Added GetBlocks payload

pkg/network/payload/getblocks.go

@@ -0,0 +1,48 @@
+package payload
+
+import (
+	"encoding/binary"
+	"io"
+
+	. "github.com/anthdm/neo-go/pkg/util"
+)
+
+// GetBlocks payload
+type GetBlocks struct {
+	// hash of latest block that node requests
+	HashStart []Uint256
+	// hash of last block that node requests
+	HashStop Uint256
+}
+
+// NewGetBlocks return a pointer to a GetBlocks object.
+func NewGetBlocks(start []Uint256, stop Uint256) *GetBlocks {
+	return &GetBlocks{
+		HashStart: start,
+		HashStop:  stop,
+	}
+}
+
+// DecodeBinary implements the payload interface.
+func (p *GetBlocks) DecodeBinary(r io.Reader) error {
+	var lenStart uint8
+
+	err := binary.Read(r, binary.LittleEndian, &lenStart)
+	p.HashStart = make([]Uint256, lenStart)
+	err = binary.Read(r, binary.LittleEndian, &p.HashStart)
+	err = binary.Read(r, binary.LittleEndian, &p.HashStop)
+
+	return err
+}
+
+// EncodeBinary implements the payload interface.
+func (p *GetBlocks) EncodeBinary(w io.Writer) error {
+	err := binary.Write(w, binary.LittleEndian, uint8(len(p.HashStart)))
+	err = binary.Write(w, binary.LittleEndian, p.HashStart)
+	err = binary.Write(w, binary.LittleEndian, p.HashStop)
+
+	return err
+}
+
+// Size implements the payload interface.
+func (p *GetBlocks) Size() uint32 { return 0 }

pkg/network/payload/getblocks_test.go

@@ -0,0 +1,37 @@
+package payload
+
+import (
+	"bytes"
+	"crypto/sha256"
+	"reflect"
+	"testing"
+
+	. "github.com/anthdm/neo-go/pkg/util"
+)
+
+func TestGetBlocksEncodeDecode(t *testing.T) {
+	start := []Uint256{
+		sha256.Sum256([]byte("a")),
+		sha256.Sum256([]byte("b")),
+	}
+	stop := sha256.Sum256([]byte("c"))
+
+	p := NewGetBlocks(start, stop)
+	buf := new(bytes.Buffer)
+	if err := p.EncodeBinary(buf); err != nil {
+		t.Fatal(err)
+	}
+
+	if have, want := buf.Len(), 1+64+32; have != want {
+		t.Fatalf("expecting a length of %d got %d", want, have)
+	}
+
+	pDecode := &GetBlocks{}
+	if err := pDecode.DecodeBinary(buf); err != nil {
+		t.Fatal(err)
+	}
+
+	if !reflect.DeepEqual(p, pDecode) {
+		t.Fatalf("expecting both getblocks payloads to be equal %v and %v", p, pDecode)
+	}
+}