IColBufferManagerRead.hpp

#pragma once
 
#include "DM/config.hpp"
#include "DM/ObjectBase.hpp"
#include "DM/ColumnTypes.hpp"
#include "DM/AutoLink.hpp" //enable autolink
#include "DM/IValueTranslator.hpp"
 
DM_NAMESPACE_BEGIN
 
/// \brief managing interface for creating and filling point coordinates and attributes into a column based continuous memory buffer 
class DM_API IColBufferManagerRead : public ObjectBase
{
protected:
  virtual ~IColBufferManagerRead() {}
 
public:
  virtual int64_t getRows()  const = 0;
  virtual int64_t getColumns()  const = 0;
 
  /// \brief get internal column type
  /**
    This function that will be called (by GenericConverter::initColBufferManager) for each column after the initial setSize function was called.
    The caller therefore communicates the type and label of each column that will be processed. The function must return the type of the internal 
    columns buffer, which may differ from the provided type. However, only fixed size type are accepted:
 
     DM::ColumnType | Memory Size and Representation 
    ----------------|--------------------------------
      int_          | 4 byte, signed integer         
      uint_         | 4 byte, unsigned integer       
      char_         | 1 byte, integer                
      uchar_        | 1 byte, unsigned integer       
      short_        | 2 byte, integer                
      ushort_       | 2 byte, unsigned integer       
      float_        | 4 byte, real                   
      double_       | 8 byte, real                   
      llong_        | 8 byte, signed integer         
    
    
    Its the managers responsibility to create appropriate sized column buffers and that are initialise with appropriate null values,
    since the subsequent buffer filling doesn't write any null values are the corresponding memory positions.
 
    \param[in] col      current column index
    \return element type of internal column buffer
  */
  virtual ColumnType getColumnType(unsigned col) const = 0;
 
  /// \brief get optional translator object for translating values before setting
  virtual const IValueTranslator* getTranslator(unsigned col) const = 0;
 
  /// \brief get the pointer to the corresponding column buffer
  /**
    Will be called after the corresponding setSize and setColumnType calls. It is assumed that the returned 
    pointer shows to an initialised and properly sized memory chunk, that can be filled. Note that null values
    do not change the corresponding memory byte(s).
  */
  virtual const void * getColumnBuffer(unsigned col) const = 0;
 
  /// \brief get stride size between subsequent elements in the column buffer
  /**
    In case of continuous memory array the stride size is equal to the element size (in bytes)
  */
  virtual unsigned getStride(unsigned col) const = 0;
 
};
 
DM_NAMESPACE_END