What's the best way to unstub the following functions?

// Convert a bit-vector to an integer. 
int bitvec2int(boolean[] b)
{
    [CODE HERE]
}

// Convert an integer x to an n-element bit-vector. 
boolean[] int2bitvec(int x, int n)
{
    [CODE HERE]
}

Or is there a better way to do that sort of thing than passing boolean arrays around?

This comes up in an Android app where we need an array of 20 booleans to persist and the easiest way to do that is to write an integer or string to the key-value store.

I'll post the way we (Bee and I) wrote the above as an answer. Thanks!