IHistogram.hpp

#pragma once
 
#include "DM/config.hpp"
#include "DM/Handle.hpp"
#include "DM/ObjectBase.hpp"
#include "DM/Iterator.hpp"
#include "DM/ColumnTypes.hpp"
 
DM_NAMESPACE_BEGIN
 
/// \brief Class for representing a histogram 
///
/// Although all DM column types are internally supported, the interface provides access to a reduced list types only (to keep the interface as simple as possible). 
/// The corresponding conversion are implicitly performed when accessing the values.
class DM_API IHistogram  : public ObjectBase
{
public:
  /// \brief Histogram entry
  template<typename T>
  struct IEntry : public ObjectBase {
    virtual ~IEntry() {};
 
    virtual T       value() const = 0;  ///< value
    virtual int64_t count() const = 0;  ///< absolute frequency
  };
 
  // Iterator typedefs ============================================================================
  typedef ConstIterator< IEntry<int64_t> >        const_iterator_integral;    ///< integral histogram iterator
  typedef ConstIterator< IEntry<double> >         const_iterator_real;        ///< real histogram iterator
  typedef ConstIterator< IEntry<bool> >           const_iterator_bool;        ///< boolean histogram iterator
  typedef ConstIterator< IEntry<const char*> >    const_iterator_string;      ///< string histogram iterator
 
  virtual ~IHistogram() {}
 
  // General member functions ====================================================================
  virtual ColumnType type() const = 0;        ///< internal type of the histogram
  virtual bool isIntegral() const = 0;        ///< is an integral data type
  virtual bool isReal()     const = 0;        ///< is a real (double or float) data type
  virtual bool isBool()     const = 0;        ///< is a boolean type
  virtual bool isString()   const = 0;        ///< is a string data type
 
  virtual int64_t size() const = 0;     ///< number of histogram value (number of distinct data values)
 
  virtual int64_t sizeData() const = 0; ///< number of data values that were used to build the histogram
  virtual int64_t sizeNull() const = 0; ///< number of null values occurred in the corresponding data set
 
  virtual bool complete() const = 0; ///< flag if histogram covers the full data set
  
  // Iterator function ============================================================================
  virtual const_iterator_integral beginIntegral() const = 0;  ///< only allowed if isIntegral() == true
  virtual const_iterator_integral endIntegral()   const = 0;
 
  virtual const_iterator_real     beginReal() const = 0;
  virtual const_iterator_real     endReal()   const = 0;
 
  virtual const_iterator_bool     beginBool() const = 0;
  virtual const_iterator_bool     endBool() const = 0;
 
  virtual const_iterator_string   beginString() const = 0;
  virtual const_iterator_string   endString() const = 0;
};
 
typedef Handle< IHistogram > HistogramHandle;
 
 
DM_NAMESPACE_END