// Copyright 2020 The Monogon Project Authors.
//
// SPDX-License-Identifier: Apache-2.0
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//     http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

package efivarfs

import (
	"github.com/google/uuid"
)

// MarshalEFIGUID returns src represented in the EFI GUID format, as defined in
// UEFI specification, version 2.9, appendix A:
// https://uefi.org/sites/default/files/resources/UEFI_Spec_2_9_2021_03_18.pdf
func MarshalEFIGUID(src uuid.UUID) []byte {
	efi := make([]byte, 16)
	transform := []int{3, 2, 1, 0, 5, 4, 7, 6, 8, 9, 10, 11, 12, 13, 14, 15}
	for dest, from := range transform {
		efi[dest] = src[from]
	}
	return efi
}