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package dhcpv4
import (
"fmt"
"strings"
)
// This option implements the parameter request list option
// https://tools.ietf.org/html/rfc2132
// OptParameterRequestList represents the parameter request list option.
type OptParameterRequestList struct {
RequestedOpts []OptionCode
}
// ParseOptParameterRequestList returns a new OptParameterRequestList from a
// byte stream, or error if any.
func ParseOptParameterRequestList(data []byte) (*OptParameterRequestList, error) {
// Should at least have code + length byte.
if len(data) < 2 {
return nil, ErrShortByteStream
}
code := OptionCode(data[0])
if code != OptionParameterRequestList {
return nil, fmt.Errorf("expected code %v, got %v", OptionParameterRequestList, code)
}
length := int(data[1])
if len(data) < length+2 {
return nil, ErrShortByteStream
}
var requestedOpts []OptionCode
for _, opt := range data[2 : length+2] {
requestedOpts = append(requestedOpts, OptionCode(opt))
}
return &OptParameterRequestList{RequestedOpts: requestedOpts}, nil
}
// Code returns the option code.
func (o *OptParameterRequestList) Code() OptionCode {
return OptionParameterRequestList
}
// ToBytes returns a serialized stream of bytes for this option.
func (o *OptParameterRequestList) ToBytes() []byte {
ret := []byte{byte(o.Code()), byte(o.Length())}
for _, req := range o.RequestedOpts {
ret = append(ret, byte(req))
}
return ret
}
// String returns a human-readable string for this option.
func (o *OptParameterRequestList) String() string {
var optNames []string
for _, ro := range o.RequestedOpts {
if name, ok := OptionCodeToString[ro]; ok {
optNames = append(optNames, name)
} else {
optNames = append(optNames, fmt.Sprintf("Unknown (%v)", ro))
}
}
return fmt.Sprintf("Parameter Request List -> [%v]", strings.Join(optNames, ", "))
}
// Length returns the length of the data portion (excluding option code and byte
// for length, if any).
func (o *OptParameterRequestList) Length() int {
return len(o.RequestedOpts)
}
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