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enigma.go
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enigma.go
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package enigma
import (
"strconv"
"strings"
"github.com/elliottpolk/enigma/internal/machine"
"github.com/elliottpolk/enigma/internal/plugboard"
"github.com/elliottpolk/enigma/internal/reflector"
"github.com/elliottpolk/enigma/internal/rotor"
"github.com/pkg/errors"
"gopkg.in/yaml.v2"
)
type config struct {
Rotors map[string]*struct {
Name string `json:"name"`
Pos int `json:"pos"`
Ring int `json:"ring"`
} `json:"rotors"`
Reflector string `json:"reflector"`
Plugboard []string `json:"plugboard"`
}
type Enigma struct {
*machine.Machine
}
//func NewMachine(c, s []byte, sf string) (*Enigma, error) {
func NewMachine(c []byte) (*Enigma, error) {
var in map[string]*config
if err := yaml.Unmarshal(c, &in); err != nil {
return nil, errors.Wrap(err, "unable to parse config file")
}
var (
cfg = in["machine"]
lr = cfg.Rotors["left"]
mr = cfg.Rotors["middle"]
rr = cfg.Rotors["right"]
conns = make([]*plugboard.Connection, 0)
)
for _, conn := range cfg.Plugboard {
if len(conn) < 2 {
return nil, errors.Errorf("invalid plugboard config %s", conn)
}
_conn := []rune(strings.ToUpper(conn))
var (
a = _conn[0]
b = _conn[1]
)
// confirm 'a' is not a number
if _, err := strconv.Atoi(string(a)); err == nil {
return nil, errors.Errorf("invalid plugboard config %s", conn)
}
// confirm 'b' is not a number
if _, err := strconv.Atoi(string(b)); err == nil {
return nil, errors.Errorf("invalid plugboard config %s", conn)
}
conns = append(conns, &plugboard.Connection{a, b})
}
pb, err := plugboard.NewPlugboard(conns)
if err != nil {
return nil, err
}
return &Enigma{
&machine.Machine{
Left: rotor.Create(lr.Name, lr.Pos, lr.Ring),
Middle: rotor.Create(mr.Name, mr.Pos, mr.Ring),
Right: rotor.Create(rr.Name, rr.Pos, rr.Ring),
Reflector: reflector.Create(cfg.Reflector),
Plugboard: pb,
},
}, nil
}