1 files changed, 64 insertions, 0 deletions
diff --git a/dht/infohash.go b/dht/infohash.go
new file mode 100644
index 0000000..9c3ea3d
--- /dev/null
+++ b/dht/infohash.go
@@ -0,0 +1,64 @@
+package dht
+
+import (
+	"crypto/sha1"
+	"encoding/hex"
+	"io"
+	"math/rand"
+	"time"
+)
+
+const ihLength = 20
+
+// Infohash -
+type Infohash []byte
+
+func (ih Infohash) String() string {
+	return hex.EncodeToString(ih)
+}
+func (ih Infohash) Valid() bool {
+	// TODO
+	return len(ih) == 20
+}
+
+func (ih Infohash) Equal(other Infohash) bool {
+	if len(ih) != len(other) {
+		return false
+	}
+	for i := 0; i < len(ih); i++ {
+		if ih[i] != other[i] {
+			return false
+		}
+	}
+	return true
+}
+
+// FromString -
+func (ih *Infohash) FromString(s string) error {
+	switch len(s) {
+	case 20:
+		// Byte string
+		*ih = Infohash([]byte(s))
+		return nil
+	case 40:
+		b, err := hex.DecodeString(s)
+		if err != nil {
+			return err
+		}
+		*ih = Infohash(b)
+	}
+	return nil
+}
+
+func (ih Infohash) GenNeighbour(other Infohash) Infohash {
+	s := append(ih[:10], other[10:]...)
+	return Infohash(s)
+}
+
+func randomInfoHash() (ih Infohash) {
+	random := rand.New(rand.NewSource(time.Now().UnixNano()))
+	hash := sha1.New()
+	io.WriteString(hash, time.Now().String())
+	io.WriteString(hash, string(random.Int()))
+	return Infohash(hash.Sum(nil))
+}