/
offset.go
72 lines (62 loc) · 2 KB
/
offset.go
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// -*- Mode: Go; indent-tabs-mode: t -*-
/*
* Copyright (C) 2020 Canonical Ltd
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 3 as
* published by the Free Software Foundation.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*
*/
package quantity
import (
"errors"
"fmt"
)
// Offset describes the offset in bytes and is a thin wrapper around Size.
type Offset Size
const (
// OffsetKiB is the byte size of one kibibyte (2^10 = 1024 bytes)
OffsetKiB = Offset(1 << 10)
// OffsetMiB is the offset of one mebibyte (2^20)
OffsetMiB = Offset(1 << 20)
)
func (o *Offset) String() string {
return (*Size)(o).String()
}
// IECString formats the offset using multiples from IEC units (i.e. kibibytes,
// mebibytes), that is as multiples of 1024. Printed values are truncated to 2
// decimal points.
func (o *Offset) IECString() string {
return iecSizeString(int64(*o))
}
func (o *Offset) UnmarshalYAML(unmarshal func(interface{}) error) error {
var gs string
if err := unmarshal(&gs); err != nil {
return errors.New(`cannot unmarshal gadget offset`)
}
var err error
*o, err = ParseOffset(gs)
if err != nil {
return fmt.Errorf("cannot parse offset %q: %v", gs, err)
}
return err
}
// ParseOffset parses a string expressing offset in a gadget specific format. The
// accepted format is one of: <bytes> | <bytes/2^20>M | <bytes/2^30>G.
func ParseOffset(gs string) (Offset, error) {
offs, err := parseSizeOrOffset(gs)
if offs < 0 {
// XXX: in theory offsets can be negative, but not in gadget
// YAML
return 0, errors.New("offset cannot be negative")
}
return Offset(offs), err
}