/
factory.go
81 lines (68 loc) · 1.46 KB
/
factory.go
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package chunk
import (
"fmt"
"strconv"
)
// Encoding defines which encoding we are using, delta, doubledelta, or varbit
type Encoding byte
const (
Dummy Encoding = iota
)
// String implements flag.Value.
func (e Encoding) String() string {
if known, found := encodings[e]; found {
return known.Name
}
return fmt.Sprintf("%d", e)
}
// Set implements flag.Value.
func (e *Encoding) Set(s string) error {
// First see if the name was given
for k, v := range encodings {
if s == v.Name {
*e = k
return nil
}
}
// Otherwise, accept a number
i, err := strconv.Atoi(s)
if err != nil {
return err
}
_, ok := encodings[Encoding(i)]
if !ok {
return fmt.Errorf("invalid chunk encoding: %s", s)
}
*e = Encoding(i)
return nil
}
type encoding struct {
Name string
New func() Data
}
var encodings = map[Encoding]encoding{
Dummy: {
Name: "dummy",
New: func() Data { return newDummyChunk() },
},
}
// NewForEncoding allows configuring what chunk type you want
func NewForEncoding(encoding Encoding) (Data, error) {
enc, ok := encodings[encoding]
if !ok {
return nil, fmt.Errorf("unknown chunk encoding: %v", encoding)
}
return enc.New(), nil
}
// MustRegisterEncoding add a new chunk encoding. There is no locking, so this
// must be called in init().
func MustRegisterEncoding(enc Encoding, name string, f func() Data) {
_, ok := encodings[enc]
if ok {
panic("double register encoding")
}
encodings[enc] = encoding{
Name: name,
New: f,
}
}