implement get_applications_id command

src/desfire/desfire.rs

@@ -51,6 +51,41 @@ impl Desfire {
         response.check()
     }
 
+    pub fn get_application_ids_cmd(&self) -> Result<APDUCommand> {
+        Ok(APDUCommand {
+            case: IsoCase::Case2Short,
+            cla: 0x90,
+            ins: APDUInstructions::GetApplicationIds as u8,
+            ..Default::default()
+        })
+    }
+
+    /// Get all application ids on the defire token
+    pub fn get_application_ids(&self) -> Result<Vec<u32>> {
+        let cmd_get_application_ids = self.get_application_ids_cmd()?;
+
+        let response = self
+            .card
+            .as_ref()
+            .unwrap()
+            .transmit(cmd_get_application_ids)?;
+        response.check()?;
+
+        if let Some(body) = response.body {
+            Ok(body
+                // application ids are 3 byte long MSB first values
+                // TODO: use `slice::array_chunks` when its stable
+                .chunks_exact(3)
+                // pad with one byte extra byte to it it into an u32
+                .map(|chunk| u32::from_le_bytes([chunk[0], chunk[1], chunk[2], 0x0]))
+                .collect())
+        } else {
+            // body is empty, there are no applications on this card
+            // except the picc 0x000000 application
+            Ok(vec![])
+        }
+    }
+
     /// Authenticate to PICC, with ISO Authenticate for DES Key
     ///
     /// Arguments:
@@ -1015,6 +1050,31 @@ mod tests {
         desfire.select_application(0xff000000).unwrap();
     }
 
+    #[test]
+    fn get_application_ids() {
+        let mut mock = MockVirtualCard::new();
+        mock.expect_transmit()
+            .withf(|x: &APDUCommand| {
+                (Vec::<u8>::try_from(x.clone()).unwrap()) == vec![0x90, 0x6a, 0x00, 0x00, 0x00]
+            })
+            .return_once(move |_| {
+                Ok(APDUResponse {
+                    body: Some(vec![0x01, 0x00, 0x00, 0x02, 0x00, 0x00]),
+                    sw1: 0x91,
+                    sw2: 0x00,
+                })
+            });
+
+        let desfire = Desfire {
+            card: Some(Box::new(mock)),
+            cbc_iv: None,
+            session_key: None,
+        };
+
+        let ids = desfire.get_application_ids().unwrap();
+        assert_eq!(ids, vec![1, 2])
+    }
+
     #[test]
     #[ignore]
     fn select_application_hardware() {