Vendor main dependencies.

vendor/github.com/mailru/easyjson/buffer/pool.go

@@ -0,0 +1,207 @@
+// 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
+}