storage: put uint32 into keys using in big endianness

Which allows to iterate over the contents easily.

pkg/core/blockchain.go

@@ -46,7 +46,7 @@ import (
 // Tuning parameters.
 const (
 	headerBatchCount = 2000
-	version          = "0.2.3"
+	version          = "0.2.4"
 
 	defaultInitialGAS                      = 52000000_00000000
 	defaultGCPeriod                        = 10000

pkg/core/dao/dao.go

@@ -6,7 +6,6 @@ import (
 	"encoding/binary"
 	"errors"
 	iocore "io"
-	"sort"
 
 	"github.com/nspcc-dev/neo-go/pkg/core/block"
 	"github.com/nspcc-dev/neo-go/pkg/core/state"
@@ -506,33 +505,19 @@ func (dao *Simple) GetStateSyncCurrentBlockHeight() (uint32, error) {
 // GetHeaderHashes returns a sorted list of header hashes retrieved from
 // the given underlying store.
 func (dao *Simple) GetHeaderHashes() ([]util.Uint256, error) {
-	hashMap := make(map[uint32][]util.Uint256)
+	var hashes = make([]util.Uint256, 0)
+
 	dao.Store.Seek(storage.SeekRange{
 		Prefix: storage.IXHeaderHashList.Bytes(),
 	}, func(k, v []byte) bool {
-		storedCount := binary.LittleEndian.Uint32(k[1:])
-		hashes, err := read2000Uint256Hashes(v)
+		newHashes, err := read2000Uint256Hashes(v)
 		if err != nil {
 			panic(err)
 		}
-		hashMap[storedCount] = hashes
+		hashes = append(hashes, newHashes...)
 		return true
 	})
 
-	var (
-		hashes     = make([]util.Uint256, 0, len(hashMap))
-		sortedKeys = make([]uint32, 0, len(hashMap))
-	)
-
-	for k := range hashMap {
-		sortedKeys = append(sortedKeys, k)
-	}
-	sort.Slice(sortedKeys, func(i, j int) bool { return sortedKeys[i] < sortedKeys[j] })
-
-	for _, key := range sortedKeys {
-		hashes = append(hashes[:key], hashMap[key]...)
-	}
-
 	return hashes, nil
 }
 

pkg/core/storage/store.go

@@ -125,7 +125,7 @@ func AppendPrefix(k KeyPrefix, b []byte) []byte {
 //   AppendPrefixInt(SYSCurrentHeader, 10001)
 func AppendPrefixInt(k KeyPrefix, n int) []byte {
 	b := make([]byte, 4)
-	binary.LittleEndian.PutUint32(b, uint32(n))
+	binary.BigEndian.PutUint32(b, uint32(n))
 	return AppendPrefix(k, b)
 }