syncthing/xdr/writer.go

140 lines
2.2 KiB
Go

// Copyright (C) 2014 Jakob Borg and Contributors (see the CONTRIBUTORS file).
// All rights reserved. Use of this source code is governed by an MIT-style
// license that can be found in the LICENSE file.
package xdr
import "io"
func pad(l int) int {
d := l % 4
if d == 0 {
return 0
}
return 4 - d
}
var padBytes = []byte{0, 0, 0}
type Writer struct {
w io.Writer
tot int
err error
b [8]byte
}
type AppendWriter []byte
func (w *AppendWriter) Write(bs []byte) (int, error) {
*w = append(*w, bs...)
return len(bs), nil
}
func NewWriter(w io.Writer) *Writer {
return &Writer{
w: w,
}
}
func (w *Writer) WriteString(s string) (int, error) {
return w.WriteBytes([]byte(s))
}
func (w *Writer) WriteBytes(bs []byte) (int, error) {
if w.err != nil {
return 0, w.err
}
w.WriteUint32(uint32(len(bs)))
if w.err != nil {
return 0, w.err
}
if debug {
if len(bs) > maxDebugBytes {
dl.Debugf("wr bytes (%d): %x...", len(bs), bs[:maxDebugBytes])
} else {
dl.Debugf("wr bytes (%d): %x", len(bs), bs)
}
}
var l, n int
n, w.err = w.w.Write(bs)
l += n
if p := pad(len(bs)); w.err == nil && p > 0 {
n, w.err = w.w.Write(padBytes[:p])
l += n
}
w.tot += l
return l, w.err
}
func (w *Writer) WriteBool(v bool) (int, error) {
if v {
return w.WriteUint32(1)
} else {
return w.WriteUint32(0)
}
}
func (w *Writer) WriteUint16(v uint16) (int, error) {
return w.WriteUint32(uint32(v))
}
func (w *Writer) WriteUint32(v uint32) (int, error) {
if w.err != nil {
return 0, w.err
}
if debug {
dl.Debugf("wr uint32=%d", v)
}
w.b[0] = byte(v >> 24)
w.b[1] = byte(v >> 16)
w.b[2] = byte(v >> 8)
w.b[3] = byte(v)
var l int
l, w.err = w.w.Write(w.b[:4])
w.tot += l
return l, w.err
}
func (w *Writer) WriteUint64(v uint64) (int, error) {
if w.err != nil {
return 0, w.err
}
if debug {
dl.Debugf("wr uint64=%d", v)
}
w.b[0] = byte(v >> 56)
w.b[1] = byte(v >> 48)
w.b[2] = byte(v >> 40)
w.b[3] = byte(v >> 32)
w.b[4] = byte(v >> 24)
w.b[5] = byte(v >> 16)
w.b[6] = byte(v >> 8)
w.b[7] = byte(v)
var l int
l, w.err = w.w.Write(w.b[:8])
w.tot += l
return l, w.err
}
func (w *Writer) Tot() int {
return w.tot
}
func (w *Writer) Error() error {
if w.err == nil {
return nil
}
return XDRError{"write", w.err}
}