Buffer

FYI

This project is based on GoLLRB which was written by Petar Maymounkov.

Thanks for the great work of him and you can follow him on Twitter @maymounkov!

The origin project GoLLRB seems have slept for a long time and will no longer to be maintained, so I think it's better to open a new repo and keep it fresh.

If anyone has any objections, please let me know.

Example

A simple case for int items.

package main

import (
    "fmt"
    "github.com/HuKeping/cache"
)

func Print(item cache.Item, buffer *cache.LLRB) bool {
    i, ok := item.(cache.Int)
    if !ok {
        return false
    }   
    fmt.Println(int(i))
    return true
}

func main() {
    buffer := cache.New()
    buffer.Add(cache.Int(1), cache.MOD_NOREPLACE)
    buffer.Add(cache.Int(2), cache.MOD_NOREPLACE)
    buffer.Add(cache.Int(3), cache.MOD_NOREPLACE)
    buffer.Add(cache.Int(4), cache.MOD_NOREPLACE)
    buffer.DeleteMin()
    buffer.Delete(cache.Int(4))
    buffer.AscendGreaterOrEqual(buffer.Min(), Print)
}

A simple case for string items and acsend order in a range

package main

import (
	"fmt"
	"github.com/HuKeping/cache"
)

func Print(item cache.Item, buffer *cache.LLRB) bool {
	i, ok := item.(cache.String)
	if !ok {
		return false
	}
	fmt.Println(cache.String(i))
	return true
}

func main() {
	buffer := cache.New()

	// For now it is not ordered.
	order := []cache.String{
		"ab", "aba", "abc", "a", "aa", "aaa", "b", "a-", "a!",
	}

	for _, i := range order {
		buffer.Add(cache.String(i), cache.MOD_REPLACE)
	}

	// We expect to get `ab`, `aba` and `abc`, otherwise something wrong happened.
	buffer.AscendRange(cache.String("ab"), cache.String("ac"), Print)
}

A quite interesting case for struct items.

package main

import (
	"fmt"
	"github.com/HuKeping/cache"
	"time"
)

type Var struct {
	Expiry time.Time `json:"expiry,omitempty"`
	ID     string    `json:"id",omitempty`
}

// We will order the node by `Time`
func (x Var) Less(than cache.Item) bool {
	return x.Expiry.Before(than.(Var).Expiry)
}

func PrintVar(item cache.Item, buffer *cache.LLRB) bool {
	i, ok := item.(Var)
	if !ok {
		return false
	}

	if i.Expiry.Before(time.Now()) {
		fmt.Printf("Item expired and to be deleted : %v\n", i)
		buffer.Delete(i)
	}
	return true
}

func main() {
	buffer := cache.New()
	var1 := Var{
		Expiry: time.Now().Add(time.Second * 10),
		ID:     "var1",
	}
	var2 := Var{
		Expiry: time.Now().Add(time.Second * 20),
		ID:     "var2",
	}
	var3 := Var{
		Expiry: time.Now().Add(time.Second * 30),
		ID:     "var3",
	}
	var4 := Var{
		Expiry: time.Now().Add(time.Second * 40),
		ID:     "var4",
	}
	var5 := Var{
		Expiry: time.Now().Add(time.Second * 50),
		ID:     "var5",
	}

	buffer.Add(var1, cache.MOD_REPLACE)
	buffer.Add(var2, cache.MOD_REPLACE)
	buffer.Add(var3, cache.MOD_REPLACE)
	buffer.Add(var4, cache.MOD_REPLACE)
	buffer.Add(var5, cache.MOD_REPLACE)

	go func() {
		for {
			time.Sleep(time.Second * 10)
			fmt.Printf("[VAR] Refreshing begin ...\n")
			buffer.AscendGreaterOrEqual(buffer.Min(), PrintVar)
			fmt.Printf("[VAR] Refreshing end...\n\n")
		}
	}()

	time.Sleep(time.Minute)
}