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// Copyright (C) 2022-2023 Luke Shumaker <lukeshu@lukeshu.com>
//
// SPDX-License-Identifier: GPL-2.0-or-later
package btrfssum
import (
"context"
"io"
"git.lukeshu.com/btrfs-progs-ng/lib/btrfs/btrfsvol"
)
type SumRun[Addr btrfsvol.IntAddr[Addr]] struct {
// How big a ShortSum is in this Run.
ChecksumSize int `json:",omitempty"`
// Base address where this run starts.
Addr Addr `json:",omitempty"`
// All of the ShortSums in this run, concatenated together.
Sums ShortSum
}
func (run SumRun[Addr]) NumSums() int {
return len(run.Sums) / run.ChecksumSize
}
func (run SumRun[Addr]) Size() btrfsvol.AddrDelta {
return btrfsvol.AddrDelta(run.NumSums()) * BlockSize
}
// Get implements diskio.Sequence[int, ShortSum]
func (run SumRun[Addr]) Get(sumIdx int64) (ShortSum, error) {
if sumIdx < 0 || int(sumIdx) >= run.NumSums() {
return "", io.EOF
}
off := int(sumIdx) * run.ChecksumSize
return run.Sums[off : off+run.ChecksumSize], nil
}
func (run SumRun[Addr]) SumForAddr(addr Addr) (ShortSum, bool) {
if addr < run.Addr || addr >= run.Addr.Add(run.Size()) {
return "", false
}
off := int((addr-run.Addr)/BlockSize) * run.ChecksumSize
return run.Sums[off : off+run.ChecksumSize], true
}
func (run SumRun[Addr]) Walk(ctx context.Context, fn func(Addr, ShortSum) error) error {
for addr, off := run.Addr, 0; off < len(run.Sums); addr, off = addr+BlockSize, off+run.ChecksumSize {
if err := ctx.Err(); err != nil {
return err
}
if err := fn(addr, run.Sums[off:off+run.ChecksumSize]); err != nil {
return err
}
}
return nil
}
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