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6876b6427f
Introduce a quantity representing an offset. Signed-off-by: Maciej Borzecki <maciej.zenon.borzecki@canonical.com>
73 lines
2.0 KiB
Go
73 lines
2.0 KiB
Go
// -*- Mode: Go; indent-tabs-mode: t -*-
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/*
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* Copyright (C) 2020 Canonical Ltd
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*
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* This program is free software: you can redistribute it and/or modify
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* it under the terms of the GNU General Public License version 3 as
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* published by the Free Software Foundation.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program. If not, see <http://www.gnu.org/licenses/>.
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*
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*/
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package quantity
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import (
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"errors"
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"fmt"
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)
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// Offset describes the offset in bytes and is a thin wrapper around Size.
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type Offset Size
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const (
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// OffsetKiB is the byte size of one kibibyte (2^10 = 1024 bytes)
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OffsetKiB = Offset(1 << 10)
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// OffsetMiB is the offset of one mebibyte (2^20)
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OffsetMiB = Offset(1 << 20)
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)
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func (o *Offset) String() string {
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return (*Size)(o).String()
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}
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// IECString formats the offset using multiples from IEC units (i.e. kibibytes,
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// mebibytes), that is as multiples of 1024. Printed values are truncated to 2
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// decimal points.
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func (o *Offset) IECString() string {
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return iecSizeString(int64(*o))
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}
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func (o *Offset) UnmarshalYAML(unmarshal func(interface{}) error) error {
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var gs string
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if err := unmarshal(&gs); err != nil {
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return errors.New(`cannot unmarshal gadget offset`)
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}
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var err error
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*o, err = ParseOffset(gs)
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if err != nil {
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return fmt.Errorf("cannot parse offset %q: %v", gs, err)
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}
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return err
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}
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// ParseOffset parses a string expressing offset in a gadget specific format. The
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// accepted format is one of: <bytes> | <bytes/2^20>M | <bytes/2^30>G.
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func ParseOffset(gs string) (Offset, error) {
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offs, err := parseSizeOrOffset(gs)
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if offs < 0 {
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// XXX: in theory offsets can be negative, but not in gadget
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// YAML
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return 0, errors.New("offset cannot be negative")
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}
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return Offset(offs), err
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}
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