How to effectively parse the contents of an INI file?

heftlas

I have an INI file that looks something like this:

[General]
Version=160
Necessary=true

I do not have access to the INI file itself, but I do have access to the data inside. So I can easily get a string like:

[General]\nVersion=160\nNecessary=true

And I can easily manipulate that string to get the information I need.

However, does Qt offer a better way to handle this?

I thought about using QSettings, but I don't really have access to the file itself, as I said.

JonB

@heftlas said in How to effectively parse the contents of an INI file?:

I can't really pass the string as a parameter like this, though, right?

No, it does not have a constructor which takes a string and parses it. But if you look at beginGroup() and setValue() you can construct an in-memory QSettings which matches your string.

If you want something which parses an existing string, without having that in a file which can be read, QSettings won't do that. Unless you want to write that string to a file, get QSettings to parse that, and then delete the file.

ollarch

If you have the data as a string, write it to a file and read it using QSettings.

heftlas

@ollarch said in How to effectively parse the contents of an INI file?:

If you have the data as a string, write it to a file and read it using QSettings.

Do you know of any other way? Writing it to a file just to read it and probably then delete that file just seems wrong to me. If it comes to that, then probably creating my own INI parser is better…but I believe Qt would have something like this done for me already.

JonB

@heftlas
It does. QSettings will read the INI file you show. And also write it if you need that too.

I thought about using QSettings, but I don't really have access to the file itself, as I said.

I don't know what this means, or what your question about this is.

heftlas

@JonB
I don't have access to the file “example.ini” (it isn't in my computer) I only have access to its contents—the string I showed. One solution, as pointed by @ollarch is to write it to a file and then read it using QSettings, but I feel like that's overkill.

JonB

@heftlas said in How to effectively parse the contents of an INI file?:

However, does Qt offer a better way to handle this?
I thought about using QSettings, but I don't really have access to the file itself, as I said.

Yes, Qt offers a better way to handle this. It is via QSettings.

You do not need to have the existing file. You can create what you have in QSettings from code without reading a file. It will write the file out, but what do you care?

So I can easily get a string like:
[General]\nVersion=160\nNecessary=true

And I can easily manipulate that string to get the information I need.

If that is what you want to do without going via QSettings then there is no point asking about using QSettings instead.

If this does not answer your question I really do not understand exactly what you are looking for.

heftlas

@JonB
I can't really pass the string as a parameter like this, though, right?

// settings is just a member variable of type QSettings*
 settings = new QSettings("[General]\nVersion=160\nNecessary=true", QSettings::IniFormat);

I tried that, but it just returns an empty QSettings object.

I just want an easier way to handle a string that is formatted like an INI file. Preferably without writing the file out, as that INI file isn't really supposed to be available to everyone, but I don't mind a solution that writes it out for the moment.

JonB

@heftlas said in How to effectively parse the contents of an INI file?:

I can't really pass the string as a parameter like this, though, right?

No, it does not have a constructor which takes a string and parses it. But if you look at beginGroup() and setValue() you can construct an in-memory QSettings which matches your string.

If you want something which parses an existing string, without having that in a file which can be read, QSettings won't do that. Unless you want to write that string to a file, get QSettings to parse that, and then delete the file.

heftlas

@JonB Exactly what I was looking for! Thank you for your help! And sorry if I wasn't very clear at first.

SGaist

Hi,

For that use case, you might be interested by QTemporaryFile.