Optimize rank comparison on x86 (little-endian)

4 files changed, 37 insertions, 18 deletions

diff --git a/src/result.go b/src/result.go
index 58cbafd7..289d83a0 100644
--- a/src/result.go
+++ b/src/result.go
@@ -70,7 +70,7 @@ func buildResult(item *Item, offsets []Offset, score int) Result {
 				}
 			}
 		}
-		result.points[idx] = val
+		result.points[3-idx] = val
 	}
 
 	return result
@@ -224,16 +224,3 @@ func (a ByRelevanceTac) Swap(i, j int) {
 func (a ByRelevanceTac) Less(i, j int) bool {
 	return compareRanks(a[i], a[j], true)
 }
-
-func compareRanks(irank Result, jrank Result, tac bool) bool {
-	for idx := 0; idx < 4; idx++ {
-		left := irank.points[idx]
-		right := jrank.points[idx]
-		if left < right {
-			return true
-		} else if left > right {
-			return false
-		}
-	}
-	return (irank.item.Index() <= jrank.item.Index()) != tac
-}
diff --git a/src/result_others.go b/src/result_others.go
new file mode 100644
index 00000000..e3363a8e
--- /dev/null
+++ b/src/result_others.go
@@ -0,0 +1,16 @@
+// +build !386,!amd64
+
+package fzf
+
+func compareRanks(irank Result, jrank Result, tac bool) bool {
+	for idx := 3; idx >= 0; idx-- {
+		left := irank.points[idx]
+		right := jrank.points[idx]
+		if left < right {
+			return true
+		} else if left > right {
+			return false
+		}
+	}
+	return (irank.item.Index() <= jrank.item.Index()) != tac
+}
diff --git a/src/result_test.go b/src/result_test.go
index 1d86b1d3..afd17307 100644
--- a/src/result_test.go
+++ b/src/result_test.go
@@ -59,10 +59,10 @@ func TestResultRank(t *testing.T) {
 	strs := [][]rune{[]rune("foo"), []rune("foobar"), []rune("bar"), []rune("baz")}
 	item1 := buildResult(
 		withIndex(&Item{text: util.RunesToChars(strs[0])}, 1), []Offset{}, 2)
-	if item1.points[0] != math.MaxUint16-2 || // Bonus
-		item1.points[1] != 3 || // Length
-		item1.points[2] != 0 || // Unused
-		item1.points[3] != 0 || // Unused
+	if item1.points[3] != math.MaxUint16-2 || // Bonus
+		item1.points[2] != 3 || // Length
+		item1.points[1] != 0 || // Unused
+		item1.points[0] != 0 || // Unused
 		item1.item.Index() != 1 {
 		t.Error(item1)
 	}
diff --git a/src/result_x86.go b/src/result_x86.go
new file mode 100644
index 00000000..60e26e99
--- /dev/null
+++ b/src/result_x86.go
@@ -0,0 +1,16 @@
+// +build 386 amd64
+
+package fzf
+
+import "unsafe"
+
+func compareRanks(irank Result, jrank Result, tac bool) bool {
+	left := *(*uint64)(unsafe.Pointer(&irank.points[0]))
+	right := *(*uint64)(unsafe.Pointer(&jrank.points[0]))
+	if left < right {
+		return true
+	} else if left > right {
+		return false
+	}
+	return (irank.item.Index() <= jrank.item.Index()) != tac
+}