// C++ informative line for the emacs editor: -*- C++ -*-
/* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *
 * 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.  *
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 * help@hdfgroup.org.                                                        *
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#ifndef __H5Attribute_H
#define __H5Attribute_H

namespace H5 {

/*! \class Attribute
    \brief Class Attribute operates on HDF5 attributes.

    An attribute has many characteristics similar to a dataset, thus both
    Attribute and DataSet are derivatives of AbstractDs.  Attribute also
    inherits from H5Location because an attribute can be used to specify
    a location.
*/
//  Inheritance: multiple H5Location/AbstractDs -> IdComponent
class H5_DLLCPP Attribute : public AbstractDs, public H5Location {
   public:

        // Copy constructor: same as the original Attribute.
        Attribute(const Attribute& original);

        // Default constructor
        Attribute();

        // Creates a copy of an existing attribute using the attribute id
        Attribute(const hid_t attr_id);

        // Closes this attribute.
        virtual void close();

        // Gets the name of this attribute.
        ssize_t getName(char* attr_name, size_t buf_size = 0) const;
        H5std_string getName(size_t len) const;
        H5std_string getName() const;
        ssize_t getName(H5std_string& attr_name, size_t len = 0) const;
        // The overloaded function below is replaced by the one above and it
        // is kept for backward compatibility purpose.
        ssize_t getName(size_t buf_size, H5std_string& attr_name) const;

        // Gets a copy of the dataspace for this attribute.
        virtual DataSpace getSpace() const;

        // Returns the amount of storage size required for this attribute.
        virtual hsize_t getStorageSize() const;

        // Returns the in memory size of this attribute's data.
        virtual size_t getInMemDataSize() const;

        // Reads data from this attribute.
        void read(const DataType& mem_type, void *buf) const;
        void read(const DataType& mem_type, H5std_string& strg) const;

        // Writes data to this attribute.
        void write(const DataType& mem_type, const void *buf) const;
        void write(const DataType& mem_type, const H5std_string& strg) const;

        ///\brief Returns this class name.
        virtual H5std_string fromClass () const { return("Attribute"); }

        // Gets the attribute id.
        virtual hid_t getId() const;

        // Destructor: properly terminates access to this attribute.
        virtual ~Attribute();

#ifndef DOXYGEN_SHOULD_SKIP_THIS
   protected:
        // Sets the attribute id.
        virtual void p_setId(const hid_t new_id);
#endif // DOXYGEN_SHOULD_SKIP_THIS

   private:
        hid_t id;        // HDF5 attribute id

        // This function contains the common code that is used by
        // getTypeClass and various API functions getXxxType
        // defined in AbstractDs for generic datatype and specific
        // sub-types
        virtual hid_t p_get_type() const;

        // Reads variable or fixed len strings from this attribute.
        void p_read_variable_len(const DataType& mem_type, H5std_string& strg) const;
        void p_read_fixed_len(const DataType& mem_type, H5std_string& strg) const;

        // Friend function to set Attribute id.  For library use only.
        friend void f_Attribute_setId(Attribute* attr, hid_t new_id);

}; // end of Attribute
} // namespace H5

#endif // __H5Attribute_H
