/* NetHack may be freely redistributed.  See license for details. */

#include <re2/re2.h>

/* RE2 is recommended for public servers as it blocks DoS attacks. It is not
 * fully POSIX-compliant, but is feature-rich. Available at
 * https://github.com/google/re2
 *
 * nhregex interface documented in sys/share/posixregex.c
 */
extern "C" {
  #include <hack.h>

  extern const char regex_id[] = "re2regex";

  struct nhregex {
    re2::RE2 *re;
    nhregex() : re(nullptr) {}
    ~nhregex() { delete re; }
  };

  struct nhregex *regex_init(void) {
    return new nhregex;
  }

  boolean regex_compile(const char *s, struct nhregex *re) {
    if (!s || !re)
      return false;

    if (re->re) {
      delete re->re;
      re->re = nullptr;
    }

    re->re = new re2::RE2(s);
    return re->re->ok();
  }

  const char *regex_error_desc(struct nhregex *re) {
    return (re && re->re && !re->re->ok()) ? re->re->error().c_str() : nullptr;
  }

  boolean regex_match(const char *s, struct nhregex *re) {
    return (s && re && re->re) ? RE2::PartialMatch(s, *(re->re)) : false;
  }

  void regex_free(struct nhregex *re) {
    delete re;
  }
}