refactor: rewrite math max and min with generics (#1447)

Signed-off-by: Gaius <gaius.qi@gmail.com>

manager/searcher/searcher.go

@@ -236,7 +236,7 @@ func calculateMultiElementAffinityScore(dst, src string) float64 {
 	var score, elementLen int
 	dstElements := strings.Split(dst, "|")
 	srcElements := strings.Split(src, "|")
-	elementLen = math.MaxInt(len(dstElements), len(srcElements))
+	elementLen = math.Min(len(dstElements), len(srcElements))
 
 	// Maximum element length is 5
 	if elementLen > maxElementLen {

pkg/math/math.go

@@ -16,50 +16,28 @@
 
 package math
 
-func MaxInt(a, b int) int {
-	if a < b {
-		return a
+import "golang.org/x/exp/constraints"
+
+// Max returns the maximum of values.
+func Max[T constraints.Ordered](values ...T) T {
+	max := values[0]
+	for _, value := range values {
+		if value > max {
+			max = value
+		}
 	}
 
-	return b
+	return max
 }
 
-func MaxInt32(a, b int32) int32 {
-	if a > b {
-		return a
+// Min returns the minimum of values.
+func Min[T constraints.Ordered](values ...T) T {
+	min := values[0]
+	for _, value := range values {
+		if value < min {
+			min = value
+		}
 	}
 
-	return b
-}
-
-func MaxInt64(a, b int64) int64 {
-	if a > b {
-		return a
-	}
-
-	return b
-}
-
-func MinInt(a, b int) int {
-	if a < b {
-		return a
-	}
-
-	return b
-}
-
-func MinInt32(a, b int32) int32 {
-	if a < b {
-		return a
-	}
-
-	return b
-}
-
-func MinInt64(a, b int64) int64 {
-	if a < b {
-		return a
-	}
-
-	return b
+	return min
 }

pkg/math/math_test.go

@@ -0,0 +1,59 @@
+/*
+ *     Copyright 2022 The Dragonfly Authors
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package math
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+)
+
+func TestMax(t *testing.T) {
+	assert := assert.New(t)
+	assert.Equal(1, Max(1))
+	assert.Equal(3, Max(1, 2, 3))
+	assert.Equal(int8(3), Max(int8(1), int8(2), int8(3)))
+	assert.Equal(int16(3), Max(int16(1), int16(2), int16(3)))
+	assert.Equal(int32(3), Max(int32(1), int32(2), int32(3)))
+	assert.Equal(int64(3), Max(int64(1), int64(2), int64(3)))
+	assert.Equal(uint(3), Max(uint(1), uint(2), uint(3)))
+	assert.Equal(uint8(3), Max(uint8(1), uint8(2), uint8(3)))
+	assert.Equal(uint16(3), Max(uint16(1), uint16(2), uint16(3)))
+	assert.Equal(uint32(3), Max(uint32(1), uint32(2), uint32(3)))
+	assert.Equal(uint64(3), Max(uint64(1), uint64(2), uint64(3)))
+	assert.Equal(float32(1.3), Max(float32(1.1), float32(1.2), float32(1.3)))
+	assert.Equal(float64(1.3), Max(1.1, 1.2, 1.3))
+	assert.Equal("c", Max("a", "b", "c"))
+}
+
+func TestMin(t *testing.T) {
+	assert := assert.New(t)
+	assert.Equal(1, Min(1))
+	assert.Equal(1, Min(1, 2, 3))
+	assert.Equal(int8(1), Min(int8(1), int8(2), int8(3)))
+	assert.Equal(int16(1), Min(int16(1), int16(2), int16(3)))
+	assert.Equal(int32(1), Min(int32(1), int32(2), int32(3)))
+	assert.Equal(int64(1), Min(int64(1), int64(2), int64(3)))
+	assert.Equal(uint(1), Min(uint(1), uint(2), uint(3)))
+	assert.Equal(uint8(1), Min(uint8(1), uint8(2), uint8(3)))
+	assert.Equal(uint16(1), Min(uint16(1), uint16(2), uint16(3)))
+	assert.Equal(uint32(1), Min(uint32(1), uint32(2), uint32(3)))
+	assert.Equal(uint64(1), Min(uint64(1), uint64(2), uint64(3)))
+	assert.Equal(float32(1.1), Min(float32(1.1), float32(1.2), float32(1.3)))
+	assert.Equal(float64(1.1), Min(1.1, 1.2, 1.3))
+	assert.Equal("a", Min("a", "b", "c"))
+}

scheduler/scheduler/evaluator/evaluator_base.go

@@ -159,7 +159,7 @@ func calculateMultiElementAffinityScore(dst, src string) float64 {
 	var score, elementLen int
 	dstElements := strings.Split(dst, "|")
 	srcElements := strings.Split(src, "|")
-	elementLen = math.MaxInt(len(dstElements), len(srcElements))
+	elementLen = math.Min(len(dstElements), len(srcElements))
 
 	// Maximum element length is 5.
 	if elementLen > maxElementLen {