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// Copyright (C) 2022-2023 Luke Shumaker <lukeshu@lukeshu.com>
//
// SPDX-License-Identifier: GPL-2.0-or-later
package btrfssum
import (
"encoding"
"encoding/binary"
"encoding/hex"
"fmt"
"hash/crc32"
"git.lukeshu.com/btrfs-progs-ng/lib/fmtutil"
)
type CSum [0x20]byte
var (
_ fmt.Stringer = CSum{}
_ fmt.Formatter = CSum{}
_ encoding.TextMarshaler = CSum{}
_ encoding.TextUnmarshaler = (*CSum)(nil)
)
func (csum CSum) String() string {
return hex.EncodeToString(csum[:])
}
func (csum CSum) MarshalText() ([]byte, error) {
var ret [len(csum) * 2]byte
hex.Encode(ret[:], csum[:])
return ret[:], nil
}
func (csum *CSum) UnmarshalText(text []byte) error {
*csum = CSum{}
_, err := hex.Decode(csum[:], text)
return err
}
func (csum CSum) Fmt(typ CSumType) string {
return hex.EncodeToString(csum[:typ.Size()])
}
func (csum CSum) Format(f fmt.State, verb rune) {
fmtutil.FormatByteArrayStringer(csum, csum[:], f, verb)
}
type CSumType uint16
const (
TYPE_CRC32 = CSumType(iota)
TYPE_XXHASH
TYPE_SHA256
TYPE_BLAKE2
)
func (typ CSumType) String() string {
names := map[CSumType]string{
TYPE_CRC32: "crc32c",
TYPE_XXHASH: "xxhash64",
TYPE_SHA256: "sha256",
TYPE_BLAKE2: "blake2",
}
if name, ok := names[typ]; ok {
return name
}
return fmt.Sprintf("%d", typ)
}
func (typ CSumType) Size() int {
//nolint:gomnd // This is where we define the magic numbers.
sizes := map[CSumType]int{
TYPE_CRC32: 4,
TYPE_XXHASH: 8,
TYPE_SHA256: 32,
TYPE_BLAKE2: 32,
}
if size, ok := sizes[typ]; ok {
return size
}
return len(CSum{})
}
func (typ CSumType) Sum(data []byte) (CSum, error) {
switch typ {
case TYPE_CRC32:
crc := crc32.Update(0, crc32.MakeTable(crc32.Castagnoli), data)
var ret CSum
binary.LittleEndian.PutUint32(ret[:], crc)
return ret, nil
case TYPE_XXHASH:
panic("TODO: XXHASH not yet implemented")
case TYPE_SHA256:
panic("TODO: SHA256 not yet implemented")
case TYPE_BLAKE2:
panic("TODO: BLAKE2 not yet implemented")
default:
return CSum{}, fmt.Errorf("unknown checksum type: %v", typ)
}
}
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