util: move ArrayReverse into package of its own

Leave just uint160 and uint256 types in util.

pkg/encoding/bigint/bigint.go

@@ -5,7 +5,7 @@ import (
 	"math/big"
 	"math/bits"
 
-	"github.com/nspcc-dev/neo-go/pkg/util"
+	"github.com/nspcc-dev/neo-go/pkg/util/slice"
 )
 
 const (
@@ -17,7 +17,7 @@ const (
 
 // FromBytesUnsigned converts data in little-endian format to an unsigned integer.
 func FromBytesUnsigned(data []byte) *big.Int {
-	bs := util.ArrayReverse(data)
+	bs := slice.CopyReverse(data)
 	return new(big.Int).SetBytes(bs)
 }
 

pkg/encoding/bigint/bigint_test.go

@@ -5,7 +5,7 @@ import (
 	"math/big"
 	"testing"
 
-	"github.com/nspcc-dev/neo-go/pkg/util"
+	"github.com/nspcc-dev/neo-go/pkg/util/slice"
 	"github.com/stretchr/testify/assert"
 	"github.com/stretchr/testify/require"
 )
@@ -204,7 +204,7 @@ func TestVeryBigInts(t *testing.T) {
 		num, ok := new(big.Int).SetString(tc.numStr, 10)
 		assert.True(t, ok)
 
-		result := FromBytes(util.ArrayReverse(tc.buf))
+		result := FromBytes(slice.CopyReverse(tc.buf))
 		assert.Equal(t, num, result, "error while converting %s from bytes", tc.numStr)
 	}
 }

pkg/util/array.go

@@ -1,10 +0,0 @@
-package util
-
-// ArrayReverse returns a reversed version of the given byte slice.
-func ArrayReverse(b []byte) []byte {
-	dest := make([]byte, len(b))
-	for i, j := 0, len(b)-1; i <= j; i, j = i+1, j-1 {
-		dest[i], dest[j] = b[j], b[i]
-	}
-	return dest
-}

pkg/util/slice/array.go

@@ -0,0 +1,14 @@
+/*
+Package slice contains byte slice helpers.
+*/
+package slice
+
+// CopyReverse returns a new byte slice containing reversed version of the
+// original.
+func CopyReverse(b []byte) []byte {
+	dest := make([]byte, len(b))
+	for i, j := 0, len(b)-1; i <= j; i, j = i+1, j-1 {
+		dest[i], dest[j] = b[j], b[i]
+	}
+	return dest
+}

pkg/util/slice/array_test.go

@@ -1,4 +1,4 @@
-package util
+package slice
 
 import (
 	"testing"
@@ -28,12 +28,12 @@ var testCases = []struct {
 	},
 }
 
-func TestArrayReverse(t *testing.T) {
+func TestCopyReverse(t *testing.T) {
 	for _, tc := range testCases {
 		arg := make([]byte, len(tc.arr))
 		copy(arg, tc.arr)
 
-		have := ArrayReverse(arg)
+		have := CopyReverse(arg)
 		require.Equal(t, tc.rev, have)
 
 		// test that argument was copied

pkg/util/uint160.go

@@ -7,6 +7,7 @@ import (
 	"strings"
 
 	"github.com/nspcc-dev/neo-go/pkg/io"
+	"github.com/nspcc-dev/neo-go/pkg/util/slice"
 )
 
 // Uint160Size is the size of Uint160 in bytes.
@@ -74,7 +75,7 @@ func (u Uint160) BytesBE() []byte {
 
 // BytesLE returns a little-endian byte representation of u.
 func (u Uint160) BytesLE() []byte {
-	return ArrayReverse(u.BytesBE())
+	return slice.CopyReverse(u.BytesBE())
 }
 
 // String implements the stringer interface.

pkg/util/uint256.go

@@ -8,6 +8,7 @@ import (
 	"strings"
 
 	"github.com/nspcc-dev/neo-go/pkg/io"
+	"github.com/nspcc-dev/neo-go/pkg/util/slice"
 )
 
 // Uint256Size is the size of Uint256 in bytes.
@@ -54,7 +55,7 @@ func Uint256DecodeBytesBE(b []byte) (u Uint256, err error) {
 
 // Uint256DecodeBytesLE attempts to decode the given string (in LE representation) into an Uint256.
 func Uint256DecodeBytesLE(b []byte) (u Uint256, err error) {
-	b = ArrayReverse(b)
+	b = slice.CopyReverse(b)
 	return Uint256DecodeBytesBE(b)
 }
 
@@ -71,7 +72,7 @@ func (u Uint256) Reverse() Uint256 {
 
 // BytesLE return a little-endian byte representation of u.
 func (u Uint256) BytesLE() []byte {
-	return ArrayReverse(u.BytesBE())
+	return slice.CopyReverse(u.BytesBE())
 }
 
 // Equals returns true if both Uint256 values are the same.

pkg/vm/cli/cli.go

@@ -21,6 +21,7 @@ import (
 	"github.com/nspcc-dev/neo-go/pkg/smartcontract/callflag"
 	"github.com/nspcc-dev/neo-go/pkg/smartcontract/manifest"
 	"github.com/nspcc-dev/neo-go/pkg/util"
+	"github.com/nspcc-dev/neo-go/pkg/util/slice"
 	"github.com/nspcc-dev/neo-go/pkg/vm"
 	"github.com/nspcc-dev/neo-go/pkg/vm/stackitem"
 	"gopkg.in/abiosoft/ishell.v2"
@@ -565,7 +566,7 @@ func Parse(args []string) (string, error) {
 		}
 		buf.WriteString(fmt.Sprintf("Hex to String\t%s\n", fmt.Sprintf("%q", string(rawStr))))
 		buf.WriteString(fmt.Sprintf("Hex to Integer\t%s\n", bigint.FromBytes(rawStr)))
-		buf.WriteString(fmt.Sprintf("Swap Endianness\t%s\n", hex.EncodeToString(util.ArrayReverse(rawStr))))
+		buf.WriteString(fmt.Sprintf("Swap Endianness\t%s\n", hex.EncodeToString(slice.CopyReverse(rawStr))))
 	}
 	if addr, err := address.StringToUint160(arg); err == nil {
 		buf.WriteString(fmt.Sprintf("Address to BE ScriptHash\t%s\n", addr))