better memory usage

src/main.c

@@ -58,7 +58,7 @@ void *arpeggio_loop(void* data);
 
 int main(int argc, char** argv)
 {
-    MidiInterface interface;
+    MidiInterface* interface;
     int result = open_midi_device(&interface, NULL);
     if(result < 0)
         exit(result);
@@ -67,7 +67,7 @@ int main(int argc, char** argv)
     Note current_note;
 
     pthread_t arpeggio_thread;
-    pthread_create(&arpeggio_thread, NULL, arpeggio_loop, (void*)&interface);
+    pthread_create(&arpeggio_thread, NULL, arpeggio_loop, (void*)interface);
 
     Message* message;
     create_message(&message);
@@ -107,7 +107,7 @@ int main(int argc, char** argv)
 
     pthread_join(arpeggio_thread, NULL);
     free_message(message);
-    close(interface.fd);
+    close_midi_device(interface);
     return 0;
 }
 
@@ -127,7 +127,7 @@ void *arpeggio_loop(void* data)
             Note out = *note;
             message->data[0] = out.pitch + pattern[step].pitch;
             message->data[1] = out.velocity + pattern[step].velocity;
-            int result = write_midi_device(*interface, message);
+            int result = write_midi_device(interface, message);
             if(result < 0)
                 fprintf(stderr, "Failed to send message: %s\n", midi_strerror(result));
 

src/midi_interface.c

@@ -9,7 +9,7 @@ static const char* devices[] = {"/dev/midi", "/dev/midi2", NULL};
 
 int try_open_device(const char* device);
 
-int open_midi_device(MidiInterface* interface, const char* device)
+int open_midi_device(MidiInterface** interface, const char* device)
 {
     int fd;
 
@@ -35,14 +35,27 @@ int open_midi_device(MidiInterface* interface, const char* device)
     else
         printf("Using device %s\n", device);
 
-    interface->fd = fd;
+    *interface = (MidiInterface*)malloc(sizeof(MidiInterface));
+
+    (*interface)->fd = fd;
+    (*interface)->out_buf = (uint8_t*)malloc(8);
     return fd;
 }
 
-int read_midi_device(MidiInterface interface, Message* buffer)
+int close_midi_device(MidiInterface* interface)
+{
+    close(interface->fd);
+
+    free(interface->out_buf);
+    free(interface);
+
+    return 0;
+}
+
+int read_midi_device(MidiInterface* interface, Message* buffer)
 {
     uint8_t status;
-    int result = read(interface.fd, &status, 1);
+    int result = read(interface->fd, &status, 1);
     if(result < 0)
         return MIDI_READ_ERROR;
 
@@ -54,7 +67,7 @@ int read_midi_device(MidiInterface interface, Message* buffer)
     if(buffer->length < 0)
         return buffer->length;
 
-    result = read(interface.fd, buffer->data, buffer->length);
+    result = read(interface->fd, buffer->data, buffer->length);
     if(result < 0)
         return MIDI_READ_ERROR;
 
@@ -66,18 +79,17 @@ int read_midi_device(MidiInterface interface, Message* buffer)
     return 0;
 }
 
-int write_midi_device(MidiInterface interface, const Message* buffer)
+int write_midi_device(MidiInterface* interface, const Message* buffer)
 {
     uint8_t status;
     int result = encode_status_byte(buffer, &status);
     if(result < 0)
         return result;
 
-    uint8_t* buffer_out = (uint8_t*)malloc(1 + buffer->length);
+    interface->out_buf[0] = status;
-    buffer_out[0] = status;
+    memcpy(interface->out_buf + 1, buffer->data, buffer->length);
-    memcpy(buffer_out + 1, buffer->data, buffer->length);
 
-    result = write(interface.fd, buffer_out, 1 + buffer->length);
+    result = write(interface->fd, interface->out_buf, 1 + buffer->length);
     if(result < 0)
         return MIDI_WRITE_ERROR;
 }

src/midi_interface.h

@@ -9,12 +9,14 @@
 typedef struct MidiInterface
 {
     int fd;
+    uint8_t* out_buf;
 } MidiInterface;
 
-int open_midi_device(MidiInterface* interface, const char* device);
+int open_midi_device(MidiInterface** interface, const char* device);
+int close_midi_device(MidiInterface* interface);
 
-int read_midi_device(MidiInterface interface, Message* buffer);
+int read_midi_device(MidiInterface* interface, Message* buffer);
-int write_midi_device(MidiInterface interface, const Message* buffer);
+int write_midi_device(MidiInterface* interface, const Message* buffer);
 
 
 #endif