Dealing with illegal VIN-Characters

[MaxClerkwell]

Pull-Request #59 provides neat improvements for the VIN input when generating training-data. Anyhow, there are only a few legal characters when it comes to the input of VINs.

I, O and Q, as well as all special characters here is a list of legal characters for all 17-chars of the VIN as regex: First to fourth character: [A-HJ-NPR-Z] Fifth to seventh character: [A-HJ-NPR-Z0-9] Ninth character: [0-9] Eleventh to seventeenth character: [A-HJ-NPR-Z0-9]

Wen a character is typed, a sort of a "filter" between stdin and the actual buffer should check, what character was entered and whether it is illegal.

Expected Behavior: If the VIN-input of

ImGui::InputTextWithHint("VIN", "Enter VIN", VIN, IM_ARRAYSIZE(VIN),
                                     // auto capitalize input string 
                                     ImGuiInputTextFlags_CharsUppercase);

is at each given place a legal character, the char shall be displayed on the screen in the text-edit-box. If an illegal character is typed, the char shall be dropped and not be displayed at all, as if nothing had happened.

[R-Abbasi]

How about Eighth and Tenth characters? This works but there also might be improvements to it. If it's not what you wanted, let me know please, and I will try another way or making it better.

  static char buf[18];
  auto vinFilter = [](ImGuiInputTextCallbackData* data) -> int
      {
          const std::regex first_to_four("[A-HJ-NPR-Z]");
          const std::regex fifth_to_seventh("[A-HJ-NPR-Z0-9]");
          const std::regex eighth_to_tenth("[0-9]");
          const std::regex eleventh_to_seventeenth("[A-HJ-NPR-Z0-9]");
          std::string s;
          s += data->EventChar;
          size_t indx = strlen(buf) + 1;

          if (indx >= 1 && indx <= 4)
              return !std::regex_match(s, first_to_four);
          else if (indx >= 5 && indx <= 7)
              return !std::regex_match(s, fifth_to_seventh);
          else if (indx >= 8 && indx <= 10)
              return !std::regex_match(s, eighth_to_tenth);
          else if (indx >= 11 && indx <= 17)
              return !std::regex_match(s, eleventh_to_seventeenth);
      };

  ImGui::InputTextWithHint("VIN", "Enter VIN", buf, IM_ARRAYSIZE(buf),
         ImGuiInputTextFlags_CharsUppercase |
         ImGuiInputTextFlags_CharsNoBlank |
         ImGuiInputTextFlags_CallbackCharFilter,
         vinFilter
  );

[MaxClerkwell]

This looks like an exact solution to the challenge! Is clearly readable and should do the job. I looked into the definition of a VIN once more and saw, that in other countries than germany, any part of the vin can have numbers and letters, so i'd only has to match: [A-HJ-NPR-Z0-9]

My initial input was to restrictive. Please implement in feature-branch and merge into master!

[AKMaily]

This has been implemented in the current version v0.9.0 and can be closed.