Add isFifo() methods (#849)

* add new isFifo() methods

* fix call to overloaded `isFifo()`

* fix copy-n-paste error

* add to py wrapper; remove const-ness from params

* fix casting in py wrapper

* ran clang-format on pyRF24.cpp

* update return type for writeAckPL() in py wrapper

* add new methods to sphinx docs

RF24.cpp

@@ -1372,6 +1372,20 @@ bool RF24::rxFifoFull()
 
 /****************************************************************************/
 
+uint8_t RF24::isFifo(bool about_tx)
+{
+    return static_cast<uint8_t>((read_register(FIFO_STATUS) >> (4 * about_tx)) & 3);
+}
+
+/****************************************************************************/
+
+bool RF24::isFifo(bool about_tx, bool check_empty)
+{
+    return static_cast<bool>(isFifo(about_tx) & _BV(!check_empty));
+}
+
+/****************************************************************************/
+
 bool RF24::txStandBy()
 {
 

RF24.h

@@ -784,6 +784,24 @@ class RF24
      */
     bool rxFifoFull();
 
+    /**
+     * @param about_tx `true` focuses on the TX FIFO, `false` focuses on the RX FIFO
+     * @return 
+     * - `0` if the specified FIFO is neither full nor empty.
+     * - `1` if the specified FIFO is empty.
+     * - `2` if the specified FIFO is full.
+     */
+    uint8_t isFifo(bool about_tx);
+
+    /** 
+     * @param about_tx `true` focuses on the TX FIFO, `false` focuses on the RX FIFO
+     * @param check_empty
+     * - `true` checks if the specified FIFO is empty
+     * - `false` checks is the specified FIFO is full.
+     * @return A boolean answer to the question "is the [TX/RX] FIFO [empty/full]?"
+     */
+    bool isFifo(bool about_tx, bool check_empty);
+
     /**
      * Enter low-power mode
      *

docs/sphinx/classRF24.rst

@@ -71,6 +71,8 @@ FIFO Management
 .. doxygenfunction:: RF24::rxFifoFull
 .. doxygenfunction:: RF24::flush_tx
 .. doxygenfunction:: RF24::flush_rx
+.. doxygenfunction:: RF24::isFifo (bool about_tx)
+.. doxygenfunction:: RF24::isFifo (bool about_tx, bool check_empty)
 
 Ambiguous Signal Detection
 **************************

pyRF24/pyRF24.cpp

@@ -60,9 +60,9 @@ bool write_wrap2(RF24& ref, bp::object buf, const bool multicast)
     return ref.write(get_bytes_or_bytearray_str(buf), get_bytes_or_bytearray_ln(buf), multicast);
 }
 
-void writeAckPayload_wrap(RF24& ref, uint8_t pipe, bp::object buf)
+bool writeAckPayload_wrap(RF24& ref, uint8_t pipe, bp::object buf)
 {
-    ref.writeAckPayload(pipe, get_bytes_or_bytearray_str(buf), get_bytes_or_bytearray_ln(buf));
+    return ref.writeAckPayload(pipe, get_bytes_or_bytearray_str(buf), get_bytes_or_bytearray_ln(buf));
 }
 
 bool writeFast_wrap1(RF24& ref, bp::object buf)
@@ -309,6 +309,8 @@ BOOST_PYTHON_MODULE(RF24)
         .def("reUseTX", &RF24::reUseTX)
         .def("read", &read_wrap, (bp::arg("maxlen")))
         .def("rxFifoFull", &RF24::rxFifoFull)
+        .def("isFifo", (uint8_t(::RF24::*)(bool))(&::RF24::isFifo), (bp::arg("about_tx")))
+        .def("isFifo", (bool (::RF24::*)(bool, bool))(&::RF24::isFifo), (bp::arg("about_tx"), bp::arg("check_empty")))
         .def("setAddressWidth", &RF24::setAddressWidth)
         .def("setAutoAck", (void (::RF24::*)(bool))(&::RF24::setAutoAck), (bp::arg("enable")))
         .def("setAutoAck", (void (::RF24::*)(::uint8_t, bool))(&::RF24::setAutoAck), (bp::arg("pipe"), bp::arg("enable")))