well-goknown/vendor/github.com/gobwas/ws/wsutil/cipher.go

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package wsutil
import (
"io"
"github.com/gobwas/pool/pbytes"
"github.com/gobwas/ws"
)
// CipherReader implements io.Reader that applies xor-cipher to the bytes read
// from source.
// It could help to unmask WebSocket frame payload on the fly.
type CipherReader struct {
r io.Reader
mask [4]byte
pos int
}
// NewCipherReader creates xor-cipher reader from r with given mask.
func NewCipherReader(r io.Reader, mask [4]byte) *CipherReader {
return &CipherReader{r, mask, 0}
}
// Reset resets CipherReader to read from r with given mask.
func (c *CipherReader) Reset(r io.Reader, mask [4]byte) {
c.r = r
c.mask = mask
c.pos = 0
}
// Read implements io.Reader interface. It applies mask given during
// initialization to every read byte.
func (c *CipherReader) Read(p []byte) (n int, err error) {
n, err = c.r.Read(p)
ws.Cipher(p[:n], c.mask, c.pos)
c.pos += n
return n, err
}
// CipherWriter implements io.Writer that applies xor-cipher to the bytes
// written to the destination writer. It does not modify the original bytes.
type CipherWriter struct {
w io.Writer
mask [4]byte
pos int
}
// NewCipherWriter creates xor-cipher writer to w with given mask.
func NewCipherWriter(w io.Writer, mask [4]byte) *CipherWriter {
return &CipherWriter{w, mask, 0}
}
// Reset reset CipherWriter to write to w with given mask.
func (c *CipherWriter) Reset(w io.Writer, mask [4]byte) {
c.w = w
c.mask = mask
c.pos = 0
}
// Write implements io.Writer interface. It applies masking during
// initialization to every sent byte. It does not modify original slice.
func (c *CipherWriter) Write(p []byte) (n int, err error) {
cp := pbytes.GetLen(len(p))
defer pbytes.Put(cp)
copy(cp, p)
ws.Cipher(cp, c.mask, c.pos)
n, err = c.w.Write(cp)
c.pos += n
return n, err
}