From 7e8c1e3394f27c86eeddf60d4e9ac6d4267035ec Mon Sep 17 00:00:00 2001
From: Sunny Aggarwal <sunnya97@gmail.com>
Date: Mon, 19 Mar 2018 21:04:52 +0100
Subject: [PATCH] added Substore

---
 Gopkg.lock              |  2 +-
 store/iavlstore.go      |  7 +++++++
 store/iavlstore_test.go | 20 ++++++++++++++++++++
 3 files changed, 28 insertions(+), 1 deletion(-)

diff --git a/Gopkg.lock b/Gopkg.lock
index c9e3eb67e5..bff5e924da 100644
--- a/Gopkg.lock
+++ b/Gopkg.lock
@@ -463,6 +463,6 @@
 [solve-meta]
   analyzer-name = "dep"
   analyzer-version = 1
-  inputs-digest = "3d1aebf798b51882ed5281b0ca0a3766c32cdb08592de57dd3d574a4b3e67987"
+  inputs-digest = "64881873c2a0899c3d6920de588c06a2b59e6b072e1a3d7e676e906cb7d5ad0e"
   solver-name = "gps-cdcl"
   solver-version = 1
diff --git a/store/iavlstore.go b/store/iavlstore.go
index e63585a16b..87b0863884 100644
--- a/store/iavlstore.go
+++ b/store/iavlstore.go
@@ -119,6 +119,13 @@ func (st *iavlStore) Iterator(start, end []byte) Iterator {
 	return newIAVLIterator(st.tree.Tree(), start, end, true)
 }
 
+func (st *iavlStore) Subspace(prefix []byte) Iterator {
+	end := make([]byte, len(prefix))
+	copy(end, prefix)
+	end[len(end)-1]++
+	return st.Iterator(prefix, end)
+}
+
 // Implements IterKVStore.
 func (st *iavlStore) ReverseIterator(start, end []byte) Iterator {
 	return newIAVLIterator(st.tree.Tree(), start, end, false)
diff --git a/store/iavlstore_test.go b/store/iavlstore_test.go
index c426e4d8a8..7adae625ea 100644
--- a/store/iavlstore_test.go
+++ b/store/iavlstore_test.go
@@ -82,6 +82,26 @@ func TestIAVLIterator(t *testing.T) {
 	}
 }
 
+func TestIAVLSubspace(t *testing.T) {
+	db := dbm.NewMemDB()
+	tree, _ := newTree(t, db)
+	iavlStore := newIAVLStore(tree, numHistory)
+
+	iavlStore.Set([]byte("test1"), []byte("test1"))
+	iavlStore.Set([]byte("test2"), []byte("test2"))
+	iavlStore.Set([]byte("test3"), []byte("test3"))
+
+	iter := iavlStore.Subspace([]byte("test"))
+	expected := []string{"test1", "test2", "test3"}
+	for i := 0; iter.Valid(); iter.Next() {
+		expectedKey := expected[i]
+		key, value := iter.Key(), iter.Value()
+		assert.EqualValues(t, key, expectedKey)
+		assert.EqualValues(t, value, expectedKey)
+		i += 1
+	}
+}
+
 func TestIAVLStoreQuery(t *testing.T) {
 	db := dbm.NewMemDB()
 	tree := iavl.NewVersionedTree(db, cacheSize)