is this okay?

backend/alsa_wrapper/alsa_wrapper.go

@@ -0,0 +1,65 @@
+package alsa_wrapper
+
+/*
+#ifndef ARREMI
+#define ARREMI
+#cgo LDFLAGS: -lasound
+#include <stdlib.h>
+#include "alsa_wrapper.h"
+#endif
+*/
+import "C"
+import (
+	"fmt"
+	"unsafe"
+)
+
+// NewClient to register new ALSA client.
+func NewClient(name string) error {
+	cDevName := C.CString(name)
+	defer C.free(unsafe.Pointer(cDevName))
+	status = int(C.new_client(cDevName))
+	if status != 0 {
+		stage, errCode := resolveErrCode(status)
+		switch stage {
+		case 1:
+			return fmt.Errorf("Error while opening sequencer. %d", errCode)
+		case 2:
+			return fmt.Errorf("Error while getting sequencer id. %d", errCode)
+		case 3:
+			return fmt.Errorf("Error while setting sequencer name. %d", errCode)
+		}
+	}
+}
+
+// NewPort to reigister new MIDI port.
+func NewPort(name string) error {
+	cPortName := C.CString(name)
+	defer C.free(unsafe.Pointer(cPortName))
+	status = int(C.new_port(cPortName))
+	if status != 0 {
+		return fmt.Errorf("Error while createing sequencer port. %d", status)
+	}
+}
+
+// SendData to ALSA
+func SendData(p []byte) error {
+	cData := (*C.char)(unsafe.Pointer(&p[0]))
+	defer C.free(unsafe.Pointer(cData))
+	var status = int(C.send_data(cData, C.int(len(p))))
+	if status != 0 {
+		stage, errCode := resolveErrCode(status)
+		switch stage {
+		case 1:
+			return 0, fmt.Errorf("Error while creating MIDI event. %d", errCode)
+		case 2:
+			return 0, fmt.Errorf("Error while encoding MIDI event. %d", errCode)
+		case 3:
+			return 0, fmt.Errorf("Error while sending data. %d", errCode)
+		}
+	}
+}
+
+func resolveErrCode(code int) (int, int) {
+	return code >> 16, code & 0xffff
+}

backend/midiDevice_linux.go

@@ -1,18 +1,7 @@
 package backend
 
-/*
-#ifndef ARREMI
-#define ARREMI
-#cgo LDFLAGS: -lasound
-#include <stdlib.h>
-#include "alsa_wrapper.h"
-#endif
-*/
-import "C"
 import (
-	"fmt"
+	alsa "github.com/tonychee7000/Arremi/backend/alsa_wrapper"
-	"unsafe"
-
 	"github.com/tonychee7000/Arremi/consts"
 )
 
@@ -30,30 +19,16 @@ func NewMIDIDevice() (*MIDIDevice, error) {
 
 // Init the client and source
 func (midiDev *MIDIDevice) Init() error {
-	var status int
+	var err error
-
 	midiDev.Signal = make(chan int, 4096)
-
+	err = alsa.NewClient(consts.ClientName)
-	cDevName := C.CString(consts.ClientName)
+	if err != nil {
-	defer C.free(unsafe.Pointer(cDevName))
+		return err
-	status = int(C.new_client(cDevName))
-	if status != 0 {
-		stage, errCode := resolveErrCode(status)
-		switch stage {
-		case 1:
-			return fmt.Errorf("Error while opening sequencer. %d", errCode)
-		case 2:
-			return fmt.Errorf("Error while getting sequencer id. %d", errCode)
-		case 3:
-			return fmt.Errorf("Error while setting sequencer name. %d", errCode)
-		}
 	}
 
-	cPortName := C.CString(consts.SourceName)
+	err = alsa.NewPort(consts.SourceName)
-	defer C.free(unsafe.Pointer(cPortName))
+	if err != nil {
-	status = int(C.new_port(cPortName))
+		return err
-	if status != 0 {
-		return fmt.Errorf("Error while createing sequencer port. %d", status)
 	}
 
 	return nil
@@ -61,20 +36,7 @@ func (midiDev *MIDIDevice) Init() error {
 
 func (midiDev *MIDIDevice) Write(p []byte) (int, error) {
 	midiDev.Signal <- 1
-	cData := (*C.char)(unsafe.Pointer(&p[0]))
+	alsa.SendData(p)
-	defer C.free(unsafe.Pointer(cData))
-	var status = int(C.send_data(cData, C.int(len(p))))
-	if status != 0 {
-		stage, errCode := resolveErrCode(status)
-		switch stage {
-		case 1:
-			return 0, fmt.Errorf("Error while creating MIDI event. %d", errCode)
-		case 2:
-			return 0, fmt.Errorf("Error while encoding MIDI event. %d", errCode)
-		case 3:
-			return 0, fmt.Errorf("Error while sending data. %d", errCode)
-		}
-	}
 	return len(p), nil
 }
 
@@ -86,7 +48,3 @@ func (midiDev *MIDIDevice) AllNoteOff() {
 		}
 	}
 }
-
-func resolveErrCode(code int) (int, int) {
-	return code >> 16, code & 0xffff
-}