Golang : Reset buffer example

There are two ways to reset a buffer that with content ( length not equal zero ). You can use either Reset() or Truncate() methods found in the bytes.NewBuffer() function. The following example demonstrates how to create a buffer, check the size and capacity before and after clearing the buffer content.

 package main

 import (
 "bytes"
 "fmt"
 )

 func main() {

 buffer := bytes.NewBuffer([]byte("abcdefghijkl"))

 // convert buffer to bytes and to string for println
 fmt.Println("Before reset : ", string(buffer.Bytes()))
 fmt.Printf("Buffer's Length %d and capacity %d \n", len(buffer.Bytes()), cap(buffer.Bytes()))

 buffer.Reset()

 fmt.Println("After reset : ", string(buffer.Bytes()))
 fmt.Printf("Buffer's Length %d and capacity %d \n", len(buffer.Bytes()), cap(buffer.Bytes()))

 buffer2 := bytes.NewBuffer([]byte("mnopqrstuvwxyz"))

 fmt.Println("Before truncate(0) : ", string(buffer2.Bytes()))
 fmt.Printf("Buffer 2's Length %d and capacity %d \n", len(buffer2.Bytes()), cap(buffer2.Bytes()))

 // alternate way to reset buffer
 buffer2.Truncate(0)

 fmt.Println("After truncate(0) : ", string(buffer2.Bytes()))
 fmt.Printf("Buffer 2's Length %d and capacity %d \n", len(buffer2.Bytes()), cap(buffer2.Bytes()))
 }

Output :

Before reset : abcdefghijkl

Buffer's Length 12 and capacity 32

After reset :

Buffer's Length 0 and capacity 32

Before truncate(0) : mnopqrstuvwxyz

Buffer 2's Length 14 and capacity 32

After truncate(0) :

Buffer 2's Length 0 and capacity 32

References :

https://www.socketloop.com/references/golang-bufio-reset-function-example

https://www.socketloop.com/references/golang-bytes-buffer-truncate-function-example