learning-go/src/buffer_reader/nice_buffer_example.go at master · pathbox/learning-go · GitHub

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package nicebuf

import (

"io"

"sync"

"unsafe"

)

type Buffer struct {

Bytes []byte

}

var _ io.Writer = &Buffer{}

// Write a chunk of bytes to the buffer

func (b *Buffer) Write(v []byte) (int, error) {

b.Bytes = append(b.Bytes, v...) // nice way

return len(v), nil

}

func (b *Buffer) WriteByte(v byte) {

b.Bytes = append(b.Bytes, v)

}

func (b *Buffer) Reset() {

b.Bytes = b.bytes[:0] // use this way to reset

}

func (b *Buffer) String() string {

return *(*string)(unsafe.Pointer(&b.Bytes))

}

// WriteTo writes the contents of our buffer to an io.Writer

func (b *Buffer) WriteTo(w io.Writer) (int64, error) {

n, err := w.Write(b.Bytes)

return int64(n), err

}

// Buffer pool

var bufpool = sync.Pool{

New: func() interface{} { return &Buffer{} },

}

// NewBufferFromPool returns a pointer to a zerod Buffer. This may be retrieved from a

// pool. When you're done with it, call 'ReturnToPool'.

func NewBufferFromPool() *Buffer {

b := bufpool.Get().(*Buffer)

b.Reset()

return b

}

// NewBufferFromPoolWithCap returns a pointer to a zero'd Buffer with its underlying

// capacity set. This may be retrieved from a pool. When you're done with it, call 'ReturnToPool'.

func NewBufferFromPoolWithCap(size int) *Buffer {

b := bufpool.Get().(*Buffer)

if c := cap(b.Bytes); c < size {

b.Bytes = make([]byte, 0, size)

} else if c > 0 {

b.Reset()

}

return b

}

// ReturnToPool puts this instance back in the underlying pool. Reading from or using this instance

// in any way after calling this is invalid.

func (b *Buffer) ReturnToPool() {

bufpool.Put(b)

}

learning-go/src/buffer_reader/nice_buffer_example.go at master · pathbox/learning-go · GitHub

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