Avoid heap allocations in Htonl (#55)

* Avoid heap allocations in Htonl

* move new allocation benchmarks in a BenchmarkXXX

pkg/inet.go

@@ -1,35 +1,17 @@
 package rpmdb
 
 import (
-	"bytes"
 	"encoding/binary"
-	"log"
 )
 
 func Htonl(val int32) int32 {
-	buf := new(bytes.Buffer)
-	if err := binary.Write(buf, binary.LittleEndian, val); err != nil {
-		log.Println(err)
-		return 0
-	}
-
-	if err := binary.Read(buf, binary.BigEndian, &val); err != nil {
-		log.Println(err)
-		return 0
-	}
-	return val
+	var buf [4]byte
+	binary.LittleEndian.PutUint32(buf[:], uint32(val))
+	return int32(binary.BigEndian.Uint32(buf[:]))
 }
 
 func HtonlU(val uint32) uint32 {
-	buf := new(bytes.Buffer)
-	if err := binary.Write(buf, binary.LittleEndian, val); err != nil {
-		log.Println(err)
-		return 0
-	}
-
-	if err := binary.Read(buf, binary.BigEndian, &val); err != nil {
-		log.Println(err)
-		return 0
-	}
-	return val
+	var buf [4]byte
+	binary.LittleEndian.PutUint32(buf[:], val)
+	return binary.BigEndian.Uint32(buf[:])
 }

pkg/rpmdb_test.go

@@ -10,8 +10,8 @@ import (
 	_ "github.com/glebarez/go-sqlite"
 )
 
-func TestPackageList(t *testing.T) {
-	tests := []struct {
+var (
+	packageTests = []struct {
 		name    string
 		file    string // Test input file
 		pkgList []*PackageInfo
@@ -87,8 +87,10 @@ func TestPackageList(t *testing.T) {
 			pkgList: Fedora35PlusMongoDBWithSQLite3(),
 		},
 	}
+)
 
-	for _, tt := range tests {
+func TestPackageList(t *testing.T) {
+	for _, tt := range packageTests {
 		t.Run(tt.name, func(t *testing.T) {
 			db, err := Open(tt.file)
 			require.NoError(t, err)
@@ -121,6 +123,24 @@ func TestPackageList(t *testing.T) {
 	}
 }
 
+func BenchmarkRpmDB_Package(b *testing.B) {
+	for _, tt := range packageTests {
+		b.Run(tt.name, func(b *testing.B) {
+			for i := 0; i < b.N; i++ {
+				db, err := Open(tt.file)
+				if err != nil {
+					b.Fatal(err)
+				}
+				_, err = db.ListPackages()
+				if err != nil {
+					b.Fatal(err)
+				}
+			}
+			b.ReportAllocs()
+		})
+	}
+}
+
 func TestRpmDB_Package(t *testing.T) {
 	tests := []struct {
 		name                   string