94 lines
2.8 KiB
Go
94 lines
2.8 KiB
Go
package main
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import (
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"bytes"
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"encoding/base64"
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"encoding/binary"
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"errors"
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"math"
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"strings"
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"github.com/johnjones4/model-rocket-telemetry/dashboard/core"
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)
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func telemetryFloatFromByteIndex(bytes []byte, index int) float64 {
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start := 8 * index
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end := start + 8
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if start >= len(bytes) || end >= len(bytes) {
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return 0
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}
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bits := binary.LittleEndian.Uint64(bytes[start:end])
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float := math.Float64frombits(bits)
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return float
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}
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func telemetryIntFromBytes(b []byte) int16 {
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buffer := bytes.NewReader(b)
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if len(b) != 2 {
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return 0
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}
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var val int16
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binary.Read(buffer, binary.LittleEndian, &val)
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return val
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}
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func decodeTelemetryBytes(bytes []byte) ([]byte, []byte, error) {
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parts := strings.Split(string(bytes), ",")
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if len(parts) != 3 || parts[0] != "T" {
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return nil, nil, errors.New(string(bytes))
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}
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telemetryBytes, err := base64.StdEncoding.DecodeString(parts[1])
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if err != nil {
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return nil, nil, err
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}
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rssiBytes, err := base64.StdEncoding.DecodeString(parts[2])
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if err != nil {
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return nil, nil, err
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}
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return telemetryBytes, rssiBytes, nil
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}
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func bytesToDataSegment(stream core.FlightData, bytes []byte) ([]core.DataSegment, float64, core.Coordinate, error) {
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telemetryBytes, rssiBytes, err := decodeTelemetryBytes(bytes)
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if err != nil {
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return nil, 0, core.Coordinate{}, err
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}
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segments := make([]core.DataSegment, PointsPerDataFrame)
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var basePressure float64
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var origin core.Coordinate
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for i := len(segments) - 1; i >= 0; i-- {
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offset := (i * 10)
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raw := core.RawDataSegment{
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FlightTime: telemetryFloatFromByteIndex(telemetryBytes, offset+core.IndexFlightTime),
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FlightPhase: telemetryFloatFromByteIndex(telemetryBytes, offset+core.IndexFightPhase),
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Altitude: telemetryFloatFromByteIndex(telemetryBytes, offset+core.IndexAltitude),
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Velocity: telemetryFloatFromByteIndex(telemetryBytes, offset+core.IndexVelocity),
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Acceleration: telemetryFloatFromByteIndex(telemetryBytes, offset+core.IndexAcceleration),
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Temperature: telemetryFloatFromByteIndex(telemetryBytes, offset+core.IndexTemperature),
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Coordinate: core.Coordinate{
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telemetryFloatFromByteIndex(telemetryBytes, offset+core.IndexCoordinateLat),
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telemetryFloatFromByteIndex(telemetryBytes, offset+core.IndexCoordinateLon),
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},
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GPSInfo: core.GPSInfo{
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telemetryFloatFromByteIndex(telemetryBytes, offset+core.IndexGpsQuality),
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telemetryFloatFromByteIndex(telemetryBytes, offset+core.IndexGpsSats),
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},
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Rssi: telemetryIntFromBytes(rssiBytes),
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}
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var computed core.ComputedDataSegment
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computed, basePressure, origin = core.ComputeDataSegment(stream, raw)
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segments[i] = core.DataSegment{
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raw,
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computed,
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}
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}
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return segments, basePressure, origin, nil
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}
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