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// Copyright (C) 2022 Luke Shumaker <lukeshu@lukeshu.com>
//
// SPDX-License-Identifier: GPL-2.0-or-later
package btrfsitem
import (
"encoding/hex"
"fmt"
"io"
"git.lukeshu.com/go/lowmemjson"
"git.lukeshu.com/btrfs-progs-ng/lib/btrfs/btrfssum"
)
const CSumBlockSize = 4 * 1024
// key.objectid = BTRFS_EXTENT_CSUM_OBJECTID
// key.offset = laddr of checksummed region
type ExtentCSum struct { // EXTENT_CSUM=128
ChecksumSize int
// Checksum of each sector starting at key.offset
Sums []btrfssum.CSum
}
func (o *ExtentCSum) UnmarshalBinary(dat []byte) (int, error) {
if o.ChecksumSize == 0 {
return 0, fmt.Errorf(".ChecksumSize must be set")
}
for len(dat) >= o.ChecksumSize {
var csum btrfssum.CSum
copy(csum[:], dat[:o.ChecksumSize])
dat = dat[o.ChecksumSize:]
o.Sums = append(o.Sums, csum)
}
return len(o.Sums) * o.ChecksumSize, nil
}
func (o ExtentCSum) MarshalBinary() ([]byte, error) {
if o.ChecksumSize == 0 {
return nil, fmt.Errorf(".ChecksumSize must be set")
}
var dat []byte
for _, csum := range o.Sums {
dat = append(dat, csum[:o.ChecksumSize]...)
}
return dat, nil
}
var (
_ lowmemjson.Encodable = ExtentCSum{}
)
func (o ExtentCSum) EncodeJSON(w io.Writer) error {
if _, err := fmt.Fprintf(w, `{"ChecksumSize":%d,"Sums":[`, o.ChecksumSize); err != nil {
return err
}
for i, sum := range o.Sums {
if i > 0 {
if _, err := w.Write([]byte(",")); err != nil {
return err
}
}
if _, err := w.Write([]byte(`"`)); err != nil {
return err
}
if _, err := hex.NewEncoder(w).Write(sum[:o.ChecksumSize]); err != nil {
return err
}
if _, err := w.Write([]byte(`"`)); err != nil {
return err
}
}
if _, err := w.Write([]byte(`]}`)); err != nil {
return err
}
return nil
}
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