Mbed OS Reference | MessageBuilder.h Source File

 /* mbed Microcontroller Library
  * Copyright (c) 2018 ARM Limited
  * SPDX-License-Identifier: Apache-2.0
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
  * You may obtain a copy of the License at
  *
  *     http://www.apache.org/licenses/LICENSE-2.0
  *
  * Unless required by applicable law or agreed to in writing, software
  * distributed under the License is distributed on an "AS IS" BASIS,
  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */
 
 #ifndef NFC_NDEF_MESSAGEBUILDER_H_
 #define NFC_NDEF_MESSAGEBUILDER_H_
 
 #include <stdint.h>
 
 #include "platform/Span.h"
 
 #include "nfc/ndef/Record.h"
 
 namespace mbed {
 namespace nfc {
 namespace ndef {
 
 /** @addtogroup nfc
  * @{
  */
 
 /**
  * Construct a NDEF Message.
  */
 class MessageBuilder {
 
 public:
     /**
      * Build a record payload.
      */
     struct PayloadBuilder {
         /**
          * Return the size of the payload built by this object.
          *
          * @return The size of the payload.
          */
         virtual size_t size() const = 0;
 
         /**
          * Build the payload in a buffer that has the required size.
          *
          * @param buffer The buffer used to construct the payload.
          */
         virtual void build(const Span<uint8_t> &buffer) const = 0;
 
     protected:
         /**
          * Non virtual destructor.
          */
         ~PayloadBuilder() { }
     };
 
     /**
      * Create a new MessageBuilder that can be used to construct valid NDEF
      * messages.
      *
      * @param buffer The data buffer that will contain the NDEF message.
      */
     MessageBuilder(const Span<uint8_t> &buffer);
 
     /**
      * Append a new record to the message being built.
      *
      * @param type The type of the record to insert.
      * @param payload The payload of the record (optional).
      * @param is_last_record true if the record to insert is the last record of
      * the payload or false otherwise.
      *
      * @return true if the record has been successfully inserted or false
      * otherwise.
      *
      * @note insertion can fail if the message is already complete or if the
      * size remaining in the message buffer is not large enough to makes the
      * record inserted fit.
      */
     bool append_record(
         const RecordType &type,
         const RecordPayload &payload = RecordPayload(),
         bool is_last_record = false
     );
 
     /**
      * Append a new record to the message being built.
      *
      * @param type The type of the record to insert.
      * @param builder The builder of the payload.
      * @param is_last_record true if the record to insert is the last record of
      * the payload or false otherwise.
      *
      * @return true if the record has been successfully inserted or false
      * otherwise.
      *
      * @note insertion can fail if the message is already complete or if the
      * size remaining in the message buffer is not large enough to makes the
      * record inserted fit.
      */
     bool append_record(
         const RecordType &type,
         const PayloadBuilder &builder,
         bool is_last_record = false
     );
 
     /**
      * Append a new record to the message being built.
      *
      * @param record The record to insert.
      * @param builder The builder that will construct the payload.
      *
      * @return true if the record has been successfully inserted or false otherwise.
      *
      * @note insertion can fail if the message is already complete or if the
      * size remaining in the message buffer is not large enough to makes the
      * record inserted fit.
      */
     bool append_record(
         const Record &record,
         const PayloadBuilder *builder = NULL
     );
 
     /**
      * Compute the size of a record.
      *
      * @param record The record used to compute the size.
      * @param builder The payload builder if any.
      *
      * @return The size of the payload for the record in input.
      */
     static size_t compute_record_size(
         const Record &record,
         const PayloadBuilder *builder = NULL
     );
 
     /**
      * Reset the builder state.
      */
     void reset();
 
     /**
      * Reset the builder state and assign a new buffer to it.
      */
     void reset(const Span<uint8_t> &buffer);
 
     /**
      * Return true if the message stored is complete and false otherwise.
      *
      * @return true if the message is complete or false.
      */
     bool is_message_complete() const;
 
     /**
      * Return the buffer storing the data if the message is complete or an empty
      * buffer if the message is not complete.
      *
      * @return The message built.
      */
     Span<const uint8_t> get_message() const;
 
 private:
     // append fields
     void append_header(const Record &record, const PayloadBuilder *);
     void append_type_length(const Record &record);
     void append_payload_length(const Record &, const PayloadBuilder *);
     void append_id_length(const Record &);
     void append_type(const Record &);
     void append_id(const Record &);
     void append_payload(const Record &, const PayloadBuilder *);
 
     // helpers
     static bool is_short_payload(const Record &record, const PayloadBuilder *);
     static size_t get_payload_size(const Record &, const PayloadBuilder *);
 
     // builder state.
     Span<uint8_t> _message_buffer;
     size_t _position;
     bool _message_started;
     bool _message_ended;
     bool _in_chunk;
 };
 /** @}*/
 } // namespace ndef
 } // namespace nfc
 } // namespace mbed
 
 #endif /* NFC_NDEF_MESSAGEBUILDER_H_ */
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