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https://github.com/golang/go
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58 lines
1.1 KiB
Go
58 lines
1.1 KiB
Go
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// run
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// Copyright 2024 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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package main
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import (
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"maps"
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_ "unsafe"
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)
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func main() {
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for i := 0; i < 100; i++ {
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f()
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}
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}
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const NB = 4
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func f() {
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// Make a map with NB buckets, at max capacity.
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// 6.5 entries/bucket.
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ne := NB * 13 / 2
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m := map[int]int{}
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for i := 0; i < ne; i++ {
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m[i] = i
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}
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// delete/insert a lot, to hopefully get lots of overflow buckets
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// and trigger a same-size grow.
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ssg := false
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for i := ne; i < ne+1000; i++ {
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delete(m, i-ne)
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m[i] = i
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if sameSizeGrow(m) {
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ssg = true
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break
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}
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}
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if !ssg {
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return
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}
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// Insert 1 more entry, which would ordinarily trigger a growth.
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// We can't grow while growing, so we instead go over our
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// target capacity.
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m[-1] = -1
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// Cloning in this state will make a map with a destination bucket
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// array twice the size of the source.
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_ = maps.Clone(m)
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}
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//go:linkname sameSizeGrow runtime.sameSizeGrowForIssue69110Test
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func sameSizeGrow(m map[int]int) bool
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