// Copyright 2012 The Go Authors.  All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.

package icmp

// A MessageBody represents an ICMP message body.
type MessageBody interface {
	// Len returns the length of ICMP message body.
	// Proto must be either the ICMPv4 or ICMPv6 protocol number.
	Len(proto int) int

	// Marshal returns the binary encoding of ICMP message body.
	// Proto must be either the ICMPv4 or ICMPv6 protocol number.
	Marshal(proto int) ([]byte, error)
}

// A DefaultMessageBody represents the default message body.
type DefaultMessageBody struct {
	Data []byte // data
}

// Len implements the Len method of MessageBody interface.
func (p *DefaultMessageBody) Len(proto int) int {
	if p == nil {
		return 0
	}
	return len(p.Data)
}

// Marshal implements the Marshal method of MessageBody interface.
func (p *DefaultMessageBody) Marshal(proto int) ([]byte, error) {
	return p.Data, nil
}

// parseDefaultMessageBody parses b as an ICMP message body.
func parseDefaultMessageBody(proto int, b []byte) (MessageBody, error) {
	p := &DefaultMessageBody{Data: make([]byte, len(b))}
	copy(p.Data, b)
	return p, nil
}