Mbed OS Reference | MessageParser.h Source File

 /* mbed Microcontroller Library
  * Copyright (c) 2018 ARM Limited
  *
  * 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_MESSAGEPARSER_H_
 #define NFC_NDEF_MESSAGEPARSER_H_
 
 #include <stdlib.h>
 #include "platform/Span.h"
 
 namespace mbed {
 namespace nfc {
 namespace ndef {
 
 /** @addtogroup nfc
  * @{
  */
 
 // Forward declaration
 class Record;
 
 /**
  * Event driven NDEF Message parser
  */
 class MessageParser {
 public:
     /**
      * Error that can be reported by the parsing operation.
      */
     enum error_t {
         /**
          * The message doesn't start with a message start tag.
          */
         INVALID_MESSAGE_START,
 
         /**
          * There is not enough data left to pursue parsing of the message.
          */
         INSUFICIENT_DATA,
 
         /**
          * The type name of a record is invalid.
          */
         INVALID_TYPE_NAME_FORMAT,
 
         /**
          * An empty record is malformed.
          */
         INVALID_EMPTY_RECORD,
 
         /**
          * Record of unknown type embed a type length different than 0.
          */
         INVALID_UNKNOWN_TYPE_LENGTH,
 
         /**
          * Record of unchanged type contains a type.
          */
         INVALID_UNCHANGED_TYPE,
 
         /**
          * Chunk record encountered.
          */
         CHUNK_RECORD_NOT_SUPPORTED,
 
         /**
          * Message is not properly closed.
          */
         MISSING_MESSAGE_END,
 
         /**
          * Type is missing in a record expecting a type (well known type, media
          * type, absolute uri or external type).
          */
         MISSING_TYPE_VALUE
     };
 
     /**
      * Report parsing event to the application.
      */
     struct Delegate {
         /**
          * Invoked when parsing as started.
          */
         virtual void on_parsing_started() { }
 
         /**
          * Invoked when a record has been parsed.
          *
          * @param record The record obtained from parsing.
          */
         virtual void on_record_parsed(const Record &record) { }
 
         /**
          * Invoked when parsing is over.
          */
         virtual void on_parsing_terminated() { }
 
         /**
          * Invoked when an error is present in the message.
          * @param error The error present in the message.
          */
         virtual void on_parsing_error(error_t error) { }
 
     protected:
         /**
          * Protected non virtual destructor.
          * Delegate is not meant to be destroyed in a polymorphic manner.
          */
         ~Delegate() { }
     };
 
     /**
      * Construct a message parser.
      */
     MessageParser();
 
     /**
      * Set the handler that processes parsing events.
      * @param delegate The parsing event handler.
      */
     void set_delegate(Delegate *delegate);
 
     /**
      * Parse an NDEF Message.
      *
      * Records and errors are reported to the handler registered with
      * set_event_handler.
      *
      * @param data_buffer The data buffer that contains the NDEF message.
      */
     void parse(const Span<const uint8_t> &data_buffer);
 
 private:
     struct parsing_state_t;
 
     // parser
     bool parse_record(parsing_state_t &it);
 
     static uint8_t compute_lengths_size(uint8_t header);
     static uint8_t extract_type_length(parsing_state_t &s);
     static uint32_t extract_payload_length(parsing_state_t &s, uint8_t header);
     static uint8_t extract_id_length(parsing_state_t &s, uint8_t header);
 
     // reporting
     void report_parsing_started();
     void report_record_parsed(const Record &record);
     void report_parsing_terminated();
     void report_parsing_error(error_t error, parsing_state_t &parsing_state);
 
     Delegate *_delegate;
 };
 /** @}*/
 } // namespace ndef
 } // namespace nfc
 } // namespace mbed
 
 
 #endif /* NFC_NDEF_MESSAGEPARSER_H_ */
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