Variable overflow when writing dDNNF to file

[raabh]

Hey,

While working with d4v2 I have encountered a bug, when writing to a file.

With the following minimal CNF example and the usage of d4v2 as ./build/d4 -i in.cnf -m ddnnf-compiler --dump-ddnnf out.nnf

p cnf 129 1
129 0

I get

o 1 0
t 2 0
1 2 1 0

as a result, but I would expect:

o 1 0
t 2 0
1 2 129 0

I am able to reproduce that bug while the total number of variables, declared in the CNF head as well as the variables in the clauses are either between 128 and 254 or between 2^15 and 2^16-2.