taf/units/units.go

119 lines
2.5 KiB
Go
Raw Normal View History

2023-08-21 23:56:17 +00:00
package units
import (
"strings"
)
// Speed represents a unit of speed
type Speed string
// Speed units
const (
MetersPerSecond Speed = "MPS"
KilometersPerHour Speed = "KMH"
Knots Speed = "KT"
)
var speedNames = map[Speed]string{
MetersPerSecond: "m/s",
KilometersPerHour: "kph",
Knots: "kts",
}
func (su Speed) String() string {
name, ok := speedNames[su]
if !ok {
return "<unknown>"
}
return name
}
// Convert converts a value from one unit to another
func (sf Speed) Convert(st Speed, val int) int {
switch {
case sf == MetersPerSecond && st == KilometersPerHour:
return int(float64(val) * 3.6)
case sf == KilometersPerHour && st == MetersPerSecond:
return int(float64(val) / 3.6)
case sf == Knots && st == KilometersPerHour:
return int(float64(val) * 1.852)
case sf == KilometersPerHour && st == Knots:
return int(float64(val) / 1.852)
case sf == MetersPerSecond && st == Knots:
return int(float64(val) * 1.94384)
case sf == Knots && st == MetersPerSecond:
return int(float64(val) / 1.94384)
default:
return val
}
}
// ParseSpeed parses a speed value. Valid inputs include:
// mps, m/s, kmh, kph, kt, and kts.
// This function is case-insensitive.
func ParseSpeed(s string) (Speed, bool) {
if _, ok := speedNames[Speed(s)]; ok {
return Speed(s), true
}
for su, name := range speedNames {
if strings.EqualFold(s, name) ||
strings.EqualFold(s, string(su)) {
return su, true
}
}
return "", false
}
// Distance represents a unit of distance
type Distance string
// Distance units
const (
StatuteMiles Distance = "SM"
Meters Distance = "M"
)
var distanceNames = map[Distance]string{
StatuteMiles: "mi",
Meters: "m",
}
func (du Distance) String() string {
name, ok := distanceNames[du]
if !ok {
return "<unknown>"
}
return name
}
// Convert converts a value from one unit to another
func (df Distance) Convert(dt Distance, val float64) float64 {
switch {
case df == StatuteMiles && dt == Meters:
return val * 1609
case df == Meters && dt == StatuteMiles:
return val / 1609
default:
return val
}
}
// ParseDistance parses a speed value. Valid inputs include:
// sm, mi, and m. This function is case-insensitive.
func ParseDistance(s string) (Distance, bool) {
if _, ok := distanceNames[Distance(s)]; ok {
return Distance(s), true
}
for d, name := range distanceNames {
if strings.EqualFold(s, name) ||
strings.EqualFold(s, string(d)) {
return d, true
}
}
return "", false
}