/
typeencoder.go
140 lines (120 loc) · 2.95 KB
/
typeencoder.go
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package util
import (
"encoding/binary"
"io"
"reflect"
"strings"
"github.com/juju/errors"
)
type TypeMarshaller interface {
Marshal(enc *TypeEncoder) error
}
type TypeEncoder struct {
w io.Writer
}
func NewTypeEncoder(w io.Writer) *TypeEncoder {
return &TypeEncoder{w}
}
func (p *TypeEncoder) EncodeVarint(i int64) error {
if i >= 0 {
return p.EncodeUVarint(uint64(i))
}
b := make([]byte, binary.MaxVarintLen64)
n := binary.PutVarint(b, i)
return p.writeBytes(b[:n])
}
func (p *TypeEncoder) EncodeUVarint(i uint64) error {
b := make([]byte, binary.MaxVarintLen64)
n := binary.PutUvarint(b, i)
return p.writeBytes(b[:n])
}
func (p *TypeEncoder) EncodeNumber(v interface{}) error {
if err := binary.Write(p.w, binary.LittleEndian, v); err != nil {
return errors.Annotatef(err, "TypeEncoder: failed to write number: %v", v)
}
return nil
}
func (p *TypeEncoder) Encode(v interface{}) error {
if v == nil {
return nil
}
val := reflect.ValueOf(v)
if val.Kind() == reflect.Ptr && val.IsNil() {
return nil
}
if m, ok := v.(TypeMarshaller); ok {
return m.Marshal(p)
}
switch v := v.(type) {
case int8:
return p.EncodeNumber(v)
case int16:
return p.EncodeNumber(v)
case int32:
return p.EncodeNumber(v)
case int:
return p.EncodeNumber(int32(v))
case int64:
return p.EncodeNumber(v)
case uint:
return p.EncodeNumber(v)
case uint8:
return p.EncodeNumber(v)
case uint16:
return p.EncodeNumber(v)
case uint32:
return p.EncodeNumber(v)
case uint64:
return p.EncodeNumber(v)
case float32:
return p.EncodeNumber(v)
case float64:
return p.EncodeNumber(v)
case string:
return p.EncodeString(v)
case []string:
return p.EncodeStringSlice(v)
case []byte:
return p.writeBytes(v)
case bool:
if v {
return p.EncodeNumber(uint8(1))
} else {
return p.EncodeNumber(uint8(0))
}
default:
return errors.Errorf("TypeEncoder: unsupported type encountered")
}
}
func (p *TypeEncoder) EncodeStringSlice(v []string) error {
if err := p.EncodeUVarint(uint64(len(v))); err != nil {
return errors.Annotate(err, "EncodeUVarint [slice length]")
}
for _, val := range v {
if err := p.EncodeUVarint(uint64(len(val))); err != nil {
return errors.Annotate(err, "EncodeUVarint [string length]")
}
if _, err := io.Copy(p.w, strings.NewReader(val)); err != nil {
return errors.Annotate(err, "Copy [string]")
}
}
return nil
}
func (p *TypeEncoder) EncodeString(v string) error {
if err := p.EncodeUVarint(uint64(len(v))); err != nil {
return errors.Annotatef(err, "EncodeUVarint [string length]", v)
}
return p.writeString(v)
}
func (p *TypeEncoder) writeBytes(bs []byte) error {
if _, err := p.w.Write(bs); err != nil {
return errors.Annotatef(err, "TypeEncoder: failed to write bytes: %v", bs)
}
return nil
}
func (p *TypeEncoder) writeString(s string) error {
if _, err := io.Copy(p.w, strings.NewReader(s)); err != nil {
return errors.Annotatef(err, "TypeEncoder: failed to write string: %v", s)
}
return nil
}