58 lines
1.9 KiB
C++
58 lines
1.9 KiB
C++
// Copyright 2008 The RE2 Authors. All Rights Reserved.
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// Use of this source code is governed by a BSD-style
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// license that can be found in the LICENSE file.
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// String generator: generates all possible strings of up to
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// maxlen letters using the set of letters in alpha.
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// Fetch strings using a Java-like Next()/HasNext() interface.
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#ifndef RE2_TESTING_STRING_GENERATOR_H__
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#define RE2_TESTING_STRING_GENERATOR_H__
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#include <string>
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#include <vector>
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#include "util/util.h"
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#include "util/random.h"
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#include "re2/stringpiece.h"
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namespace re2 {
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class StringGenerator {
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public:
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StringGenerator(int maxlen, const vector<string>& alphabet);
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~StringGenerator();
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const StringPiece& Next();
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bool HasNext() { return hasnext_; }
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// Resets generator to start sequence over.
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void Reset();
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// Causes generator to emit random strings for next n calls to Next().
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void Random(int32 seed, int n);
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// Causes generator to emit a NULL as the next call.
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void GenerateNULL();
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private:
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bool IncrementDigits();
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bool RandomDigits();
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// Global state.
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int maxlen_; // Maximum length string to generate.
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vector<string> alphabet_; // Alphabet, one string per letter.
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// Iteration state.
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StringPiece sp_; // Last StringPiece returned by Next().
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string s_; // String data in last StringPiece returned by Next().
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bool hasnext_; // Whether Next() can be called again.
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vector<int> digits_; // Alphabet indices for next string.
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bool generate_null_; // Whether to generate a NULL StringPiece next.
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bool random_; // Whether generated strings are random.
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int nrandom_; // Number of random strings left to generate.
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ACMRandom* acm_; // Random number generator
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DISALLOW_EVIL_CONSTRUCTORS(StringGenerator);
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};
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} // namespace re2
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#endif // RE2_TESTING_STRING_GENERATOR_H__
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