nfc_target_receive_bits() function returns now received bits count on success and libnfc error code on failure.

examples/nfc-emulate-uid.c

@@ -172,7 +172,7 @@ main (int argc, char *argv[])
 
   while (true) {
     // Test if we received a frame
-    if (nfc_target_receive_bits (pnd, abtRecv, &szRecvBits, NULL)) {
+    if (nfc_target_receive_bits (pnd, abtRecv, &szRecvBits, NULL) > 0) {
       // Prepare the command to send back for the anti-collision request
       switch (szRecvBits) {
       case 7:                  // Request or Wakeup

examples/nfc-relay.c

@@ -175,7 +175,7 @@ main (int argc, char *argv[])
 
   while (!quitting) {
     // Test if we received a frame from the reader
-    if (nfc_target_receive_bits (pndTag, abtReaderRx, &szReaderRxBits, abtReaderRxPar)) {
+    if (nfc_target_receive_bits (pndTag, abtReaderRx, &szReaderRxBits, abtReaderRxPar) > 0) {
       // Drop down the field before sending a REQA command and start a new session
       if (szReaderRxBits == 7 && abtReaderRx[0] == 0x26) {
         // Drop down field for a very short time (original tag will reboot)

include/nfc/nfc.h

@@ -87,7 +87,7 @@ extern  "C" {
   NFC_EXPORT int nfc_target_send_bytes (nfc_device *pnd, const uint8_t *pbtTx, const size_t szTx, int timeout);
   NFC_EXPORT int nfc_target_receive_bytes (nfc_device *pnd, uint8_t *pbtRx, size_t *pszRx, int timeout);
   NFC_EXPORT int nfc_target_send_bits (nfc_device *pnd, const uint8_t *pbtTx, const size_t szTxBits, const uint8_t *pbtTxPar);
-  NFC_EXPORT bool nfc_target_receive_bits (nfc_device *pnd, uint8_t *pbtRx, size_t *pszRxBits, uint8_t *pbtRxPar);
+  NFC_EXPORT int nfc_target_receive_bits (nfc_device *pnd, uint8_t *pbtRx, size_t *pszRxBits, uint8_t *pbtRxPar);
 
 /* Error reporting */
   NFC_EXPORT const char *nfc_strerror (const nfc_device *pnd);

libnfc/chips/pn53x.c

@@ -1747,21 +1747,23 @@ pn53x_target_init (struct nfc_device *pnd, nfc_target *pnt, uint8_t *pbtRx, size
   return NFC_SUCCESS;
 }
 
-bool
+int
 pn53x_target_receive_bits (struct nfc_device *pnd, uint8_t *pbtRx, size_t *pszRxBits, uint8_t *pbtRxPar)
 {
   uint8_t  abtCmd[] = { TgGetInitiatorCommand };
 
   uint8_t  abtRx[PN53x_EXTENDED_FRAME__DATA_MAX_LEN];
   size_t  szRx = sizeof (abtRx);
+  int res = 0;
+  
   // Try to gather a received frame from the reader
-  if (pn53x_transceive (pnd, abtCmd, sizeof (abtCmd), abtRx, &szRx, -1) < 0)
-    return false;
+  if ((res = pn53x_transceive (pnd, abtCmd, sizeof (abtCmd), abtRx, &szRx, -1)) < 0)
+    return res;
 
   // Get the last bit-count that is stored in the received byte
   uint8_t ui8rcc;
-  if (pn53x_read_register (pnd, PN53X_REG_CIU_Control, &ui8rcc) < 0)
-    return false;
+  if ((res = pn53x_read_register (pnd, PN53X_REG_CIU_Control, &ui8rcc)) < 0)
+    return res;
   uint8_t ui8Bits = ui8rcc & SYMBOL_RX_LAST_BITS;
 
   // Recover the real frame length in bits
@@ -1778,8 +1780,8 @@ pn53x_target_receive_bits (struct nfc_device *pnd, uint8_t *pbtRx, size_t *pszRx
     // Copy the received bytes
     memcpy (pbtRx, abtRx + 1, szRx - 1);
   }
-  // Everyting seems ok, return true
-  return true;
+  // Everyting seems ok, return received bits count
+  return *pszRxBits;
 }
 
 int
@@ -1821,13 +1823,13 @@ pn53x_target_receive_bytes (struct nfc_device *pnd, uint8_t *pbtRx, size_t *pszR
   if (pn53x_transceive (pnd, abtCmd, sizeof (abtCmd), abtRx, &szRx, timeout) < 0)
     return pnd->last_error;
 
-  // Save the received byte count
+  // Save the received bytes count
   *pszRx = szRx - 1;
 
   // Copy the received bytes
   memcpy (pbtRx, abtRx + 1, *pszRx);
 
-  // Everyting seems ok, return true
+  // Everyting seems ok, return received bytes count
   return *pszRx;
 }
 

libnfc/chips/pn53x.h

@@ -313,7 +313,7 @@ int    pn53x_initiator_deselect_target (struct nfc_device *pnd);
 
 // NFC device as Target functions
 int    pn53x_target_init (struct nfc_device *pnd, nfc_target *pnt, uint8_t *pbtRx, size_t *pszRx);
-bool    pn53x_target_receive_bits (struct nfc_device *pnd, uint8_t *pbtRx, size_t *pszRxBits, uint8_t *pbtRxPar);
+int    pn53x_target_receive_bits (struct nfc_device *pnd, uint8_t *pbtRx, size_t *pszRxBits, uint8_t *pbtRxPar);
 int    pn53x_target_receive_bytes (struct nfc_device *pnd, uint8_t *pbtRx, size_t *pszRx, int timeout);
 int    pn53x_target_send_bits (struct nfc_device *pnd, const uint8_t *pbtTx, const size_t szTxBits, const uint8_t *pbtTxPar);
 int    pn53x_target_send_bytes (struct nfc_device *pnd, const uint8_t *pbtTx, const size_t szTx, int timeout);

libnfc/nfc-internal.h

@@ -146,7 +146,7 @@ struct nfc_driver_t {
   int (*target_send_bytes) (struct nfc_device *pnd, const uint8_t * pbtTx, const size_t szTx, int timeout);
   int (*target_receive_bytes) (struct nfc_device *pnd, uint8_t * pbtRx, size_t * pszRx, int timeout);
   int (*target_send_bits) (struct nfc_device *pnd, const uint8_t * pbtTx, const size_t szTxBits, const uint8_t * pbtTxPar);
-  bool (*target_receive_bits) (struct nfc_device *pnd, uint8_t * pbtRx, size_t * pszRxBits, uint8_t * pbtRxPar);
+  int (*target_receive_bits) (struct nfc_device *pnd, uint8_t * pbtRx, size_t * pszRxBits, uint8_t * pbtRxPar);
 
   int (*device_set_property_bool) (struct nfc_device *pnd, const nfc_property property, const bool bEnable);
   int (*device_set_property_int) (struct nfc_device *pnd, const nfc_property property, const int value);

libnfc/nfc.c

@@ -749,7 +749,7 @@ nfc_target_send_bits (nfc_device *pnd, const uint8_t *pbtTx, const size_t szTxBi
 
 /**
  * @brief Receive bit-frames
- * @return Returns \c true if action was successfully performed; otherwise returns \c false.
+ * @return Returns received bits count on success, otherwise returns libnfc's error code
  *
  * This function makes it possible to receive (raw) bit-frames.  It returns all
  * the messages that are stored in the FIFO buffer of the \e PN53x chip.  It
@@ -758,7 +758,7 @@ nfc_target_send_bits (nfc_device *pnd, const uint8_t *pbtTx, const size_t szTxBi
  * NP_ACCEPT_MULTIPLE_FRAMES configuration option to avoid losing transmitted
  * frames.
  */
-bool
+int
 nfc_target_receive_bits (nfc_device *pnd, uint8_t *pbtRx, size_t *pszRxBits, uint8_t *pbtRxPar)
 {
   HAL (target_receive_bits, pnd, pbtRx, pszRxBits, pbtRxPar);