func CreateMarkovChain(prefixlen int, dbpath string, create bool, getchan func() (chan Token, error)) (mc *MarkovChain, err error) {
var opts = new(kv.Options)
var conerr error
mc = new(MarkovChain)
opts.Compare = bytes.Compare
mc.prefixLen = prefixlen
if create {
mc.CorpusDB, conerr = kv.Create(dbpath, opts)
if conerr != nil {
if mc.CorpusDB, conerr = kv.Open(dbpath, opts); conerr != nil {
err = errors.New(fmt.Sprintf("cannot create new database %s : %s", dbpath, conerr))
return
}
} else {
c, e := getchan()
if e != nil {
mc.CorpusDB.Close()
os.Remove(dbpath)
err = nil
return
}
mc.PopulateCorpus(c)
}
} else {
mc.CorpusDB, conerr = kv.Open(dbpath, opts)
if conerr != nil {
err = errors.New(fmt.Sprintf("cannot open database %s : %s", dbpath, conerr))
return
}
}
return
}
