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108 lines
1.9 KiB
108 lines
1.9 KiB
// +build cgo
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// run -race
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// Copyright 2018 The Go Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style
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// license that can be found in the LICENSE file.
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// +build linux,amd64
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package main
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import (
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"fmt"
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)
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type LineString []Point
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type Point [2]float64
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//go:noinline
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func benchmarkData() LineString {
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return LineString{{1.0, 2.0}}
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}
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func (ls LineString) Clone() LineString {
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ps := MultiPoint(ls)
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return LineString(ps.Clone())
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}
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type MultiPoint []Point
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func (mp MultiPoint) Clone() MultiPoint {
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if mp == nil {
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return nil
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}
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points := make([]Point, len(mp))
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copy(points, mp)
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return MultiPoint(points)
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}
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func F1() {
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cases := []struct {
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threshold float64
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length int
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}{
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{0.1, 1118},
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{0.5, 257},
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{1.0, 144},
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{1.5, 95},
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{2.0, 71},
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{3.0, 46},
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{4.0, 39},
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{5.0, 33},
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}
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ls := benchmarkData()
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for k := 0; k < 100; k++ {
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for i, tc := range cases {
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r := DouglasPeucker(tc.threshold).LineString(ls.Clone())
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if len(r) == tc.length {
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fmt.Printf("%d: unexpected\n", i)
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}
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}
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}
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}
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// A DouglasPeuckerSimplifier wraps the DouglasPeucker function.
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type DouglasPeuckerSimplifier struct {
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Threshold float64
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}
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// DouglasPeucker creates a new DouglasPeuckerSimplifier.
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func DouglasPeucker(threshold float64) *DouglasPeuckerSimplifier {
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return &DouglasPeuckerSimplifier{
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Threshold: threshold,
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}
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}
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func (s *DouglasPeuckerSimplifier) LineString(ls LineString) LineString {
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return lineString(s, ls)
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}
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type simplifier interface {
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simplify(LineString, bool) (LineString, []int)
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}
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func lineString(s simplifier, ls LineString) LineString {
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return runSimplify(s, ls)
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}
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func runSimplify(s simplifier, ls LineString) LineString {
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if len(ls) <= 2 {
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return ls
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}
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ls, _ = s.simplify(ls, false)
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return ls
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}
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func (s *DouglasPeuckerSimplifier) simplify(ls LineString, wim bool) (LineString, []int) {
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return nil, nil
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}
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func main() {
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F1()
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}
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