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reader.go
173 lines (149 loc) · 3.38 KB
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reader.go
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package buf
import (
"io"
"v2ray.com/core/common/errors"
)
// BytesToBufferReader is a Reader that adjusts its reading speed automatically.
type BytesToBufferReader struct {
io.Reader
buffer []byte
}
func NewBytesToBufferReader(reader io.Reader) Reader {
return &BytesToBufferReader{
Reader: reader,
}
}
const mediumSize = 8 * 1024
const largeSize = 64 * 1024
func (r *BytesToBufferReader) readSmall() (MultiBuffer, error) {
b := New()
err := b.Reset(ReadFrom(r.Reader))
if b.IsFull() {
r.buffer = make([]byte, mediumSize)
}
if !b.IsEmpty() {
return NewMultiBufferValue(b), nil
}
b.Release()
return nil, err
}
// ReadMultiBuffer implements Reader.
func (r *BytesToBufferReader) ReadMultiBuffer() (MultiBuffer, error) {
if r.buffer == nil {
return r.readSmall()
}
nBytes, err := r.Reader.Read(r.buffer)
if nBytes > 0 {
mb := NewMultiBufferCap(nBytes/Size + 1)
mb.Write(r.buffer[:nBytes])
if nBytes == len(r.buffer) && len(r.buffer) == mediumSize {
r.buffer = make([]byte, largeSize)
}
return mb, nil
}
return nil, err
}
var (
_ Reader = (*BufferedReader)(nil)
_ io.Reader = (*BufferedReader)(nil)
_ io.ByteReader = (*BufferedReader)(nil)
_ io.WriterTo = (*BufferedReader)(nil)
)
type BufferedReader struct {
stream Reader
leftOver MultiBuffer
buffered bool
}
func NewBufferedReader(reader Reader) *BufferedReader {
return &BufferedReader{
stream: reader,
buffered: true,
}
}
func (r *BufferedReader) SetBuffered(f bool) {
r.buffered = f
}
func (r *BufferedReader) IsBuffered() bool {
return r.buffered
}
func (r *BufferedReader) ReadByte() (byte, error) {
var b [1]byte
_, err := r.Read(b[:])
return b[0], err
}
func (r *BufferedReader) Read(b []byte) (int, error) {
if r.leftOver != nil {
nBytes, _ := r.leftOver.Read(b)
if r.leftOver.IsEmpty() {
r.leftOver.Release()
r.leftOver = nil
}
return nBytes, nil
}
if !r.buffered {
if reader, ok := r.stream.(io.Reader); ok {
return reader.Read(b)
}
}
mb, err := r.stream.ReadMultiBuffer()
if mb != nil {
nBytes, _ := mb.Read(b)
if !mb.IsEmpty() {
r.leftOver = mb
}
return nBytes, err
}
return 0, err
}
func (r *BufferedReader) ReadMultiBuffer() (MultiBuffer, error) {
if r.leftOver != nil {
mb := r.leftOver
r.leftOver = nil
return mb, nil
}
return r.stream.ReadMultiBuffer()
}
// ReadAtMost returns a MultiBuffer with at most size.
func (r *BufferedReader) ReadAtMost(size int) (MultiBuffer, error) {
if r.leftOver == nil {
mb, err := r.stream.ReadMultiBuffer()
if mb.IsEmpty() && err != nil {
return nil, err
}
r.leftOver = mb
}
mb := r.leftOver.SliceBySize(size)
if r.leftOver.IsEmpty() {
r.leftOver = nil
}
return mb, nil
}
func (r *BufferedReader) writeToInternal(writer io.Writer) (int64, error) {
mbWriter := NewWriter(writer)
totalBytes := int64(0)
if r.leftOver != nil {
totalBytes += int64(r.leftOver.Len())
if err := mbWriter.WriteMultiBuffer(r.leftOver); err != nil {
return 0, err
}
}
for {
mb, err := r.stream.ReadMultiBuffer()
if mb != nil {
totalBytes += int64(mb.Len())
if werr := mbWriter.WriteMultiBuffer(mb); werr != nil {
return totalBytes, err
}
}
if err != nil {
return totalBytes, err
}
}
}
func (r *BufferedReader) WriteTo(writer io.Writer) (int64, error) {
nBytes, err := r.writeToInternal(writer)
if errors.Cause(err) == io.EOF {
return nBytes, nil
}
return nBytes, err
}