llvm-project/llvm/lib/Support/Regex.cpp

93 lines
2.4 KiB
C++

//===-- Regex.cpp - Regular Expression matcher implementation -------------===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This file implements a POSIX regular expression matcher.
//
//===----------------------------------------------------------------------===//
#include "llvm/Support/Regex.h"
#include "llvm/Support/ErrorHandling.h"
#include "llvm/Support/raw_ostream.h"
#include "llvm/ADT/SmallVector.h"
#include "regex_impl.h"
#include <string>
using namespace llvm;
Regex::Regex(const StringRef &regex, unsigned Flags) {
unsigned flags = 0;
preg = new llvm_regex();
preg->re_endp = regex.end();
if (Flags & IgnoreCase)
flags |= REG_ICASE;
if (Flags & Newline)
flags |= REG_NEWLINE;
error = llvm_regcomp(preg, regex.data(), flags|REG_EXTENDED|REG_PEND);
}
Regex::~Regex() {
llvm_regfree(preg);
delete preg;
}
bool Regex::isValid(std::string &Error) {
if (!error)
return true;
size_t len = llvm_regerror(error, preg, NULL, 0);
Error.resize(len);
llvm_regerror(error, preg, &Error[0], len);
return false;
}
/// getNumMatches - In a valid regex, return the number of parenthesized
/// matches it contains.
unsigned Regex::getNumMatches() const {
return preg->re_nsub;
}
bool Regex::match(const StringRef &String, SmallVectorImpl<StringRef> *Matches){
unsigned nmatch = Matches ? preg->re_nsub+1 : 0;
// pmatch needs to have at least one element.
SmallVector<llvm_regmatch_t, 8> pm;
pm.resize(nmatch > 0 ? nmatch : 1);
pm[0].rm_so = 0;
pm[0].rm_eo = String.size();
int rc = llvm_regexec(preg, String.data(), nmatch, pm.data(), REG_STARTEND);
if (rc == REG_NOMATCH)
return false;
if (rc != 0) {
// regexec can fail due to invalid pattern or running out of memory.
error = rc;
return false;
}
// There was a match.
if (Matches) { // match position requested
Matches->clear();
for (unsigned i = 0; i != nmatch; ++i) {
if (pm[i].rm_so == -1) {
// this group didn't match
Matches->push_back(StringRef());
continue;
}
assert(pm[i].rm_eo > pm[i].rm_so);
Matches->push_back(StringRef(String.data()+pm[i].rm_so,
pm[i].rm_eo-pm[i].rm_so));
}
}
return true;
}