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chunk.go
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chunk.go
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package crypto
import (
"io"
"v2ray.com/core/common"
"v2ray.com/core/common/buf"
"v2ray.com/core/common/serial"
)
// ChunkSizeDecoder is an utility class to decode size value from bytes.
type ChunkSizeDecoder interface {
SizeBytes() int
Decode([]byte) (uint16, error)
}
// ChunkSizeEncoder is an utility class to encode size value into bytes.
type ChunkSizeEncoder interface {
SizeBytes() int
Encode(uint16, []byte) []byte
}
type PlainChunkSizeParser struct{}
func (PlainChunkSizeParser) SizeBytes() int {
return 2
}
func (PlainChunkSizeParser) Encode(size uint16, b []byte) []byte {
return serial.Uint16ToBytes(size, b)
}
func (PlainChunkSizeParser) Decode(b []byte) (uint16, error) {
return serial.BytesToUint16(b), nil
}
type AEADChunkSizeParser struct {
Auth *AEADAuthenticator
}
func (p *AEADChunkSizeParser) SizeBytes() int {
return 2 + p.Auth.Overhead()
}
func (p *AEADChunkSizeParser) Encode(size uint16, b []byte) []byte {
b = serial.Uint16ToBytes(size-uint16(p.Auth.Overhead()), b)
b, err := p.Auth.Seal(b[:0], b)
common.Must(err)
return b
}
func (p *AEADChunkSizeParser) Decode(b []byte) (uint16, error) {
b, err := p.Auth.Open(b[:0], b)
if err != nil {
return 0, err
}
return serial.BytesToUint16(b) + uint16(p.Auth.Overhead()), nil
}
type ChunkStreamReader struct {
sizeDecoder ChunkSizeDecoder
reader *buf.BufferedReader
buffer []byte
leftOverSize int
}
func NewChunkStreamReader(sizeDecoder ChunkSizeDecoder, reader io.Reader) *ChunkStreamReader {
return &ChunkStreamReader{
sizeDecoder: sizeDecoder,
reader: buf.NewBufferedReader(buf.NewReader(reader)),
buffer: make([]byte, sizeDecoder.SizeBytes()),
}
}
func (r *ChunkStreamReader) readSize() (uint16, error) {
if _, err := io.ReadFull(r.reader, r.buffer); err != nil {
return 0, err
}
return r.sizeDecoder.Decode(r.buffer)
}
func (r *ChunkStreamReader) ReadMultiBuffer() (buf.MultiBuffer, error) {
size := r.leftOverSize
if size == 0 {
nextSize, err := r.readSize()
if err != nil {
return nil, err
}
if nextSize == 0 {
return nil, io.EOF
}
size = int(nextSize)
}
r.leftOverSize = size
mb, err := r.reader.ReadAtMost(size)
if !mb.IsEmpty() {
r.leftOverSize -= mb.Len()
return mb, nil
}
return nil, err
}
type ChunkStreamWriter struct {
sizeEncoder ChunkSizeEncoder
writer buf.Writer
}
func NewChunkStreamWriter(sizeEncoder ChunkSizeEncoder, writer io.Writer) *ChunkStreamWriter {
return &ChunkStreamWriter{
sizeEncoder: sizeEncoder,
writer: buf.NewWriter(writer),
}
}
func (w *ChunkStreamWriter) WriteMultiBuffer(mb buf.MultiBuffer) error {
const sliceSize = 8192
mbLen := mb.Len()
mb2Write := buf.NewMultiBufferCap(mbLen/buf.Size + mbLen/sliceSize + 2)
for {
slice := mb.SliceBySize(sliceSize)
b := buf.New()
common.Must(b.Reset(func(buffer []byte) (int, error) {
w.sizeEncoder.Encode(uint16(slice.Len()), buffer[:0])
return w.sizeEncoder.SizeBytes(), nil
}))
mb2Write.Append(b)
mb2Write.AppendMulti(slice)
if mb.IsEmpty() {
break
}
}
return w.writer.WriteMultiBuffer(mb2Write)
}