Merge pull request #440 from peterstace/eliminate-copy-in-force-cw-ccw

Eliminate copy in ForceCW and ForceCCW

geom/perf_test.go

@@ -4,6 +4,7 @@ import (
 	"fmt"
 	"math"
 	"math/rand"
+	"strconv"
 	"testing"
 
 	"github.com/peterstace/simplefeatures/geom"
@@ -421,3 +422,38 @@ func BenchmarkMultiLineStringIsSimpleManyLineStrings(b *testing.B) {
 		})
 	}
 }
+
+func BenchmarkForceCWandForceCCW(b *testing.B) {
+	for i, tc := range []struct {
+		wkt     string
+		geoType GeometryType
+		isCW    bool
+		isCCW   bool
+		note    string
+	}{
+		{"POLYGON((0 0,0 5,5 5,5 0,0 0))", TypePolygon, true, false, "CW"},
+		{"POLYGON((1 1,3 1,2 2,2 4,1 1))", TypePolygon, false, true, "CCW"},
+		{"POLYGON((0 0,0 5,5 5,5 0,0 0), (1 1,3 1,2 2,2 4,1 1))", TypePolygon, true, false, "outer CW inner CCW"},
+		{"POLYGON((0 0,5 0,5 5,0 5,0 0), (1 1,1 2,2 2,2 1,1 1))", TypePolygon, false, true, "outer CCW inner CW"},
+		{"MULTIPOLYGON(((40 40, 45 30, 20 45, 40 40)),((20 35, 45 20, 30 5, 10 10, 10 30, 20 35),(30 20, 20 25, 20 15, 30 20)))", TypeMultiPolygon, true, false, "all CW"},
+		{"MULTIPOLYGON(((40 40, 20 45, 45 30, 40 40)),((20 35, 10 30, 10 10, 30 5, 45 20, 20 35),(30 20, 20 15, 20 25, 30 20)))", TypeMultiPolygon, false, true, "all CCW"},
+		{"GEOMETRYCOLLECTION(POLYGON((0 0,0 5,5 5,5 0,0 0)), MULTIPOLYGON(((40 40, 45 30, 20 45, 40 40)),((20 35, 45 20, 30 5, 10 10, 10 30, 20 35),(30 20, 20 25, 20 15, 30 20))))", TypeGeometryCollection, true, false, "all CW"},
+	} {
+		g := geomFromWKT(b, tc.wkt)
+		for _, correct := range map[string]bool{
+			"correct":   true,
+			"incorrect": false,
+		} {
+			b.Run(strconv.Itoa(i), func(b *testing.B) {
+				b.ResetTimer()
+				for i := 0; i < b.N; i++ {
+					if tc.isCW && correct || tc.isCCW && !correct {
+						g.ForceCW()
+					} else if tc.isCCW && correct || tc.isCW && !correct {
+						g.ForceCCW()
+					}
+				}
+			})
+		}
+	}
+}

geom/type_geometry.go

@@ -765,13 +765,19 @@ func (g Geometry) PointOnSurface() Point {
 // clockwise orientation and any inner rings in a counter-clockwise
 // orientation. Non-areal geometrys are returned as is.
 func (g Geometry) ForceCW() Geometry {
+	if g.IsCW() {
+		return g
+	}
 	return g.forceOrientation(true)
 }
 
 // ForceCCW returns the equivalent Geometry that has its exterior rings in a
 // counter-clockwise orientation and any inner rings in a clockwise
 // orientation. Non-areal geometrys are returned as is.
 func (g Geometry) ForceCCW() Geometry {
+	if g.IsCCW() {
+		return g
+	}
 	return g.forceOrientation(false)
 }
 

geom/type_geometry_collection.go

@@ -433,6 +433,9 @@ func (c GeometryCollection) PointOnSurface() Point {
 // exterior rings clockwise and interior rings counter-clockwise). Geometries
 // other that Polygons and MultiPolygons are unchanged.
 func (c GeometryCollection) ForceCW() GeometryCollection {
+	if c.IsCW() {
+		return c
+	}
 	return c.forceOrientation(true)
 }
 
@@ -441,6 +444,9 @@ func (c GeometryCollection) ForceCW() GeometryCollection {
 // exterior rings counter-clockwise and interior rings clockwise). Geometries
 // other that Polygons and MultiPolygons are unchanged.
 func (c GeometryCollection) ForceCCW() GeometryCollection {
+	if c.IsCCW() {
+		return c
+	}
 	return c.forceOrientation(false)
 }
 

geom/type_multi_polygon.go

@@ -436,13 +436,19 @@ func (m MultiPolygon) PointOnSurface() Point {
 // clockwise orientation and any inner rings in a counter-clockwise
 // orientation.
 func (m MultiPolygon) ForceCW() MultiPolygon {
+	if m.IsCW() {
+		return m
+	}
 	return m.forceOrientation(true)
 }
 
 // ForceCCW returns the equivalent MultiPolygon that has its exterior rings in
 // a counter-clockwise orientation and any inner rings in a clockwise
 // orientation.
 func (m MultiPolygon) ForceCCW() MultiPolygon {
+	if m.IsCCW() {
+		return m
+	}
 	return m.forceOrientation(false)
 }
 

geom/type_polygon.go

@@ -536,13 +536,19 @@ func (p Polygon) PointOnSurface() Point {
 // clockwise orientation and any inner rings in a counter-clockwise
 // orientation.
 func (p Polygon) ForceCW() Polygon {
+	if p.IsCW() {
+		return p
+	}
 	return p.forceOrientation(true)
 }
 
 // ForceCCW returns the equivalent Polygon that has its exterior ring in a
 // counter-clockwise orientation and any inner rings in a clockwise
 // orientation.
 func (p Polygon) ForceCCW() Polygon {
+	if p.IsCCW() {
+		return p
+	}
 	return p.forceOrientation(false)
 }