less structs and defines publicly exposed

- nfc_device is now an opaque type;
 - PN53x specific errors are not public anymore;
 - nfc_device_name() renamed to nfc_device_get_name() for the sake of consistency;
 - examples/*, utils/* uses the new nfc_device_get_name() function instead of access directly to struct's content;
 - new error defined: NFC_ERFTRANS for notifying about RF transmission error, its used by mifare.c to detect permissions error on mifare;
 - drivers initiator_transceive_bytes() function now returns libnfc's error code on failure (<0), and received bytes count on success (>=0);
 - remove some unused errors.

examples/nfc-anticol.c

@@ -175,7 +175,7 @@ main (int argc, char *argv[])
     exit (EXIT_FAILURE);
   }
 
-  printf ("Connected to NFC reader: %s\n\n", pnd->acName);
+  printf ("Connected to NFC reader: %s\n\n", nfc_device_get_name (pnd));
 
   // Send the 7 bits request command specified in ISO 14443A (0x26)
   if (!transmit_bits (abtReqa, 7)) {

examples/nfc-dep-initiator.c

@@ -77,7 +77,7 @@ main (int argc, const char *argv[])
     printf("Unable to connect to NFC device.\n");
     return EXIT_FAILURE;
   }
-  printf ("Connected to NFC device: %s\n", pnd->acName);
+  printf ("Connected to NFC device: %s\n", nfc_device_get_name (pnd));
 
   signal (SIGINT, stop_dep_communication);
 

examples/nfc-dep-target.c

@@ -111,7 +111,7 @@ main (int argc, const char *argv[])
     printf("Unable to connect to NFC device.\n");
     return EXIT_FAILURE;
   }
-  printf ("Connected to NFC device: %s\n", pnd->acName);
+  printf ("Connected to NFC device: %s\n", nfc_device_get_name (pnd));
 
   signal (SIGINT, stop_dep_communication);
 

examples/nfc-emulate-forum-tag2.c

@@ -189,7 +189,7 @@ main(int argc, char *argv[])
     exit (EXIT_FAILURE);
   }
 
-  printf ("Connected to NFC device: %s\n", pnd->acName);
+  printf ("Connected to NFC device: %s\n", nfc_device_get_name (pnd));
   printf ("Emulating NDEF tag now, please touch it with a second NFC device\n");
 
   if (nfc_emulate_target (pnd, &emulator) < 0) {

examples/nfc-emulate-tag.c

@@ -191,7 +191,7 @@ main (int argc, char *argv[])
     exit (EXIT_FAILURE);
   }
 
-  printf ("Connected to NFC device: %s\n", pnd->acName);
+  printf ("Connected to NFC device: %s\n", nfc_device_get_name (pnd));
 
   // Notes for ISO14443-A emulated tags:
   // * Only short UIDs are supported

examples/nfc-emulate-uid.c

@@ -134,7 +134,7 @@ main (int argc, char *argv[])
   }
 
   printf ("\n");
-  printf ("Connected to NFC device: %s\n", pnd->acName);
+  printf ("Connected to NFC device: %s\n", nfc_device_get_name (pnd));
   printf ("[+] Try to break out the auto-emulation, this requires a second NFC device!\n");
   printf ("[+] To do this, please send any command after the anti-collision\n");
   printf ("[+] For example, send a RATS command or use the \"nfc-anticol\" or \"nfc-list\" tool.\n");

examples/nfc-poll.c

@@ -101,19 +101,18 @@ main (int argc, const char *argv[])
 
   nfc_initiator_init (pnd);
 
-  printf ("Connected to NFC reader: %s\n", pnd->acName);
+  printf ("Connected to NFC reader: %s\n", nfc_device_get_name (pnd));
   printf ("NFC device will poll during %ld ms (%u pollings of %lu ms for %zd modulations)\n", (unsigned long) uiPollNr * szModulations * uiPeriod * 150, uiPollNr, (unsigned long) uiPeriod * 150, szModulations);
-  res = nfc_initiator_poll_target (pnd, nmModulations, szModulations, uiPollNr, uiPeriod, &nt);
-  if (res) {
+  if ((res = nfc_initiator_poll_target (pnd, nmModulations, szModulations, uiPollNr, uiPeriod, &nt))  < 0) {
+    nfc_perror (pnd, "nfc_initiator_poll_targets");
+    nfc_disconnect (pnd);
+    exit (EXIT_FAILURE);
+  }
+
+  if (res > 0) {
     print_nfc_target ( nt, verbose );
   } else {
-    if (pnd->iLastError) {
-      nfc_perror (pnd, "nfc_initiator_poll_targets");
-      nfc_disconnect (pnd);
-      exit (EXIT_FAILURE);
-    } else {
-      printf ("No target found.\n");
-    }
+    printf ("No target found.\n");
   }
   nfc_disconnect (pnd);
   exit (EXIT_SUCCESS);

examples/nfc-relay.c

@@ -125,7 +125,7 @@ main (int argc, char *argv[])
 
   printf ("Hint: tag <---> initiator (relay) <---> target (relay) <---> original reader\n\n");
 
-  printf ("Connected to the NFC emulator device: %s\n", pndTag->acName);
+  printf ("Connected to the NFC emulator device: %s\n", nfc_device_get_name (pndTag));
   printf ("[+] Try to break out the auto-emulation, this requires a second reader!\n");
   printf ("[+] To do this, please send any command after the anti-collision\n");
   printf ("[+] For example, send a RATS command or use the \"nfc-anticol\" tool\n");
@@ -162,7 +162,7 @@ main (int argc, char *argv[])
   // Try to open the NFC reader
   pndReader = nfc_connect (connstrings[1]);
 
-  printf ("Connected to the NFC reader device: %s", pndReader->acName);
+  printf ("Connected to the NFC reader device: %s", nfc_device_get_name (pndReader));
   printf ("%s", "Configuring NFC reader settings...");
   nfc_initiator_init (pndReader);
   if ((nfc_device_set_property_bool (pndReader, NP_HANDLE_CRC, false) < 0) ||

examples/pn53x-diagnose.c

@@ -86,7 +86,7 @@ main (int argc, const char *argv[])
       return EXIT_FAILURE;
     }
 
-    printf ("NFC device [%s] connected.\n", pnd->acName);
+    printf ("NFC device [%s] connected.\n", nfc_device_get_name (pnd));
 
     result = pn53x_transceive (pnd, pncmd_diagnose_communication_line_test, sizeof (pncmd_diagnose_communication_line_test), abtRx, &szRx, 0);
     if (result) {

examples/pn53x-sam.c

@@ -89,7 +89,7 @@ main (int argc, const char *argv[])
     return EXIT_FAILURE;
   }
 
-  printf ("Connected to NFC device: %s\n", pnd->acName);
+  printf ("Connected to NFC device: %s\n", nfc_device_get_name (pnd));
 
   // Print the example's menu
   printf ("\nSelect the communication mode:\n");

examples/pn53x-tamashell.c

@@ -94,7 +94,7 @@ int main(int argc, const char* argv[])
     return EXIT_FAILURE;
   }
 
-  printf ("Connected to NFC reader: %s\n", pnd->acName);
+  printf ("Connected to NFC reader: %s\n", nfc_device_get_name (pnd));
   nfc_initiator_init(pnd);
 
   char *cmd;