feat: add xml marshal for Uint type (#364)

* feat: add xml marshal for Uint type

* feat: add ut for xml marshal for Uint type

* fix: refine comments

---------

Co-authored-by: dylanhuang <j75689@gmail.com>
Co-authored-by: Clyde <clyde.m@nodereal.io>

math/uint.go

@@ -1,6 +1,7 @@
 package math
 
 import (
+	"encoding/xml"
 	"errors"
 	"fmt"
 	"math/big"
@@ -137,6 +138,21 @@ func MaxUint(u1, u2 Uint) Uint { return NewUintFromBigInt(max(u1.i, u2.i)) }
 // Human readable string
 func (u Uint) String() string { return u.i.String() }
 
+// MarshalXML defines custom encoding for xml Marshaler
+func (u Uint) MarshalXML(e *xml.Encoder, start xml.StartElement) error {
+	return e.EncodeElement(u.String(), start)
+}
+
+// UnmarshalXML defines custom decoding for xml Marshaler
+func (u *Uint) UnmarshalXML(d *xml.Decoder, start xml.StartElement) error {
+	var s string
+	if err := d.DecodeElement(&s, &start); err != nil {
+		return err
+	}
+	*u = NewUintFromString(s)
+	return nil
+}
+
 // MarshalJSON defines custom encoding scheme
 func (u Uint) MarshalJSON() ([]byte, error) {
 	if u.i == nil { // Necessary since default Uint initialization has i.i as nil

math/uint_test.go

@@ -1,6 +1,7 @@
 package math_test
 
 import (
+	"encoding/xml"
 	"fmt"
 	"math"
 	"math/big"
@@ -377,3 +378,11 @@ func (s *uintTestSuite) TestUintBigEndian() {
 	s.Require().Equal(u1, u2)
 
 }
+
+func (s *uintTestSuite) TestUintXmlMarshalRoundTrip() {
+	u1 := sdkmath.NewUint(256)
+	marshalResult, _ := xml.Marshal(u1)
+	u2 := sdkmath.Uint{}
+	xml.Unmarshal(marshalResult, &u2)
+	s.Require().Equal(u1, u2)
+}