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// Copyright (C) 2022 Luke Shumaker <lukeshu@lukeshu.com>
//
// SPDX-License-Identifier: GPL-2.0-or-later
package btrfsitem
import (
"fmt"
"git.lukeshu.com/btrfs-progs-ng/lib/binstruct"
"git.lukeshu.com/btrfs-progs-ng/lib/btrfs/internal"
"git.lukeshu.com/btrfs-progs-ng/lib/fmtutil"
)
type Extent struct { // EXTENT_ITEM=168
Head ExtentHeader
Info TreeBlockInfo // only if .Head.Flags.Has(EXTENT_FLAG_TREE_BLOCK)
Refs []ExtentInlineRef
}
func (o *Extent) UnmarshalBinary(dat []byte) (int, error) {
n, err := binstruct.Unmarshal(dat, &o.Head)
if err != nil {
return n, err
}
if o.Head.Flags.Has(EXTENT_FLAG_TREE_BLOCK) {
_n, err := binstruct.Unmarshal(dat[n:], &o.Info)
n += _n
if err != nil {
return n, err
}
}
o.Refs = nil
for n < len(dat) {
var ref ExtentInlineRef
_n, err := binstruct.Unmarshal(dat[n:], &ref)
n += _n
o.Refs = append(o.Refs, ref)
if err != nil {
return n, err
}
}
return n, nil
}
func (o Extent) MarshalBinary() ([]byte, error) {
dat, err := binstruct.Marshal(o.Head)
if err != nil {
return dat, err
}
if o.Head.Flags.Has(EXTENT_FLAG_TREE_BLOCK) {
bs, err := binstruct.Marshal(o.Info)
dat = append(dat, bs...)
if err != nil {
return dat, err
}
}
for _, ref := range o.Refs {
bs, err := binstruct.Marshal(ref)
dat = append(dat, bs...)
if err != nil {
return dat, err
}
}
return dat, nil
}
type ExtentHeader struct {
Refs int64 `bin:"off=0, siz=8"`
Generation internal.Generation `bin:"off=8, siz=8"`
Flags ExtentFlags `bin:"off=16, siz=8"`
binstruct.End `bin:"off=24"`
}
type TreeBlockInfo struct {
Key internal.Key `bin:"off=0, siz=0x11"`
Level uint8 `bin:"off=0x11, siz=0x1"`
binstruct.End `bin:"off=0x12"`
}
type ExtentFlags uint64
const (
EXTENT_FLAG_DATA = ExtentFlags(1 << iota)
EXTENT_FLAG_TREE_BLOCK
)
var extentFlagNames = []string{
"DATA",
"TREE_BLOCK",
}
func (f ExtentFlags) Has(req ExtentFlags) bool { return f&req == req }
func (f ExtentFlags) String() string {
return fmtutil.BitfieldString(f, extentFlagNames, fmtutil.HexNone)
}
type ExtentInlineRef struct {
Type Type // only 4 valid values: {TREE,SHARED}_BLOCK_REF_KEY, {EXTENT,SHARED}_DATA_REF_KEY
Offset uint64 // only when Type != EXTENT_DATA_REF_KEY
Body Item // only when Type == *_DATA_REF_KEY
}
func (o *ExtentInlineRef) UnmarshalBinary(dat []byte) (int, error) {
o.Type = Type(dat[0])
n := 1
switch o.Type {
case TREE_BLOCK_REF_KEY, SHARED_BLOCK_REF_KEY:
_n, err := binstruct.Unmarshal(dat[n:], &o.Offset)
n += _n
if err != nil {
return n, err
}
case EXTENT_DATA_REF_KEY:
var dref ExtentDataRef
_n, err := binstruct.Unmarshal(dat[n:], &dref)
n += _n
o.Body = dref
if err != nil {
return n, err
}
case SHARED_DATA_REF_KEY:
_n, err := binstruct.Unmarshal(dat[n:], &o.Offset)
n += _n
if err != nil {
return n, err
}
var sref SharedDataRef
_n, err = binstruct.Unmarshal(dat[n:], &sref)
n += _n
o.Body = sref
if err != nil {
return n, err
}
default:
return n, fmt.Errorf("unexpected item type %v", o.Type)
}
return n, nil
}
func (o ExtentInlineRef) MarshalBinary() ([]byte, error) {
dat := []byte{byte(o.Type)}
switch o.Type {
case TREE_BLOCK_REF_KEY, SHARED_BLOCK_REF_KEY:
_dat, err := binstruct.Marshal(o.Offset)
dat = append(dat, _dat...)
if err != nil {
return dat, err
}
case EXTENT_DATA_REF_KEY:
_dat, err := binstruct.Marshal(o.Body)
dat = append(dat, _dat...)
if err != nil {
return dat, err
}
case SHARED_DATA_REF_KEY:
_dat, err := binstruct.Marshal(o.Offset)
dat = append(dat, _dat...)
if err != nil {
return dat, err
}
_dat, err = binstruct.Marshal(o.Body)
dat = append(dat, _dat...)
if err != nil {
return dat, err
}
default:
return dat, fmt.Errorf("unexpected item type %v", o.Type)
}
return dat, nil
}
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