |
| 137 | |
| 138 | // Interface for Regexp::Walker, which helps traverse the Regexp. |
| 139 | // The walk is purely post-recursive: given the machines for the |
| 140 | // children, PostVisit combines them to create the machine for |
| 141 | // the current node. The child_args are Frags. |
| 142 | // The Compiler traverses the Regexp parse tree, visiting |
| 143 | // each node in depth-first order. It invokes PreVisit before |
| 144 | // visiting the node's children and PostVisit after visiting |
| 145 | // the children. |
| 146 | Frag PreVisit(Regexp* re, Frag parent_arg, bool* stop); |
| 147 | Frag PostVisit(Regexp* re, Frag parent_arg, Frag pre_arg, Frag* child_args, |
| 148 | int nchild_args); |
| 149 | Frag ShortVisit(Regexp* re, Frag parent_arg); |
| 150 | Frag Copy(Frag arg); |
| 151 | |
| 152 | // Given fragment a, returns a+ or a+?; a* or a*?; a? or a?? |
| 153 | Frag Plus(Frag a, bool nongreedy); |
| 154 | Frag Star(Frag a, bool nongreedy); |
| 155 | Frag Quest(Frag a, bool nongreedy); |
| 156 | |
| 157 | // Given fragment a, returns (a) capturing as \n. |
| 158 | Frag Capture(Frag a, int n); |
| 159 | |
| 160 | // Given fragments a and b, returns ab; a|b |
| 161 | Frag Cat(Frag a, Frag b); |
| 162 | Frag Alt(Frag a, Frag b); |
| 163 | |
| 164 | // Returns a fragment that can't match anything. |
| 165 | Frag NoMatch(); |
| 166 | |
| 167 | // Returns a fragment that matches the empty string. |
| 168 | Frag Match(int32 id); |
| 169 | |
| 170 | // Returns a no-op fragment. |
| 171 | Frag Nop(); |
| 172 | |
| 173 | // Returns a fragment matching the byte range lo-hi. |
| 174 | Frag ByteRange(int lo, int hi, bool foldcase); |
| 175 | |
| 176 | // Returns a fragment matching an empty-width special op. |
| 177 | Frag EmptyWidth(EmptyOp op); |
| 178 | |
| 179 | // Adds n instructions to the program. |
| 180 | // Returns the index of the first one. |
| 181 | // Returns -1 if no more instructions are available. |
| 182 | int AllocInst(int n); |
| 183 | |
| 184 | // Deletes unused instructions. |
| 185 | void Trim(); |
| 186 | |
| 187 | // Rune range compiler. |
| 188 | |
| 189 | // Begins a new alternation. |
| 190 | void BeginRange(); |
| 191 | |
| 192 | // Adds a fragment matching the rune range lo-hi. |
| 193 | void AddRuneRange(Rune lo, Rune hi, bool foldcase); |
| 194 | void AddRuneRangeLatin1(Rune lo, Rune hi, bool foldcase); |
| 195 | void AddRuneRangeUTF8(Rune lo, Rune hi, bool foldcase); |
| 196 | void Add_80_10ffff(); |
| 197 | |
| 198 | // New suffix that matches the byte range lo-hi, then goes to next. |
| 199 | int RuneByteSuffix(uint8 lo, uint8 hi, bool foldcase, int next); |
| 200 | int UncachedRuneByteSuffix(uint8 lo, uint8 hi, bool foldcase, int next); |
| 201 | |
| 202 | // Adds a suffix to alternation. |
| 203 | void AddSuffix(int id); |
| 204 | |
| 205 | // Returns the alternation of all the added suffixes. |
| 206 | Frag EndRange(); |
| 207 | |
| 208 | // Single rune. |
| 209 | Frag Literal(Rune r, bool foldcase); |
| 210 | |
| 211 | void Setup(Regexp::ParseFlags, int64, RE2::Anchor); |
| 212 | Prog* Finish(); |
| 213 | |
| 214 | // Returns .* where dot = any byte |
| 215 | Frag DotStar(); |
| 216 | |
| 217 | private: |
| 218 | Prog* prog_; // Program being built. |
| 219 | bool failed_; // Did we give up compiling? |
| 220 | Encoding encoding_; // Input encoding |
| 221 | bool reversed_; // Should program run backward over text? |
| 222 | |
| 223 | int max_inst_; // Maximum number of instructions. |
| 224 | |
| 225 | Prog::Inst* inst_; // Pointer to first instruction. |
| 226 | int inst_len_; // Number of instructions used. |
| 227 | int inst_cap_; // Number of instructions allocated. |
| 228 | |
| 229 | int64 max_mem_; // Total memory budget. |
| 230 | |
| 231 | map<uint64, int> rune_cache_; |
| 232 | Frag rune_range_; |
| 233 | |
| 234 | RE2::Anchor anchor_; // anchor mode for RE2::Set |
| 235 | |
| 236 | DISALLOW_EVIL_CONSTRUCTORS(Compiler); |
| 237 | }; |
| 238 | |
| 239 | Compiler::Compiler() { |
| 240 | prog_ = new Prog(); |
| 241 | failed_ = false; |
| 242 | encoding_ = kEncodingUTF8; |
| 243 | reversed_ = false; |
| 244 | inst_ = NULL; |
| 245 | inst_len_ = 0; |
| 246 | inst_cap_ = 0; |
| 247 | max_inst_ = 1; // make AllocInst for fail instruction okay |
| 248 | max_mem_ = 0; |
| 249 | int fail = AllocInst(1); |
| 250 | inst_[fail].InitFail(); |
| 251 | max_inst_ = 0; // Caller must change |
| 252 | } |
| 253 | |
| 254 | Compiler::~Compiler() { |
| 255 | delete prog_; |
| 256 | delete[] inst_; |
| 257 | } |
| 258 | |
| 259 | int Compiler::AllocInst(int n) { |
| 260 | if (failed_ || inst_len_ + n > max_inst_) { |
| 261 | failed_ = true; |
| 262 | return -1; |
| 263 | } |
| 264 | |
| 265 | if (inst_len_ + n > inst_cap_) { |
| 266 | if (inst_cap_ == 0) |
| 267 | inst_cap_ = 8; |
| 268 | while (inst_len_ + n > inst_cap_) |
| 269 | inst_cap_ *= 2; |
| 270 | Prog::Inst* ip = new Prog::Inst[inst_cap_]; |
| 271 | memmove(ip, inst_, inst_len_ * sizeof ip[0]); |
| 272 | memset(ip + inst_len_, 0, (inst_cap_ - inst_len_) * sizeof ip[0]); |
| 273 | delete[] inst_; |
| 274 | inst_ = ip; |
| 275 | } |
| 276 | int id = inst_len_; |
| 277 | inst_len_ += n; |
| 278 | return id; |
| 279 | } |
| 280 | |
| 281 | void Compiler::Trim() { |
| 282 | if (inst_len_ < inst_cap_) { |
| 283 | Prog::Inst* ip = new Prog::Inst[inst_len_]; |
| 284 | memmove(ip, inst_, inst_len_ * sizeof ip[0]); |
| 285 | delete[] inst_; |
| 286 | inst_ = ip; |
| 287 | inst_cap_ = inst_len_; |
| 288 | } |
| 289 | } |
| 290 | |
| 291 | // These routines are somewhat hard to visualize in text -- |
| 292 | // see http://swtch.com/~rsc/regexp/regexp1.html for |
| 293 | // pictures explaining what is going on here. |
| 294 | |
| 295 | // Returns an unmatchable fragment. |
| 296 | Frag Compiler::NoMatch() { |
| 297 | return Frag(0, nullPatchList); |
| 298 | } |
| 299 | |
| 300 | // Is a an unmatchable fragment? |
| 301 | static bool IsNoMatch(Frag a) { |
| 302 | return a.begin == 0; |
| 303 | } |
| 304 | |
| 305 | // Given fragments a and b, returns fragment for ab. |
| 306 | Frag Compiler::Cat(Frag a, Frag b) { |
| 307 | if (IsNoMatch(a) || IsNoMatch(b)) |
| 308 | return NoMatch(); |
| 309 | |
| 310 | // Elide no-op. |
| 311 | Prog::Inst* begin = &inst_[a.begin]; |
| 312 | if (begin->opcode() == kInstNop && |
| 313 | a.end.p == (a.begin << 1) && |
| 314 | begin->out() == 0) { |
| 315 | PatchList::Patch(inst_, a.end, b.begin); // in case refs to a somewhere |
| 316 | return b; |
| 317 | } |
| 318 | |
| 319 | // To run backward over string, reverse all concatenations. |
| 320 | if (reversed_) { |
| 321 | PatchList::Patch(inst_, b.end, a.begin); |
| 322 | return Frag(b.begin, a.end); |
| 323 | } |
| 324 | |
| 325 | PatchList::Patch(inst_, a.end, b.begin); |
| 326 | return Frag(a.begin, b.end); |
| 327 | } |
| 328 | |
| 329 | // Given fragments for a and b, returns fragment for a|b. |
| 330 | Frag Compiler::Alt(Frag a, Frag b) { |
| 331 | // Special case for convenience in loops. |
| 332 | if (IsNoMatch(a)) |
| 333 | return b; |
| 334 | if (IsNoMatch(b)) |
| 335 | return a; |
| 336 | |
| 337 | int id = AllocInst(1); |
| 338 | if (id < 0) |
| 339 | return NoMatch(); |
| 340 | |
| 341 | inst_[id].InitAlt(a.begin, b.begin); |
| 342 | return Frag(id, PatchList::Append(inst_, a.end, b.end)); |
| 343 | } |
| 344 | |
| 345 | // When capturing submatches in like-Perl mode, a kOpAlt Inst |
| 346 | // treats out_ as the first choice, out1_ as the second. |
| 347 | // |
| 348 | // For *, +, and ?, if out_ causes another repetition, |
| 349 | // then the operator is greedy. If out1_ is the repetition |
| 350 | // (and out_ moves forward), then the operator is non-greedy. |
| 351 | |
| 352 | // Given a fragment a, returns a fragment for a* or a*? (if nongreedy) |
| 353 | Frag Compiler::Star(Frag a, bool nongreedy) { |
| 354 | int id = AllocInst(1); |
| 355 | if (id < 0) |
| 356 | return NoMatch(); |
| 357 | inst_[id].InitAlt(0, 0); |
| 358 | PatchList::Patch(inst_, a.end, id); |
| 359 | if (nongreedy) { |
| 360 | inst_[id].out1_ = a.begin; |
| 361 | return Frag(id, PatchList::Mk(id << 1)); |
| 362 | } else { |
| 363 | inst_[id].set_out(a.begin); |
| 364 | return Frag(id, PatchList::Mk((id << 1) | 1)); |
| 365 | } |
| 366 | } |
| 367 | |
| 368 | // Given a fragment for a, returns a fragment for a+ or a+? (if nongreedy) |
| 369 | Frag Compiler::Plus(Frag a, bool nongreedy) { |
| 370 | // a+ is just a* with a different entry point. |
| 371 | Frag f = Star(a, nongreedy); |
| 372 | return Frag(a.begin, f.end); |
| 373 | } |
| 374 | |
| 375 | // Given a fragment for a, returns a fragment for a? or a?? (if nongreedy) |
| 376 | Frag Compiler::Quest(Frag a, bool nongreedy) { |
| 377 | int id = AllocInst(1); |
| 378 | if (id < 0) |
| 379 | return NoMatch(); |
| 380 | PatchList pl; |
| 381 | if (nongreedy) { |
| 382 | inst_[id].InitAlt(0, a.begin); |
| 383 | pl = PatchList::Mk(id << 1); |
| 384 | } else { |
| 385 | inst_[id].InitAlt(a.begin, 0); |
| 386 | pl = PatchList::Mk((id << 1) | 1); |
| 387 | } |
| 388 | return Frag(id, PatchList::Append(inst_, pl, a.end)); |
| 389 | } |
| 390 | |
| 391 | // Returns a fragment for the byte range lo-hi. |
| 392 | Frag Compiler::ByteRange(int lo, int hi, bool foldcase) { |
| 393 | int id = AllocInst(1); |
| 394 | if (id < 0) |
| 395 | return NoMatch(); |
| 396 | inst_[id].InitByteRange(lo, hi, foldcase, 0); |
| 397 | prog_->byte_inst_count_++; |
| 398 | prog_->MarkByteRange(lo, hi); |
| 399 | if (foldcase && lo <= 'z' && hi >= 'a') { |
| 400 | if (lo < 'a') |
| 401 | lo = 'a'; |
| 402 | if (hi > 'z') |
| 403 | hi = 'z'; |
| 404 | if (lo <= hi) |
| 405 | prog_->MarkByteRange(lo + 'A' - 'a', hi + 'A' - 'a'); |
| 406 | } |
| 407 | return Frag(id, PatchList::Mk(id << 1)); |
| 408 | } |
| 409 | |
| 410 | // Returns a no-op fragment. Sometimes unavoidable. |
| 411 | Frag Compiler::Nop() { |
| 412 | int id = AllocInst(1); |
| 413 | if (id < 0) |
| 414 | return NoMatch(); |
| 415 | inst_[id].InitNop(0); |
| 416 | return Frag(id, PatchList::Mk(id << 1)); |
| 417 | } |
| 418 | |
| 419 | // Returns a fragment that signals a match. |
| 420 | Frag Compiler::Match(int32 match_id) { |
| 421 | int id = AllocInst(1); |
| 422 | if (id < 0) |
| 423 | return NoMatch(); |
| 424 | inst_[id].InitMatch(match_id); |
| 425 | return Frag(id, nullPatchList); |
| 426 | } |
| 427 | |
| 428 | // Returns a fragment matching a particular empty-width op (like ^ or $) |
| 429 | Frag Compiler::EmptyWidth(EmptyOp empty) { |
| 430 | int id = AllocInst(1); |
| 431 | if (id < 0) |
| 432 | return NoMatch(); |
| 433 | inst_[id].InitEmptyWidth(empty, 0); |
| 434 | if (empty & (kEmptyBeginLine|kEmptyEndLine)) |
| 435 | prog_->MarkByteRange('\n', '\n'); |
| 436 | if (empty & (kEmptyWordBoundary|kEmptyNonWordBoundary)) { |
| 437 | int j; |
| 438 | for (int i = 0; i < 256; i = j) { |
| 439 | for (j = i+1; j < 256 && Prog::IsWordChar(i) == Prog::IsWordChar(j); j++) |
| 440 | ; |
| 441 | prog_->MarkByteRange(i, j-1); |
| 442 | } |
| 443 | } |
| 444 | return Frag(id, PatchList::Mk(id << 1)); |
| 445 | } |
| 446 | |
| 447 | // Given a fragment a, returns a fragment with capturing parens around a. |
| 448 | Frag Compiler::Capture(Frag a, int n) { |
| 449 | int id = AllocInst(2); |
| 450 | if (id < 0) |
| 451 | return NoMatch(); |
| 452 | inst_[id].InitCapture(2*n, a.begin); |
| 453 | inst_[id+1].InitCapture(2*n+1, 0); |
| 454 | PatchList::Patch(inst_, a.end, id+1); |
| 455 | |
| 456 | return Frag(id, PatchList::Mk((id+1) << 1)); |
| 457 | } |
| 458 | |
| 459 | // A Rune is a name for a Unicode code point. |
| 460 | // Returns maximum rune encoded by UTF-8 sequence of length len. |
| 461 | static int MaxRune(int len) { |
Alexander Gutkin | 0d4c523 | 2013-02-28 13:47:27 +0000 | [diff] [blame] | 462 | int b; // number of Rune bits in len-byte UTF-8 sequence (len < UTFmax) |
Ian Hodson | 2ee91b4 | 2012-05-14 12:29:36 +0100 | [diff] [blame] | 463 | if (len == 1) |
| 464 | b = 7; |
| 465 | else |
| 466 | b = 8-(len+1) + 6*(len-1); |
| 467 | return (1<<b) - 1; // maximum Rune for b bits. |
| 468 | } |
| 469 | |
| 470 | // The rune range compiler caches common suffix fragments, |
| 471 | // which are very common in UTF-8 (e.g., [80-bf]). |
| 472 | // The fragment suffixes are identified by their start |
| 473 | // instructions. NULL denotes the eventual end match. |
| 474 | // The Frag accumulates in rune_range_. Caching common |
| 475 | // suffixes reduces the UTF-8 "." from 32 to 24 instructions, |
| 476 | // and it reduces the corresponding one-pass NFA from 16 nodes to 8. |
| 477 | |
| 478 | void Compiler::BeginRange() { |
| 479 | rune_cache_.clear(); |
| 480 | rune_range_.begin = 0; |
| 481 | rune_range_.end = nullPatchList; |
| 482 | } |
| 483 | |
| 484 | int Compiler::UncachedRuneByteSuffix(uint8 lo, uint8 hi, bool foldcase, |
| 485 | int next) { |
| 486 | Frag f = ByteRange(lo, hi, foldcase); |
| 487 | if (next != 0) { |
| 488 | PatchList::Patch(inst_, f.end, next); |
| 489 | } else { |
| 490 | rune_range_.end = PatchList::Append(inst_, rune_range_.end, f.end); |
| 491 | } |
| 492 | return f.begin; |
| 493 | } |
| 494 | |
| 495 | int Compiler::RuneByteSuffix(uint8 lo, uint8 hi, bool foldcase, int next) { |
| 496 | // In Latin1 mode, there's no point in caching. |
| 497 | // In forward UTF-8 mode, only need to cache continuation bytes. |
| 498 | if (encoding_ == kEncodingLatin1 || |
| 499 | (encoding_ == kEncodingUTF8 && |
| 500 | !reversed_ && |
| 501 | !(0x80 <= lo && hi <= 0xbf))) { |
| 502 | return UncachedRuneByteSuffix(lo, hi, foldcase, next); |
| 503 | } |
| 504 | |
| 505 | uint64 key = ((uint64)next << 17) | (lo<<9) | (hi<<1) | foldcase; |
| 506 | map<uint64, int>::iterator it = rune_cache_.find(key); |
| 507 | if (it != rune_cache_.end()) |
| 508 | return it->second; |
| 509 | int id = UncachedRuneByteSuffix(lo, hi, foldcase, next); |
| 510 | rune_cache_[key] = id; |
| 511 | return id; |
| 512 | } |
| 513 | |
| 514 | void Compiler::AddSuffix(int id) { |
| 515 | if (rune_range_.begin == 0) { |
| 516 | rune_range_.begin = id; |
| 517 | return; |
| 518 | } |
| 519 | |
| 520 | int alt = AllocInst(1); |
| 521 | if (alt < 0) { |
| 522 | rune_range_.begin = 0; |
| 523 | return; |
| 524 | } |
| 525 | inst_[alt].InitAlt(rune_range_.begin, id); |
| 526 | rune_range_.begin = alt; |
| 527 | } |
| 528 | |
| 529 | Frag Compiler::EndRange() { |
| 530 | return rune_range_; |
| 531 | } |
| 532 | |
| 533 | // Converts rune range lo-hi into a fragment that recognizes |
| 534 | // the bytes that would make up those runes in the current |
| 535 | // encoding (Latin 1 or UTF-8). |
| 536 | // This lets the machine work byte-by-byte even when |
| 537 | // using multibyte encodings. |
| 538 | |
| 539 | void Compiler::AddRuneRange(Rune lo, Rune hi, bool foldcase) { |
| 540 | switch (encoding_) { |
| 541 | default: |
| 542 | case kEncodingUTF8: |
| 543 | AddRuneRangeUTF8(lo, hi, foldcase); |
| 544 | break; |
| 545 | case kEncodingLatin1: |
| 546 | AddRuneRangeLatin1(lo, hi, foldcase); |
| 547 | break; |
| 548 | } |
| 549 | } |
| 550 | |
| 551 | void Compiler::AddRuneRangeLatin1(Rune lo, Rune hi, bool foldcase) { |
| 552 | // Latin1 is easy: runes *are* bytes. |
| 553 | if (lo > hi || lo > 0xFF) |
| 554 | return; |
| 555 | if (hi > 0xFF) |
| 556 | hi = 0xFF; |
| 557 | AddSuffix(RuneByteSuffix(lo, hi, foldcase, 0)); |
| 558 | } |
| 559 | |
| 560 | // Table describing how to make a UTF-8 matching machine |
| 561 | // for the rune range 80-10FFFF (Runeself-Runemax). |
| 562 | // This range happens frequently enough (for example /./ and /[^a-z]/) |
| 563 | // and the rune_cache_ map is slow enough that this is worth |
| 564 | // special handling. Makes compilation of a small expression |
| 565 | // with a dot in it about 10% faster. |
| 566 | // The * in the comments below mark whole sequences. |
| 567 | static struct ByteRangeProg { |
| 568 | int next; |
| 569 | int lo; |
| 570 | int hi; |
| 571 | } prog_80_10ffff[] = { |
| 572 | // Two-byte |
| 573 | { -1, 0x80, 0xBF, }, // 0: 80-BF |
| 574 | { 0, 0xC2, 0xDF, }, // 1: C2-DF 80-BF* |
| 575 | |
| 576 | // Three-byte |
| 577 | { 0, 0xA0, 0xBF, }, // 2: A0-BF 80-BF |
| 578 | { 2, 0xE0, 0xE0, }, // 3: E0 A0-BF 80-BF* |
| 579 | { 0, 0x80, 0xBF, }, // 4: 80-BF 80-BF |
| 580 | { 4, 0xE1, 0xEF, }, // 5: E1-EF 80-BF 80-BF* |
| 581 | |
| 582 | // Four-byte |
| 583 | { 4, 0x90, 0xBF, }, // 6: 90-BF 80-BF 80-BF |
| 584 | { 6, 0xF0, 0xF0, }, // 7: F0 90-BF 80-BF 80-BF* |
| 585 | { 4, 0x80, 0xBF, }, // 8: 80-BF 80-BF 80-BF |
| 586 | { 8, 0xF1, 0xF3, }, // 9: F1-F3 80-BF 80-BF 80-BF* |
| 587 | { 4, 0x80, 0x8F, }, // 10: 80-8F 80-BF 80-BF |
| 588 | { 10, 0xF4, 0xF4, }, // 11: F4 80-8F 80-BF 80-BF* |
| 589 | }; |
| 590 | |
| 591 | void Compiler::Add_80_10ffff() { |
Alexander Gutkin | 0d4c523 | 2013-02-28 13:47:27 +0000 | [diff] [blame] | 592 | int inst[arraysize(prog_80_10ffff)] = { 0 }; // does not need to be initialized; silences gcc warning |
Ian Hodson | 2ee91b4 | 2012-05-14 12:29:36 +0100 | [diff] [blame] | 593 | for (int i = 0; i < arraysize(prog_80_10ffff); i++) { |
| 594 | const ByteRangeProg& p = prog_80_10ffff[i]; |
| 595 | int next = 0; |
| 596 | if (p.next >= 0) |
| 597 | next = inst[p.next]; |
| 598 | inst[i] = UncachedRuneByteSuffix(p.lo, p.hi, false, next); |
| 599 | if ((p.lo & 0xC0) != 0x80) |
| 600 | AddSuffix(inst[i]); |
| 601 | } |
| 602 | } |
| 603 | |
| 604 | void Compiler::AddRuneRangeUTF8(Rune lo, Rune hi, bool foldcase) { |
| 605 | if (lo > hi) |
| 606 | return; |
| 607 | |
| 608 | // Pick off 80-10FFFF as a common special case |
| 609 | // that can bypass the slow rune_cache_. |
| 610 | if (lo == 0x80 && hi == 0x10ffff && !reversed_) { |
| 611 | Add_80_10ffff(); |
| 612 | return; |
| 613 | } |
| 614 | |
| 615 | // Split range into same-length sized ranges. |
| 616 | for (int i = 1; i < UTFmax; i++) { |
| 617 | Rune max = MaxRune(i); |
| 618 | if (lo <= max && max < hi) { |
| 619 | AddRuneRangeUTF8(lo, max, foldcase); |
| 620 | AddRuneRangeUTF8(max+1, hi, foldcase); |
| 621 | return; |
| 622 | } |
| 623 | } |
| 624 | |
| 625 | // ASCII range is always a special case. |
| 626 | if (hi < Runeself) { |
| 627 | AddSuffix(RuneByteSuffix(lo, hi, foldcase, 0)); |
| 628 | return; |
| 629 | } |
| 630 | |
| 631 | // Split range into sections that agree on leading bytes. |
| 632 | for (int i = 1; i < UTFmax; i++) { |
| 633 | uint m = (1<<(6*i)) - 1; // last i bytes of a UTF-8 sequence |
| 634 | if ((lo & ~m) != (hi & ~m)) { |
| 635 | if ((lo & m) != 0) { |
| 636 | AddRuneRangeUTF8(lo, lo|m, foldcase); |
| 637 | AddRuneRangeUTF8((lo|m)+1, hi, foldcase); |
| 638 | return; |
| 639 | } |
| 640 | if ((hi & m) != m) { |
| 641 | AddRuneRangeUTF8(lo, (hi&~m)-1, foldcase); |
| 642 | AddRuneRangeUTF8(hi&~m, hi, foldcase); |
| 643 | return; |
| 644 | } |
| 645 | } |
| 646 | } |
| 647 | |
| 648 | // Finally. Generate byte matching equivalent for lo-hi. |
| 649 | uint8 ulo[UTFmax], uhi[UTFmax]; |
| 650 | int n = runetochar(reinterpret_cast<char*>(ulo), &lo); |
| 651 | int m = runetochar(reinterpret_cast<char*>(uhi), &hi); |
| 652 | (void)m; // USED(m) |
| 653 | DCHECK_EQ(n, m); |
| 654 | |
| 655 | int id = 0; |
| 656 | if (reversed_) { |
| 657 | for (int i = 0; i < n; i++) |
| 658 | id = RuneByteSuffix(ulo[i], uhi[i], false, id); |
| 659 | } else { |
| 660 | for (int i = n-1; i >= 0; i--) |
| 661 | id = RuneByteSuffix(ulo[i], uhi[i], false, id); |
| 662 | } |
| 663 | AddSuffix(id); |
| 664 | } |
| 665 | |
| 666 | // Should not be called. |
| 667 | Frag Compiler::Copy(Frag arg) { |
| 668 | // We're using WalkExponential; there should be no copying. |
| 669 | LOG(DFATAL) << "Compiler::Copy called!"; |
| 670 | failed_ = true; |
| 671 | return NoMatch(); |
| 672 | } |
| 673 | |
| 674 | // Visits a node quickly; called once WalkExponential has |
| 675 | // decided to cut this walk short. |
| 676 | Frag Compiler::ShortVisit(Regexp* re, Frag) { |
| 677 | failed_ = true; |
| 678 | return NoMatch(); |
| 679 | } |
| 680 | |
| 681 | // Called before traversing a node's children during the walk. |
| 682 | Frag Compiler::PreVisit(Regexp* re, Frag, bool* stop) { |
| 683 | // Cut off walk if we've already failed. |
| 684 | if (failed_) |
| 685 | *stop = true; |
| 686 | |
| 687 | return kNullFrag; // not used by caller |
| 688 | } |
| 689 | |
| 690 | Frag Compiler::Literal(Rune r, bool foldcase) { |
| 691 | switch (encoding_) { |
| 692 | default: |
| 693 | return kNullFrag; |
| 694 | |
| 695 | case kEncodingLatin1: |
| 696 | return ByteRange(r, r, foldcase); |
| 697 | |
| 698 | case kEncodingUTF8: { |
| 699 | if (r < Runeself) // Make common case fast. |
| 700 | return ByteRange(r, r, foldcase); |
| 701 | uint8 buf[UTFmax]; |
| 702 | int n = runetochar(reinterpret_cast<char*>(buf), &r); |
| 703 | Frag f = ByteRange((uint8)buf[0], buf[0], false); |
| 704 | for (int i = 1; i < n; i++) |
| 705 | f = Cat(f, ByteRange((uint8)buf[i], buf[i], false)); |
| 706 | return f; |
| 707 | } |
| 708 | } |
| 709 | } |
| 710 | |
| 711 | // Called after traversing the node's children during the walk. |
| 712 | // Given their frags, build and return the frag for this re. |
| 713 | Frag Compiler::PostVisit(Regexp* re, Frag, Frag, Frag* child_frags, |
| 714 | int nchild_frags) { |
| 715 | // If a child failed, don't bother going forward, especially |
| 716 | // since the child_frags might contain Frags with NULLs in them. |
| 717 | if (failed_) |
| 718 | return NoMatch(); |
| 719 | |
| 720 | // Given the child fragments, return the fragment for this node. |
| 721 | switch (re->op()) { |
| 722 | case kRegexpRepeat: |
| 723 | // Should not see; code at bottom of function will print error |
| 724 | break; |
| 725 | |
| 726 | case kRegexpNoMatch: |
| 727 | return NoMatch(); |
| 728 | |
| 729 | case kRegexpEmptyMatch: |
| 730 | return Nop(); |
| 731 | |
| 732 | case kRegexpHaveMatch: { |
| 733 | Frag f = Match(re->match_id()); |
| 734 | // Remember unanchored match to end of string. |
| 735 | if (anchor_ != RE2::ANCHOR_BOTH) |
Alexander Gutkin | 0d4c523 | 2013-02-28 13:47:27 +0000 | [diff] [blame] | 736 | f = Cat(DotStar(), Cat(EmptyWidth(kEmptyEndText), f)); |
Ian Hodson | 2ee91b4 | 2012-05-14 12:29:36 +0100 | [diff] [blame] | 737 | return f; |
| 738 | } |
| 739 | |
| 740 | case kRegexpConcat: { |
| 741 | Frag f = child_frags[0]; |
| 742 | for (int i = 1; i < nchild_frags; i++) |
| 743 | f = Cat(f, child_frags[i]); |
| 744 | return f; |
| 745 | } |
| 746 | |
| 747 | case kRegexpAlternate: { |
| 748 | Frag f = child_frags[0]; |
| 749 | for (int i = 1; i < nchild_frags; i++) |
| 750 | f = Alt(f, child_frags[i]); |
| 751 | return f; |
| 752 | } |
| 753 | |
| 754 | case kRegexpStar: |
| 755 | return Star(child_frags[0], re->parse_flags()&Regexp::NonGreedy); |
| 756 | |
| 757 | case kRegexpPlus: |
| 758 | return Plus(child_frags[0], re->parse_flags()&Regexp::NonGreedy); |
| 759 | |
| 760 | case kRegexpQuest: |
| 761 | return Quest(child_frags[0], re->parse_flags()&Regexp::NonGreedy); |
| 762 | |
| 763 | case kRegexpLiteral: |
| 764 | return Literal(re->rune(), re->parse_flags()&Regexp::FoldCase); |
| 765 | |
| 766 | case kRegexpLiteralString: { |
| 767 | // Concatenation of literals. |
| 768 | if (re->nrunes() == 0) |
| 769 | return Nop(); |
| 770 | Frag f; |
| 771 | for (int i = 0; i < re->nrunes(); i++) { |
| 772 | Frag f1 = Literal(re->runes()[i], re->parse_flags()&Regexp::FoldCase); |
| 773 | if (i == 0) |
| 774 | f = f1; |
| 775 | else |
| 776 | f = Cat(f, f1); |
| 777 | } |
| 778 | return f; |
| 779 | } |
| 780 | |
| 781 | case kRegexpAnyChar: |
| 782 | BeginRange(); |
| 783 | AddRuneRange(0, Runemax, false); |
| 784 | return EndRange(); |
| 785 | |
| 786 | case kRegexpAnyByte: |
| 787 | return ByteRange(0x00, 0xFF, false); |
| 788 | |
| 789 | case kRegexpCharClass: { |
| 790 | CharClass* cc = re->cc(); |
| 791 | if (cc->empty()) { |
| 792 | // This can't happen. |
| 793 | LOG(DFATAL) << "No ranges in char class"; |
| 794 | failed_ = true; |
| 795 | return NoMatch(); |
| 796 | } |
| 797 | |
| 798 | // ASCII case-folding optimization: if the char class |
| 799 | // behaves the same on A-Z as it does on a-z, |
| 800 | // discard any ranges wholly contained in A-Z |
| 801 | // and mark the other ranges as foldascii. |
| 802 | // This reduces the size of a program for |
| 803 | // (?i)abc from 3 insts per letter to 1 per letter. |
| 804 | bool foldascii = cc->FoldsASCII(); |
| 805 | |
| 806 | // Character class is just a big OR of the different |
| 807 | // character ranges in the class. |
| 808 | BeginRange(); |
| 809 | for (CharClass::iterator i = cc->begin(); i != cc->end(); ++i) { |
| 810 | // ASCII case-folding optimization (see above). |
| 811 | if (foldascii && 'A' <= i->lo && i->hi <= 'Z') |
| 812 | continue; |
| 813 | |
| 814 | // If this range contains all of A-Za-z or none of it, |
| 815 | // the fold flag is unnecessary; don't bother. |
| 816 | bool fold = foldascii; |
| 817 | if ((i->lo <= 'A' && 'z' <= i->hi) || i->hi < 'A' || 'z' < i->lo) |
| 818 | fold = false; |
| 819 | |
| 820 | AddRuneRange(i->lo, i->hi, fold); |
| 821 | } |
| 822 | return EndRange(); |
| 823 | } |
| 824 | |
| 825 | case kRegexpCapture: |
| 826 | // If this is a non-capturing parenthesis -- (?:foo) -- |
| 827 | // just use the inner expression. |
| 828 | if (re->cap() < 0) |
| 829 | return child_frags[0]; |
| 830 | return Capture(child_frags[0], re->cap()); |
| 831 | |
| 832 | case kRegexpBeginLine: |
| 833 | return EmptyWidth(reversed_ ? kEmptyEndLine : kEmptyBeginLine); |
| 834 | |
| 835 | case kRegexpEndLine: |
| 836 | return EmptyWidth(reversed_ ? kEmptyBeginLine : kEmptyEndLine); |
| 837 | |
| 838 | case kRegexpBeginText: |
| 839 | return EmptyWidth(reversed_ ? kEmptyEndText : kEmptyBeginText); |
| 840 | |
| 841 | case kRegexpEndText: |
| 842 | return EmptyWidth(reversed_ ? kEmptyBeginText : kEmptyEndText); |
| 843 | |
| 844 | case kRegexpWordBoundary: |
| 845 | return EmptyWidth(kEmptyWordBoundary); |
| 846 | |
| 847 | case kRegexpNoWordBoundary: |
| 848 | return EmptyWidth(kEmptyNonWordBoundary); |
| 849 | } |
| 850 | LOG(DFATAL) << "Missing case in Compiler: " << re->op(); |
| 851 | failed_ = true; |
| 852 | return NoMatch(); |
| 853 | } |
| 854 | |
| 855 | // Is this regexp required to start at the beginning of the text? |
| 856 | // Only approximate; can return false for complicated regexps like (\Aa|\Ab), |
| 857 | // but handles (\A(a|b)). Could use the Walker to write a more exact one. |
| 858 | static bool IsAnchorStart(Regexp** pre, int depth) { |
| 859 | Regexp* re = *pre; |
| 860 | Regexp* sub; |
| 861 | // The depth limit makes sure that we don't overflow |
| 862 | // the stack on a deeply nested regexp. As the comment |
| 863 | // above says, IsAnchorStart is conservative, so returning |
| 864 | // a false negative is okay. The exact limit is somewhat arbitrary. |
| 865 | if (re == NULL || depth >= 4) |
| 866 | return false; |
| 867 | switch (re->op()) { |
| 868 | default: |
| 869 | break; |
| 870 | case kRegexpConcat: |
| 871 | if (re->nsub() > 0) { |
| 872 | sub = re->sub()[0]->Incref(); |
| 873 | if (IsAnchorStart(&sub, depth+1)) { |
| 874 | Regexp** subcopy = new Regexp*[re->nsub()]; |
| 875 | subcopy[0] = sub; // already have reference |
| 876 | for (int i = 1; i < re->nsub(); i++) |
| 877 | subcopy[i] = re->sub()[i]->Incref(); |
| 878 | *pre = Regexp::Concat(subcopy, re->nsub(), re->parse_flags()); |
| 879 | delete[] subcopy; |
| 880 | re->Decref(); |
| 881 | return true; |
| 882 | } |
| 883 | sub->Decref(); |
| 884 | } |
| 885 | break; |
| 886 | case kRegexpCapture: |
| 887 | sub = re->sub()[0]->Incref(); |
| 888 | if (IsAnchorStart(&sub, depth+1)) { |
| 889 | *pre = Regexp::Capture(sub, re->parse_flags(), re->cap()); |
| 890 | re->Decref(); |
| 891 | return true; |
| 892 | } |
| 893 | sub->Decref(); |
| 894 | break; |
| 895 | case kRegexpBeginText: |
| 896 | *pre = Regexp::LiteralString(NULL, 0, re->parse_flags()); |
| 897 | re->Decref(); |
| 898 | return true; |
| 899 | } |
| 900 | return false; |
| 901 | } |
| 902 | |
| 903 | // Is this regexp required to start at the end of the text? |
| 904 | // Only approximate; can return false for complicated regexps like (a\z|b\z), |
| 905 | // but handles ((a|b)\z). Could use the Walker to write a more exact one. |
| 906 | static bool IsAnchorEnd(Regexp** pre, int depth) { |
| 907 | Regexp* re = *pre; |
| 908 | Regexp* sub; |
| 909 | // The depth limit makes sure that we don't overflow |
| 910 | // the stack on a deeply nested regexp. As the comment |
| 911 | // above says, IsAnchorEnd is conservative, so returning |
| 912 | // a false negative is okay. The exact limit is somewhat arbitrary. |
| 913 | if (re == NULL || depth >= 4) |
| 914 | return false; |
| 915 | switch (re->op()) { |
| 916 | default: |
| 917 | break; |
| 918 | case kRegexpConcat: |
| 919 | if (re->nsub() > 0) { |
| 920 | sub = re->sub()[re->nsub() - 1]->Incref(); |
| 921 | if (IsAnchorEnd(&sub, depth+1)) { |
| 922 | Regexp** subcopy = new Regexp*[re->nsub()]; |
| 923 | subcopy[re->nsub() - 1] = sub; // already have reference |
| 924 | for (int i = 0; i < re->nsub() - 1; i++) |
| 925 | subcopy[i] = re->sub()[i]->Incref(); |
| 926 | *pre = Regexp::Concat(subcopy, re->nsub(), re->parse_flags()); |
| 927 | delete[] subcopy; |
| 928 | re->Decref(); |
| 929 | return true; |
| 930 | } |
| 931 | sub->Decref(); |
| 932 | } |
| 933 | break; |
| 934 | case kRegexpCapture: |
| 935 | sub = re->sub()[0]->Incref(); |
| 936 | if (IsAnchorEnd(&sub, depth+1)) { |
| 937 | *pre = Regexp::Capture(sub, re->parse_flags(), re->cap()); |
| 938 | re->Decref(); |
| 939 | return true; |
| 940 | } |
| 941 | sub->Decref(); |
| 942 | break; |
| 943 | case kRegexpEndText: |
| 944 | *pre = Regexp::LiteralString(NULL, 0, re->parse_flags()); |
| 945 | re->Decref(); |
| 946 | return true; |
| 947 | } |
| 948 | return false; |
| 949 | } |
| 950 | |
| 951 | void Compiler::Setup(Regexp::ParseFlags flags, int64 max_mem, |
| 952 | RE2::Anchor anchor) { |
| 953 | prog_->set_flags(flags); |
| 954 | |
| 955 | if (flags & Regexp::Latin1) |
| 956 | encoding_ = kEncodingLatin1; |
| 957 | max_mem_ = max_mem; |
| 958 | if (max_mem <= 0) { |
| 959 | max_inst_ = 100000; // more than enough |
| 960 | } else if (max_mem <= sizeof(Prog)) { |
| 961 | // No room for anything. |
| 962 | max_inst_ = 0; |
| 963 | } else { |
| 964 | int64 m = (max_mem - sizeof(Prog)) / sizeof(Prog::Inst); |
| 965 | // Limit instruction count so that inst->id() fits nicely in an int. |
| 966 | // SparseArray also assumes that the indices (inst->id()) are ints. |
| 967 | // The call to WalkExponential uses 2*max_inst_ below, |
| 968 | // and other places in the code use 2 or 3 * prog->size(). |
| 969 | // Limiting to 2^24 should avoid overflow in those places. |
| 970 | // (The point of allowing more than 32 bits of memory is to |
| 971 | // have plenty of room for the DFA states, not to use it up |
| 972 | // on the program.) |
| 973 | if (m >= 1<<24) |
| 974 | m = 1<<24; |
| 975 | |
| 976 | // Inst imposes its own limit (currently bigger than 2^24 but be safe). |
| 977 | if (m > Prog::Inst::kMaxInst) |
| 978 | m = Prog::Inst::kMaxInst; |
| 979 | |
| 980 | max_inst_ = m; |
| 981 | } |
| 982 | |
| 983 | anchor_ = anchor; |
| 984 | } |
| 985 | |
| 986 | // Compiles re, returning program. |
| 987 | // Caller is responsible for deleting prog_. |
| 988 | // If reversed is true, compiles a program that expects |
| 989 | // to run over the input string backward (reverses all concatenations). |
| 990 | // The reversed flag is also recorded in the returned program. |
| 991 | Prog* Compiler::Compile(Regexp* re, bool reversed, int64 max_mem) { |
| 992 | Compiler c; |
| 993 | |
| 994 | c.Setup(re->parse_flags(), max_mem, RE2::ANCHOR_BOTH /* unused */); |
| 995 | c.reversed_ = reversed; |
| 996 | |
| 997 | // Simplify to remove things like counted repetitions |
| 998 | // and character classes like \d. |
| 999 | Regexp* sre = re->Simplify(); |
| 1000 | if (sre == NULL) |
| 1001 | return NULL; |
| 1002 | |
| 1003 | // Record whether prog is anchored, removing the anchors. |
| 1004 | // (They get in the way of other optimizations.) |
| 1005 | bool is_anchor_start = IsAnchorStart(&sre, 0); |
| 1006 | bool is_anchor_end = IsAnchorEnd(&sre, 0); |
| 1007 | |
| 1008 | // Generate fragment for entire regexp. |
| 1009 | Frag f = c.WalkExponential(sre, kNullFrag, 2*c.max_inst_); |
| 1010 | sre->Decref(); |
| 1011 | if (c.failed_) |
| 1012 | return NULL; |
| 1013 | |
| 1014 | // Success! Finish by putting Match node at end, and record start. |
| 1015 | // Turn off c.reversed_ (if it is set) to force the remaining concatenations |
| 1016 | // to behave normally. |
| 1017 | c.reversed_ = false; |
| 1018 | Frag all = c.Cat(f, c.Match(0)); |
| 1019 | c.prog_->set_start(all.begin); |
| 1020 | |
| 1021 | if (reversed) { |
| 1022 | c.prog_->set_anchor_start(is_anchor_end); |
| 1023 | c.prog_->set_anchor_end(is_anchor_start); |
| 1024 | } else { |
| 1025 | c.prog_->set_anchor_start(is_anchor_start); |
| 1026 | c.prog_->set_anchor_end(is_anchor_end); |
| 1027 | } |
| 1028 | |
| 1029 | // Also create unanchored version, which starts with a .*? loop. |
| 1030 | if (c.prog_->anchor_start()) { |
| 1031 | c.prog_->set_start_unanchored(c.prog_->start()); |
| 1032 | } else { |
| 1033 | Frag unanchored = c.Cat(c.DotStar(), all); |
| 1034 | c.prog_->set_start_unanchored(unanchored.begin); |
| 1035 | } |
| 1036 | |
| 1037 | c.prog_->set_reversed(reversed); |
| 1038 | |
| 1039 | // Hand ownership of prog_ to caller. |
| 1040 | return c.Finish(); |
| 1041 | } |
| 1042 | |
| 1043 | Prog* Compiler::Finish() { |
| 1044 | if (failed_) |
| 1045 | return NULL; |
| 1046 | |
| 1047 | if (prog_->start() == 0 && prog_->start_unanchored() == 0) { |
| 1048 | // No possible matches; keep Fail instruction only. |
| 1049 | inst_len_ = 1; |
| 1050 | } |
| 1051 | |
| 1052 | // Trim instruction to minimum array and transfer to Prog. |
| 1053 | Trim(); |
| 1054 | prog_->inst_ = inst_; |
| 1055 | prog_->size_ = inst_len_; |
| 1056 | inst_ = NULL; |
| 1057 | |
| 1058 | // Compute byte map. |
| 1059 | prog_->ComputeByteMap(); |
| 1060 | |
| 1061 | prog_->Optimize(); |
| 1062 | |
| 1063 | // Record remaining memory for DFA. |
| 1064 | if (max_mem_ <= 0) { |
| 1065 | prog_->set_dfa_mem(1<<20); |
| 1066 | } else { |
| 1067 | int64 m = max_mem_ - sizeof(Prog) - inst_len_*sizeof(Prog::Inst); |
| 1068 | if (m < 0) |
| 1069 | m = 0; |
| 1070 | prog_->set_dfa_mem(m); |
| 1071 | } |
| 1072 | |
| 1073 | Prog* p = prog_; |
| 1074 | prog_ = NULL; |
| 1075 | return p; |
| 1076 | } |
| 1077 | |
| 1078 | // Converts Regexp to Prog. |
| 1079 | Prog* Regexp::CompileToProg(int64 max_mem) { |
| 1080 | return Compiler::Compile(this, false, max_mem); |
| 1081 | } |
| 1082 | |
| 1083 | Prog* Regexp::CompileToReverseProg(int64 max_mem) { |
| 1084 | return Compiler::Compile(this, true, max_mem); |
| 1085 | } |
| 1086 | |
| 1087 | Frag Compiler::DotStar() { |
| 1088 | return Star(ByteRange(0x00, 0xff, false), true); |
| 1089 | } |
| 1090 | |
| 1091 | // Compiles RE set to Prog. |
| 1092 | Prog* Compiler::CompileSet(const RE2::Options& options, RE2::Anchor anchor, |
| 1093 | Regexp* re) { |
| 1094 | Compiler c; |
| 1095 | |
| 1096 | Regexp::ParseFlags pf = static_cast<Regexp::ParseFlags>(options.ParseFlags()); |
| 1097 | c.Setup(pf, options.max_mem(), anchor); |
| 1098 | |
| 1099 | // Compile alternation of fragments. |
| 1100 | Frag all = c.WalkExponential(re, kNullFrag, 2*c.max_inst_); |
| 1101 | re->Decref(); |
| 1102 | if (c.failed_) |
| 1103 | return NULL; |
| 1104 | |
| 1105 | if (anchor == RE2::UNANCHORED) { |
| 1106 | // The trailing .* was added while handling kRegexpHaveMatch. |
| 1107 | // We just have to add the leading one. |
| 1108 | all = c.Cat(c.DotStar(), all); |
| 1109 | } |
| 1110 | |
| 1111 | c.prog_->set_start(all.begin); |
| 1112 | c.prog_->set_start_unanchored(all.begin); |
| 1113 | c.prog_->set_anchor_start(true); |
| 1114 | c.prog_->set_anchor_end(true); |
| 1115 | |
| 1116 | Prog* prog = c.Finish(); |
| 1117 | if (prog == NULL) |
| 1118 | return NULL; |
| 1119 | |
| 1120 | // Make sure DFA has enough memory to operate, |
| 1121 | // since we're not going to fall back to the NFA. |
| 1122 | bool failed; |
| 1123 | StringPiece sp = "hello, world"; |
| 1124 | prog->SearchDFA(sp, sp, Prog::kAnchored, Prog::kManyMatch, |
| 1125 | NULL, &failed, NULL); |
| 1126 | if (failed) { |
| 1127 | delete prog; |
| 1128 | return NULL; |
| 1129 | } |
| 1130 | |
| 1131 | return prog; |
| 1132 | } |
| 1133 | |
| 1134 | Prog* Prog::CompileSet(const RE2::Options& options, RE2::Anchor anchor, |
| 1135 | Regexp* re) { |
| 1136 | return Compiler::CompileSet(options, anchor, re); |
| 1137 | } |
| 1138 | |
| 1139 | } // namespace re2 |