YODA::H5DataSetReader Class Reference

Helper class to extract information from YODA_H5::DataSets. More...

#include <H5Utils.h>

Public Member Functions
	H5DataSetReader ()
	Nullary constructor.
	H5DataSetReader (const YODA_H5::File &h5file, const string &label)
void	skip (size_t len) noexcept
	Move internal cursor by len elements.
template<typename T = size_t>
T	next () noexcept
	Load next item and increment cursor.
template<typename T >
vector< T >	read () noexcept
	Method to read and return the entire 1D dataset.
template<typename T >
vector< T >	read (size_t len) noexcept
	Method to read a subset of the 1D dataset.
template<typename T >
vector< T >	readSlice (size_t len) noexcept
	Method to read a subset of the 1D dataset.
template<typename T >
vector< T >	readAt (size_t row, size_t len) noexcept
	Method to read a subset of the 1D dataset starting from row row.
template<typename T = size_t>
vector< T >	readAttribute (const string &label) const noexcept
	Method to read an attribute decorated onto this dataset.

Detailed Description

Helper class to extract information from YODA_H5::DataSets.

Definition at line 66 of file H5Utils.h.

Constructor & Destructor Documentation

H5DataSetReader() [1/2]

YODA::H5DataSetReader::H5DataSetReader ( )

inline

Nullary constructor.

Definition at line 70 of file H5Utils.h.

{ }

H5DataSetReader() [2/2]

YODA::H5DataSetReader::H5DataSetReader ( const YODA_H5::File &  h5file, const string &  label  )

inline

Definition at line 73 of file H5Utils.h.

          : _nrows(0), _thisrow(0), _ncols(0), _thiscol(0), _ds(nullptr) {
      _ds = std::make_unique<YODA_H5::DataSet>(h5file.getDataSet(label));
      const auto& dims = _ds->getDimensions();
      _nrows = dims.at(0);
      if (dims.size() > 1)  _ncols = dims.at(1);
    }

Member Function Documentation

next()

template<typename T = size_t>

T YODA::H5DataSetReader::next ( )

inlinenoexcept

Load next item and increment cursor.

Definition at line 86 of file H5Utils.h.

                      {
      T item;
      _ds->select({_thisrow++}, {1}).read(item);
      return item;
    }

References read().

read() [1/2]

template<typename T >

vector< T > YODA::H5DataSetReader::read ( )

inlinenoexcept

Method to read and return the entire 1D dataset.

Definition at line 94 of file H5Utils.h.

                              {
      if (_nrows == 0)  return vector<T>{};
      vector<T> data; data.reserve(_nrows);
      _ds->select({0}, {_nrows}).read(data);
      return data;
    }

References read().

Referenced by next(), read(), read(), and readSlice().

read() [2/2]

template<typename T >

vector< T > YODA::H5DataSetReader::read ( size_t  len )

inlinenoexcept

Method to read a subset of the 1D dataset.

Definition at line 103 of file H5Utils.h.

                                        {
      if (len == 0)  return {};
      vector<T> data; data.reserve(len);
      _ds->select({_thisrow}, {len}).read(data);
      _thisrow += len;
      return data;
    }

References read().

readAt()

template<typename T >

vector< T > YODA::H5DataSetReader::readAt ( size_t  row, size_t  len  )

inlinenoexcept

Method to read a subset of the 1D dataset starting from row row.

Definition at line 134 of file H5Utils.h.

                                                      {
      _thisrow = row;
      return read<T>(len);
    }

readAttribute()

template<typename T = size_t>

vector< T > YODA::H5DataSetReader::readAttribute ( const string &  label ) const

inlinenoexcept

Method to read an attribute decorated onto this dataset.

Definition at line 141 of file H5Utils.h.

                                                                {
      vector<T> data;
      _ds->getAttribute(label).read(data);
      return data;
    }

readSlice()

template<typename T >

vector< T > YODA::H5DataSetReader::readSlice ( size_t  len )

inlinenoexcept

Method to read a subset of the 1D dataset.

Definition at line 113 of file H5Utils.h.

                                             {
      if (len == 0)  return {};
      vector<T> data; data.reserve(len);
      while (len) {
        vector<vector<T>> tmp;
        size_t ncols = std::min(len, _ncols - _thiscol);
        size_t nrows = 1+(ncols-1)/_ncols; // C-style ceil
        _ds->select({_thisrow,_thiscol}, {nrows,ncols}).read(tmp);
        for (size_t i=0; i < tmp.size(); ++i) {
          data.insert(data.end(), std::make_move_iterator(std::begin(tmp[i])),
                                  std::make_move_iterator(std::end(tmp[i])));
        }
        if ((_thiscol + ncols) == _ncols)  ++_thisrow;
        _thiscol = (_thiscol + ncols) % _ncols;
        len -= ncols;
      }
      return data;
    }

References read().

skip()

void YODA::H5DataSetReader::skip ( size_t  len )

inlinenoexcept

Move internal cursor by len elements.

Definition at line 82 of file H5Utils.h.

{ _thisrow += len; }

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The documentation for this class was generated from the following file:

• include/YODA/Utils/H5Utils.h