File content as of revision 2:9b44be6e79ac:

/*  _  __  ____    _   _ 
 * | |/ / |  _ \  | \ | |
 * | ' /  | |_) | |  \| |
 * | . \  |  __/  | |\  |
 * |_|\_\ |_|     |_| \_|
 * 
 * (c) 2018 KPN
 * License: MIT License.
 * Author: Jan Bogaerts
 * 
 * base class for all senml objects header
 */

#ifndef SENMLBASE
#define SENMLBASE

#ifdef __MBED__
    #include "mbed.h"
    #include "sstream"
#else
    #include <stream.h>
#endif
#include <senml_enums.h>
#include <math.h>

/**
 * the base class for all objects that can be used in the senml data tree.
 */
class SenMLBase
{
friend class SenMLPack; 
friend class SenMLRecord; 
friend class SenMLJsonListener; 
friend class SenMLBaseParser;
public:
    SenMLBase();
    ~SenMLBase();

    /** get the next item in the list.
     * @returns: a pointer to the next SenMLBase object in the list or NULL when at the end of the list.
     */
    SenMLBase* getNext(){ return this->_next; };

    /**
     * Get the root object of this list. Usually, this is a SenMLPack object.
     * The root object is defined as the first item in the list. 
     * @returns: a pointer to the first SenMLBase object in the list or NULL when there is none.
     */
    SenMLBase* getRoot();

    //This function is called by the root SenMLPack object to indicate that the object
    //should adjust it's time info relative to the new base time (if applicable)
    //doesn't do anything by default
    //params: prev: previous base time
    //        time: new base time
    virtual void adjustToBaseTime(double prev, double time) {};

    /**
     * renders all the fields to json, without the starting and ending brackets.
     * Inheriters can extend this function if they want to add extra fields to the json output
     * note: this is public so that custom implementations for the record object can use other objects 
     * internally and render to json using this function (ex: coordinatesRecord using 3 floatRecrods for lat, lon & alt.
     * @returns: None
    */
    virtual void fieldsToJson() = 0;

    /**
     * renders all the fields to cbor format. renders all the fields of the object without the length info 
     * at the beginning
     * note: this is public so that custom implementations for the record object can use other objects 
     * internally and render to json using this function (ex: coordinatesRecord using 3 floatRecrods for 
     * lat, lon & alt.
     * @returns: The number of bytes that were written.
    */
    virtual int fieldsToCbor() = 0;

protected:

    /*
    renders all the fields to json, with the starting and ending brackets.
    Inheriters can extend this function if they want to add extra fields to the json output
    note: tihs is public so that custom implementations for the record object can use other objects internally and render to json using this function (ex: coordinatesRecord using 3 floatRecrods for lat, lon & alt.
    */
    virtual void contentToJson() = 0;


    //assign the element in the list that this object points to.
    void setNext(SenMLBase* value);
    
    //assign the previous element in the list that thisobject points to.
    void setPrev(SenMLBase* value);
    //assign the previous element in the list that thisobject points to.
    SenMLBase* getPrev();

    //derived classes can use this function to see if the root object (getRoot) is a SenMLPack
    //class or not.
    virtual bool isPack() { return false; }

    //renders the content of the pack object without [], but still with {} for objects
    virtual int contentToCbor() = 0;    

    //calculates the nr of items that this object will put in the json array in senml representation
    //this is used for rendering cbor which needs to declare the nr of elements in an array.
    //packs can have multiple elements in the array, but also custom implementations for records that wrap muliple 
    //records.
    virtual int getArrayLength() { return 1; };

    //calculates the nr of fields that this object will produce.
    virtual int getFieldLength() = 0;


private:
    SenMLBase* _next;                               //reference to the next element in the list.
    SenMLBase* _prev;                               //reference to the previous element, needed for deletion of record
};



#endif // SENMLBASE