neoneo-go/pkg/util/io.go
Anthony De Meulemeester a67728628e
Persist blockchain with leveldb on disk (#48)
* Created test_data folder with block json files for testing + create separate file for block base.

* Fixed bug in WriteVarUint + Trim logic + unit tests

* Refactored store and add more tests for it.

* restore headerList from chain file

* Fix tx decode bug + lots of housekeeping.

* Implemented Node restore state from chain file.

* Created standalone package for storage. Added couple more methods to Batch and Store interfaces.

* Block persisting + tests

* bumped version -> 0.31.0
2018-03-17 12:53:21 +01:00

78 lines
1.8 KiB
Go

package util
import (
"bytes"
"encoding/binary"
"errors"
"io"
)
// Variable length integer, can be encoded to save space according to the value typed.
// len 1 uint8
// len 3 0xfd + uint16
// len 5 0xfe = uint32
// len 9 0xff = uint64
// For more information about this:
// https://github.com/neo-project/neo/wiki/Network-Protocol
// ReadVarUint reads a variable unsigned integer and returns it as a uint64.
func ReadVarUint(r io.Reader) uint64 {
var b uint8
binary.Read(r, binary.LittleEndian, &b)
if b == 0xfd {
var v uint16
binary.Read(r, binary.LittleEndian, &v)
return uint64(v)
}
if b == 0xfe {
var v uint32
binary.Read(r, binary.LittleEndian, &v)
return uint64(v)
}
if b == 0xff {
var v uint64
binary.Read(r, binary.LittleEndian, &v)
return v
}
return uint64(b)
}
// WriteVarUint writes a variable unsigned integer.
func WriteVarUint(w io.Writer, val uint64) error {
if val < 0 {
return errors.New("value out of range")
}
if val < 0xfd {
binary.Write(w, binary.LittleEndian, uint8(val))
return nil
}
if val < 0xFFFF {
binary.Write(w, binary.LittleEndian, byte(0xfd))
binary.Write(w, binary.LittleEndian, uint16(val))
return nil
}
if val < 0xFFFFFFFF {
binary.Write(w, binary.LittleEndian, byte(0xfe))
binary.Write(w, binary.LittleEndian, uint32(val))
return nil
}
binary.Write(w, binary.LittleEndian, byte(0xff))
binary.Write(w, binary.LittleEndian, val)
return nil
}
// Read2000Uint256Hashes attempt to read 2000 Uint256 hashes from
// the given byte array.
func Read2000Uint256Hashes(b []byte) ([]Uint256, error) {
r := bytes.NewReader(b)
lenHashes := ReadVarUint(r)
hashes := make([]Uint256, lenHashes)
if err := binary.Read(r, binary.LittleEndian, hashes); err != nil {
return nil, err
}
return hashes, nil
}