NFCNDEFCapable.h

00001 /* mbed Microcontroller Library
00002  * Copyright (c) 2018 ARM Limited
00003  *
00004  * Licensed under the Apache License, Version 2.0 (the "License");
00005  * you may not use this file except in compliance with the License.
00006  * You may obtain a copy of the License at
00007  *
00008  *     http://www.apache.org/licenses/LICENSE-2.0
00009  *
00010  * Unless required by applicable law or agreed to in writing, software
00011  * distributed under the License is distributed on an "AS IS" BASIS,
00012  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
00013  * See the License for the specific language governing permissions and
00014  * limitations under the License.
00015  */
00016 
00017 #ifndef MBED_NFC_NDEF_CAPABLE_H
00018 #define MBED_NFC_NDEF_CAPABLE_H
00019 
00020 #include <stdint.h>
00021 
00022 #include "platform/Span.h"
00023 
00024 #include "NFCDefinitions.h"
00025 
00026 #include "nfc/stack/ndef/ndef.h"
00027 #include "nfc/acore/acore/ac_buffer.h"
00028 #include "nfc/acore/acore/ac_buffer_reader.h"
00029 #include "nfc/acore/acore/ac_buffer_builder.h"
00030 
00031 namespace mbed {
00032 namespace nfc {
00033 
00034 /**
00035  * @addtogroup nfc
00036  * @{
00037  */
00038 
00039 /**
00040  * The base class for all endpoints that can support NDEF content.
00041  */
00042 class NFCNDEFCapable {
00043 public:
00044     /**
00045      * Construct a NFCNDEFCapable instance.
00046      * @param[in] buffer a bytes array used to store NDEF messages
00047      */
00048     NFCNDEFCapable(const Span<uint8_t>  &buffer);
00049 
00050     /**
00051      * Check if this instance actually supports NDEF content.
00052      *
00053      * @return whether NDEF content is supported
00054      */
00055     virtual bool is_ndef_supported() const
00056     {
00057         return false;
00058     }
00059 
00060     struct Delegate {
00061         /**
00062          * Parse a NDEF message.
00063          *
00064          * @param[in] buffer a buffer containing the message to parse
00065          */
00066         virtual void parse_ndef_message(const Span<const uint8_t>  &buffer) { }
00067 
00068         /**
00069          * Build a NDEF message.
00070          *
00071          * @param[in] buffer a mutable buffer in which the message should be stored
00072          *
00073          * @return the number of bytes actually used
00074          */
00075         virtual size_t build_ndef_message(const Span<uint8_t>  &buffer)
00076         {
00077             return 0;
00078         }
00079 
00080     protected:
00081         ~Delegate() {}
00082     };
00083 
00084 protected:
00085     /**
00086      * Parse a NDEF message.
00087      *
00088      * @param[in] buffer a buffer containing a NDEF message
00089      */
00090     void parse_ndef_message(const ac_buffer_t &buffer);
00091 
00092     /**
00093      * Build NDEF message.
00094      *
00095      * @param[in,out] buffer_builder a buffer builder in which to create the NDEF message.
00096      * The backing buffer is guaranteed to be continuous.
00097      */
00098     void build_ndef_message(ac_buffer_builder_t &buffer_builder);
00099 
00100     /**
00101      * Retrieve underlying NDEF message instance
00102      * @return pointer to NDEF message instance
00103      */
00104     ndef_msg_t *ndef_message();
00105 
00106 private:
00107     /**
00108      * Get the delegate that will receive events generated by this class.
00109      *
00110      * @return the delegate instance to use
00111      */
00112     virtual Delegate *ndef_capable_delegate();
00113 
00114     // Callbacks from NDEF stack
00115     static nfc_err_t s_ndef_encode(ndef_msg_t *pTag, ac_buffer_builder_t *pBufferBldr, void *pUserData);
00116     static nfc_err_t s_ndef_decode(ndef_msg_t *pTag, ac_buffer_t *pBuffer, void *pUserData);
00117     nfc_err_t ndef_encode(ac_buffer_builder_t *pBufferBldr);
00118     nfc_err_t ndef_decode(ac_buffer_t *pBuffer);
00119 
00120     ndef_msg_t _ndef_message;
00121 };
00122 
00123 /**
00124  * @}
00125  */
00126 
00127 } // namespace nfc
00128 } // namespace mbed
00129 
00130 #endif