syncthing/vendor/github.com/calmh/xdr/marshaller.go

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2016-02-02 11:43:33 +00:00
// Copyright (C) 2014 Jakob Borg. 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"
// The Marshaller is a thin wrapper around a byte buffer. The buffer must be
// of sufficient size to hold the complete marshalled object, or an
// io.ErrShortBuffer error will result. The Marshal... methods don't
// individually return an error - the intention is that multiple fields are
// marshalled in rapid succession, followed by a check of the Error field on
// the Marshaller.
type Marshaller struct {
Data []byte
Error error
offset int
}
// MarshalRaw copies the raw bytes to the buffer, without a size prefix or
// padding. This is suitable for appending data already in XDR format from
// another source.
func (m *Marshaller) MarshalRaw(bs []byte) {
if m.Error != nil {
return
}
if len(m.Data) < m.offset+len(bs) {
m.Error = io.ErrShortBuffer
return
}
m.offset += copy(m.Data[m.offset:], bs)
}
// MarshalString appends the string to the buffer, with a size prefix and
// correct padding.
func (m *Marshaller) MarshalString(s string) {
if m.Error != nil {
return
}
if len(m.Data) < m.offset+4+len(s)+Padding(len(s)) {
m.Error = io.ErrShortBuffer
return
}
m.MarshalUint32(uint32(len(s)))
m.offset += copy(m.Data[m.offset:], s)
m.offset += copy(m.Data[m.offset:], padBytes[:Padding(len(s))])
}
// MarshalString appends the bytes to the buffer, with a size prefix and
// correct padding.
func (m *Marshaller) MarshalBytes(bs []byte) {
if m.Error != nil {
return
}
if len(m.Data) < m.offset+4+len(bs)+Padding(len(bs)) {
m.Error = io.ErrShortBuffer
return
}
m.MarshalUint32(uint32(len(bs)))
m.offset += copy(m.Data[m.offset:], bs)
m.offset += copy(m.Data[m.offset:], padBytes[:Padding(len(bs))])
}
// MarshalString appends the bool to the buffer, as an uint32.
func (m *Marshaller) MarshalBool(v bool) {
if v {
m.MarshalUint8(1)
} else {
m.MarshalUint8(0)
}
}
// MarshalString appends the uint8 to the buffer, as an uint32.
func (m *Marshaller) MarshalUint8(v uint8) {
m.MarshalUint32(uint32(v))
}
// MarshalString appends the uint16 to the buffer, as an uint32.
func (m *Marshaller) MarshalUint16(v uint16) {
m.MarshalUint32(uint32(v))
}
// MarshalString appends the uint32 to the buffer.
func (m *Marshaller) MarshalUint32(v uint32) {
if m.Error != nil {
return
}
if len(m.Data) < m.offset+4 {
m.Error = io.ErrShortBuffer
return
}
m.Data[m.offset+0] = byte(v >> 24)
m.Data[m.offset+1] = byte(v >> 16)
m.Data[m.offset+2] = byte(v >> 8)
m.Data[m.offset+3] = byte(v)
m.offset += 4
}
// MarshalString appends the uint64 to the buffer.
func (m *Marshaller) MarshalUint64(v uint64) {
if m.Error != nil {
return
}
if len(m.Data) < m.offset+8 {
m.Error = io.ErrShortBuffer
return
}
m.Data[m.offset+0] = byte(v >> 56)
m.Data[m.offset+1] = byte(v >> 48)
m.Data[m.offset+2] = byte(v >> 40)
m.Data[m.offset+3] = byte(v >> 32)
m.Data[m.offset+4] = byte(v >> 24)
m.Data[m.offset+5] = byte(v >> 16)
m.Data[m.offset+6] = byte(v >> 8)
m.Data[m.offset+7] = byte(v)
m.offset += 8
}