Avoid heap allocations in Htonl

Author: jinroh

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

@@ -119,6 +119,17 @@ func TestPackageList(t *testing.T) {
 			}
 		})
 	}
+
+	for _, tt := range tests {
+		allocs := testing.AllocsPerRun(10, func() {
+			db, err := Open(tt.file)
+			require.NoError(t, err)
+
+			_, err = db.ListPackages()
+			require.NoError(t, err)
+		})
+		t.Logf("Allocations per run %q: %f", tt.name, allocs)
+	}
 }
 
 func TestRpmDB_Package(t *testing.T) {