/usr/share/gocode/src/github.com/mailru/easyjson/buffer/pool.go is in golang-github-mailru-easyjson-dev 0.0~git20161103.0.159cdb8-1.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 | // Package buffer implements a buffer for serialization, consisting of a chain of []byte-s to
// reduce copying and to allow reuse of individual chunks.
package buffer
import (
"io"
"sync"
)
// PoolConfig contains configuration for the allocation and reuse strategy.
type PoolConfig struct {
StartSize int // Minimum chunk size that is allocated.
PooledSize int // Minimum chunk size that is reused, reusing chunks too small will result in overhead.
MaxSize int // Maximum chunk size that will be allocated.
}
var config = PoolConfig{
StartSize: 128,
PooledSize: 512,
MaxSize: 32768,
}
// Reuse pool: chunk size -> pool.
var buffers = map[int]*sync.Pool{}
func initBuffers() {
for l := config.PooledSize; l <= config.MaxSize; l *= 2 {
buffers[l] = new(sync.Pool)
}
}
func init() {
initBuffers()
}
// Init sets up a non-default pooling and allocation strategy. Should be run before serialization is done.
func Init(cfg PoolConfig) {
config = cfg
initBuffers()
}
// putBuf puts a chunk to reuse pool if it can be reused.
func putBuf(buf []byte) {
size := cap(buf)
if size < config.PooledSize {
return
}
if c := buffers[size]; c != nil {
c.Put(buf[:0])
}
}
// getBuf gets a chunk from reuse pool or creates a new one if reuse failed.
func getBuf(size int) []byte {
if size < config.PooledSize {
return make([]byte, 0, size)
}
if c := buffers[size]; c != nil {
v := c.Get()
if v != nil {
return v.([]byte)
}
}
return make([]byte, 0, size)
}
// Buffer is a buffer optimized for serialization without extra copying.
type Buffer struct {
// Buf is the current chunk that can be used for serialization.
Buf []byte
toPool []byte
bufs [][]byte
}
// EnsureSpace makes sure that the current chunk contains at least s free bytes,
// possibly creating a new chunk.
func (b *Buffer) EnsureSpace(s int) {
if cap(b.Buf)-len(b.Buf) >= s {
return
}
l := len(b.Buf)
if l > 0 {
if cap(b.toPool) != cap(b.Buf) {
// Chunk was reallocated, toPool can be pooled.
putBuf(b.toPool)
}
if cap(b.bufs) == 0 {
b.bufs = make([][]byte, 0, 8)
}
b.bufs = append(b.bufs, b.Buf)
l = cap(b.toPool) * 2
} else {
l = config.StartSize
}
if l > config.MaxSize {
l = config.MaxSize
}
b.Buf = getBuf(l)
b.toPool = b.Buf
}
// AppendByte appends a single byte to buffer.
func (b *Buffer) AppendByte(data byte) {
if cap(b.Buf) == len(b.Buf) { // EnsureSpace won't be inlined.
b.EnsureSpace(1)
}
b.Buf = append(b.Buf, data)
}
// AppendBytes appends a byte slice to buffer.
func (b *Buffer) AppendBytes(data []byte) {
for len(data) > 0 {
if cap(b.Buf) == len(b.Buf) { // EnsureSpace won't be inlined.
b.EnsureSpace(1)
}
sz := cap(b.Buf) - len(b.Buf)
if sz > len(data) {
sz = len(data)
}
b.Buf = append(b.Buf, data[:sz]...)
data = data[sz:]
}
}
// AppendBytes appends a string to buffer.
func (b *Buffer) AppendString(data string) {
for len(data) > 0 {
if cap(b.Buf) == len(b.Buf) { // EnsureSpace won't be inlined.
b.EnsureSpace(1)
}
sz := cap(b.Buf) - len(b.Buf)
if sz > len(data) {
sz = len(data)
}
b.Buf = append(b.Buf, data[:sz]...)
data = data[sz:]
}
}
// Size computes the size of a buffer by adding sizes of every chunk.
func (b *Buffer) Size() int {
size := len(b.Buf)
for _, buf := range b.bufs {
size += len(buf)
}
return size
}
// DumpTo outputs the contents of a buffer to a writer and resets the buffer.
func (b *Buffer) DumpTo(w io.Writer) (written int, err error) {
var n int
for _, buf := range b.bufs {
if err == nil {
n, err = w.Write(buf)
written += n
}
putBuf(buf)
}
if err == nil {
n, err = w.Write(b.Buf)
written += n
}
putBuf(b.toPool)
b.bufs = nil
b.Buf = nil
b.toPool = nil
return
}
// BuildBytes creates a single byte slice with all the contents of the buffer. Data is
// copied if it does not fit in a single chunk.
func (b *Buffer) BuildBytes() []byte {
if len(b.bufs) == 0 {
ret := b.Buf
b.toPool = nil
b.Buf = nil
return ret
}
ret := make([]byte, 0, b.Size())
for _, buf := range b.bufs {
ret = append(ret, buf...)
putBuf(buf)
}
ret = append(ret, b.Buf...)
putBuf(b.toPool)
b.bufs = nil
b.toPool = nil
b.Buf = nil
return ret
}
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