Add Inner Ring code

pkg/morph/client/balance/decimals.go

@@ -0,0 +1,44 @@
+package balance
+
+import (
+	"github.com/nspcc-dev/neofs-node/pkg/morph/client"
+	"github.com/pkg/errors"
+)
+
+// DecimalsArgs groups the arguments
+// of decimals test invoke call.
+type DecimalsArgs struct {
+}
+
+// DecimalsValues groups the stack parameters
+// returned by decimals test invoke.
+type DecimalsValues struct {
+	decimals int64 // decimals value
+}
+
+// Decimals returns the decimals value.
+func (d *DecimalsValues) Decimals() int64 {
+	return d.decimals
+}
+
+// Decimals performs the test invoke of decimals
+// method of NeoFS Balance contract.
+func (c *Client) Decimals(args DecimalsArgs) (*DecimalsValues, error) {
+	prms, err := c.client.TestInvoke(
+		c.decimalsMethod,
+	)
+	if err != nil {
+		return nil, errors.Wrapf(err, "could not perform test invocation (%s)", c.decimalsMethod)
+	} else if ln := len(prms); ln != 1 {
+		return nil, errors.Errorf("unexpected stack item count (%s): %d", c.decimalsMethod, ln)
+	}
+
+	decimals, err := client.IntFromStackParameter(prms[0])
+	if err != nil {
+		return nil, errors.Wrapf(err, "could not get integer stack item from stack item (%s)", c.decimalsMethod)
+	}
+
+	return &DecimalsValues{
+		decimals: decimals,
+	}, nil
+}