Add serialize/deserialize for sequence list

Signed-off-by: Alessandro Boch <aboch@docker.com>

libnetwork/bitseq/sequence.go

@@ -5,6 +5,8 @@ package bitseq
 
 import (
 	"fmt"
+
+	"github.com/docker/libnetwork/netutils"
 )
 
 // Block Sequence constants
@@ -74,6 +76,45 @@ func (s *Sequence) Equal(o *Sequence) bool {
 	return true
 }
 
+// ToByteArray converts the sequence into a byte array
+// TODO (aboch): manage network/host order stuff
+func (s *Sequence) ToByteArray() ([]byte, error) {
+	var bb []byte
+
+	p := s
+	for p != nil {
+		bb = append(bb, netutils.U32ToA(p.Block)...)
+		bb = append(bb, netutils.U32ToA(p.Count)...)
+		p = p.Next
+	}
+
+	return bb, nil
+}
+
+// FromByteArray construct the sequence from the byte array
+// TODO (aboch): manage network/host order stuff
+func (s *Sequence) FromByteArray(data []byte) error {
+	l := len(data)
+	if l%8 != 0 {
+		return fmt.Errorf("cannot deserialize byte sequence of lenght %d", l)
+	}
+
+	p := s
+	i := 0
+	for {
+		p.Block = netutils.ATo32(data[i : i+4])
+		p.Count = netutils.ATo32(data[i+4 : i+8])
+		i += 8
+		if i == l {
+			break
+		}
+		p.Next = &Sequence{}
+		p = p.Next
+	}
+
+	return nil
+}
+
 // GetFirstAvailable looks for the first unset bit in passed mask
 func GetFirstAvailable(head *Sequence) (int, int) {
 	byteIndex := 0

libnetwork/bitseq/sequence_test.go

@@ -331,3 +331,45 @@ func TestPushReservation(t *testing.T) {
 		}
 	}
 }
+
+func TestSerializeDeserialize(t *testing.T) {
+	s := &Sequence{
+		Block: 0xffffffff,
+		Count: 1,
+		Next: &Sequence{
+			Block: 0xFF000000,
+			Count: 1,
+			Next: &Sequence{
+				Block: 0xffffffff,
+				Count: 6,
+				Next: &Sequence{
+					Block: 0xffffffff,
+					Count: 1,
+					Next: &Sequence{
+						Block: 0xFF800000,
+						Count: 1,
+						Next: &Sequence{
+							Block: 0xffffffff,
+							Count: 6,
+						},
+					},
+				},
+			},
+		},
+	}
+
+	data, err := s.ToByteArray()
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	r := &Sequence{}
+	err = r.FromByteArray(data)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	if !s.Equal(r) {
+		t.Fatalf("Sequences are different: \n%v\n%v", s, r)
+	}
+}

libnetwork/netutils/utils.go

@@ -168,3 +168,53 @@ func GenerateIfaceName(prefix string, len int) (string, error) {
 	}
 	return "", types.InternalErrorf("could not generate interface name")
 }
+
+func byteArrayToInt(array []byte, numBytes int) uint64 {
+	if numBytes <= 0 || numBytes > 8 {
+		panic("Invalid argument")
+	}
+	num := 0
+	for i := 0; i <= len(array)-1; i++ {
+		num += int(array[len(array)-1-i]) << uint(i*8)
+	}
+	return uint64(num)
+}
+
+// ATo64 converts a byte array into a uint32
+func ATo64(array []byte) uint64 {
+	return byteArrayToInt(array, 8)
+}
+
+// ATo32 converts a byte array into a uint32
+func ATo32(array []byte) uint32 {
+	return uint32(byteArrayToInt(array, 4))
+}
+
+// ATo16 converts a byte array into a uint16
+func ATo16(array []byte) uint16 {
+	return uint16(byteArrayToInt(array, 2))
+}
+
+func intToByteArray(val uint64, numBytes int) []byte {
+	array := make([]byte, numBytes)
+	for i := numBytes - 1; i >= 0; i-- {
+		array[i] = byte(val & 0xff)
+		val = val >> 8
+	}
+	return array
+}
+
+// U64ToA converts a uint64 to a byte array
+func U64ToA(val uint64) []byte {
+	return intToByteArray(uint64(val), 8)
+}
+
+// U32ToA converts a uint64 to a byte array
+func U32ToA(val uint32) []byte {
+	return intToByteArray(uint64(val), 4)
+}
+
+// U16ToA converts a uint64 to a byte array
+func U16ToA(val uint16) []byte {
+	return intToByteArray(uint64(val), 2)
+}