fix: GCDSlice returns 1 when slice is empty

Signed-off-by: lowzj <[email protected]>
dragonflyoss · Apr 27, 2020 · 10cfda1 · 10cfda1
1 parent a8ade02
commit 10cfda1
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Showing 3 changed files with 8 additions and 1 deletion.
diff --git a/dfget/config/supernode_value.go b/dfget/config/supernode_value.go
@@ -152,7 +152,7 @@ func ParseNodesSlice(value []string) ([]*NodeWeight, error) {
 	for _, v := range nodeWeightSlice {
 		result = append(result, &NodeWeight{
 			Node:   v.Node,
-			Weight: (v.Weight / gcdNumber),
+			Weight: v.Weight / gcdNumber,
 		})
 	}
 

diff --git a/pkg/algorithm/algorithm.go b/pkg/algorithm/algorithm.go
@@ -17,8 +17,13 @@
 package algorithm
 
 // GCDSlice returns the greatest common divisor of a slice.
+// It returns 1 when s is empty because that any number divided by 1 is still
+// itself.
 func GCDSlice(s []int) int {
 	length := len(s)
+	if length == 0 {
+		return 1
+	}
 	if length == 1 {
 		return s[0]
 	}

diff --git a/pkg/algorithm/algorithm_test.go b/pkg/algorithm/algorithm_test.go
@@ -53,6 +53,8 @@ func (suit *AlgorithmSuite) TestGCDSlice() {
 		slice  []int
 		result int
 	}{
+		{nil, 1},
+		{[]int{2}, 2},
 		{[]int{2, 2, 4}, 2},
 		{[]int{5, 10, 25}, 5},
 		{[]int{1, 3, 5}, 1},