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// 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.
// String generator: generates all possible strings of up to
// maxlen letters using the set of letters in alpha.
// Fetch strings using a Java-like Next()/HasNext() interface.
#ifndef RE2_TESTING_STRING_GENERATOR_H__
#define RE2_TESTING_STRING_GENERATOR_H__
#include <string>
#include <vector>
#include "util/util.h"
#include "util/random.h"
#include "re2/stringpiece.h"
namespace re2 {
class StringGenerator {
public:
StringGenerator(int maxlen, const vector<string>& alphabet);
~StringGenerator();
const StringPiece& Next();
bool HasNext() { return hasnext_; }
// Resets generator to start sequence over.
void Reset();
// Causes generator to emit random strings for next n calls to Next().
void Random(int32 seed, int n);
// Causes generator to emit a NULL as the next call.
void GenerateNULL();
private:
bool IncrementDigits();
bool RandomDigits();
// Global state.
int maxlen_; // Maximum length string to generate.
vector<string> alphabet_; // Alphabet, one string per letter.
// Iteration state.
StringPiece sp_; // Last StringPiece returned by Next().
string s_; // String data in last StringPiece returned by Next().
bool hasnext_; // Whether Next() can be called again.
vector<int> digits_; // Alphabet indices for next string.
bool generate_null_; // Whether to generate a NULL StringPiece next.
bool random_; // Whether generated strings are random.
int nrandom_; // Number of random strings left to generate.
ACMRandom* acm_; // Random number generator
DISALLOW_EVIL_CONSTRUCTORS(StringGenerator);
};
} // namespace re2
#endif // RE2_TESTING_STRING_GENERATOR_H__
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