buffered reader and writer

common/io/buffered_writer.go

@@ -0,0 +1,63 @@
+package io
+
+import (
+	"io"
+
+	"github.com/v2ray/v2ray-core/common/alloc"
+)
+
+type BufferedWriter struct {
+	writer io.Writer
+	buffer *alloc.Buffer
+	cached bool
+}
+
+func NewBufferedWriter(rawWriter io.Writer) *BufferedWriter {
+	return &BufferedWriter{
+		writer: rawWriter,
+		buffer: alloc.NewBuffer().Clear(),
+		cached: true,
+	}
+}
+
+func (this *BufferedWriter) Write(b []byte) (int, error) {
+	if !this.cached {
+		return this.writer.Write(b)
+	}
+	nBytes, _ := this.buffer.Write(b)
+	if this.buffer.IsFull() {
+		err := this.flush()
+		if err != nil {
+			return nBytes, err
+		}
+	}
+	return nBytes, nil
+}
+
+func (this *BufferedWriter) flush() error {
+	nBytes, err := this.writer.Write(this.buffer.Value)
+	this.buffer.SliceFrom(nBytes)
+	if !this.buffer.IsEmpty() {
+		nBytes, err = this.writer.Write(this.buffer.Value)
+		this.buffer.SliceFrom(nBytes)
+	}
+	if this.buffer.IsEmpty() {
+		this.buffer.Clear()
+	}
+	return err
+}
+
+func (this *BufferedWriter) Cached() bool {
+	return this.cached
+}
+
+func (this *BufferedWriter) SetCached(cached bool) {
+	this.cached = cached
+	if !cached && !this.buffer.IsEmpty() {
+		this.flush()
+	}
+}
+
+func (this *BufferedWriter) Release() {
+	this.buffer.Release()
+}