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package struc
import (
"encoding/binary"
"fmt"
"io"
"reflect"
)
type Options struct {
ByteAlign int
PtrSize int
Order binary.ByteOrder
}
func (o *Options) Validate() error {
if o.PtrSize == 0 {
o.PtrSize = 32
} else {
switch o.PtrSize {
case 8, 16, 32, 64:
default:
return fmt.Errorf("Invalid Options.PtrSize: %d. Must be in (8, 16, 32, 64)", o.PtrSize)
}
}
return nil
}
var emptyOptions = &Options{}
func prep(data interface{}) (reflect.Value, Packer, error) {
value := reflect.ValueOf(data)
for value.Kind() == reflect.Ptr {
next := value.Elem().Kind()
if next == reflect.Struct || next == reflect.Ptr {
value = value.Elem()
} else {
break
}
}
switch value.Kind() {
case reflect.Struct:
fields, err := parseFields(value)
return value, fields, err
default:
if !value.IsValid() {
return reflect.Value{}, nil, fmt.Errorf("Invalid reflect.Value for %+v", data)
}
if c, ok := data.(Custom); ok {
return value, customFallback{c}, nil
}
return value, binaryFallback(value), nil
}
}
func Pack(w io.Writer, data interface{}) error {
return PackWithOptions(w, data, nil)
}
func PackWithOptions(w io.Writer, data interface{}, options *Options) error {
if options == nil {
options = emptyOptions
}
if err := options.Validate(); err != nil {
return err
}
val, packer, err := prep(data)
if err != nil {
return err
}
if val.Type().Kind() == reflect.String {
val = val.Convert(reflect.TypeOf([]byte{}))
}
size := packer.Sizeof(val, options)
buf := make([]byte, size)
if _, err := packer.Pack(buf, val, options); err != nil {
return err
}
_, err = w.Write(buf)
return err
}
func Unpack(r io.Reader, data interface{}) error {
return UnpackWithOptions(r, data, nil)
}
func UnpackWithOptions(r io.Reader, data interface{}, options *Options) error {
if options == nil {
options = emptyOptions
}
if err := options.Validate(); err != nil {
return err
}
val, packer, err := prep(data)
if err != nil {
return err
}
return packer.Unpack(r, val, options)
}
func Sizeof(data interface{}) (int, error) {
return SizeofWithOptions(data, nil)
}
func SizeofWithOptions(data interface{}, options *Options) (int, error) {
if options == nil {
options = emptyOptions
}
if err := options.Validate(); err != nil {
return 0, err
}
val, packer, err := prep(data)
if err != nil {
return 0, err
}
return packer.Sizeof(val, options), nil
}
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