forked from TrueCloudLab/neoneo-go
141 lines
3.2 KiB
Go
141 lines
3.2 KiB
Go
package io
|
|
|
|
import (
|
|
"bytes"
|
|
"encoding/binary"
|
|
"io"
|
|
"reflect"
|
|
)
|
|
|
|
// BinReader is a convenient wrapper around a io.Reader and err object.
|
|
// Used to simplify error handling when reading into a struct with many fields.
|
|
type BinReader struct {
|
|
r io.Reader
|
|
Err error
|
|
}
|
|
|
|
// NewBinReaderFromIO makes a BinReader from io.Reader.
|
|
func NewBinReaderFromIO(ior io.Reader) *BinReader {
|
|
return &BinReader{r: ior}
|
|
}
|
|
|
|
// NewBinReaderFromBuf makes a BinReader from byte buffer.
|
|
func NewBinReaderFromBuf(b []byte) *BinReader {
|
|
r := bytes.NewReader(b)
|
|
return NewBinReaderFromIO(r)
|
|
}
|
|
|
|
// ReadLE reads from the underlying io.Reader
|
|
// into the interface v in little-endian format.
|
|
func (r *BinReader) ReadLE(v interface{}) {
|
|
if r.Err != nil {
|
|
return
|
|
}
|
|
r.Err = binary.Read(r.r, binary.LittleEndian, v)
|
|
}
|
|
|
|
// ReadArray reads array into value which must be
|
|
// a pointer to a slice.
|
|
func (r *BinReader) ReadArray(t interface{}) {
|
|
value := reflect.ValueOf(t)
|
|
if value.Kind() != reflect.Ptr || value.Elem().Kind() != reflect.Slice {
|
|
panic(value.Type().String() + " is not a pointer to a slice")
|
|
}
|
|
|
|
sliceType := value.Elem().Type()
|
|
elemType := sliceType.Elem()
|
|
isPtr := elemType.Kind() == reflect.Ptr
|
|
if isPtr {
|
|
checkHasDecodeBinary(elemType)
|
|
} else {
|
|
checkHasDecodeBinary(reflect.PtrTo(elemType))
|
|
}
|
|
|
|
if r.Err != nil {
|
|
return
|
|
}
|
|
|
|
l := int(r.ReadVarUint())
|
|
arr := reflect.MakeSlice(sliceType, l, l)
|
|
|
|
for i := 0; i < l; i++ {
|
|
var elem reflect.Value
|
|
if isPtr {
|
|
elem = reflect.New(elemType.Elem())
|
|
arr.Index(i).Set(elem)
|
|
} else {
|
|
elem = arr.Index(i).Addr()
|
|
}
|
|
method := elem.MethodByName("DecodeBinary")
|
|
method.Call([]reflect.Value{reflect.ValueOf(r)})
|
|
}
|
|
|
|
value.Elem().Set(arr)
|
|
}
|
|
|
|
func checkHasDecodeBinary(v reflect.Type) {
|
|
method, ok := v.MethodByName("DecodeBinary")
|
|
if !ok || !isDecodeBinaryMethod(method) {
|
|
panic(v.String() + " does not have DecodeBinary(*io.BinReader)")
|
|
}
|
|
}
|
|
|
|
func isDecodeBinaryMethod(method reflect.Method) bool {
|
|
t := method.Type
|
|
return t != nil &&
|
|
t.NumIn() == 2 && t.In(1) == reflect.TypeOf((*BinReader)(nil)) &&
|
|
t.NumOut() == 0
|
|
}
|
|
|
|
// ReadBE reads from the underlying io.Reader
|
|
// into the interface v in big-endian format.
|
|
func (r *BinReader) ReadBE(v interface{}) {
|
|
if r.Err != nil {
|
|
return
|
|
}
|
|
r.Err = binary.Read(r.r, binary.BigEndian, v)
|
|
}
|
|
|
|
// ReadVarUint reads a variable-length-encoded integer from the
|
|
// underlying reader.
|
|
func (r *BinReader) ReadVarUint() uint64 {
|
|
if r.Err != nil {
|
|
return 0
|
|
}
|
|
|
|
var b uint8
|
|
r.Err = binary.Read(r.r, binary.LittleEndian, &b)
|
|
|
|
if b == 0xfd {
|
|
var v uint16
|
|
r.Err = binary.Read(r.r, binary.LittleEndian, &v)
|
|
return uint64(v)
|
|
}
|
|
if b == 0xfe {
|
|
var v uint32
|
|
r.Err = binary.Read(r.r, binary.LittleEndian, &v)
|
|
return uint64(v)
|
|
}
|
|
if b == 0xff {
|
|
var v uint64
|
|
r.Err = binary.Read(r.r, binary.LittleEndian, &v)
|
|
return v
|
|
}
|
|
|
|
return uint64(b)
|
|
}
|
|
|
|
// ReadBytes reads the next set of bytes from the underlying reader.
|
|
// ReadVarUInt() is used to determine how large that slice is
|
|
func (r *BinReader) ReadBytes() []byte {
|
|
n := r.ReadVarUint()
|
|
b := make([]byte, n)
|
|
r.ReadLE(b)
|
|
return b
|
|
}
|
|
|
|
// ReadString calls ReadBytes and casts the results as a string.
|
|
func (r *BinReader) ReadString() string {
|
|
b := r.ReadBytes()
|
|
return string(b)
|
|
}
|