1// Copyright 2022 The Go Authors. All rights reserved.
2// Use of this source code is governed by a BSD-style
3// license that can be found in the LICENSE file.
4
5// Package buffer provides a pool-allocated byte buffer.
6package buffer
7
8import "sync"
9
10// Buffer is a byte buffer.
11//
12// This implementation is adapted from the unexported type buffer
13// in go/src/fmt/print.go.
14type Buffer []byte
15
16// Having an initial size gives a dramatic speedup.
17var bufPool = sync.Pool{
18	New: func() any {
19		b := make([]byte, 0, 1024)
20		return (*Buffer)(&b)
21	},
22}
23
24func New() *Buffer {
25	return bufPool.Get().(*Buffer)
26}
27
28func (b *Buffer) Free() {
29	// To reduce peak allocation, return only smaller buffers to the pool.
30	const maxBufferSize = 16 << 10
31	if cap(*b) <= maxBufferSize {
32		*b = (*b)[:0]
33		bufPool.Put(b)
34	}
35}
36
37func (b *Buffer) Reset() {
38	b.SetLen(0)
39}
40
41func (b *Buffer) Write(p []byte) (int, error) {
42	*b = append(*b, p...)
43	return len(p), nil
44}
45
46func (b *Buffer) WriteString(s string) (int, error) {
47	*b = append(*b, s...)
48	return len(s), nil
49}
50
51func (b *Buffer) WriteByte(c byte) error {
52	*b = append(*b, c)
53	return nil
54}
55
56func (b *Buffer) String() string {
57	return string(*b)
58}
59
60func (b *Buffer) Len() int {
61	return len(*b)
62}
63
64func (b *Buffer) SetLen(n int) {
65	*b = (*b)[:n]
66}
67