fix dsf bug

[diablo2049]

No description provided.

[jniemann66]

Hi Diablo2049.
I'm back, after a long hiatus !
just looking at your pull request now. Thanks for that !
Is there any chance you could privately send me the dsf file that was causing the grief (if it's not too huge) ? I want to replicate this problem myself.
I can see that you have added a check of the blocksize in the main loop.
I think the dsf reader should guarantee that it always returns exactly the number of frames it says it will ( in frames() function )
Looks to me like the reported chunk lengths in your dsf file might not match the actual lengths.
(That's why I'd love to study the file ...)

Sorry it's taken me 10 months to look at this :-)

Cheers
Judd