func()

in nmxact/mtech_lora/mtech_lora_sesn.go [246:303]

• 53 lines of code
• 6 McCabe index (conditional complexity)

func (s *LoraSesn) sendFragments(b []byte) error {
	segSz := s.Mtu()
	crc := crc16.Crc16(b)
	idx := 0
	for off := 0; off < len(b); {
		var seg bytes.Buffer
		var blkLen int
		if off == 0 {
			hdr := lora.CoapLoraFragStart{
				FragNum: 0,
				Crc:     crc,
			}
			blkLen = segSz - 4
			if blkLen >= len(b) {
				blkLen = len(b)
				hdr.FragNum |= lora.COAP_LORA_LAST_FRAG
			}
			binary.Write(&seg, binary.LittleEndian, hdr)
			seg.Write(b[0:blkLen])
		} else {
			hdr := lora.CoapLoraFrag{
				FragNum: uint8(idx),
			}
			blkLen = segSz - 1
			if blkLen >= len(b)-off {
				blkLen = len(b) - off
				hdr.FragNum |= lora.COAP_LORA_LAST_FRAG
			}
			binary.Write(&seg, binary.LittleEndian, hdr)
			seg.Write(b[off : off+blkLen])
		}
		off += blkLen
		idx++

		seg64 := make([]byte, base64.StdEncoding.EncodedLen(len(seg.Bytes())))
		base64.StdEncoding.Encode(seg64, seg.Bytes())

		msg := mtechLoraTx{
			Port: s.cfg.Lora.Port,
			Ack:  s.cfg.Lora.ConfirmedTx,
			Data: string(seg64),
		}

		payload := []byte{}
		enc := codec.NewEncoderBytes(&payload, new(codec.JsonHandle))
		enc.Encode(msg)

		var outData bytes.Buffer

		outData.Write([]byte(fmt.Sprintf("lora/%s/down %s",
			DenormalizeAddr(s.cfg.Lora.Addr), payload)))
		err := s.xport.Tx(outData.Bytes())
		if err != nil {
			return err
		}
	}
	return nil
}