bugfix: slimtrie: getStep should use int32 id instead of uint16 id. fix

#104; thanks to @aaaton
openacid · May 28, 2019 · 4d4ced5 · 4d4ced5
1 parent 4430458
commit 4d4ced5
Show file tree

Hide file tree

Showing 3 changed files with 50,037 additions and 5 deletions.
diff --git a/trie/slimtrie.go b/trie/slimtrie.go
@@ -290,7 +290,7 @@ func (st *SlimTrie) searchID(key string) (lID, eqID, rID int32) {
 			break
 		}
 
-		i += int(st.getStep(uint16(eqID)))
+		i += int(st.getStep(eqID))
 
 		if lenWords < i {
 			rID = eqID
@@ -382,7 +382,7 @@ func (st *SlimTrie) Get(key string) (eqVal interface{}, found bool) {
 			break
 		}
 
-		idx += int(st.getStep(uint16(eqID)))
+		idx += int(st.getStep(eqID))
 		if lenWords < idx {
 			eqID = -1
 			break
@@ -397,7 +397,7 @@ func (st *SlimTrie) Get(key string) (eqVal interface{}, found bool) {
 		shift := 4 - (idx&1)*4
 		word = ((key[idx>>1] >> uint(shift)) & 0x0f)
 
-		if (bm >> word & 1) == 1 {
+		if ((bm >> word) & 1) == 1 {
 			chNum := bits.OnesCount16(bm & ((uint16(1) << word) - 1))
 			eqID = of + int32(chNum)
 		} else {
@@ -421,8 +421,8 @@ func (st *SlimTrie) getChild(idx int32) (bitmap uint16, offset int32, found bool
 	return 0, 0, false
 }
 
-func (st *SlimTrie) getStep(idx uint16) uint16 {
-	step, found := st.Steps.Get(int32(idx))
+func (st *SlimTrie) getStep(idx int32) uint16 {
+	step, found := st.Steps.Get(idx)
 	if found {
 		return step
 	}

diff --git a/trie/slimtrie_test.go b/trie/slimtrie_test.go
@@ -553,6 +553,33 @@ func TestSlimTrie_RangeGet_rangeindex_bug_2019_05_21(t *testing.T) {
 	}
 }
 
+func TestSlimTrie_u16step_bug_2019_05_29(t *testing.T) {
+
+	// Reported by @aaaton
+	// 2019 May 29
+	//
+	// When number of keys becomes greater than 50000,
+	// SlimTrie.Get() returns negaitve for some existent keys.
+	// Caused by SlimTrie.step has been using uint16 id, it should be int32.
+
+	ta := require.New(t)
+	keys := keys50k
+	n := len(keys)
+	values := make([]int32, n)
+	for i := 0; i < n; i++ {
+		values[i] = int32(i)
+	}
+	st, err := NewSlimTrie(encode.I32{}, keys, values)
+	ta.Nil(err)
+
+	for i, c := range keys {
+		rst, found := st.Get(c)
+		ta.Equal(values[i], rst, "%d-th: Get: %+v", i+1, c)
+		ta.Equal(true, found, "%d-th: Get: %+v", i+1, c)
+	}
+
+}
+
 func TestNewSlimTrie(t *testing.T) {
 
 	st, err := NewSlimTrie(encode.Int{}, []string{"ab", "cd"}, []int{1, 2})