Question

当我尝试使用boost :: regex搜索并替换字符串中的某些数据时，我遇到了很多错误valgrind。我得到了正确的输出，但我有点害怕这个错误

有趣的是，当我用替换来评论该行时，我没有从搜索行中得到任何错误。

所以我有以下功能

  static void    replaceVar(std::string & input, std::map<std::string, TEMPLATE_PARAM> &param)
  {
    boost::regex ex(REGEX_TAG);
    boost::match_results<std::string::const_iterator> extend;
    std::string::const_iterator start, end;
    boost::match_flag_type flags;

    start = input.begin();
    end = input.end();
    flags = boost::match_default;
    while (boost::regex_search(start, end, extend, ex, flags)) // line 78
      {
        try
          {
            const std::string *ptr = tools::visitor_fct<std::string>(param.at(extend[1])); // this line is working fine
            if (ptr != nullptr)
              input = boost::regex_replace(input, ex, *ptr, boost::match_default | boost::format_first_only); //line 84
          }
        catch (const std::out_of_range& err)
          {
            input = boost::regex_replace(input, ex, std::string(""), boost::match_default | boost::format_first_only);
          }
        start = extend[0].second;
        end = input.end();
        flags |= boost::match_prev_avail;
        flags |= boost::match_not_bob;
      }
  }

我从valgrind

获得以下输出

==21743== Thread 2:
==21743== Invalid read of size 1
==21743==    at 0x54C24B0: boost::re_detail::perl_matcher<__gnu_cxx::__normal_iterator<char const*, std::string>, std::allocator<boost::sub_match<__gnu_cxx::__normal_iterator<char const*, std::string> > >, boost::regex_traits<char, boost::cpp_regex_traits<char> > >::find_restart_any() (in /usr/local/lib/libboost_regex.so.1.53.0)
==21743==    by 0x54D83BA: boost::re_detail::perl_matcher<__gnu_cxx::__normal_iterator<char const*, std::string>, std::allocator<boost::sub_match<__gnu_cxx::__normal_iterator<char const*, std::string> > >, boost::regex_traits<char, boost::cpp_regex_traits<char> > >::find_imp() (in /usr/local/lib/libboost_regex.so.1.53.0)
==21743==    by 0x4BADB7: bool boost::regex_search<__gnu_cxx::__normal_iterator<char const*, std::string>, std::allocator<boost::sub_match<__gnu_cxx::__normal_iterator<char const*, std::string> > >, char, boost::regex_traits<char, boost::cpp_regex_traits<char> > >(__gnu_cxx::__normal_iterator<char const*, std::string>, __gnu_cxx::__normal_iterator<char const*, std::string>, boost::match_results<__gnu_cxx::__normal_iterator<char const*, std::string>, std::allocator<boost::sub_match<__gnu_cxx::__normal_iterator<char const*, std::string> > > >&, boost::basic_regex<char, boost::regex_traits<char, boost::cpp_regex_traits<char> > > const&, boost::regex_constants::_match_flags, __gnu_cxx::__normal_iterator<char const*, std::string>) (regex_search.hpp:56)
==21743==    by 0x4F40D7: bool boost::regex_search<__gnu_cxx::__normal_iterator<char const*, std::string>, std::allocator<boost::sub_match<__gnu_cxx::__normal_iterator<char const*, std::string> > >, char, boost::regex_traits<char, boost::cpp_regex_traits<char> > >(__gnu_cxx::__normal_iterator<char const*, std::string>, __gnu_cxx::__normal_iterator<char const*, std::string>, boost::match_results<__gnu_cxx::__normal_iterator<char const*, std::string>, std::allocator<boost::sub_match<__gnu_cxx::__normal_iterator<char const*, std::string> > > >&, boost::basic_regex<char, boost::regex_traits<char, boost::cpp_regex_traits<char> > > const&, boost::regex_constants::_match_flags) (regex_search.hpp:42)
==21743==    by 0x4F2BB4: ... line 78

和

==21743==  Address 0x6543315 is 197 bytes inside a block of size 293 free'd
==21743==    at 0x4C2A4BC: operator delete(void*) (in /usr/lib/valgrind/vgpreload_memcheck-amd64-linux.so)
==21743==    by 0x57EBC12: std::basic_string<char, std::char_traits<char>, std::allocator<char> >::~basic_string() (in /usr/lib/x86_64-linux-gnu/libstdc++.so.6.0.16)
==21743==    by 0x4F2B0C: (l:84)

我认为这是在创作所有这些错误的作业，因为我只放了

boost::regex_replace(input, ex, *ptr, boost::match_default | boost::format_first_only); //line 84

我没有得到任何valgrind错误

我还尝试从regex_replace的输出创建一个新字符串，然后将其分配给输出但我仍然会收到此错误

有什么想法吗？

Answer 1

要删除所有这些错误，我只需要在每次更改时重新启动循环，因为字符串的结尾和开头不一样。

所以我只是将循环改为

 bool flag = true;
 while (flag)
  {
    flag = false;
    start = input.begin();
    end = input.end();
    while (boost::regex_search(start, end, extend, ex, boost::match_default))
      {
        try
          {
            const std::string *ptr = tools::visitor_fct<std::string>(param.at(extend[1]));
            if (ptr != nullptr)
              input = boost::regex_replace(input, ex, *ptr, boost::match_default | boost::format_first_only);
          }
        catch (const std::out_of_range& err)
          {
            input = boost::regex_replace(input, ex, std::string(""), boost::match_default | boost::format_first_only);
          }
        flag = true;
        break;
      }
  }

一切正常。

boost :: regex_search并替换valgrind错误

1 个答案: