vendor.github.com.pion.sctp.paramheader.go Maven / Gradle / Ivy
package sctp
import (
"encoding/binary"
"encoding/hex"
"errors"
"fmt"
)
type paramHeader struct {
typ paramType
len int
raw []byte
}
const (
paramHeaderLength = 4
)
var (
errParamHeaderTooShort = errors.New("param header too short")
errParamHeaderSelfReportedLengthShorter = errors.New("param self reported length is shorter than header length")
errParamHeaderSelfReportedLengthLonger = errors.New("param self reported length is longer than header length")
errParamHeaderParseFailed = errors.New("failed to parse param type")
)
func (p *paramHeader) marshal() ([]byte, error) {
paramLengthPlusHeader := paramHeaderLength + len(p.raw)
rawParam := make([]byte, paramLengthPlusHeader)
binary.BigEndian.PutUint16(rawParam[0:], uint16(p.typ))
binary.BigEndian.PutUint16(rawParam[2:], uint16(paramLengthPlusHeader))
copy(rawParam[paramHeaderLength:], p.raw)
return rawParam, nil
}
func (p *paramHeader) unmarshal(raw []byte) error {
if len(raw) < paramHeaderLength {
return errParamHeaderTooShort
}
paramLengthPlusHeader := binary.BigEndian.Uint16(raw[2:])
if int(paramLengthPlusHeader) < paramHeaderLength {
return fmt.Errorf("%w: param self reported length (%d) shorter than header length (%d)", errParamHeaderSelfReportedLengthShorter, int(paramLengthPlusHeader), paramHeaderLength)
}
if len(raw) < int(paramLengthPlusHeader) {
return fmt.Errorf("%w: param length (%d) shorter than its self reported length (%d)", errParamHeaderSelfReportedLengthLonger, len(raw), int(paramLengthPlusHeader))
}
typ, err := parseParamType(raw[0:])
if err != nil {
return fmt.Errorf("%w: %v", errParamHeaderParseFailed, err)
}
p.typ = typ
p.raw = raw[paramHeaderLength:paramLengthPlusHeader]
p.len = int(paramLengthPlusHeader)
return nil
}
func (p *paramHeader) length() int {
return p.len
}
// String makes paramHeader printable
func (p paramHeader) String() string {
return fmt.Sprintf("%s (%d): %s", p.typ, p.len, hex.Dump(p.raw))
}