Replace RE2 import with a dependency

third_party/re2/re2/testing/string_generator.cc

-// 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.
-
-#include <string>
-#include <vector>
-#include "util/test.h"
-#include "re2/testing/string_generator.h"
-
-namespace re2 {
-
-StringGenerator::StringGenerator(int maxlen, const vector<string>& alphabet)
-    : maxlen_(maxlen), alphabet_(alphabet),
-      generate_null_(false),
-      random_(false), nrandom_(0), acm_(NULL) {
-
-  // Degenerate case: no letters, no non-empty strings.
-  if (alphabet_.size() == 0)
-    maxlen_ = 0;
-
-  // Next() will return empty string (digits_ is empty).
-  hasnext_ = true;
-}
-
-StringGenerator::~StringGenerator() {
-  delete acm_;
-}
-
-// Resets the string generator state to the beginning.
-void StringGenerator::Reset() {
-  digits_.clear();
-  hasnext_ = true;
-  random_ = false;
-  nrandom_ = 0;
-  generate_null_ = false;
-}
-
-// Increments the big number in digits_, returning true if successful.
-// Returns false if all the numbers have been used.
-bool StringGenerator::IncrementDigits() {
-  // First try to increment the current number.
-  for (int i = static_cast<int>(digits_.size()) - 1; i >= 0; i--) {
-    if (++digits_[i] < static_cast<int>(alphabet_.size()))
-      return true;
-    digits_[i] = 0;
-  }
-
-  // If that failed, make a longer number.
-  if (static_cast<int>(digits_.size()) < maxlen_) {
-    digits_.push_back(0);
-    return true;
-  }
-
-  return false;
-}
-
-// Generates random digits_, return true if successful.
-// Returns false if the random sequence is over.
-bool StringGenerator::RandomDigits() {
-  if (--nrandom_ <= 0)
-    return false;
-
-  // Pick length.
-  int len = acm_->Uniform(maxlen_+1);
-  digits_.resize(len);
-  for (int i = 0; i < len; i++)
-    digits_[i] = acm_->Uniform(static_cast<int32>(alphabet_.size()));
-  return true;
-}
-
-// Returns the next string in the iteration, which is the one
-// currently described by digits_.  Calls IncrementDigits
-// after computing the string, so that it knows the answer
-// for subsequent HasNext() calls.
-const StringPiece& StringGenerator::Next() {
-  CHECK(hasnext_);
-  if (generate_null_) {
-    generate_null_ = false;
-    sp_ = NULL;
-    return sp_;
-  }
-  s_.clear();
-  for (size_t i = 0; i < digits_.size(); i++) {
-    s_ += alphabet_[digits_[i]];
-  }
-  hasnext_ = random_ ? RandomDigits() : IncrementDigits();
-  sp_ = s_;
-  return sp_;
-}
-
-// Sets generator up to return n random strings.
-void StringGenerator::Random(int32 seed, int n) {
-  if (acm_ == NULL)
-    acm_ = new ACMRandom(seed);
-  else
-    acm_->Reset(seed);
-
-  random_ = true;
-  nrandom_ = n;
-  hasnext_ = nrandom_ > 0;
-}
-
-void StringGenerator::GenerateNULL() {
-  generate_null_ = true;
-  hasnext_ = true;
-}
-
-}  // namespace re2