add NewZrFromUInt64 to instantiate a new Zr directly from a uint64

Signed-off-by: Angelo De Caro <adc@zurich.ibm.com>

Author: adecaro

driver/common/curve.go

@@ -65,6 +65,10 @@ func (c *CurveBase) NewZrFromInt(i int64) driver.Zr {
 	return &BaseZr{Int: *big.NewInt(i), Modulus: c.Modulus}
 }
 
+func (c *CurveBase) NewZrFromUInt64(i uint64) driver.Zr {
+	return &BaseZr{Int: *new(big.Int).SetUint64(i), Modulus: c.Modulus}
+}
+
 func (c *CurveBase) NewRandomZr(rng io.Reader) driver.Zr {
 	bi, err := rand.Int(rng, &c.Modulus)
 	if err != nil {

driver/math.go

@@ -30,6 +30,7 @@ type Curve interface {
 	NewG2() G2
 	NewZrFromBytes(b []byte) Zr
 	NewZrFromInt(i int64) Zr
+	NewZrFromUInt64(i uint64) Zr
 	NewG1FromBytes(b []byte) G1
 	NewG1FromCompressed(b []byte) G1
 	NewG2FromBytes(b []byte) G2

math.go

@@ -483,6 +483,10 @@ func (c *Curve) NewZrFromInt(i int64) *Zr {
 	return &Zr{zr: c.c.NewZrFromInt(i), curveID: c.curveID}
 }
 
+func (c *Curve) NewZrFromUInt64(i uint64) *Zr {
+	return &Zr{zr: c.c.NewZrFromUInt64(i), curveID: c.curveID}
+}
+
 func (c *Curve) NewG2() *G2 {
 	return &G2{g2: c.c.NewG2(), curveID: c.curveID}
 }