fermentord/pkg/tilt/ibeacon.go

71 lines
2 KiB
Go

// MIT License
//
// Copyright (c) 2020 Alex Howarth
//
// Permission is hereby granted, free of charge, to any person obtaining a copy
// of this software and associated documentation files (the "Software"), to deal
// in the Software without restriction, including without limitation the rights
// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
// copies of the Software, and to permit persons to whom the Software is
// furnished to do so, subject to the following conditions:
//
// The above copyright notice and this permission notice shall be included in all
// copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
// SOFTWARE.
package tilt
import (
"encoding/binary"
"encoding/hex"
"errors"
)
//iBeaconType identifies an iBeacon
const iBeaconType uint32 = 0x4c000215
// ErrNotBeacon - the BLE device is not an iBeacon
var ErrNotBeacon = errors.New("not an iBeacon")
// IBeacon data
type IBeacon struct {
UUID string
Major uint16
Minor uint16
}
// IsIBeacon to determine if data is an iBeacon
func IsIBeacon(data []byte) bool {
if len(data) < 25 {
return false
}
if binary.BigEndian.Uint32(data) != iBeaconType {
return false
}
return true
}
// NewIBeacon creates an iBeacon from a valid BLE event
func NewIBeacon(data []byte) (b *IBeacon, err error) {
if !IsIBeacon(data) {
err = ErrNotBeacon
return
}
b = &IBeacon{
UUID: hex.EncodeToString(data[4:20]),
Major: binary.BigEndian.Uint16(data[20:22]),
Minor: binary.BigEndian.Uint16(data[22:24]),
}
return
}