I currently have a protobuf struct that looks like this:
type RequestEnvelop_MessageQuad struct {
F1 [][]byte `protobuf:"bytes,1,rep,name=f1,proto3" json:"f1,omitempty"`
F2 []byte `protobuf:"bytes,2,opt,name=f2,proto3" json:"f2,omitempty"`
Lat float64 `protobuf:"fixed64,3,opt,name=lat" json:"lat,omitempty"`
Long float64 `protobuf:"fixed64,4,opt,name=long" json:"long,omitempty"`
}
F1 takes some S2 Geometry data which I have generated like so:
ll := s2.LatLngFromDegrees(location.Latitude, location.Longitude)
cid := s2.CellIDFromLatLng(ll).Parent(15)
walkData := []uint64{cid.Pos()}
next := cid.Next()
prev := cid.Prev()
// 10 Before, 10 After
for i := 0; i < 10; i++ {
walkData = append(walkData, next.Pos())
walkData = append(walkData, prev.Pos())
next = next.Next()
prev = prev.Prev()
}
log.Println(walkData)
The only problem is, the protobuf struct expects a type of [][]byte I'm just not sure how I can get my uint64 data into bytes. Thanks.
Integer values can be encoded into byte arrays with the encoding/binary package from the standard library.
For instance, to encode a uint64 into a byte buffer, we could use the binary.PutUvarint function:
big := uint64(257)
buf := make([]byte, 2)
n := binary.PutUvarint(buf, big)
fmt.Printf("Wrote %d bytes into buffer: [% x]
", n, buf)
Which would print:
Wrote 2 bytes into buffer: [81 02]
We can also write a generic stream to the buffer using the binary.Write function:
buf := new(bytes.Buffer)
var pi float64 = math.Pi
err := binary.Write(buf, binary.LittleEndian, pi)
if err != nil {
fmt.Println("binary.Write failed:", err)
}
fmt.Printf("% x", buf.Bytes())
Which outputs:
18 2d 44 54 fb 21 09 40
(this second example was borrowed from that packages documentation, where you will find other simliar examples)