mox/moxio/limitatreader.go
Mechiel Lukkien cb229cb6cf
mox!
2023-01-30 14:27:06 +01:00

20 lines
458 B
Go

package moxio
import (
"io"
)
// LimitAtReader is a reader at that returns ErrLimit if reads would extend
// beyond Limit.
type LimitAtReader struct {
R io.ReaderAt
Limit int64
}
// ReadAt passes the read on to R, but returns an error if the read data would extend beyond Limit.
func (r *LimitAtReader) ReadAt(buf []byte, offset int64) (int, error) {
if offset+int64(len(buf)) > r.Limit {
return 0, ErrLimit
}
return r.R.ReadAt(buf, offset)
}