refactor: move applicable root methods to MerkleRoot and inherit in M…

…erkleSumRoot

root.go

@@ -5,33 +5,10 @@ import (
 	"fmt"
 )
 
-// MustSum returns the uint64 sum of the merkle root, it checks the length of the
-// merkle root and if it is no the same as the size of the SMST's expected
-// root hash it will panic.
-func (root MerkleSumRoot) MustSum() uint64 {
-	sum, err := root.Sum()
-	if err != nil {
-		panic(err)
-	}
-
-	return sum
-}
-
-// Sum returns the uint64 sum of the merkle root, it checks the length of the
-// merkle root and if it is no the same as the size of the SMST's expected
-// root hash it will return an error.
-func (root MerkleSumRoot) Sum() (uint64, error) {
-	if err := root.validateBasic(); err != nil {
-		return 0, err
-	}
-
-	return root.sum(), nil
-}
-
 // MustCount returns the uint64 count of the merkle root, a cryptographically secure
 // count of the number of non-empty leafs in the tree. It panics if the root length
 // is invalid.
-func (root MerkleSumRoot) MustCount() uint64 {
+func (root MerkleRoot) MustCount() uint64 {
 	count, err := root.Count()
 	if err != nil {
 		panic(err)
@@ -43,7 +20,7 @@ func (root MerkleSumRoot) MustCount() uint64 {
 // Count returns the uint64 count of the merkle root, a cryptographically secure
 // count of the number of non-empty leafs in the tree. It returns an error if the
 // root length is invalid.
-func (root MerkleSumRoot) Count() (uint64, error) {
+func (root MerkleRoot) Count() (uint64, error) {
 	if err := root.validateBasic(); err != nil {
 		return 0, err
 	}
@@ -52,39 +29,62 @@ func (root MerkleSumRoot) Count() (uint64, error) {
 }
 
 // DigestSize returns the length of the digest portion of the root.
-func (root MerkleSumRoot) DigestSize() int {
+func (root MerkleRoot) DigestSize() int {
 	return len(root) - countSizeBytes - sumSizeBytes
 }
 
 // HasDigestSize returns true if the root digest size is the same as
 // that of the size of the given hasher.
-func (root MerkleSumRoot) HasDigestSize(size int) bool {
+func (root MerkleRoot) HasDigestSize(size int) bool {
 	return root.DigestSize() == size
 }
 
+// MustSum returns the uint64 sum of the merkle root, it checks the length of the
+// merkle root and if it is no the same as the size of the SMST's expected
+// root hash it will panic.
+func (root MerkleSumRoot) MustSum() uint64 {
+	sum, err := root.Sum()
+	if err != nil {
+		panic(err)
+	}
+
+	return sum
+}
+
+// Sum returns the uint64 sum of the merkle root, it checks the length of the
+// merkle root and if it is no the same as the size of the SMST's expected
+// root hash it will return an error.
+func (root MerkleSumRoot) Sum() (uint64, error) {
+	if err := root.validateBasic(); err != nil {
+		return 0, err
+	}
+
+	return root.sum(), nil
+}
+
 // validateBasic returns an error if the root digest size is not a power of two.
-func (root MerkleSumRoot) validateBasic() error {
+func (root MerkleRoot) validateBasic() error {
 	if !isPowerOfTwo(root.DigestSize()) {
 		return fmt.Errorf("MerkleSumRoot#validateBasic: invalid root length")
 	}
 
 	return nil
 }
 
+// count returns the count of the node stored in the root.
+func (root MerkleRoot) count() uint64 {
+	_, firstCountByteIdx := getFirstMetaByteIdx(root)
+
+	return binary.BigEndian.Uint64(root[firstCountByteIdx:])
+}
+
 // sum returns the sum of the node stored in the root.
 func (root MerkleSumRoot) sum() uint64 {
 	firstSumByteIdx, firstCountByteIdx := getFirstMetaByteIdx(root)
 
 	return binary.BigEndian.Uint64(root[firstSumByteIdx:firstCountByteIdx])
 }
 
-// count returns the count of the node stored in the root.
-func (root MerkleSumRoot) count() uint64 {
-	_, firstCountByteIdx := getFirstMetaByteIdx(root)
-
-	return binary.BigEndian.Uint64(root[firstCountByteIdx:])
-}
-
 // isPowerOfTwo function returns true if the input n is a power of 2
 func isPowerOfTwo(n int) bool {
 	// A power of 2 has only one bit set in its binary representation

types.go

@@ -26,7 +26,7 @@ var (
 type MerkleRoot []byte
 
 // MerkleSumRoot is a type alias for a byte slice returned from SparseMerkleSumTrie#Root().
-type MerkleSumRoot []byte
+type MerkleSumRoot = MerkleRoot
 
 // A high-level interface that captures the behaviour of all types of nodes
 type trieNode interface {