fixed dependencies

vendor/github.com/paulmach/orb/ring.go

@@ -0,0 +1,75 @@
+package orb
+
+// Ring represents a set of ring on the earth.
+type Ring LineString
+
+// GeoJSONType returns the GeoJSON type for the object.
+func (r Ring) GeoJSONType() string {
+	return "Polygon"
+}
+
+// Dimensions returns 2 because a Ring is a 2d object.
+func (r Ring) Dimensions() int {
+	return 2
+}
+
+// Closed will return true if the ring is a real ring.
+// ie. 4+ points and the first and last points match.
+// NOTE: this will not check for self-intersection.
+func (r Ring) Closed() bool {
+	return (len(r) >= 4) && (r[0] == r[len(r)-1])
+}
+
+// Reverse changes the direction of the ring.
+// This is done inplace, ie. it modifies the original data.
+func (r Ring) Reverse() {
+	LineString(r).Reverse()
+}
+
+// Bound returns a rect around the ring. Uses rectangular coordinates.
+func (r Ring) Bound() Bound {
+	return MultiPoint(r).Bound()
+}
+
+// Orientation returns 1 if the the ring is in couter-clockwise order,
+// return -1 if the ring is the clockwise order and 0 if the ring is
+// degenerate and had no area.
+func (r Ring) Orientation() Orientation {
+	area := 0.0
+
+	// This is a fast planar area computation, which is okay for this use.
+	// implicitly move everything to near the origin to help with roundoff
+	offsetX := r[0][0]
+	offsetY := r[0][1]
+	for i := 1; i < len(r)-1; i++ {
+		area += (r[i][0]-offsetX)*(r[i+1][1]-offsetY) -
+			(r[i+1][0]-offsetX)*(r[i][1]-offsetY)
+	}
+
+	if area > 0 {
+		return CCW
+	}
+
+	if area < 0 {
+		return CW
+	}
+
+	// degenerate case, no area
+	return 0
+}
+
+// Equal compares two rings. Returns true if lengths are the same
+// and all points are Equal.
+func (r Ring) Equal(ring Ring) bool {
+	return MultiPoint(r).Equal(MultiPoint(ring))
+}
+
+// Clone returns a new copy of the ring.
+func (r Ring) Clone() Ring {
+	if r == nil {
+		return nil
+	}
+
+	ps := MultiPoint(r)
+	return Ring(ps.Clone())
+}