Function GetCachedProg

extern/re2/re2/testing/regexp_benchmark.cc:944–958

// search time without the per-regexp overhead.

Prog* GetCachedProg(const char* regexp) {
  static auto& mutex = *new Mutex;
  MutexLock lock(&mutex);
  static auto& cache = *new std::unordered_map<std::string, Prog*>;
  Prog* prog = cache[regexp];
  if (prog == NULL) {
    Regexp* re = Regexp::Parse(regexp, Regexp::LikePerl, NULL);
    CHECK(re);
    prog = re->CompileToProg(int64_t{1}<<31);  // mostly for the DFA
    CHECK(prog);
    cache[regexp] = prog;
    re->Decref();
  }
  return prog;
}

PCRE* GetCachedPCRE(const char* regexp) {
  static auto& mutex = *new Mutex;