Method CompileSet

extern/re2/re2/compile.cc:1199–1239

Compiles RE set to Prog.

// Compiles RE set to Prog.
Prog* Compiler::CompileSet(Regexp* re, RE2::Anchor anchor, int64_t max_mem) {
  Compiler c;
  c.Setup(re->parse_flags(), max_mem, anchor);

  Regexp* sre = re->Simplify();
  if (sre == NULL)
    return NULL;

  Frag all = c.WalkExponential(sre, Frag(), 2*c.max_ninst_);
  sre->Decref();
  if (c.failed_)
    return NULL;

  c.prog_->set_anchor_start(true);
  c.prog_->set_anchor_end(true);

  if (anchor == RE2::UNANCHORED) {
    // Prepend .* or else the expression will effectively be anchored.
    // Complemented by the ANCHOR_BOTH case in PostVisit().
    all = c.Cat(c.DotStar(), all);
  }
  c.prog_->set_start(all.begin);
  c.prog_->set_start_unanchored(all.begin);

  Prog* prog = c.Finish(re);
  if (prog == NULL)
    return NULL;

  // Make sure DFA has enough memory to operate,
  // since we're not going to fall back to the NFA.
  bool dfa_failed = false;
  StringPiece sp = "hello, world";
  prog->SearchDFA(sp, sp, Prog::kAnchored, Prog::kManyMatch,
                  NULL, &dfa_failed, NULL);
  if (dfa_failed) {
    delete prog;
    return NULL;
  }

  return prog;
}

Prog* Prog::CompileSet(Regexp* re, RE2::Anchor anchor, int64_t max_mem) {
  return Compiler::CompileSet(re, anchor, max_mem);