mirror of
https://github.com/nspcc-dev/neo-go.git
synced 2024-11-23 03:38:35 +00:00
96 lines
2.6 KiB
Go
96 lines
2.6 KiB
Go
package io
|
|
|
|
import (
|
|
"fmt"
|
|
"reflect"
|
|
)
|
|
|
|
// This structure is used to calculate the wire size of the serializable
|
|
// structure. It's an io.Writer that doesn't do any real writes, but instead
|
|
// just counts the number of bytes to be written.
|
|
type counterWriter struct {
|
|
counter int
|
|
}
|
|
|
|
// Write implements the io.Writer interface.
|
|
func (cw *counterWriter) Write(p []byte) (int, error) {
|
|
n := len(p)
|
|
cw.counter += n
|
|
return n, nil
|
|
}
|
|
|
|
// getVarIntSize returns the size in number of bytes of a variable integer.
|
|
// (reference: GetVarSize(int value), https://github.com/neo-project/neo/blob/master/neo/IO/Helper.cs)
|
|
func getVarIntSize(value int) int {
|
|
var size uintptr
|
|
|
|
if value < 0xFD {
|
|
size = 1 // unit8
|
|
} else if value <= 0xFFFF {
|
|
size = 3 // byte + uint16
|
|
} else {
|
|
size = 5 // byte + uint32
|
|
}
|
|
return int(size)
|
|
}
|
|
|
|
// GetVarSize returns the number of bytes in a serialized variable. It supports ints/uints (estimating
|
|
// them using variable-length encoding that is used in NEO), strings, pointers to Serializable structures,
|
|
// slices and arrays of ints/uints or Serializable structures. It's similar to GetVarSize<T>(this T[] value)
|
|
// used in C#, but differs in that it also supports things like Uint160 or Uint256.
|
|
func GetVarSize(value interface{}) int {
|
|
v := reflect.ValueOf(value)
|
|
switch v.Kind() {
|
|
case reflect.String:
|
|
valueSize := len([]byte(v.String()))
|
|
return getVarIntSize(valueSize) + valueSize
|
|
case reflect.Int,
|
|
reflect.Int8,
|
|
reflect.Int16,
|
|
reflect.Int32,
|
|
reflect.Int64:
|
|
return getVarIntSize(int(v.Int()))
|
|
case reflect.Uint,
|
|
reflect.Uint8,
|
|
reflect.Uint16,
|
|
reflect.Uint32,
|
|
reflect.Uint64:
|
|
return getVarIntSize(int(v.Uint()))
|
|
case reflect.Ptr:
|
|
vser, ok := v.Interface().(Serializable)
|
|
if !ok {
|
|
panic("unable to calculate GetVarSize for a non-Serializable pointer")
|
|
}
|
|
cw := counterWriter{}
|
|
w := NewBinWriterFromIO(&cw)
|
|
vser.EncodeBinary(w)
|
|
if w.Err != nil {
|
|
panic(fmt.Sprintf("error serializing %s: %s", reflect.TypeOf(value), w.Err.Error()))
|
|
}
|
|
return cw.counter
|
|
case reflect.Slice, reflect.Array:
|
|
valueLength := v.Len()
|
|
valueSize := 0
|
|
|
|
if valueLength != 0 {
|
|
switch reflect.ValueOf(value).Index(0).Interface().(type) {
|
|
case Serializable:
|
|
for i := 0; i < valueLength; i++ {
|
|
valueSize += GetVarSize(v.Index(i).Interface())
|
|
}
|
|
case uint8, int8:
|
|
valueSize = valueLength
|
|
case uint16, int16:
|
|
valueSize = valueLength * 2
|
|
case uint32, int32:
|
|
valueSize = valueLength * 4
|
|
case uint64, int64:
|
|
valueSize = valueLength * 8
|
|
}
|
|
}
|
|
|
|
return getVarIntSize(valueLength) + valueSize
|
|
default:
|
|
panic(fmt.Sprintf("unable to calculate GetVarSize, %s", reflect.TypeOf(value)))
|
|
}
|
|
}
|