[#42] netmap: move package from neofs-api-go

Signed-off-by: Evgenii Stratonikov <evgeniy@nspcc.ru>

netmap/clause.go

@@ -0,0 +1,69 @@
+package netmap
+
+import (
+	"github.com/nspcc-dev/neofs-api-go/v2/netmap"
+)
+
+// Clause is an enumeration of selector modifiers
+// that shows how the node set will be formed.
+type Clause uint32
+
+const (
+	ClauseUnspecified Clause = iota
+
+	// ClauseSame is a selector modifier to select only nodes having the same value of bucket attribute.
+	ClauseSame
+
+	// ClauseDistinct is a selector modifier to select nodes having different values of bucket attribute.
+	ClauseDistinct
+)
+
+// ClauseFromV2 converts v2 Clause to Clause.
+func ClauseFromV2(c netmap.Clause) Clause {
+	switch c {
+	default:
+		return ClauseUnspecified
+	case netmap.Same:
+		return ClauseSame
+	case netmap.Distinct:
+		return ClauseDistinct
+	}
+}
+
+// ToV2 converts Clause to v2 Clause.
+func (c Clause) ToV2() netmap.Clause {
+	switch c {
+	default:
+		return netmap.UnspecifiedClause
+	case ClauseDistinct:
+		return netmap.Distinct
+	case ClauseSame:
+		return netmap.Same
+	}
+}
+
+// String returns string representation of Clause.
+//
+// String mapping:
+//  * ClauseDistinct: DISTINCT;
+//  * ClauseSame: SAME;
+//  * ClauseUnspecified, default: CLAUSE_UNSPECIFIED.
+func (c Clause) String() string {
+	return c.ToV2().String()
+}
+
+// FromString parses Clause from a string representation.
+// It is a reverse action to String().
+//
+// Returns true if s was parsed successfully.
+func (c *Clause) FromString(s string) bool {
+	var g netmap.Clause
+
+	ok := g.FromString(s)
+
+	if ok {
+		*c = ClauseFromV2(g)
+	}
+
+	return ok
+}