byte_order.go

// Copyright 2016 Platina Systems, Inc. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.

package vnet

import (
	"net"
)

// Network byte order helpers.
type Uint8 uint8 // dummy used to satisfy MaskedStringer interface
type Uint16 uint16
type Uint32 uint32
type Uint64 uint64

func (x Uint16) ToHost() uint16   { return swap16(uint16(x)) }
func (x Uint16) FromHost() Uint16 { return Uint16(swap16(uint16(x))) }
func (x *Uint16) Set(v uint)      { *x = Uint16(swap16(uint16(v))) }

func (x Uint32) ToHost() uint32   { return swap32(uint32(x)) }
func (x Uint32) FromHost() Uint32 { return Uint32(swap32(uint32(x))) }
func (x *Uint32) Set(v uint)      { *x = Uint32(swap32(uint32(v))) }

func (x Uint64) ToHost() uint64   { return swap64(uint64(x)) }
func (x Uint64) FromHost() Uint64 { return Uint64(swap64(uint64(x))) }
func (x *Uint64) Set(v uint)      { *x = Uint64(swap64(uint64(v))) }

func HostIsNetworkByteOrder() bool { return Uint16(0x1234).FromHost() == 0x1234 }

func ByteAdd(a []byte, x uint64) {
	i := len(a) - 1
	for x != 0 && i >= 0 {
		ai := uint64(a[i])
		y := ai + (x & 0xff)
		a[i] = byte(y)
		x >>= 8
		// Carry.
		if y < ai {
			x += 1
		}
		i--
	}
}

func IPAdd(ip *net.IP, x uint64) {
	var a []byte
	addr := *ip
	a = append(addr[:0:0], addr[:]...)
	ByteAdd(a, x)
	addr = append(a[:0:0], a[:]...)
	ip = &addr
	return
}