1 //===-- Regex.cpp - Regular Expression matcher implementation -------------===// 2 // 3 // The LLVM Compiler Infrastructure 4 // 5 // This file is distributed under the University of Illinois Open Source 6 // License. See LICENSE.TXT for details. 7 // 8 //===----------------------------------------------------------------------===// 9 // 10 // This file implements a POSIX regular expression matcher. 11 // 12 //===----------------------------------------------------------------------===// 13 14 #include "llvm/Support/Regex.h" 15 #include "llvm/Support/ErrorHandling.h" 16 #include "llvm/Support/raw_ostream.h" 17 #include "llvm/ADT/SmallVector.h" 18 #include "regex_impl.h" 19 #include <string> 20 using namespace llvm; 21 22 Regex::Regex(const StringRef ®ex, unsigned Flags) { 23 unsigned flags = 0; 24 preg = new llvm_regex(); 25 preg->re_endp = regex.end(); 26 if (Flags & IgnoreCase) 27 flags |= REG_ICASE; 28 if (Flags & Newline) 29 flags |= REG_NEWLINE; 30 error = llvm_regcomp(preg, regex.data(), flags|REG_EXTENDED|REG_PEND); 31 } 32 33 Regex::~Regex() { 34 llvm_regfree(preg); 35 delete preg; 36 } 37 38 bool Regex::isValid(std::string &Error) { 39 if (!error) 40 return true; 41 42 size_t len = llvm_regerror(error, preg, NULL, 0); 43 44 Error.resize(len); 45 llvm_regerror(error, preg, &Error[0], len); 46 return false; 47 } 48 49 /// getNumMatches - In a valid regex, return the number of parenthesized 50 /// matches it contains. 51 unsigned Regex::getNumMatches() const { 52 return preg->re_nsub; 53 } 54 55 bool Regex::match(const StringRef &String, SmallVectorImpl<StringRef> *Matches){ 56 unsigned nmatch = Matches ? preg->re_nsub+1 : 0; 57 58 // pmatch needs to have at least one element. 59 SmallVector<llvm_regmatch_t, 8> pm; 60 pm.resize(nmatch > 0 ? nmatch : 1); 61 pm[0].rm_so = 0; 62 pm[0].rm_eo = String.size(); 63 64 int rc = llvm_regexec(preg, String.data(), nmatch, pm.data(), REG_STARTEND); 65 66 if (rc == REG_NOMATCH) 67 return false; 68 if (rc != 0) { 69 // regexec can fail due to invalid pattern or running out of memory. 70 error = rc; 71 return false; 72 } 73 74 // There was a match. 75 76 if (Matches) { // match position requested 77 Matches->clear(); 78 79 for (unsigned i = 0; i != nmatch; ++i) { 80 if (pm[i].rm_so == -1) { 81 // this group didn't match 82 Matches->push_back(StringRef()); 83 continue; 84 } 85 assert(pm[i].rm_eo > pm[i].rm_so); 86 Matches->push_back(StringRef(String.data()+pm[i].rm_so, 87 pm[i].rm_eo-pm[i].rm_so)); 88 } 89 } 90 91 return true; 92 } 93