[#428] reputation: Define basic types

Define PeerID, TrustValue and Trust types and basic methods on them.

Signed-off-by: Leonard Lyubich <leonard@nspcc.ru>

pkg/services/reputation/peer.go

@@ -0,0 +1,17 @@
+package reputation
+
+const peerIDLength = 33
+
+// PeerID represents identifier of reputation system participant.
+type PeerID [peerIDLength]byte
+
+// Bytes converts PeerID to []byte.
+func (id PeerID) Bytes() []byte {
+	return id[:]
+}
+
+// PeerIDFromBytes restores PeerID from []byte.
+func PeerIDFromBytes(data []byte) (id PeerID) {
+	copy(id[:], data)
+	return
+}

pkg/services/reputation/trust.go

@@ -0,0 +1,80 @@
+package reputation
+
+import (
+	"strconv"
+)
+
+// TrustValue represents the numeric value of the node's trust.
+type TrustValue float64
+
+// TrustOne is a trust value equal to one.
+const TrustOne = TrustValue(1)
+
+// TrustValueFromFloat64 converts float64 to TrustValue.
+func TrustValueFromFloat64(v float64) TrustValue {
+	return TrustValue(v)
+}
+
+// TrustValueFromInt converts int to TrustValue.
+func TrustValueFromInt(v int) TrustValue {
+	return TrustValue(v)
+}
+
+func (v TrustValue) String() string {
+	return strconv.FormatFloat(float64(v), 'f', -1, 64)
+}
+
+// Float64 converts TrustValue to float64.
+func (v TrustValue) Float64() float64 {
+	return float64(v)
+}
+
+// Add adds v2 to v.
+func (v *TrustValue) Add(v2 TrustValue) {
+	*v = *v + v2
+}
+
+// Div returns the result of dividing v by v2.
+func (v TrustValue) Div(v2 TrustValue) TrustValue {
+	return v / v2
+}
+
+// IsZero returns true if v equal to zero.
+func (v TrustValue) IsZero() bool {
+	return v == 0
+}
+
+// Trust represents peer's trust (reputation).
+type Trust struct {
+	peer PeerID
+
+	val TrustValue
+}
+
+// TrustHandler describes the signature of the reputation.Trust
+// value handling function.
+//
+// Termination of processing without failures is usually signaled
+// with a zero error, while a specific value may describe the reason
+// for failure.
+type TrustHandler func(Trust) error
+
+// Value returns peer's trust value.
+func (t Trust) Value() TrustValue {
+	return t.val
+}
+
+// SetValue sets peer's trust value.
+func (t *Trust) SetValue(val TrustValue) {
+	t.val = val
+}
+
+// Peer returns trusted peer ID.
+func (t Trust) Peer() PeerID {
+	return t.peer
+}
+
+// SetPeer sets trusted peer ID.
+func (t *Trust) SetPeer(id PeerID) {
+	t.peer = id
+}