path: root/c++/src/H5DataType.cpp

/* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *
 * Copyright by The HDF Group.                                               *
 * Copyright by the Board of Trustees of the University of Illinois.         *
 * All rights reserved.                                                      *
 *                                                                           *
 * This file is part of HDF5.  The full HDF5 copyright notice, including     *
 * terms governing use, modification, and redistribution, is contained in    *
 * the COPYING file, which can be found at the root of the source code       *
 * distribution tree, or in https://support.hdfgroup.org/ftp/HDF5/releases.  *
 * If you do not have access to either file, you may request a copy from     *
 * help@hdfgroup.org.                                                        *
 * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * */

#ifdef OLD_HEADER_FILENAME
#include <iostream.h>
#else
#include <iostream>
#endif
#include <string>

#include "H5private.h"          // for HDcalloc
#include "H5Include.h"
#include "H5Exception.h"
#include "H5IdComponent.h"
#include "H5PropList.h"
#include "H5StrcreatProp.h"
#include "H5LcreatProp.h"
#include "H5LaccProp.h"
#include "H5Location.h"
#include "H5Object.h"
#include "H5DxferProp.h"
#include "H5DataType.h"
#include "H5AtomType.h"
#include "H5PredType.h"
#include "H5AbstractDs.h"
#include "H5DataSpace.h"
#include "H5DataSet.h"
#include "H5Attribute.h"

namespace H5 {
#ifndef H5_NO_STD
    using std::cerr;
    using std::endl;
#endif  // H5_NO_STD

//--------------------------------------------------------------------------
// Function:    DataType default constructor
///\brief       Default constructor: Creates a stub datatype
// Programmer   Binh-Minh Ribler - 2000
//--------------------------------------------------------------------------
DataType::DataType() : H5Object(), id(H5I_INVALID_HID), encoded_buf(NULL), buf_size(0) {}

//--------------------------------------------------------------------------
// Function:    DataType overloaded constructor
///\brief       Creates a datatype using an existing datatype's id
///\param       existing_id - IN: Id of the existing datatype
// Description
//              Constructor creates a copy of an existing DataType using
//              its id.
// Programmer   Binh-Minh Ribler - 2000
// Modification
//      Dec, 2005
//              Removed second argument, "predefined", after changing to the
//              new ref counting mechanism that relies on C's ref counting.
//--------------------------------------------------------------------------
DataType::DataType(const hid_t existing_id) : H5Object(), id(existing_id), encoded_buf(NULL), buf_size(0)
{
    incRefCount(); // increment number of references to this id
}

//--------------------------------------------------------------------------
// Function:    DataType overloaded constructor
///\brief       Creates a object given its class and size
///\param       type_class - IN: Class of datatype to create
///\param       size       - IN: Number of bytes in the datatype to create
///\exception   H5::DataTypeIException
// Programmer   Binh-Minh Ribler - 2000
//--------------------------------------------------------------------------
DataType::DataType(const H5T_class_t type_class, size_t size) : H5Object(), encoded_buf(NULL), buf_size(0)
{
    // Call C routine to create the new datatype
    id = H5Tcreate(type_class, size);
    if(id < 0)
    {
        throw DataTypeIException("DataType constructor", "H5Tcreate failed");
    }
}

//--------------------------------------------------------------------------
// Function:    DataType overload constructor - dereference
///\brief       Given a reference, ref, to an hdf5 group, creates a
///             DataType object
///\param       loc - IN: Location referenced object is in
///\param       ref - IN: Reference pointer
///\param       ref_type - IN: Reference type - default to H5R_OBJECT
///\exception   H5::ReferenceException
// Programmer   Binh-Minh Ribler - Oct, 2006
// Modification
//      Jul, 2008
//              Added for application convenience.
//--------------------------------------------------------------------------
DataType::DataType(const H5Location& loc, const void* ref, H5R_type_t ref_type) : H5Object(), encoded_buf(NULL), buf_size(0)
{
    id = H5Location::p_dereference(loc.getId(), ref, ref_type, "constructor - by dereference");
}

//--------------------------------------------------------------------------
// Function:    DataType overload constructor - dereference
///\brief       Given a reference, ref, to an hdf5 group, creates a
///             DataType object
///\param       attr - IN: Specifying location where the referenced object is in
///\param       ref - IN: Reference pointer
///\param       ref_type - IN: Reference type - default to H5R_OBJECT
///\exception   H5::ReferenceException
// Programmer   Binh-Minh Ribler - Oct, 2006
// Modification
//      Jul, 2008
//              Added for application convenience.
//--------------------------------------------------------------------------
DataType::DataType(const Attribute& attr, const void* ref, H5R_type_t ref_type) : H5Object(), id(H5I_INVALID_HID), encoded_buf(NULL), buf_size(0)
{
    id = H5Location::p_dereference(attr.getId(), ref, ref_type, "constructor - by dereference");
}

//--------------------------------------------------------------------------
// Function:    DataType copy constructor
///\brief       Copy constructor: makes a copy of the original DataType object.
// Programmer   Binh-Minh Ribler - 2000
//--------------------------------------------------------------------------
DataType::DataType(const DataType& original) : H5Object(), id(original.id), encoded_buf(NULL), buf_size(0)
{
    incRefCount(); // increment number of references to this id
}

//--------------------------------------------------------------------------
// Function:    DataType overloaded constructor
///\brief       Creates a DataType instance using a predefined type
///\param       pred_type - IN: Predefined datatype
///\exception   H5::DataTypeIException
// Programmer   Binh-Minh Ribler - 2015
// Description
//              Copying the type so that when a predefined type is passed in,
//              a copy of it is made, not just a duplicate of the HDF5 id.
//              Note: calling DataType::copy will invoke DataType::close()
//              unnecessarily and will produce undefined behavior.
//              -BMR, Apr 2015
//--------------------------------------------------------------------------
DataType::DataType(const PredType& pred_type) : H5Object(), encoded_buf(NULL), buf_size(0)
{
    // call C routine to copy the datatype
    id = H5Tcopy(pred_type.getId());
    if (id < 0)
        throw DataTypeIException("DataType constructor", "H5Tcopy failed");
}

//--------------------------------------------------------------------------
// Function:    DataType overloaded constructor
///\brief       Creates a DataType instance by opening an HDF5 datatype given
///             its name as a char*.
///\param       loc       - IN: Location of the type
///\param       type_name - IN: Datatype name
///\exception   H5::DataTypeIException
// Programmer   Binh-Minh Ribler - Sept 2017
// Description
//              In 1.8.20, this constructor was introduced and may replace the
//              existing function CommonFG::openDataType(const char*) to
//              improve usability.
//              -BMR, Sept 2017
//--------------------------------------------------------------------------
DataType::DataType(const H5Location& loc, const char *type_name) : H5Object(), encoded_buf(NULL), buf_size(0)
{
    id = p_opentype(loc, type_name);
}

//--------------------------------------------------------------------------
// Function:    DataType overloaded constructor
///\brief       Creates a DataType instance by opening an HDF5 datatype given
///             its name as an \c H5std_string.
///\param       loc       - IN: Location of the type
///\param       type_name - IN: Datatype name
///\exception   H5::DataTypeIException
// Programmer   Binh-Minh Ribler - Sept 2017
// Description
//              In 1.8.20, this constructor was introduced and may replace the
//              existing function CommonFG::openDataType(const H5std_string&)
//              to improve usability.
//              -BMR, Sept 2017
//--------------------------------------------------------------------------
DataType::DataType(const H5Location& loc, const H5std_string& type_name) : H5Object(), encoded_buf(NULL), buf_size(0)
{
    id = p_opentype(loc, type_name.c_str());
}

//--------------------------------------------------------------------------
// Function:    DataType::copy
///\brief       Copies an existing datatype to this datatype object
///\param       like_type - IN: Datatype to be copied
///\exception   H5::DataTypeIException
// Programmer   Binh-Minh Ribler - 2000
// Modification
//              - Replaced resetIdComponent() with decRefCount() to use C
//              library ID reference counting mechanism - BMR, Jun 1, 2004
//              - Replaced decRefCount with close() to let the C library
//              handle the reference counting - BMR, Jun 1, 2006
//--------------------------------------------------------------------------
void DataType::copy(const DataType& like_type)
{
    // close the current data type before copying like_type to this object
    try {
        close();
    }
    catch (Exception& close_error) {
        throw DataTypeIException(inMemFunc("copy"), close_error.getDetailMsg());
    }

    // call C routine to copy the datatype
    id = H5Tcopy(like_type.getId());
    if(id < 0)
        throw DataTypeIException(inMemFunc("copy"), "H5Tcopy failed");
}

//--------------------------------------------------------------------------
// Function:    DataType::copy
///\brief       Copies the datatype of the given dataset to this datatype object
///\param       dset - IN: Dataset
///\exception   H5::DataTypeIException
// Programmer   Binh-Minh Ribler - Jan, 2007
///\par Description
///             The resulted dataset will be transient and modifiable.
//--------------------------------------------------------------------------
void DataType::copy(const DataSet& dset)
{
    // close the current data type before copying dset's datatype to this object
    try {
        close();
    }
    catch (Exception& close_error) {
        throw DataTypeIException(inMemFunc("copy"), close_error.getDetailMsg());
    }

    // call C routine to copy the datatype
    id = H5Tcopy(dset.getId());
    if(id < 0)
        throw DataTypeIException(inMemFunc("copy"), "H5Tcopy failed");
}

//--------------------------------------------------------------------------
// Function:    DataType::decode
///\brief       Returns a DataType instance by decoding the binary object
///             description of this datatype.
///\exception   H5::DataTypeIException
// Programmer   Binh-Minh Ribler - Sept 2017
//--------------------------------------------------------------------------
DataType* DataType::decode() const
{
    hid_t encoded_dtype_id = H5I_INVALID_HID;
    try {
        encoded_dtype_id = p_decode();
    }
    catch (DataTypeIException &err) {
        throw;
    }
    DataType *encoded_dtype = new DataType;
    encoded_dtype->p_setId(encoded_dtype_id);
    return(encoded_dtype);
}

//--------------------------------------------------------------------------
// Function:    DataType::encode
///\brief       Creates a binary object description of this datatype.
///\exception   H5::DataTypeIException
// Programmer   Binh-Minh Ribler - Sept 2017
//--------------------------------------------------------------------------
void DataType::encode()
{
    // Call H5Tencode passing in null to determine the size of the buffer
    herr_t ret_value = H5Tencode(id, NULL, &buf_size);
    if (ret_value < 0)
    {
        throw DataTypeIException("DataType::encode", "Failed to get buf_size");
    }

    // Allocate buffer and call C function again to encode
    if (buf_size > 0)
    {
        encoded_buf = (unsigned char *)HDcalloc((size_t)1, buf_size);
        ret_value = H5Tencode(id, encoded_buf, &buf_size);
        if (ret_value < 0)
        {
            throw DataTypeIException("DataType::encode", "H5Tencode failed");
        }
    }
    else
    {
        throw DataTypeIException("DataType::encode", "Failed to allocate buffer for encoding");
    }
}

//--------------------------------------------------------------------------
// Function:    DataType::hasBinaryDesc
///\brief       Determines whether this datatype has a binary object
///             description.
///\exception   H5::DataTypeIException
// Programmer   Binh-Minh Ribler - Sept 2017
//--------------------------------------------------------------------------
bool DataType::hasBinaryDesc() const
{
    if (encoded_buf != NULL)
        return true;
    else
        return false;
}

//--------------------------------------------------------------------------
// Function:    DataType::operator=
///\brief       Assignment operator
///\param       rhs - IN: Reference to the existing datatype
///\return      Reference to DataType instance
///\exception   H5::DataTypeIException
// Description
//              Makes a copy of the type on the right hand side and stores
//              the new id in the left hand side object.
// Programmer   Binh-Minh Ribler - 2000
// Modification
//              Changed operator= to simply copy the id of rhs instead of
//              calling H5Tcopy because, when the operator= is invoked, a
//              different datatype id is created and it won't have the same
//              characteristics as the original one, specifically, if the
//              rhs represents a named datatype, "this" would still be a
//              transient datatype.
//              BMR - Mar, 2015
//--------------------------------------------------------------------------
DataType& DataType::operator=(const DataType& rhs)
{
    if (this != &rhs)
    {
        setId(rhs.id);
    }
    return(*this);
}

//--------------------------------------------------------------------------
// Function:    DataType::operator==
///\brief       Compares this DataType against the given one to determines
///             whether the two objects refer to the same actual datatype.
///\param       compared_type - IN: Reference to the datatype to compare
///\return      true if the datatypes are equal, and false, otherwise.
///\exception   H5::DataTypeIException
// Programmer   Binh-Minh Ribler - 2000
//--------------------------------------------------------------------------
bool DataType::operator==(const DataType& compared_type) const
{
    // Call C routine H5Tequal to determines whether two datatype
    // identifiers refer to the same datatype
    htri_t ret_value = H5Tequal(id, compared_type.getId());
    if(ret_value > 0)
        return true;
    else if(ret_value == 0)
        return false;
    else
    {
        throw DataTypeIException(inMemFunc("operator=="), "H5Tequal returns negative value");
    }
}

//--------------------------------------------------------------------------
// Function:    DataType::commit
///\brief       Commits a transient datatype to a file, creating a new
///             named datatype
///\param       loc - IN: A location (file, dataset, datatype, or group)
///\param       name - IN: Name of the datatype
///\exception   H5::DataTypeIException
// Programmer   Binh-Minh Ribler - 2000
//--------------------------------------------------------------------------
void DataType::commit(const H5Location& loc, const char* name)
{
    p_commit(loc.getId(), name);
}

//--------------------------------------------------------------------------
// Function:    DataType::commit
// Purpose      This is an overloaded member function, kept for backward
//              compatibility.  It differs from the above function in that it
//              misses const's.  This wrapper will be removed in future release.
// Param        loc - IN: A location (file, dataset, datatype, or group)
// Param        name - IN: Name of the datatype
// Exception    H5::DataTypeIException
// Programmer   Binh-Minh Ribler - Jan, 2007
// Modification
//              Planned for removal. -BMR, 2014/04/16
//              Removed from documentation. -BMR, 2016/03/07 1.8.17 and 1.10.0
//              Removed from code. -BMR, 2016/08/11 1.8.18 and 1.10.1
//--------------------------------------------------------------------------
//void DataType::commit(H5Location& loc, const char* name)
//{
//   p_commit(loc.getId(), name);
//}

//--------------------------------------------------------------------------
// Function:    DataType::commit
///\brief       This is an overloaded member function, provided for convenience.
///             It differs from the above function only in the type of the
///             argument \a name.
// Programmer   Binh-Minh Ribler - 2000
//--------------------------------------------------------------------------
void DataType::commit(const H5Location& loc, const H5std_string& name)
{
    p_commit(loc.getId(), name.c_str());
}

//--------------------------------------------------------------------------
// Function:    DataType::commit
// Purpose      This is an overloaded member function, kept for backward
//              compatibility.  It differs from the above function in that it
//              misses const's.  This wrapper will be removed in future release.
// Param        loc - IN: A location (file, dataset, datatype, or group)
// Param        name - IN: Name of the datatype
// Exception    H5::DataTypeIException
// Programmer   Binh-Minh Ribler - Jan, 2007
// Modification
//              Planned for removal. -BMR, 2014/04/16
//              Removed from documentation. -BMR, 2016/03/07 1.8.17 and 1.10.0
//              Removed from code. -BMR, 2016/08/11 1.8.18 and 1.10.1
//--------------------------------------------------------------------------
//void DataType::commit(H5Location& loc, const H5std_string& name)
//{
//   p_commit(loc.getId(), name.c_str());
//}

//--------------------------------------------------------------------------
// Function:    DataType::committed
///\brief       Determines whether a datatype is a named type or a
///             transient type.
///\return      \c true if the datatype is a named type, and \c false,
///             otherwise.
///\exception   H5::DataTypeIException
// Programmer   Binh-Minh Ribler - 2000
//--------------------------------------------------------------------------
bool DataType::committed() const
{
    // Call C function to determine if a datatype is a named one
    htri_t is_committed = H5Tcommitted(id);
    if (is_committed > 0)
        return true;
    else if (is_committed == 0)
        return false;
    else
    {
        throw DataTypeIException(inMemFunc("committed"), "H5Tcommitted return negative value");
    }
}

//--------------------------------------------------------------------------
// Function:    DataType::find
///\brief       Finds a conversion function that can handle a conversion
///             from this datatype to the specified datatype, \a dest.
///\param       dest   - IN: Destination datatype
///\param       pcdata - IN: Pointer to type conversion data
///\return      Pointer to a suitable conversion function
///\exception   H5::DataTypeIException
// Programmer   Binh-Minh Ribler - 2000
//--------------------------------------------------------------------------
H5T_conv_t DataType::find(const DataType& dest, H5T_cdata_t **pcdata) const
{
    // Call C routine to find the conversion function
    H5T_conv_t func = H5Tfind(id, dest.getId(), pcdata);
    if(func == NULL)
    {
        throw DataTypeIException(inMemFunc("find"), "H5Tfind returns a NULL function");
    }
    return(func);
}

//--------------------------------------------------------------------------
// Function:    DataType::convert
///\brief       Converts data from this datatype to the specified datatypes.
///\param       dest       - IN: Destination datatype
///\param       nelmts     - IN: Size of array \a buf
///\param       buf        - IN/OUT: Array containing pre- and post-conversion
///                             values
///\param       background - IN: Optional backgroud buffer
///\param       plist - IN: Property list - default to PropList::DEFAULT
///\return      Pointer to a suitable conversion function
///\exception   H5::DataTypeIException
// Programmer   Binh-Minh Ribler - 2000
//--------------------------------------------------------------------------
void DataType::convert(const DataType& dest, size_t nelmts, void *buf, void *background, const PropList& plist) const
{
    // Get identifiers for C API
    hid_t dest_id = dest.getId();
    hid_t plist_id = plist.getId();

    // Call C routine H5Tconvert to convert the data
    herr_t ret_value;
    ret_value = H5Tconvert(id, dest_id, nelmts, buf, background, plist_id);
    if(ret_value < 0)
    {
        throw DataTypeIException(inMemFunc("convert"), "H5Tconvert failed");
    }
}

//--------------------------------------------------------------------------
// Function:    DataType::lock
///\brief       Locks a datatype, making it read-only and non-destructible.
///
///\exception   H5::DataTypeIException
///\par Descrition
///             This is normally done by the library for predefined data
///             types so the application doesn't inadvertently change or
///             delete a predefined type.
///
///             Once a data type is locked it can never be unlocked unless
///             the entire library is closed.
// Programmer   Binh-Minh Ribler - 2000
//--------------------------------------------------------------------------
void DataType::lock() const
{
    // Call C routine to lock the datatype
    herr_t ret_value = H5Tlock(id);
    if(ret_value < 0)
    {
        throw DataTypeIException(inMemFunc("lock"), "H5Tlock failed");
    }
}

//--------------------------------------------------------------------------
// Function:    DataType::getClass
///\brief       Returns the datatype class identifier.
///\return      Datatype class identifier
///\exception   H5::DataTypeIException
// Programmer   Binh-Minh Ribler - 2000
//--------------------------------------------------------------------------
H5T_class_t DataType::getClass() const
{
    H5T_class_t type_class = H5Tget_class(id);

    // Return datatype class identifier if successful
    if(type_class == H5T_NO_CLASS)
    {
        throw DataTypeIException(inMemFunc("getClass"), "H5Tget_class returns H5T_NO_CLASS");
    }
    return(type_class);
}

//--------------------------------------------------------------------------
// Function:    DataType::getSize
///\brief       Returns the size of a datatype.
///\return      Datatype size in bytes
///\exception   H5::DataTypeIException
// Programmer   Binh-Minh Ribler - 2000
//--------------------------------------------------------------------------
size_t DataType::getSize() const
{
    // Call C routine to get the datatype size
    size_t type_size = H5Tget_size(id);
    if(type_size <= 0) // valid data types are never zero size
    {
        throw DataTypeIException(inMemFunc("getSize"), "H5Tget_size returns invalid datatype size");
    }
    return(type_size);
}

//--------------------------------------------------------------------------
// Function:    DataType::getSuper
///\brief       Returns the base datatype from which a datatype is derived.
///\return      DataType object
///\exception   H5::DataTypeIException
// Programmer   Binh-Minh Ribler - 2000
//--------------------------------------------------------------------------
DataType DataType::getSuper() const
{
    // Call C routine to get the base datatype from which the specified
    // datatype is derived.
    hid_t base_type_id = H5Tget_super(id);

    // If H5Tget_super returns a valid datatype id, create and return
    // the base type, otherwise, raise exception
    if(base_type_id > 0)
    {
        DataType base_type;
        base_type.p_setId(base_type_id);
        return(base_type);
    }
    else
    {
        throw DataTypeIException(inMemFunc("getSuper"), "H5Tget_super failed");
    }
}

//--------------------------------------------------------------------------
// Function:    DataType::registerFunc
///\brief       Registers the specified conversion function.
///\param       pers - IN: Conversion option
///                     \li \c H5T_PERS_HARD for hard conversion functions
///                     \li \c H5T_PERS_SOFT for soft conversion functions.
///\param       name - IN: Name displayed in diagnostic output.
///\param       dest - IN: Destination datatype.
///\param       func - IN: Function to convert between source and
///             destination datatypes.
///\exception   H5::DataTypeIException
///\par Description
///             For more information, please see:
/// https://support.hdfgroup.org/HDF5/doc/RM/RM_H5T.html#Datatype-Register
// Programmer   Binh-Minh Ribler - 2000
//--------------------------------------------------------------------------
void DataType::registerFunc(H5T_pers_t pers, const char* name, const DataType& dest, H5T_conv_t func) const
{
    hid_t dest_id = dest.getId();  // get id of the destination datatype

    // Call C routine H5Tregister to register the conversion function
    herr_t ret_value = H5Tregister(pers, name, id, dest_id, func);
    if(ret_value < 0)
    {
        throw DataTypeIException(inMemFunc("registerFunc"), "H5Tregister failed");
    }
}

//--------------------------------------------------------------------------
// Function:    DataType::registerFunc
///\brief       This is an overloaded member function, provided for convenience.
///             It differs from the above function only in the type of the
///             argument \a name.
// Programmer   Binh-Minh Ribler - 2000
//--------------------------------------------------------------------------
void DataType::registerFunc(H5T_pers_t pers, const H5std_string& name, const DataType& dest, H5T_conv_t func) const
{
    registerFunc(pers, name.c_str(), dest, func);
}

//--------------------------------------------------------------------------
// Function:    DataType::unregister
///\brief       Removes a conversion function from all conversion paths.
///\param       pers - IN: Conversion option
///                     \li \c H5T_PERS_HARD for hard conversion functions
///                     \li \c H5T_PERS_SOFT for soft conversion functions.
///\param       name - IN: Name displayed in diagnostic output.
///\param       dest - IN: Destination datatype.
///\param       func - IN: Function to convert between source and
///             destination datatypes.
///\exception   H5::DataTypeIException
// Programmer   Binh-Minh Ribler - 2000
//--------------------------------------------------------------------------
void DataType::unregister(H5T_pers_t pers, const char* name, const DataType& dest, H5T_conv_t func) const
{
    hid_t dest_id = dest.getId();  // get id of the dest datatype for C API

    // Call C routine H5Tunregister to remove the conversion function
    herr_t ret_value = H5Tunregister(pers, name, id, dest_id, func);
    if(ret_value < 0)
    {
        throw DataTypeIException(inMemFunc("unregister"), "H5Tunregister failed");
    }
}

//--------------------------------------------------------------------------
// Function:    DataType::unregister
///\brief       This is an overloaded member function, provided for convenience.
///             It differs from the above function only in the type of the
///             argument \a name.
// Programmer   Binh-Minh Ribler - 2000
//--------------------------------------------------------------------------
void DataType::unregister(H5T_pers_t pers, const H5std_string& name, const DataType& dest, H5T_conv_t func) const
{
    unregister(pers, name.c_str(), dest, func);
}

//--------------------------------------------------------------------------
// Function:    DataType::setTag
///\brief       Tags an opaque datatype.
///\param       tag - IN: Descriptive ASCII string with which the opaque
///             datatype is to be tagged.
///\exception   H5::DataTypeIException
// Programmer   Binh-Minh Ribler - 2000
//--------------------------------------------------------------------------
void DataType::setTag(const char* tag) const
{
    // Call C routine H5Tset_tag to tag an opaque datatype.
    herr_t ret_value = H5Tset_tag(id, tag);
    if(ret_value < 0)
    {
        throw DataTypeIException(inMemFunc("setTag"), "H5Tset_tag failed");
    }
}

//--------------------------------------------------------------------------
// Function:    DataType::setTag
///\brief       This is an overloaded member function, provided for convenience.
///             It differs from the above function only in the type of the
///             argument \a name.
// Programmer   Binh-Minh Ribler - 2000
//--------------------------------------------------------------------------
void DataType::setTag(const H5std_string& tag) const
{
    setTag(tag.c_str());
}

//--------------------------------------------------------------------------
// Function:    DataType::getTag
///\brief       Gets the tag associated with an opaque datatype.
///\return      Tag associated with the opaque datatype
///\exception   H5::DataTypeIException
// Programmer   Binh-Minh Ribler - 2000
//--------------------------------------------------------------------------
H5std_string DataType::getTag() const
{
    char* tag_Cstr = H5Tget_tag(id);

    // if the tag C-string returned is not NULL, convert it to C++ string
    // and return it, otherwise, raise an exception
    if(tag_Cstr != NULL)
    {
        H5std_string tag = H5std_string(tag_Cstr); // C string to string object
        H5free_memory(tag_Cstr); // free the C string
        return (tag); // return the tag
    }
    else
    {
        throw DataTypeIException(inMemFunc("getTag"), "H5Tget_tag returns NULL for tag");
    }
}

//--------------------------------------------------------------------------
// Function:    DataType::detectClass
///\brief       Checks whether a datatype contains (or is) a certain type of
///             datatype.
///\return      true if this datatype contains or is the specified type,
///             and false, otherwise.
///\exception   H5::DataTypeIException
// Programmer   Binh-Minh Ribler - May, 2004
//--------------------------------------------------------------------------
bool DataType::detectClass(H5T_class_t cls) const
{
    htri_t ret_value = H5Tdetect_class(id, cls);
    if(ret_value > 0)
        return true;
    else if(ret_value == 0)
        return false;
    else
    {
        throw DataTypeIException(inMemFunc("detectClass"),
                                "H5Tdetect_class returns negative value");
    }
}

//--------------------------------------------------------------------------
// Function:    DataType::isVariableStr
///\brief       Check whether this datatype is a variable-length string.
///\return      true if this datatype is a variable-length string, and
///             false, otherwise.
///\exception   H5::DataTypeIException
// Programmer   Binh-Minh Ribler - May, 2004
//--------------------------------------------------------------------------
bool DataType::isVariableStr() const
{
    htri_t is_varlen_str = H5Tis_variable_str(id);
    if(is_varlen_str == 1)
        return true;
    else if(is_varlen_str == 0)
        return false;
    else
    {
        throw DataTypeIException(inMemFunc("isVariableStr"),
                                "H5Tis_variable_str returns negative value");
    }
}

//--------------------------------------------------------------------------
// Function:    DataType::getCreatePlist
///\brief       Returns a copy of the property list, which is for datatype
///             creation.
///\return      A property list object
///\exception   H5::DataTypeIException
// Programmer   Binh-Minh Ribler - May, 2017
// Description
//              Currently, there is no datatype creation property list class
//              in the C++ API because there is no associated functionality.
//--------------------------------------------------------------------------
PropList DataType::getCreatePlist() const
{
    hid_t create_plist_id = H5Tget_create_plist(id);
    if (create_plist_id < 0)
    {
        throw DataTypeIException(inMemFunc("getCreatePlist"),
            "H5Tget_create_plist returns negative value");
    }
    // create and return the DSetCreatPropList object
    PropList create_plist;
    f_PropList_setId(&create_plist, create_plist_id);
    return(create_plist);
}

//--------------------------------------------------------------------------
// Function:    DataType::getId
///\brief       Get the id of this datatype
///\return      Datatype identifier
// Modification:
//      May 2008 - BMR
//              Class hierarchy is revised to address bugzilla 1068.  Class
//              AbstractDS and Attribute are moved out of H5Object.  In
//              addition, member IdComponent::id is moved into subclasses, and
//              IdComponent::getId now becomes pure virtual function.
// Programmer   Binh-Minh Ribler - May, 2008
//--------------------------------------------------------------------------
hid_t DataType::getId() const
{
    return(id);
}

#ifndef DOXYGEN_SHOULD_SKIP_THIS
//--------------------------------------------------------------------------
// Function:    DataType::p_commit (private)
//\brief        Commits a transient datatype to a file, creating a new
//              named datatype
//\param        loc_id - IN: The id of either a file, group, dataset, named
//                       datatype, or attribute.
//\param        name - IN: Name of the datatype
//\exception    H5::DataTypeIException
// Programmer   Binh-Minh Ribler - 2000
// Modification:
//              Copied from DataType::commit and made into private function
//              to be commonly used by several overloads of DataType::commit.
//              BMR - Jan, 2007
//--------------------------------------------------------------------------
void DataType::p_commit(hid_t loc_id, const char* name)
{
    // Call C routine to commit the transient datatype
    herr_t ret_value = H5Tcommit2(loc_id, name, id, H5P_DEFAULT, H5P_DEFAULT, H5P_DEFAULT);
    if(ret_value < 0)
        throw DataTypeIException(inMemFunc("p_commit"), "H5Tcommit2 failed");
}

//--------------------------------------------------------------------------
// Function:    DataType::p_decode
// Purpose      Returns an id of a type by decoding the binary object
///             description of this datatype.
///\exception   H5::DataTypeIException
// Programmer   Binh-Minh Ribler - Sept 2017
//--------------------------------------------------------------------------
hid_t DataType::p_decode() const
{
    // Make sure that the buffer can be decoded
    if (encoded_buf == NULL)
    {
        throw DataTypeIException("DataType::p_decode", "No encoded buffer");
    }

    // Call C function to decode the binary object description
    hid_t encoded_dtype_id = H5Tdecode(encoded_buf);

    // If H5Tdecode fails, raise exception
    if (encoded_dtype_id < 0)
    {
        throw DataTypeIException("DataType::p_decode", "H5Tdecode failed");
    }
    else
    {
        return(encoded_dtype_id);
    }
}

//--------------------------------------------------------------------------
// Function:    DataType::p_opentype (private)
///\brief       Opens an HDF5 datatype given its name
///\param       loc        - IN: Location of the type
///\param       type_name - IN: Datatype name
///\exception   H5::DataTypeIException
// Programmer   Binh-Minh Ribler - Sept 2017
// Description
//              This function was introduced in 1.8.20 to be used by the
//              new XxxType constructors that open a datatype. -BMR, Sept 2017
//--------------------------------------------------------------------------
hid_t DataType::p_opentype(const H5Location& loc, const char *type_name) const
{
    // Call C function to open the named datatype at this location
    hid_t ret_value = H5Topen2(loc.getId(), type_name, H5P_DEFAULT);
    if (ret_value < 0)
        throw DataTypeIException(inMemFunc("constructor"), "H5Topen2 failed");
    return(ret_value);
}

//--------------------------------------------------------------------------
// Function:    DataType::p_setId
///\brief       Sets the identifier of this object to a new value.
///
///\exception   H5::IdComponentException when the attempt to close the HDF5
///             object fails
// Description:
//              The underlaying reference counting in the C library ensures
//              that the current valid id of this object is properly closed.
//              Then the object's id is reset to the new id.
// Programmer   Binh-Minh Ribler - 2000
//--------------------------------------------------------------------------
void DataType::p_setId(const hid_t new_id)
{
    // handling references to this old id
    try {
        close();
    }
    catch (Exception& close_error) {
        throw DataTypeIException(inMemFunc("p_setId"), close_error.getDetailMsg());
    }
    // reset object's id to the given id
    id = new_id;
}
#endif // DOXYGEN_SHOULD_SKIP_THIS

//--------------------------------------------------------------------------
// Function:    DataType::close
///\brief       Closes the datatype if it is not a predefined type.
///
///\exception   H5::DataTypeIException
// Programmer   Binh-Minh Ribler - Mar 9, 2005
//--------------------------------------------------------------------------
void DataType::close()
{
    if (p_valid_id(id))
    {
        herr_t ret_value = H5Tclose(id);
        if(ret_value < 0)
        {
            throw DataTypeIException(inMemFunc("close"), "H5Tclose failed");
        }
        // reset the id
        id = H5I_INVALID_HID;
    }
}

//--------------------------------------------------------------------------
// Function:    DataType::throwException
///\brief       Throws H5::DataTypeIException.
///\param       func_name - Name of the function where failure occurs
///\param       msg       - Message describing the failure
///\exception   H5::DataTypeIException
// May 2018
//--------------------------------------------------------------------------
void DataType::throwException(const H5std_string& func_name, const H5std_string& msg) const
{
    throw DataTypeIException(inMemFunc(func_name.c_str()), msg);
}

//--------------------------------------------------------------------------
// Function:    DataType destructor
///\brief       Properly terminates access to this datatype.
// Programmer   Binh-Minh Ribler - 2000
// Modification
//              - Replaced resetIdComponent() with decRefCount() to use C
//                library ID reference counting mechanism - BMR, Jun 1, 2004
//              - Replaced decRefCount with close() to let the C library
//                handle the reference counting - BMR, Jun 1, 2006
//              - Added the use of H5CPP_EXITED to terminate the HDF5 library
//                and elimiate previous memory leaks.  See comments in the
//                header file "H5PredType.h" for details. - BMR, Mar 30, 2012
//              - Major re-implementation of the global constants was done
//                to avoid relying on the order of the creation and deletion
//                of the global constants.  Hence, H5CPP_EXITED was removed.
//                See Design Notes in "H5PredType.cpp" for details.
//                - BMR, Sep 30, 2015
//--------------------------------------------------------------------------
DataType::~DataType()
{
    try
    {
        close();
    }
    catch (Exception& close_error) {
        cerr << inMemFunc("~DataType - ") << close_error.getDetailMsg() << endl;
    }
}
} // end namespace