Merge pull request #624 from nspcc-dev/feature/bigint

compiler: emit integers correctly

pkg/compiler/emit.go

@@ -7,7 +7,7 @@ import (
 	"math/big"
 
 	"github.com/CityOfZion/neo-go/pkg/io"
-	"github.com/CityOfZion/neo-go/pkg/util"
+	"github.com/CityOfZion/neo-go/pkg/vm"
 	"github.com/CityOfZion/neo-go/pkg/vm/opcode"
 )
 
@@ -47,7 +47,7 @@ func emitInt(w *io.BinWriter, i int64) {
 	}
 
 	bInt := big.NewInt(i)
-	val := util.ArrayReverse(bInt.Bytes())
+	val := vm.IntToBytes(bInt)
 	emitBytes(w, val)
 }
 

pkg/compiler/limit_test.go

@@ -0,0 +1,26 @@
+package compiler_test
+
+import (
+	"bytes"
+	"fmt"
+	"math/big"
+	"testing"
+)
+
+// Test for #605, #623.
+// Codegen should emit integers in proper format.
+func TestManyVariables(t *testing.T) {
+	// any number with MSB=1 is suitable
+	// 155 was in the contract where this bug was first found.
+	const count = 155
+
+	buf := bytes.NewBufferString("package main\n")
+	for i := 0; i < count; i++ {
+		buf.WriteString(fmt.Sprintf("var a%d = %d\n", i, i))
+	}
+	buf.WriteString("func Main() int {\nreturn 7\n}\n")
+
+	src := buf.String()
+
+	eval(t, src, big.NewInt(7))
+}

pkg/vm/bigint.go

@@ -9,9 +9,9 @@ import (
 // wordSizeBytes is a size of a big.Word (uint) in bytes.`
 const wordSizeBytes = bits.UintSize / 8
 
-// bytesToInt converts data in little-endian format to
+// BytesToInt converts data in little-endian format to
 // an integer.
-func bytesToInt(data []byte) *big.Int {
+func BytesToInt(data []byte) *big.Int {
 	n := new(big.Int)
 	size := len(data)
 	if size == 0 {
@@ -79,8 +79,8 @@ func getEffectiveSize(buf []byte, isNeg bool) int {
 	return size
 }
 
-// intToBytes converts integer to a slice in little-endian format.
-func intToBytes(n *big.Int) []byte {
+// IntToBytes converts integer to a slice in little-endian format.
+func IntToBytes(n *big.Int) []byte {
 	sign := n.Sign()
 	if sign == 0 {
 		return []byte{0}

pkg/vm/bigint_test.go

@@ -106,19 +106,19 @@ var testCases = []struct {
 
 func TestIntToBytes(t *testing.T) {
 	for _, tc := range testCases {
-		buf := intToBytes(big.NewInt(tc.number))
+		buf := IntToBytes(big.NewInt(tc.number))
 		assert.Equal(t, tc.buf, buf, "error while converting %d", tc.number)
 	}
 }
 
 func TestBytesToInt(t *testing.T) {
 	for _, tc := range testCases {
-		num := bytesToInt(tc.buf)
+		num := BytesToInt(tc.buf)
 		assert.Equal(t, tc.number, num.Int64(), "error while converting %d", tc.number)
 	}
 
 	t.Run("empty array", func(t *testing.T) {
-		require.EqualValues(t, 0, bytesToInt([]byte{}).Int64())
+		require.EqualValues(t, 0, BytesToInt([]byte{}).Int64())
 	})
 }
 
@@ -131,7 +131,7 @@ func TestEquivalentRepresentations(t *testing.T) {
 			buf = append(buf, 0xFF, 0xFF, 0xFF)
 		}
 
-		num := bytesToInt(buf)
+		num := BytesToInt(buf)
 		assert.Equal(t, tc.number, num.Int64(), "error while converting %d", tc.number)
 	}
 }
@@ -170,16 +170,16 @@ func TestVeryBigInts(t *testing.T) {
 		num, ok := new(big.Int).SetString(tc.numStr, 10)
 		assert.True(t, ok)
 
-		result := bytesToInt(tc.buf)
+		result := BytesToInt(tc.buf)
 		assert.Equal(t, num, result, "error while converting %s from bytes", tc.numStr)
-		assert.Equal(t, tc.buf, intToBytes(result), "error while converting %s to bytes", tc.numStr)
+		assert.Equal(t, tc.buf, IntToBytes(result), "error while converting %s to bytes", tc.numStr)
 	}
 
 	for _, tc := range stdlibCases {
 		num, ok := new(big.Int).SetString(tc.numStr, 10)
 		assert.True(t, ok)
 
-		result := bytesToInt(util.ArrayReverse(tc.buf))
+		result := BytesToInt(util.ArrayReverse(tc.buf))
 		assert.Equal(t, num, result, "error while converting %s from bytes", tc.numStr)
 	}
 }

pkg/vm/json_test.go

@@ -196,7 +196,7 @@ func compareItems(t *testing.T, a, b StackItem) {
 		case *BigIntegerItem:
 			require.Equal(t, val, ac.value.Int64())
 		case *ByteArrayItem:
-			require.Equal(t, val, bytesToInt(ac.value).Int64())
+			require.Equal(t, val, BytesToInt(ac.value).Int64())
 		case *BoolItem:
 			if ac.value {
 				require.Equal(t, val, int64(1))

pkg/vm/serialization.go

@@ -48,7 +48,7 @@ func serializeItemTo(item StackItem, w *io.BinWriter, seen map[StackItem]bool) {
 		w.WriteBool(t.value)
 	case *BigIntegerItem:
 		w.WriteBytes([]byte{byte(integerT)})
-		w.WriteVarBytes(intToBytes(t.value))
+		w.WriteVarBytes(IntToBytes(t.value))
 	case *InteropItem:
 		w.Err = errors.New("not supported")
 	case *ArrayItem, *StructItem:
@@ -106,7 +106,7 @@ func DecodeBinaryStackItem(r *io.BinReader) StackItem {
 		return NewBoolItem(b)
 	case integerT:
 		data := r.ReadVarBytes()
-		num := bytesToInt(data)
+		num := BytesToInt(data)
 		return &BigIntegerItem{
 			value: num,
 		}

pkg/vm/stack.go

@@ -81,7 +81,7 @@ func (e *Element) BigInt() *big.Int {
 		return big.NewInt(0)
 	default:
 		b := t.Value().([]uint8)
-		return bytesToInt(b)
+		return BytesToInt(b)
 	}
 }
 

pkg/vm/stack_item.go

@@ -142,7 +142,7 @@ func NewBigIntegerItem(value int) *BigIntegerItem {
 
 // Bytes converts i to a slice of bytes.
 func (i *BigIntegerItem) Bytes() []byte {
-	return intToBytes(i.value)
+	return IntToBytes(i.value)
 }
 
 // Value implements StackItem interface.