// DiscoverDescriptors finds all the descriptors within a characteristic. [Vol 3, Part G, 4.7.1]
// If filter is specified, only filtered descriptors are returned.
func (p *Client) DiscoverDescriptors(filter []ble.UUID, c *ble.Characteristic) ([]*ble.Descriptor, error) {
p.Lock()
defer p.Unlock()
start := c.ValueHandle + 1
for start <= c.EndHandle {
fmt, b, err := p.ac.FindInformation(start, c.EndHandle)
if err == ble.ErrAttrNotFound {
break
} else if err != nil {
return nil, err
}
length := 2 + 2
if fmt == 0x02 {
length = 2 + 16
}
for len(b) != 0 {
h := binary.LittleEndian.Uint16(b[:2])
u := ble.UUID(b[2:length])
d := &ble.Descriptor{UUID: u, Handle: h}
if filter == nil || ble.Contains(filter, u) {
c.Descriptors = append(c.Descriptors, d)
}
if u.Equal(ble.ClientCharacteristicConfigUUID) {
c.CCCD = d
}
start = h + 1
b = b[length:]
}
}
return c.Descriptors, nil
}
// DiscoverServices finds all the primary services on a server. [Vol 3, Part G, 4.4.1]
// If filter is specified, only filtered services are returned.
func (p *Client) DiscoverServices(filter []ble.UUID) ([]*ble.Service, error) {
p.Lock()
defer p.Unlock()
if p.profile == nil {
p.profile = &ble.Profile{}
}
start := uint16(0x0001)
for {
length, b, err := p.ac.ReadByGroupType(start, 0xFFFF, ble.PrimaryServiceUUID)
if err == ble.ErrAttrNotFound {
return p.profile.Services, nil
}
if err != nil {
return nil, err
}
for len(b) != 0 {
h := binary.LittleEndian.Uint16(b[:2])
endh := binary.LittleEndian.Uint16(b[2:4])
u := ble.UUID(b[4:length])
if filter == nil || ble.Contains(filter, u) {
s := &ble.Service{
UUID: u,
Handle: h,
EndHandle: endh,
}
p.profile.Services = append(p.profile.Services, s)
}
if endh == 0xFFFF {
return p.profile.Services, nil
}
start = endh + 1
b = b[length:]
}
}
}
// 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
}
