84 lines
1.8 KiB
Go
84 lines
1.8 KiB
Go
package bearing
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import (
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"fmt"
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"strings"
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"github.com/mdiluz/rove/pkg/vector"
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)
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// Bearing describes a compass direction
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type Bearing int
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const (
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// North describes a 0,1 vector
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North Bearing = iota
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// NorthEast describes a 1,1 vector
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NorthEast
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// East describes a 1,0 vector
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East
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// SouthEast describes a 1,-1 vector
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SouthEast
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// South describes a 0,-1 vector
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South
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// SouthWest describes a -1,-1 vector
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SouthWest
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// West describes a -1,0 vector
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West
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// NorthWest describes a -1,1 vector
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NorthWest
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)
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// bearingString simply describes the strings associated with a direction
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type bearingString struct {
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Long string
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Short string
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}
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// bearingStrings is the set of strings for each direction
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var bearingStrings = []bearingString{
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{"North", "N"},
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{"NorthEast", "NE"},
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{"East", "E"},
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{"SouthEast", "SE"},
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{"South", "S"},
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{"SouthWest", "SW"},
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{"West", "W"},
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{"NorthWest", "NW"},
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}
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// String converts a Direction to a String
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func (d Bearing) String() string {
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return bearingStrings[d].Long
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}
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// ShortString converts a Direction to a short string version
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func (d Bearing) ShortString() string {
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return bearingStrings[d].Short
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}
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// FromString gets the Direction from a string
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func FromString(s string) (Bearing, error) {
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for i, d := range bearingStrings {
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if strings.ToLower(d.Long) == strings.ToLower(s) || strings.ToLower(d.Short) == strings.ToLower(s) {
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return Bearing(i), nil
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}
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}
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return -1, fmt.Errorf("unknown bearing: %s", s)
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}
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var bearingVectors = []vector.Vector{
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{X: 0, Y: 1}, // N
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{X: 1, Y: 1}, // NE
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{X: 1, Y: 0}, // E
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{X: 1, Y: -1}, // SE
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{X: 0, Y: -1}, // S
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{X: -1, Y: 1}, // SW
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{X: -1, Y: 0}, // W
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{X: -1, Y: 1}, // NW
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}
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// Vector converts a Direction to a Vector
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func (d Bearing) Vector() vector.Vector {
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return bearingVectors[d]
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}
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