/
metadata.go
141 lines (117 loc) · 2.71 KB
/
metadata.go
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package minecraft
import (
"bytes"
"io"
"github.com/minero/minero/util/must"
"github.com/minero/minero/types"
)
const (
TypeByte byte = iota // 0: 000
TypeShort // 1: 001
TypeInt // 2: 010
TypeFloat // 3: 011
TypeString // 4: 100
TypeSlot // 5: 101
TypeVector // 6: 110
)
func EntryFrom(e byte) (r Entry) {
switch e {
case 0:
r = new(EntryByte)
case 1:
r = new(EntryShort)
case 2:
r = new(EntryInt)
case 3:
r = new(EntryFloat)
case 4:
r = new(EntryString)
case 5:
r = new(EntrySlot)
case 6:
r = new(EntryVector)
}
return
}
type Metadata struct {
Entries map[byte]Entry
}
type Entry interface {
Type() byte
io.ReaderFrom
io.WriterTo
}
func NewMetadata() Metadata {
return Metadata{
Entries: make(map[byte]Entry),
}
}
func MetadataFrom(s []byte) (m Metadata, err error) {
m = NewMetadata()
_, err = m.ReadFrom(bytes.NewBuffer(s))
return
}
func (m Metadata) ReadFrom(r io.Reader) (n int64, err error) {
var rw must.ReadWriter
var key byte
for key != 0x7f {
// Read type+key
key = byte(rw.ReadInt8(r))
if key == 0x7f {
break
}
var (
typ byte = key & 0xE0 >> 5
index byte = key & 0x1F
payload Entry = EntryFrom(typ)
)
// Read payload
rw.Must(payload.ReadFrom(r))
m.Entries[index] = payload
}
return rw.Result()
}
func (m Metadata) WriteTo(w io.Writer) (n int64, err error) {
var rw must.ReadWriter
var buf bytes.Buffer
for index, payload := range m.Entries {
buf.Reset()
typ := payload.Type()
rw.Check(buf.WriteByte(typ<<5 | (index & 0x1F)))
// Write type+key & payload
rw.Must(buf.WriteTo(w))
rw.Must(payload.WriteTo(w))
}
buf.Reset()
rw.Check(buf.WriteByte(0x7f))
rw.Must(buf.WriteTo(w))
return rw.Result()
}
type EntryByte struct{ types.Int8 }
type EntryShort struct{ types.Int16 }
type EntryInt struct{ types.Int32 }
type EntryFloat struct{ types.Float32 }
type EntryString struct{ String }
type EntrySlot struct{ Slot }
type EntryVector struct{ Data [3]types.Int32 }
func (e EntryByte) Type() byte { return 0 }
func (e EntryShort) Type() byte { return 1 }
func (e EntryInt) Type() byte { return 2 }
func (e EntryFloat) Type() byte { return 3 }
func (e EntryString) Type() byte { return 4 }
func (e EntrySlot) Type() byte { return 5 }
func (e EntryVector) Type() byte { return 6 }
func (e *EntryVector) ReadFrom(r io.Reader) (n int64, err error) {
var rw must.ReadWriter
for i := 0; i < len(e.Data); i++ {
rw.Must(e.Data[i].ReadFrom(r))
}
return rw.Result()
}
func (e *EntryVector) WriteTo(w io.Writer) (n int64, err error) {
var rw must.ReadWriter
for i := 0; i < len(e.Data); i++ {
rw.Must(e.Data[i].WriteTo(w))
}
return rw.Result()
}