JDAQFileReader.hh

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#ifndef __JSUPPORT__JDAQFILEREADER__
#define __JSUPPORT__JDAQFILEREADER__

#include <vector>
#include <string.h>

#include "JIO/JBinaryFileReader.hh"
#include "JIO/JByteArrayIO.hh"
#include "JDAQ/JDAQDataTypes.hh"
#include "JDAQ/JDAQPreamble.hh"
#include "JLang/JObjectIterator.hh"
#include "JLang/JConversion.hh"


/**
 * \author mdejong
 */

namespace JSUPPORT {}
namespace JPP { using namespace JSUPPORT; }

namespace JSUPPORT {

  using JIO::JBinaryFileReader;
  using KM3NETDAQ::JDAQPreamble;
  using JLANG::JAccessibleObjectIterator;
  using JLANG::JNullIterator;
  using JLANG::JNullAccess;


  /**
   * DAQ object reading from binary file (i.e. .dat).
   */
  template<class T, bool = JLANG::JConversion<T,JDAQPreamble>::is_derived>
  class JDAQFileReader;


  /**
   * Template specialisation of JDAQFileReader for DAQ compatible data types.
   *
   * This class provides for an implementation of the JLANG::JAccessibleObjectIterator interface.
   * It overwrites the method setObject of the JLANG::JAbstractObjectIterator interface so that
   * the desired object is read from the file which may contain also other objects.
   */
  template<class T>
  class JDAQFileReader<T,true> :
    public JBinaryFileReader<T>
  {
  public:
    /**
     * Set object.
     *
     * \param  object     reference to object to be set
     * \return            true if set; else false
     */
    virtual bool setObject(T& object)
    {
      using namespace std;
      using namespace KM3NETDAQ;
      using namespace JIO;

      for (JStreamReader& in = static_cast<JStreamReader&>(*this); in >> preamble; ) {
        
        if        (preamble.getLength() < JDAQPreamble::sizeOf()) {
              
          this->setstate(ios::badbit);
          
          return false;
          
        } else if (preamble.getDataType() == getDataType<T>()) {
            
          buffer.resize(preamble.getLength());

          memcpy(buffer.data(), static_cast<JDAQAbstractPreamble*>(&preamble), JDAQPreamble::sizeOf());
          
          in.read(buffer.data()        + JDAQPreamble::sizeOf(),
                  preamble.getLength() - JDAQPreamble::sizeOf());
          
          JByteArrayReader bin(buffer.data(), buffer.size());

          bin >> object;
          
          return (bool) in;
          
        } else {
            
          this->ignore((streamsize) (preamble.getLength() - JDAQPreamble::sizeOf()));
        }
      }  

      return false;
    }
 
  private:
    mutable JDAQPreamble      preamble;
    mutable std::vector<char> buffer;
  };


  /**
   * Template specialisation of JDAQFileReader for DAQ incompatible data types.
   *
   * This class provides for a null implementation of the JLANG::JAccessibleObjectIterator interface.
   */
  template<class T>
  class JDAQFileReader<T,false> :
    public JAccessibleObjectIterator<T>,
    public JNullAccess,
    public JNullIterator<T>
  {};
}

#endif