can we implement filter in model

I wanted to implement a filter in model itself, I don't want to use proxy model (I am having some performance issues with this).
So is there a way to implement filter() in model only, just like re implementing sort() function in model??

Of course, the model has always full control over what it exposes through its API.

You implement rowCount(), columnCount() and data(), you decide which values to return.

Cheers,
_