Urho3D reads data wrong


So I’m working on an importer for a map file. But the deserializer reads the data wrong.
Let me give an example.

For the header in the map file, it has some data then states a name that declares it’s a valid file, such as:
[Some data] MAPFILE [More data]. Instead, I have to do file.ReadLine().Contains to make sure it contains it which I don’t think it’s an approach I’d like, especially since I need to do a lot more reading with Strings, such as texture images and entity data, and when I do ReadString, it treats all data as a String.

All I’m asking is how would I approach this and fix this, as it’s causing my a big headache and pushing back development.


Toss a map file onto pastebin or a github gist so someone can see it.

There’s nothing inherently wrong with the ReadLine().Contains(...) though as a quick failure check but you do need to be aware that you need to Seek(0) later to reset the position if you’re going to be feeding a lexer with ReadAll() or so on.

ReadString does exactly what it should, it eats every character until a null terminal. Deserializer is fairly raw and not meant for tokenizing and other lexer tasks. If you need to do lexing consider using stb_c_lexer or another lexer.

If there are no quoted strings (that could contain spaces) in the map format in question then you could chop into words like ReadIES(...) does in the RampGenerator. That’s only viable for really really simple text formats, beyond that you need a tokenizer.

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Thank you for the reply.

For the map file data, it’s structured like the RMesh in SCP: Containment Breach. Here’s a file that I picked out: Example RMesh file

I’m glad you pointed these functions out, as I was really just confused about any other option. I’ll experiment some more.

It’s a binary file so deserializer will work, it looks that format is using sized strings instead of null terminated strings like Deserializer expects. In which case a uint32 is storing the size of the string that follows.

Something along the lines of this should do:

String ReadSizePrefixedString(Deserializer& src)
    static char tempBuffer[512];
    const unsigned strSize = src.ReadUInt();
    src.Read(tempBuffer, strSize);
    return String(tempBuffer, strSize);

Do be aware that Deserializer knows nothing about endianness so if the format isn’t in the system’s natural endianness you’re going to have problems.

Thanks for the reply, and thank you for the helpful start!