Add Hash type hex parser

merkletree.go

@@ -7,6 +7,7 @@ import (
 	"fmt"
 	"io"
 	"math/big"
+	"strings"
 	"sync"
 
 	"github.com/iden3/go-iden3-core/common"
@@ -120,6 +121,16 @@ func NewHashFromBytes(b []byte) (*Hash, error) {
 	return &h, nil
 }
 
+// NewHashFromHex returns a *Hash representation of the given hex string
+func NewHashFromHex(h string) (*Hash, error) {
+	h = strings.TrimPrefix(h, "0x")
+	b, err := hex.DecodeString(h)
+	if err != nil {
+		return nil, err
+	}
+	return NewHashFromBytes(b)
+}
+
 // MerkleTree is the struct with the main elements of the MerkleTree
 type MerkleTree struct {
 	sync.RWMutex

merkletree_test.go

@@ -55,6 +55,12 @@ func TestHashParsers(t *testing.T) {
 	b2, err := NewHashFromBytes(b.Bytes())
 	assert.Nil(t, err)
 	assert.Equal(t, b.String(), b2.BigInt().String())
+
+	h2, err := NewHashFromHex(h.Hex())
+	assert.Nil(t, err)
+	assert.Equal(t, h, h2)
+	_, err = NewHashFromHex("0x12")
+	assert.NotNil(t, err)
 }
 
 func TestNewTree(t *testing.T) {