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version.go
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version.go
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/*
* Copyright 2021 ICON Foundation
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package block
import (
"bufio"
"bytes"
"io"
"github.com/icon-project/goloop/common/codec"
)
func ReadVersion(r io.Reader) (int, error) {
d := codec.BC.NewDecoder(r)
d2, err := d.DecodeList()
if err != nil {
return -1, err
}
var version int
err = d2.Decode(&version)
if err != nil {
return -1, err
}
_ = d.Close()
return version, nil
}
func PeekVersion(r io.Reader) (int, io.Reader, error) {
type Peeker interface {
Peek(n int) ([]byte, error)
}
var version int
if br, ok := r.(io.ReadSeeker); ok {
pos, err := br.Seek(0, io.SeekCurrent)
if err != nil {
return -1, nil, err
}
version, err = ReadVersion(br)
if err != nil {
return -1, nil, err
}
_, err = br.Seek(pos, io.SeekStart)
if err != nil {
return -1, nil, err
}
return version, br, nil
}
if _, ok := r.(Peeker); !ok {
r = bufio.NewReader(r)
}
header, _ := r.(Peeker).Peek(32)
tr := bytes.NewReader(header)
version, err := ReadVersion(tr)
if err != nil {
return -1, nil, err
}
return version, r, nil
}