example_mapof_test.go

//go:build go1.18
// +build go1.18

package cmap_test

import (
	"fmt"

	"github.com/fufuok/cmap"
)

func ExampleNewOf() {
	m := cmap.NewOf[int, int]()
	m.Set(1, 1)
	v := m.Upsert(1, 2, func(exist bool, valueInMap int, newValue int) int {
		if valueInMap == 1 {
			return newValue + 1
		}
		return 0
	})
	fmt.Println(v)
	fmt.Println(m.Get(1))
	m.SetIfAbsent(2, 42)
	m.Remove(1)
	fmt.Println(m.Count())
	for item := range m.IterBuffered() {
		fmt.Println(item)
	}
	m.Clear()

	// Output:
	// 3
	// 3 true
	// 1
	// {2 42}
}

type Person struct {
	name string
	age  int16
}

func ExampleNewTypedMapOf() {
	hasher := func(p Person) uint64 {
		return uint64(fnv32(p.name))<<32 | uint64(31*p.age)
	}
	m := cmap.NewTypedMapOf[Person, int](hasher)
	m.Set(Person{"ff", 18}, 1)
	v := m.Upsert(Person{"ff", 18}, 2, func(exist bool, valueInMap int, newValue int) int {
		if valueInMap == 1 {
			return newValue + 1
		}
		return 0
	})
	fmt.Println(v)
	fmt.Println(m.Get(Person{"ff", 18}))
	m.SetIfAbsent(Person{"uu", 20}, 42)
	m.Remove(Person{"ff", 18})
	fmt.Println(m.Count())
	for item := range m.IterBuffered() {
		fmt.Println(item)
	}
	m.Clear()

	// Output:
	// 3
	// 3 true
	// 1
	// {{uu 20} 42}
}

func fnv32(key string) uint32 {
	hash := uint32(2166136261)
	const prime32 = uint32(16777619)
	keyLength := len(key)
	for i := 0; i < keyLength; i++ {
		hash *= prime32
		hash ^= uint32(key[i])
	}
	return hash
}