kopia lustrzana https://github.com/cyoung/stratux
76 wiersze
1.5 KiB
Go
76 wiersze
1.5 KiB
Go
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package main
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import (
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"bufio"
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"encoding/hex"
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"fmt"
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"os"
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"strings"
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)
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const (
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UPLINK_FRAME_DATA_BYTES = 432
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)
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func decodeUplink(frame []byte) {
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raw_lat := (uint32(frame[0]) << 15) | (uint32(frame[1]) << 7) | (uint32(frame[2]) >> 1)
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raw_lon := ((uint32(frame[2]) & 0x01) << 23) | (uint32(frame[3]) << 15) | (uint32(frame[4]) << 7) | (uint32(frame[5]) >> 1)
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lat := float64(raw_lat) * 360.0 / 16777216.0
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lon := float64(raw_lon) * 360.0 / 16777216.0
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if lat > 90 {
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lat = lat - 180
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}
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if lon > 180 {
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lon = lon - 360
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}
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fmt.Printf("%.04f, %.04f\n", lat, lon)
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}
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func parseInput(buf string) {
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buf = strings.Trim(buf, "\r\n") // Remove newlines.
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x := strings.Split(buf, ";") // We want to discard everything before the first ';'.
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if len(x) == 0 {
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return
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}
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s := x[0]
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if len(s) == 0 {
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return
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}
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if s[0] != '+' {
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return // Only want + ("Uplink") messages currently. - (Downlink) or messages that start with other are discarded.
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}
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s = s[1:]
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if len(s)%2 != 0 { // Bad format.
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return
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}
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if len(s)/2 != UPLINK_FRAME_DATA_BYTES {
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fmt.Printf("UPLINK_FRAME_DATA_BYTES=%d, len(s)=%d\n", UPLINK_FRAME_DATA_BYTES, len(s))
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panic("Error")
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}
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// Now, begin converting the string into a byte array.
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frame := make([]byte, UPLINK_FRAME_DATA_BYTES)
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hex.Decode(frame, []byte(s))
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// Decode the frame.
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decodeUplink(frame)
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}
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func main() {
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reader := bufio.NewReader(os.Stdin)
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for {
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buf, err := reader.ReadString('\n')
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if err != nil {
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break
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}
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parseInput(buf)
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}
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}
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