ipld-eth-server/vendor/github.com/status-im/keycard-go/apdu/command.go
2019-12-02 13:24:46 -06:00

79 lines
1.6 KiB
Go

package apdu
import (
"bytes"
"encoding/binary"
)
// Command struct represent the data sent as an APDU command with CLA, Ins, P1, P2, Lc, Data, and Le.
type Command struct {
Cla uint8
Ins uint8
P1 uint8
P2 uint8
Data []byte
le uint8
requiresLe bool
}
// NewCommand returns a new apdu Command.
func NewCommand(cla, ins, p1, p2 uint8, data []byte) *Command {
return &Command{
Cla: cla,
Ins: ins,
P1: p1,
P2: p2,
Data: data,
requiresLe: false,
}
}
// SetLe sets the expected Le value and makes sure the Le value is sent in the apdu Command.
func (c *Command) SetLe(le uint8) {
c.requiresLe = true
c.le = le
}
// Le returns if Le is set and its value.
func (c *Command) Le() (bool, uint8) {
return c.requiresLe, c.le
}
// Serialize serielizes the command into a raw bytes sequence.
func (c *Command) Serialize() ([]byte, error) {
buf := new(bytes.Buffer)
if err := binary.Write(buf, binary.BigEndian, c.Cla); err != nil {
return nil, err
}
if err := binary.Write(buf, binary.BigEndian, c.Ins); err != nil {
return nil, err
}
if err := binary.Write(buf, binary.BigEndian, c.P1); err != nil {
return nil, err
}
if err := binary.Write(buf, binary.BigEndian, c.P2); err != nil {
return nil, err
}
if len(c.Data) > 0 {
if err := binary.Write(buf, binary.BigEndian, uint8(len(c.Data))); err != nil {
return nil, err
}
if err := binary.Write(buf, binary.BigEndian, c.Data); err != nil {
return nil, err
}
}
if c.requiresLe {
if err := binary.Write(buf, binary.BigEndian, c.le); err != nil {
return nil, err
}
}
return buf.Bytes(), nil
}