Replace RE2 import with a dependency

third_party/re2/re2/testing/regexp_generator.h

-// Copyright 2008 The RE2 Authors.  All Rights Reserved.
-// Use of this source code is governed by a BSD-style
-// license that can be found in the LICENSE file.
-
-// Regular expression generator: generates all possible
-// regular expressions within given parameters (see below for details).
-
-#ifndef RE2_TESTING_REGEXP_GENERATOR_H__
-#define RE2_TESTING_REGEXP_GENERATOR_H__
-
-#include <string>
-#include <vector>
-#include "util/random.h"
-#include "util/util.h"
-#include "re2/stringpiece.h"
-
-namespace re2 {
-
-// Regular expression generator.
-//
-// Given a set of atom expressions like "a", "b", or "."
-// and operators like "%s*", generates all possible regular expressions
-// using at most maxbases base expressions and maxops operators.
-// For each such expression re, calls HandleRegexp(re).
-//
-// Callers are expected to subclass RegexpGenerator and provide HandleRegexp.
-//
-class RegexpGenerator {
- public:
-  RegexpGenerator(int maxatoms, int maxops, const vector<string>& atoms,
-                  const vector<string>& ops);
-  virtual ~RegexpGenerator() {}
-
-  // Generates all the regular expressions, calling HandleRegexp(re) for each.
-  void Generate();
-
-  // Generates n random regular expressions, calling HandleRegexp(re) for each.
-  void GenerateRandom(int32 seed, int n);
-
-  // Handles a regular expression.  Must be provided by subclass.
-  virtual void HandleRegexp(const string& regexp) = 0;
-
-  // The egrep regexp operators: * + ? | and concatenation.
-  static const vector<string>& EgrepOps();
-
- private:
-  void RunPostfix(const vector<string>& post);
-  void GeneratePostfix(vector<string>* post, int nstk, int ops, int lits);
-  bool GenerateRandomPostfix(vector<string>* post, int nstk, int ops, int lits);
-
-  int maxatoms_;           // Maximum number of atoms allowed in expr.
-  int maxops_;             // Maximum number of ops allowed in expr.
-  vector<string> atoms_;   // Possible atoms.
-  vector<string> ops_;     // Possible ops.
-  ACMRandom* acm_;         // Random generator.
-  DISALLOW_COPY_AND_ASSIGN(RegexpGenerator);
-};
-
-// Helpers for preparing arguments to RegexpGenerator constructor.
-
-// Returns one string for each character in s.
-vector<string> Explode(const StringPiece& s);
-
-// Splits string everywhere sep is found, returning
-// vector of pieces.
-vector<string> Split(const StringPiece& sep, const StringPiece& s);
-
-}  // namespace re2
-
-#endif  // RE2_TESTING_REGEXP_GENERATOR_H__