how to load a cfg from a file by tree-ssa

[Andrea Callia D'Iddio]

Hi all,
I need to load a control flow graph (cfg) in a C structure because I'd
like to optimize the graph. I've found this library
http://people.redhat.com/dnovillo/pub/tree-ssa/doc/html/files.html
but I don't understand how to use it to build such structure from a file .cfg
Is there in C a structure that represents a cfg?
Is there in C a function that construct automatically such structure
from a file?
Thanks to all,

Andrea