sbpool

Easy to use strings.Builder pool

Example

package main

import (
	"strings"

	"github.com/ergopkg/sbpool"
)

func main() {
	sbOne := sbpool.AcquireStringsBuilder()
	sbOne.WriteString("hello")
	sbOne.WriteString(" ")
	sbOne.WriteString("world")
	sbTwo := sbpool.AcquireStringsBuilder()
    
	defer func() {
		sbpool.ReleaseStringsBuilder(sbOne)
		sbpool.ReleaseStringsBuilder(sbTwo)
	}()
}

Concurrency supporting

As bytes.Buffer, the strings.Builder doesn’t support concurrency when writing and reading. So we should take care it if we need them. We can try a little bit with strings.Builder to add 10000 character, at the same time.

package main

import (
	"fmt"
	"strings"
	"sync"

	"github.com/ergopkg/sbpool"
)

func main() {
	b := sbpool.AcquireStringsBuilder()
	defer sbpool.ReleaseStringsBuilder(b)
	var wait sync.WaitGroup
	for i := 0; i < 10000; i++ {
		wait.Add(1)
		go func() {
			b.WriteString("1")
			wait.Done()
		}()
	}
	wait.Wait()
	fmt.Println(len(b.String()))
}

If you run it, you had different result’s lengths. But they aren’t enough 10000 as we add.

go run main.go => 7329
go run main.go => 7650
go run main.go => 7623

io.Writer interface

The io.Writer interface is implemented on strings.Builder with Write() method Write(p []byte) (n int, err error). So, we have a lot of useful case with io.Writer:

• io.Copy(dst Writer, src Reader) (written int64, err error)
• bufio.NewWriter(w io.Writer) *Writer
• fmt.Fprint(w io.Writer, a …interface{}) (n int, err error)
• func (r *http.Request) Write(w io.Writer) error
• and other libraries that uses io.Writer

Usefull articles

• 7 notes about strings.builder in Golang

Special thanks

Inspired by valyala/fasthttp ideas.