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// Copyright (C) 2022-2023 Luke Shumaker <lukeshu@lukeshu.com>
//
// SPDX-License-Identifier: GPL-2.0-or-later
package btrfsprim
import (
"fmt"
"math"
"git.lukeshu.com/btrfs-progs-ng/lib/binstruct"
"git.lukeshu.com/btrfs-progs-ng/lib/containers"
)
type Key struct {
ObjectID ObjID `bin:"off=0x0, siz=0x8"` // Each tree has its own set of Object IDs.
ItemType ItemType `bin:"off=0x8, siz=0x1"`
Offset uint64 `bin:"off=0x9, siz=0x8"` // The meaning depends on the item type.
binstruct.End `bin:"off=0x11"`
}
const MaxOffset uint64 = math.MaxUint64
// Format returns a human-friendly string representation of the Key,
// according to which tree it appears in.
//
// The formatting of the key mimics print-tree.c:btrfs_print_key().
func (key Key) Format(tree ObjID) string {
switch tree {
case UUID_TREE_OBJECTID:
return fmt.Sprintf("(%v %v %#08x)",
key.ObjectID.Format(tree),
key.ItemType,
key.Offset)
case ROOT_TREE_OBJECTID, QUOTA_TREE_OBJECTID:
return fmt.Sprintf("(%v %v %v)",
key.ObjectID.Format(tree),
key.ItemType,
ObjID(key.Offset).Format(tree))
default:
if key.Offset == math.MaxUint64 {
return fmt.Sprintf("(%v %v -1)",
key.ObjectID.Format(tree),
key.ItemType)
}
return fmt.Sprintf("(%v %v %v)",
key.ObjectID.Format(tree),
key.ItemType,
key.Offset)
}
}
func (key Key) String() string {
return key.Format(0)
}
var MaxKey = Key{
ObjectID: math.MaxUint64,
ItemType: math.MaxUint8,
Offset: math.MaxUint64,
}
func (key Key) Mm() Key {
switch {
case key.Offset > 0:
key.Offset--
case key.ItemType > 0:
key.ItemType--
key.Offset = MaxOffset
case key.ObjectID > 0:
key.ObjectID--
key.ItemType = MAX_KEY
key.Offset = MaxOffset
}
return key
}
func (key Key) Pp() Key {
switch {
case key.Offset < MaxOffset:
key.Offset++
case key.ItemType < MAX_KEY:
key.ItemType++
key.Offset = 0
case key.ObjectID < MAX_OBJECTID:
key.ObjectID++
key.ItemType = 0
key.Offset = 0
}
return key
}
func (a Key) Compare(b Key) int {
if d := containers.NativeCompare(a.ObjectID, b.ObjectID); d != 0 {
return d
}
if d := containers.NativeCompare(a.ItemType, b.ItemType); d != 0 {
return d
}
return containers.NativeCompare(a.Offset, b.Offset)
}
var _ containers.Ordered[Key] = Key{}
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