Function RandomText

extern/re2/re2/testing/regexp_benchmark.cc:157–174

Generate random text that won't contain the search string, to test worst-case search behavior.

// Generate random text that won't contain the search string,
// to test worst-case search behavior.
std::string RandomText(int64_t nbytes) {
  static const std::string* const text = []() {
    std::string* text = new std::string;
    srand(1);
    text->resize(16<<20);
    for (int64_t i = 0; i < 16<<20; i++) {
      // Generate a one-byte rune that isn't a control character (e.g. '\n').
      // Clipping to 0x20 introduces some bias, but we don't need uniformity.
      int byte = rand() & 0x7F;
      if (byte < 0x20)
        byte = 0x20;
      (*text)[i] = byte;
    }
    return text;
  }();
  CHECK_LE(nbytes, 16<<20);
  return text->substr(0, nbytes);
}

// Makes text of size nbytes, then calls run to search
// the text for regexp iters times.