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Add pointer module (#24)
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‎.github/dependabot.yml

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patterns:
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- "*"
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- package-ecosystem: "gomod"
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directory: "/pointer"
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schedule:
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interval: "monthly"
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groups:
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dependencies:
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patterns:
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- "*"
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- package-ecosystem: "gomod"
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directory: "/probe"
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schedule:

‎.github/workflows/pointer.yml

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name: check-pointer
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on:
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push:
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branches:
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- "main"
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paths:
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- "pointer/**"
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- ".github/workflows/pointer.yml"
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pull_request:
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branches:
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- "*"
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paths:
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- "pointer/**"
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- ".github/workflows/pointer.yml"
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jobs:
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clean:
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name: clean
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runs-on: ubuntu-latest
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timeout-minutes: 2
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strategy:
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matrix:
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go: [stable]
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fail-fast: true
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steps:
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- name: Checkout repo
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uses: actions/checkout@v4
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- name: Set up Go
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uses: actions/setup-go@v5
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with:
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go-version: ${{ matrix.go }}
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cache: true
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- name: Run go mod tidy
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working-directory: pointer
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run: go mod tidy && git diff --exit-code
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- name: Run go mod verify
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working-directory: pointer
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run: go mod verify
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- name: Run formatting
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working-directory: pointer
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run: go run golang.org/x/tools/cmd/goimports@latest -w . && git diff --exit-code
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lint:
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name: lint
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runs-on: ubuntu-latest
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timeout-minutes: 4
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strategy:
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matrix:
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go: [stable]
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fail-fast: true
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steps:
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- name: Checkout repo
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uses: actions/checkout@v4
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- name: Set up Go
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uses: actions/setup-go@v5
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with:
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go-version: ${{ matrix.go }}
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cache: true
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- name: Run go linting
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uses: golangci/golangci-lint-action@v4
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with:
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version: latest
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args: --timeout=4m
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working-directory: pointer
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test:
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name: test
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runs-on: ubuntu-latest
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timeout-minutes: 2
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strategy:
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matrix:
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go: [stable]
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fail-fast: true
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steps:
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- name: Checkout repo
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uses: actions/checkout@v4
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- name: Set up Go
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uses: actions/setup-go@v5
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with:
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go-version: ${{ matrix.go }}
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cache: true
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- name: Run tests
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working-directory: pointer
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run: go test -shuffle=on -v -count=1 -race -failfast -timeout=30s -covermode=atomic -coverprofile=coverage.out ./...
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benchmark:
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name: benchmark
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runs-on: ubuntu-latest
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timeout-minutes: 2
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strategy:
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matrix:
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go: [stable]
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fail-fast: true
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steps:
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- name: Checkout repo
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uses: actions/checkout@v4
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- name: Set up Go
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uses: actions/setup-go@v5
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with:
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go-version: ${{ matrix.go }}
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cache: true
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- name: Run benchmarks
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working-directory: pointer
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run: go test -v -shuffle=on -run=- -bench=. -benchtime=1x -timeout=10s ./...
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build:
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name: build
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runs-on: ubuntu-latest
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timeout-minutes: 4
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strategy:
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matrix:
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go: [stable]
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fail-fast: true
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steps:
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- name: Checkout repo
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uses: actions/checkout@v4
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- name: Set up Go
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uses: actions/setup-go@v5
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with:
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go-version: ${{ matrix.go }}
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cache: true
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- name: Run go generate
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working-directory: pointer
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run: go generate ./... && git diff --exit-code
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- name: Run go build
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working-directory: pointer
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run: go build -o /dev/null ./...

‎pointer/LICENSE

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MIT License
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Copyright (c) 2025 Ben Wakeford
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Permission is hereby granted, free of charge, to any person obtaining a copy
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of this software and associated documentation files (the "Software"), to deal
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in the Software without restriction, including without limitation the rights
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to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
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copies of the Software, and to permit persons to whom the Software is
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furnished to do so, subject to the following conditions:
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The above copyright notice and this permission notice shall be included in all
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copies or substantial portions of the Software.
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THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
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AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
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OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
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SOFTWARE.

‎pointer/README.md

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# pointer
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[![go reference](https://pkg.go.dev/badge/github.com/wafer-bw/go-toolbox/pointer.svg)](https://pkg.go.dev/github.com/wafer-bw/go-toolbox/pointer)
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[![Go Report Card](https://goreportcard.com/badge/github.com/wafer-bw/go-toolbox/pointer)](https://goreportcard.com/report/github.com/wafer-bw/go-toolbox/pointer)

‎pointer/go.mod

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module github.com/wafer-bw/go-toolbox/pointer
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go 1.24.2

‎pointer/go.sum

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‎pointer/pointer.go

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package pointer
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type IsZeroer interface {
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IsZero() bool
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}
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// To returns a pointer to v.
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func To[T any](v T) *T {
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return &v
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}
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// ToOrNil returns a pointer to v if it is not zero or nil otherwise.
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//
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// If v implements the [IsZeroer] interface it will use that to determine if it
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// is zero.
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func ToOrNil[T comparable](v T) *T {
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if z, ok := any(v).(IsZeroer); ok {
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if z.IsZero() {
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return nil
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}
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return &v
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}
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var z T
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if v == z {
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return nil
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}
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return &v
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}
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// From returns the value pointed at by p or the zero value of p's type if it is
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// nil.
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func From[T any](p *T) T {
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if p == nil {
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var z T
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return z
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}
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return *p
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}

‎pointer/pointer_benchmark_test.go

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package pointer_test
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import (
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"testing"
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"time"
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"github.com/wafer-bw/go-toolbox/pointer"
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)
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func BenchmarkTo(b *testing.B) {
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v := true
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for b.Loop() {
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pv := pointer.To(v)
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_ = pv
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}
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}
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func BenchmarkToOrNil(b *testing.B) {
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b.Run("zero value to nil", func(b *testing.B) {
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var v string
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for b.Loop() {
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pv := pointer.ToOrNil(v)
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_ = pv
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}
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})
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b.Run("non-zero value to pointer", func(b *testing.B) {
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v := "non-zero"
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for b.Loop() {
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pv := pointer.ToOrNil(v)
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_ = pv
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}
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})
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b.Run("non-zero value to pointer with IsZero", func(b *testing.B) {
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v := time.Date(2014, 6, 25, 12, 24, 40, 0, time.UTC)
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for b.Loop() {
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pv := pointer.ToOrNil(v)
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_ = pv
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}
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})
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b.Run("zero value to pointer with IsZero", func(b *testing.B) {
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v := time.Time{}
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for b.Loop() {
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pv := pointer.ToOrNil(v)
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_ = pv
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}
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})
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}
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func BenchmarkFrom(b *testing.B) {
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b.Run("not nil", func(b *testing.B) {
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var pv *bool = new(bool)
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for b.Loop() {
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v := pointer.From(pv)
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_ = v
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}
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})
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b.Run("nil", func(b *testing.B) {
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var pv *bool
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for b.Loop() {
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v := pointer.From(pv)
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_ = v
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}
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})
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}

‎pointer/pointer_test.go

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package pointer_test
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import (
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"testing"
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"time"
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"github.com/wafer-bw/go-toolbox/pointer"
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)
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func TestTo(t *testing.T) {
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t.Parallel()
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v := true
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pv := pointer.To(v)
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if pv == nil {
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t.Fatal("expected non-nil pointer")
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} else if v != *pv {
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t.Fatalf("expected %v, got %v", v, *pv)
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}
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}
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func TestFrom(t *testing.T) {
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t.Parallel()
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t.Run("not nil", func(t *testing.T) {
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t.Parallel()
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var pv *bool = new(bool)
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v := pointer.From(pv)
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if v != *pv {
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t.Fatalf("expected %v, got %v", *pv, v)
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}
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})
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t.Run("nil", func(t *testing.T) {
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t.Parallel()
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var e bool
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var pv *bool
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v := pointer.From(pv)
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if v != e {
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t.Fatalf("expected %v, got %v", e, v)
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}
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})
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}
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func TestToOrNil(t *testing.T) {
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t.Parallel()
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t.Run("zero value to nil", func(t *testing.T) {
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t.Parallel()
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var v string
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pv := pointer.ToOrNil(v)
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if pv != nil {
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t.Fatalf("expected nil pointer, got %v", pv)
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}
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})
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t.Run("non-zero value to pointer", func(t *testing.T) {
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t.Parallel()
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v := "non-zero"
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pv := pointer.ToOrNil(v)
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if pv == nil {
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t.Fatal("expected non-nil pointer")
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} else if v != *pv {
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t.Fatalf("expected %v, got %v", v, *pv)
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}
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})
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t.Run("non-zero value to pointer with IsZero", func(t *testing.T) {
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t.Parallel()
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v := time.Date(2014, 6, 25, 12, 24, 40, 0, time.UTC)
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pv := pointer.ToOrNil(v)
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if pv == nil {
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t.Fatal("expected non-nil pointer")
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} else if v != *pv {
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t.Fatalf("expected %v, got %v", v, *pv)
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}
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})
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t.Run("zero value to pointer with IsZero", func(t *testing.T) {
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t.Parallel()
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v := time.Time{}
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pv := pointer.ToOrNil(v)
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if pv != nil {
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t.Fatal("expected nil pointer")
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}
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})
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}

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