Add option to input empty values at AddBatch

Add option to input empty values at AddBatch & different number of keys
& values.

addbatch_test.go

@@ -75,11 +75,17 @@ func TestAddBatchTreeEmpty(t *testing.T) {
 	defer tree.db.Close() //nolint:errcheck
 
 	bLen := tree.HashFunction().Len()
-	start := time.Now()
+	var keys, values [][]byte
 	for i := 0; i < nLeafs; i++ {
 		k := BigIntToBytes(bLen, big.NewInt(int64(i)))
 		v := BigIntToBytes(bLen, big.NewInt(int64(i*2)))
-		if err := tree.Add(k, v); err != nil {
+		keys = append(keys, k)
+		values = append(values, v)
+	}
+
+	start := time.Now()
+	for i := 0; i < nLeafs; i++ {
+		if err := tree.Add(keys[i], values[i]); err != nil {
 			t.Fatal(err)
 		}
 	}
@@ -92,13 +98,6 @@ func TestAddBatchTreeEmpty(t *testing.T) {
 	defer tree2.db.Close() //nolint:errcheck
 	tree2.dbgInit()
 
-	var keys, values [][]byte
-	for i := 0; i < nLeafs; i++ {
-		k := BigIntToBytes(bLen, big.NewInt(int64(i)))
-		v := BigIntToBytes(bLen, big.NewInt(int64(i*2)))
-		keys = append(keys, k)
-		values = append(values, v)
-	}
 	start = time.Now()
 	indexes, err := tree2.AddBatch(keys, values)
 	c.Assert(err, qt.IsNil)
@@ -916,6 +915,77 @@ func TestLoadVT(t *testing.T) {
 	c.Check(tree.Root(), qt.DeepEquals, vt.root.h)
 }
 
+// TestAddKeysWithEmptyValues calls AddBatch giving an array of empty values
+func TestAddKeysWithEmptyValues(t *testing.T) {
+	c := qt.New(t)
+
+	nLeafs := 1024
+
+	database, err := db.NewBadgerDB(c.TempDir())
+	c.Assert(err, qt.IsNil)
+	tree, err := NewTree(database, 100, HashFunctionPoseidon)
+	c.Assert(err, qt.IsNil)
+	defer tree.db.Close() //nolint:errcheck
+
+	bLen := tree.HashFunction().Len()
+	var keys, values [][]byte
+	for i := 0; i < nLeafs; i++ {
+		k := BigIntToBytes(bLen, big.NewInt(int64(i)))
+		v := []byte{}
+		keys = append(keys, k)
+		values = append(values, v)
+	}
+
+	for i := 0; i < nLeafs; i++ {
+		if err := tree.Add(keys[i], values[i]); err != nil {
+			t.Fatal(err)
+		}
+	}
+
+	database2, err := db.NewBadgerDB(c.TempDir())
+	c.Assert(err, qt.IsNil)
+	tree2, err := NewTree(database2, 100, HashFunctionPoseidon)
+	c.Assert(err, qt.IsNil)
+	defer tree2.db.Close() //nolint:errcheck
+	tree2.dbgInit()
+
+	indexes, err := tree2.AddBatch(keys, values)
+	c.Assert(err, qt.IsNil)
+	c.Check(len(indexes), qt.Equals, 0)
+
+	// check that both trees roots are equal
+	checkRoots(c, tree, tree2)
+
+	kAux, proofV, siblings, existence, err := tree2.GenProof(keys[9])
+	c.Assert(err, qt.IsNil)
+	c.Assert(proofV, qt.DeepEquals, values[9])
+	c.Assert(keys[9], qt.DeepEquals, kAux)
+	c.Assert(existence, qt.IsTrue)
+
+	// check with empty array
+	verif, err := CheckProof(tree.hashFunction, keys[9], []byte{}, tree.Root(), siblings)
+	c.Assert(err, qt.IsNil)
+	c.Check(verif, qt.IsTrue)
+
+	// check with array with only 1 zero
+	verif, err = CheckProof(tree.hashFunction, keys[9], []byte{0}, tree.Root(), siblings)
+	c.Assert(err, qt.IsNil)
+	c.Check(verif, qt.IsTrue)
+
+	// check with array with 32 zeroes
+	e32 := []byte{0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
+		0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0}
+	c.Assert(len(e32), qt.Equals, 32)
+	verif, err = CheckProof(tree.hashFunction, keys[9], e32, tree.Root(), siblings)
+	c.Assert(err, qt.IsNil)
+	c.Check(verif, qt.IsTrue)
+
+	// check with array with value!=0 returns false at verification
+	verif, err = CheckProof(tree.hashFunction, keys[9], []byte{0, 1}, tree.Root(), siblings)
+	c.Assert(err, qt.IsNil)
+	c.Check(verif, qt.IsFalse)
+}
+
 // TODO test adding batch with multiple invalid keys
 // TODO for tests of AddBatch, if the root does not match the Add root, bulk
 // all the leafs of both trees into a log file to later be able to debug and

tree.go

@@ -83,10 +83,11 @@ type Tree struct {
 	dbg *dbgStats
 }
 
-const bmSize = sha256.Size
+// bmKeySize stands for batchMemoryKeySize
+const bmKeySize = sha256.Size
 
 // TMP
-type kvMap map[[bmSize]byte]kv
+type kvMap map[[bmKeySize]byte]kv
 
 // Get retreives the value respective to a key from the KvMap
 func (m kvMap) Get(k []byte) ([]byte, bool) {
@@ -109,7 +110,7 @@ func NewTree(database db.Database, maxLevels int, hash HashFunction) (*Tree, err
 	if err == ErrKeyNotFound {
 		// store new root 0
 		t.dbBatch = t.db.NewBatch()
-		t.batchMemory = make(map[[bmSize]byte]kv) // TODO TMP
+		t.batchMemory = make(map[[bmKeySize]byte]kv) // TODO TMP
 		t.root = t.emptyHash
 		if err = t.dbPut(dbKeyRoot, t.root); err != nil {
 			return nil, err
@@ -139,7 +140,8 @@ func (t *Tree) HashFunction() HashFunction {
 }
 
 // AddBatch adds a batch of key-values to the Tree. Returns an array containing
-// the indexes of the keys failed to add.
+// the indexes of the keys failed to add. Supports empty values as input
+// parameters, which is equivalent to 0 valued byte array.
 func (t *Tree) AddBatch(keys, values [][]byte) ([]int, error) {
 	t.Lock()
 	defer t.Unlock()
@@ -151,6 +153,17 @@ func (t *Tree) AddBatch(keys, values [][]byte) ([]int, error) {
 
 	// TODO check validity of keys & values for Tree.hashFunction
 
+	// equal the number of keys & values
+	if len(keys) > len(values) {
+		// add missing values
+		for i := len(values); i < len(keys); i++ {
+			values = append(values, emptyValue)
+		}
+	} else if len(keys) < len(values) {
+		// crop extra values
+		values = values[:len(keys)]
+	}
+
 	invalids, err := vt.addBatch(keys, values)
 	if err != nil {
 		return nil, err
@@ -166,7 +179,7 @@ func (t *Tree) AddBatch(keys, values [][]byte) ([]int, error) {
 
 	// store pairs in db
 	t.dbBatch = t.db.NewBatch()
-	t.batchMemory = make(map[[bmSize]byte]kv) // TODO TMP
+	t.batchMemory = make(map[[bmKeySize]byte]kv) // TODO TMP
 	for i := 0; i < len(pairs); i++ {
 		if err := t.dbPut(pairs[i][0], pairs[i][1]); err != nil {
 			return nil, err
@@ -217,7 +230,7 @@ func (t *Tree) Add(k, v []byte) error {
 
 	var err error
 	t.dbBatch = t.db.NewBatch()
-	t.batchMemory = make(map[[bmSize]byte]kv) // TODO TMP
+	t.batchMemory = make(map[[bmKeySize]byte]kv) // TODO TMP
 
 	// TODO check validity of key & value for Tree.hashFunction
 
@@ -491,7 +504,7 @@ func (t *Tree) Update(k, v []byte) error {
 
 	var err error
 	t.dbBatch = t.db.NewBatch()
-	t.batchMemory = make(map[[bmSize]byte]kv) // TODO TMP
+	t.batchMemory = make(map[[bmKeySize]byte]kv) // TODO TMP
 
 	keyPath := make([]byte, t.hashFunction.Len())
 	copy(keyPath[:], k)

vt.go

@@ -319,7 +319,7 @@ func (t *vt) computeHashes() ([][2][]byte, error) {
 				t.params.maxLevels, bucketVT.params, bucketPairs[cpu])
 			if err != nil {
 				// TODO WIP
-				panic("TODO" + err.Error())
+				panic("TODO: " + err.Error())
 			}
 
 			subRoots[cpu] = bucketVT.root