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9784cae23b
This makes it easy to compact slices that contain duplicate elements by sorting and then uniqing. This is an alternative to constructing an intermediate map and then extracting elements from it. It also provides more control over equality than using a map key does. Signed-off-by: Josh Bleecher Snyder <josh@tailscale.com>
89 lines
1.9 KiB
Go
89 lines
1.9 KiB
Go
// Copyright (c) 2020 Tailscale Inc & 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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package uniq_test
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import (
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"reflect"
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"strconv"
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"testing"
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"tailscale.com/util/uniq"
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)
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func TestModifySlice(t *testing.T) {
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tests := []struct {
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in []int
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want []int
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}{
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{in: []int{0, 1, 2}, want: []int{0, 1, 2}},
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{in: []int{0, 1, 2, 2}, want: []int{0, 1, 2}},
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{in: []int{0, 0, 1, 2}, want: []int{0, 1, 2}},
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{in: []int{0, 1, 0, 2}, want: []int{0, 1, 0, 2}},
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{in: []int{0}, want: []int{0}},
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{in: []int{0, 0}, want: []int{0}},
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{in: []int{}, want: []int{}},
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}
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for _, test := range tests {
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in := make([]int, len(test.in))
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copy(in, test.in)
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uniq.ModifySlice(&test.in, func(i, j int) bool { return test.in[i] == test.in[j] })
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if !reflect.DeepEqual(test.in, test.want) {
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t.Errorf("uniq.Slice(%v) = %v, want %v", in, test.in, test.want)
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}
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start := len(test.in)
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test.in = test.in[:cap(test.in)]
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for i := start; i < len(in); i++ {
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if test.in[i] != 0 {
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t.Errorf("uniq.Slice(%v): non-0 in tail of %v at index %v", in, test.in, i)
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}
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}
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}
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}
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func Benchmark(b *testing.B) {
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benches := []struct {
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name string
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reset func(s []byte)
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}{
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{name: "AllDups",
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reset: func(s []byte) {
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for i := range s {
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s[i] = '*'
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}
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},
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},
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{name: "NoDups",
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reset: func(s []byte) {
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for i := range s {
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s[i] = byte(i)
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}
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},
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},
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}
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for _, bb := range benches {
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b.Run(bb.name, func(b *testing.B) {
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for size := 1; size <= 4096; size *= 16 {
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b.Run(strconv.Itoa(size), func(b *testing.B) {
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benchmark(b, 64, bb.reset)
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})
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}
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})
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}
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}
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func benchmark(b *testing.B, size int64, reset func(s []byte)) {
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b.ReportAllocs()
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b.SetBytes(size)
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s := make([]byte, size)
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b.ResetTimer()
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for i := 0; i < b.N; i++ {
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s = s[:size]
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reset(s)
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uniq.ModifySlice(&s, func(i, j int) bool { return s[i] == s[j] })
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}
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}
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