58 lines
1.1 KiB
Go
58 lines
1.1 KiB
Go
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package srarchive
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import (
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"encoding/json"
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"errors"
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"fmt"
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"strconv"
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)
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type SourceSetDescriptorType rune
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const (
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PixelDensity SourceSetDescriptorType = 'x'
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Width SourceSetDescriptorType = 'w'
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)
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type SourceSetSpecifier struct {
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Value int
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DescriptorType SourceSetDescriptorType
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}
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func (s *SourceSetSpecifier) String() string {
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return fmt.Sprintf("%d%c", s.Value, s.DescriptorType)
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}
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func (s *SourceSetSpecifier) parse(value string) error {
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if len(value) < 2 {
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return errors.New("too short string")
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}
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s.DescriptorType = SourceSetDescriptorType(value[len(value)-1])
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switch s.DescriptorType {
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case PixelDensity:
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case Width:
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default:
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return errors.New("invalid source-set-value descriptor")
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}
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var err error
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s.Value, err = strconv.Atoi(value[0 : len(value)-1])
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if err != nil {
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return err
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}
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return nil
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}
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func (s *SourceSetSpecifier) UnmarshalJSON(b []byte) error {
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var str string
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err := json.Unmarshal(b, &str)
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if err != nil {
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return err
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}
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return s.parse(str)
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}
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func (s *SourceSetSpecifier) MarshalJSON() ([]byte, error) {
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return json.Marshal(s.String())
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}
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