Aggregator.h

00001 /*
00002  * Aggregator.h
00003  *
00004  * Created on: Nov 1, 2013
00005  * * Authors: Vincent Wochnik <v.wochnik@gmail.com>
00006  *
00007  * Copyright (c) 2013 Cumulocity GmbH
00008  *
00009  * Permission is hereby granted, free of charge, to any person obtaining
00010  * a copy of this software and associated documentation files (the
00011  * "Software"), to deal in the Software without restriction, including
00012  * without limitation the rights to use, copy, modify, merge, publish,
00013  * distribute, sublicense, and/or sell copies of the Software, and to
00014  * permit persons to whom the Software is furnished to do so, subject to
00015  * the following conditions:
00016  *
00017  * The above copyright notice and this permission notice shall be
00018  * included in all copies or substantial portions of the Software.
00019  *
00020  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
00021  * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
00022  * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
00023  * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
00024  * LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
00025  * OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
00026  * WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
00027  */
00028 
00029 #ifndef AGGREGATOR_H
00030 #define AGGREGATOR_H
00031 
00032 #ifdef HAVE_CONFIG_H
00033 #include <config.h>
00034 #endif
00035 
00036 #include <stddef.h>
00037 #include "DataGenerator.h"
00038 
00039 #ifndef AGGREGATOR_INITIAL_CAPACITY
00040 #define AGGREGATOR_INITIAL_CAPACITY 50
00041 #endif
00042 #ifndef AGGREGATOR_MEMORY_INCREMENT
00043 #define AGGREGATOR_MEMORY_INCREMENT 25
00044 #endif
00045 //#define AGGREGATOR_FIXED_SIZE 100
00046 
00047 /**
00048  * An aggregator of data generators. This class can aggregate instances of
00049  * itself.
00050  * If the aggregator is set to copying all added data generators using
00051  * the copy() method, all objects are being properly deallocated on
00052  * destruction.
00053  */
00054 class Aggregator : public DataGenerator
00055 {
00056 public:
00057     #ifndef AGGREGATOR_FIXED_SIZE
00058     /**
00059      * Creates a new Aggregator instance.
00060      * @param capacity the initial capacity of the instance
00061      * @param growing specifies the capability of this instance to grow
00062      * @param copy specifies whether all added data generators shall be
00063      *             copied using the copy() method
00064      */
00065     Aggregator(size_t=AGGREGATOR_INITIAL_CAPACITY, bool=true, bool=false);
00066     #else
00067     /**
00068      * Creates a new Aggregator instance.
00069      * @param copy specifies whether all added data generators shall be
00070      *             copied using the copy() method
00071      */
00072     Aggregator(bool=false);
00073     #endif
00074     ~Aggregator();
00075 
00076     /**
00077      * Adds a data generator to the aggregator.
00078      * @param generator the data generator to add
00079      * @return true if added, false otherwise.
00080      */
00081     bool add(const DataGenerator&);
00082 
00083     /**
00084      * Clears the aggregator. The capacity will shrink to it's initial
00085      * size.
00086      */
00087     void clear();
00088 
00089     /**
00090      * Returns the number of data generators aggregated by this instance.
00091      * @return the number of data generators aggregated
00092      */
00093     size_t length();
00094 
00095     /**
00096      * Returns whether the aggregator is full. If growing, this will
00097      * always return false.
00098      * @return whether the aggregator is full
00099      */
00100     bool full();
00101 
00102     /**
00103      * Returns the capacity of the aggregator. This will always return zero
00104      * if the aggregator is growing.
00105      */
00106     size_t capacity();
00107 
00108     size_t writeTo(AbstractDataSink&) const;
00109     size_t writtenLength() const;
00110     DataGenerator* copy() const;
00111 
00112 private:
00113     #ifdef AGGREGATOR_FIXED_SIZE
00114     const DataGenerator *_list[AGGREGATOR_FIXED_SIZE];
00115     #else
00116     const DataGenerator **_list;
00117     #endif
00118     size_t _length;
00119     bool _alloc;
00120     #ifndef AGGREGATOR_FIXED_SIZE
00121     size_t _capacity, _initial;
00122     bool _growing;
00123     #endif
00124 };
00125 
00126 #endif