// DiscoverCharacteristics finds all the characteristics within a service. [Vol 3, Part G, 4.6.1]
// If filter is specified, only filtered characteristics are returned.
func (cln *Client) DiscoverCharacteristics(cs []ble.UUID, s *ble.Service) ([]*ble.Characteristic, error) {
rsp := cln.conn.sendReq(62, xpc.Dict{
"kCBMsgArgDeviceUUID": cln.id,
"kCBMsgArgServiceStartHandle": s.Handle,
"kCBMsgArgServiceEndHandle": s.EndHandle,
"kCBMsgArgUUIDs": uuidSlice(cs),
})
if rsp.err() != nil {
return nil, rsp.err()
}
for _, xcs := range rsp.characteristics() {
xc := msg(xcs.(xpc.Dict))
s.Characteristics = append(s.Characteristics, &ble.Characteristic{
UUID: ble.MustParse(xc.uuid()),
Property: ble.Property(xc.characteristicProperties()),
Handle: uint16(xc.characteristicHandle()),
ValueHandle: uint16(xc.characteristicValueHandle()),
})
}
return s.Characteristics, nil
}
// DiscoverCharacteristics finds all the characteristics within a service. [Vol 3, Part G, 4.6.1]
// If filter is specified, only filtered characteristics are returned.
func (p *Client) DiscoverCharacteristics(filter []ble.UUID, s *ble.Service) ([]*ble.Characteristic, error) {
p.Lock()
defer p.Unlock()
start := s.Handle
var lastChar *ble.Characteristic
for start <= s.EndHandle {
length, b, err := p.ac.ReadByType(start, s.EndHandle, ble.CharacteristicUUID)
if err == ble.ErrAttrNotFound {
break
} else if err != nil {
return nil, err
}
for len(b) != 0 {
h := binary.LittleEndian.Uint16(b[:2])
p := ble.Property(b[2])
vh := binary.LittleEndian.Uint16(b[3:5])
u := ble.UUID(b[5:length])
c := &ble.Characteristic{
UUID: u,
Property: p,
Handle: h,
ValueHandle: vh,
EndHandle: s.EndHandle,
}
if filter == nil || ble.Contains(filter, u) {
s.Characteristics = append(s.Characteristics, c)
}
if lastChar != nil {
lastChar.EndHandle = c.Handle - 1
}
lastChar = c
start = vh + 1
b = b[length:]
}
}
return s.Characteristics, nil
}