path: root/c++/src/H5Attribute.cpp

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 * Copyright by The HDF Group.                                               *
 * Copyright by the Board of Trustees of the University of Illinois.         *
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#ifdef OLD_HEADER_FILENAME
#include <iostream.h>
#else
#include <iostream>
#endif
#include <string>

#include "H5Include.h"
#include "H5Exception.h"
#include "H5IdComponent.h"
#include "H5PropList.h"
#include "H5Object.h"
#include "H5AbstractDs.h"
#include "H5FaccProp.h"
#include "H5FcreatProp.h"
#include "H5DcreatProp.h"
#include "H5CommonFG.h"
#include "H5DataType.h"
#include "H5DataSpace.h"
#include "H5File.h"
#include "H5Attribute.h"
#include "H5private.h"		// for HDfree

#ifndef H5_NO_NAMESPACE
namespace H5 {
#ifndef H5_NO_STD
    using std::cerr;
    using std::endl;
#endif  // H5_NO_STD
#endif

//--------------------------------------------------------------------------
// Function:	Attribute default constructor
///\brief	Default constructor: Creates a stub attribute
// Programmer	Binh-Minh Ribler - May, 2004
//--------------------------------------------------------------------------
Attribute::Attribute() : AbstractDs(), IdComponent(), id(0) {}

//--------------------------------------------------------------------------
// Function:	Attribute copy constructor
///\brief	Copy constructor: makes a copy of the original Attribute object.
///\param	original  - IN: Original Attribute object to copy
// Programmer	Binh-Minh Ribler - 2000
//--------------------------------------------------------------------------
Attribute::Attribute(const Attribute& original) : AbstractDs(), IdComponent()
{
    id = original.getId();
    incRefCount(); // increment number of references to this id
}

//--------------------------------------------------------------------------
// Function:	Attribute overloaded constructor
///\brief	Creates an Attribute object using the id of an existing
///		attribute.
///\param	existing_id - IN: Id of an existing attribute
///\exception	H5::AttributeIException
// Programmer	Binh-Minh Ribler - 2000
//--------------------------------------------------------------------------
Attribute::Attribute(const hid_t existing_id) : AbstractDs(), IdComponent()
{
   id = existing_id;
}

//--------------------------------------------------------------------------
// Function:	Attribute::write
///\brief	Writes data to this attribute.
///\param	mem_type  - IN: Attribute datatype (in memory)
///\param	buf       - IN: Data to be written
///\exception	H5::AttributeIException
// Programmer	Binh-Minh Ribler - 2000
//--------------------------------------------------------------------------
void Attribute::write( const DataType& mem_type, const void *buf ) const
{
   herr_t ret_value = H5Awrite( id, mem_type.getId(), buf );
   if( ret_value < 0 )
   {
      throw AttributeIException("Attribute::write", "H5Awrite failed");
   }
}

//--------------------------------------------------------------------------
// Function:	Attribute::write
///\brief	This is an overloaded member function, provided for convenience.
///		It writes a \a H5std_string to this attribute.
///\param	mem_type  - IN: Attribute datatype (in memory)
///\param	strg      - IN: Data to be written
///\exception	H5::AttributeIException
// Programmer	Binh-Minh Ribler - Apr, 2003
//--------------------------------------------------------------------------
void Attribute::write(const DataType& mem_type, const H5std_string& strg) const
{
    // Check if this attribute has variable-len string or fixed-len string and
    // proceed appropriately.
    htri_t is_variable_len = H5Tis_variable_str(mem_type.getId());
    if (is_variable_len < 0)
    {
	throw AttributeIException("Attribute::write", "H5Tis_variable_str failed");
    }
    // Convert string to C-string
    const char* strg_C;
    strg_C = strg.c_str();  // strg_C refers to the contents of strg as a C-str
    herr_t ret_value = 0;

    // Pass string in differently depends on variable or fixed length
    if (!is_variable_len)
    {
	ret_value = H5Awrite(id, mem_type.getId(), strg_C);
    }
    else
    {
	// passing third argument by address
	ret_value = H5Awrite(id, mem_type.getId(), &strg_C);
    }
    if (ret_value < 0)
    {
	throw AttributeIException("Attribute::write", "H5Awrite failed");
    }
}

//--------------------------------------------------------------------------
// Function:	Attribute::read
///\brief	Reads data from this attribute.
///\param	mem_type -  IN: Attribute datatype (in memory)
///\param	buf      - OUT: Buffer for read data
///\exception	H5::AttributeIException
// Programmer	Binh-Minh Ribler - 2000
//--------------------------------------------------------------------------
void Attribute::read( const DataType& mem_type, void *buf ) const
{
   herr_t ret_value = H5Aread( id, mem_type.getId(), buf );
   if( ret_value < 0 )
   {
      throw AttributeIException("Attribute::read", "H5Aread failed");
   }
}

//--------------------------------------------------------------------------
// Function:	Attribute::read
///\brief	This is an overloaded member function, provided for convenience.
///		It reads a \a H5std_string from this attribute.
///\param	mem_type  - IN: Attribute datatype (in memory)
///\param	strg      - IN: Buffer for read string
///\exception	H5::AttributeIException
// Programmer	Binh-Minh Ribler - Apr, 2003
// Modification
//	Mar 2008
//		Corrected a misunderstanding that H5Aread would allocate
//		space for the buffer.  Obtained the attribute size and
//		allocated memory properly. - BMR
//	Apr 2009
//		Used getInMemDataSize to get attribute data size. - BMR
//	Jul 2009
//		Divided into specific private functions for fixed- and
//		variable-len string data: p_read_fixed_len and
//		p_read_variable_len.  This should improve readability.
//--------------------------------------------------------------------------
void Attribute::read(const DataType& mem_type, H5std_string& strg) const
{
    // Check if this attribute has variable-len string or fixed-len string and
    // proceed appropriately.
    htri_t is_variable_len = H5Tis_variable_str(mem_type.getId());
    if (is_variable_len < 0)
    {
        throw AttributeIException("Attribute::read", "H5Tis_variable_str failed");
    }

    if (!is_variable_len)       // only allocate for fixed-len string
    {
        p_read_fixed_len(mem_type, strg);
    }
    else
    {
        p_read_variable_len(mem_type, strg);
    }
}

//--------------------------------------------------------------------------
// Function:	Attribute::getInMemDataSize
///\brief	Gets the size in memory of the attribute's data.
///\return	Size of data (in memory)
///\exception	H5::AttributeIException
// Programmer	Binh-Minh Ribler - Apr 2009
//--------------------------------------------------------------------------
size_t Attribute::getInMemDataSize() const
{
    char *func = "Attribute::getInMemDataSize";

    // Get the data type of this attribute
    hid_t mem_type_id = H5Aget_type(id);
    if( mem_type_id < 0 )
    {
	throw AttributeIException(func, "H5Aget_type failed");
    }

    // Get the data type's size
    hid_t native_type = H5Tget_native_type(mem_type_id, H5T_DIR_DEFAULT);
    if (native_type < 0)
    {
	throw AttributeIException(func, "H5Tget_native_type failed");
    }
    size_t type_size = H5Tget_size(native_type);
    if (type_size == 0)
    {
	throw AttributeIException(func, "H5Tget_size failed");
    }

    // Get number of elements of the attribute
    hid_t space_id = H5Aget_space(id);
    if (space_id < 0)
    {
	throw AttributeIException(func, "H5Aget_space failed");
    }
    hssize_t num_elements = H5Sget_simple_extent_npoints(space_id);
    if (num_elements < 0)
    {
	throw AttributeIException(func, "H5Sget_simple_extent_npoints failed");
    }

    // Calculate and return the size of the data
    size_t data_size = type_size * num_elements;
    return(data_size);
}

//--------------------------------------------------------------------------
// Function:	Attribute::getSpace
///\brief	Gets a copy of the dataspace for this attribute.
///\return	Dataspace instance
///\exception	H5::AttributeIException
// Programmer	Binh-Minh Ribler - 2000
//--------------------------------------------------------------------------
DataSpace Attribute::getSpace() const
{
   // Calls C function H5Aget_space to get the id of the dataspace
   hid_t dataspace_id = H5Aget_space( id );

   // If the dataspace id is valid, create and return the DataSpace object
   if( dataspace_id > 0 )
   {
      DataSpace dataspace( dataspace_id );
      return( dataspace );
   }
   else
   {
      throw AttributeIException("Attribute::getSpace", "H5Aget_space failed");
   }
}

//--------------------------------------------------------------------------
// Function:	Attribute::getFileName
///\brief	Gets the name of the file, in which this attribute belongs.
///\return	File name
///\exception	H5::IdComponentException
// Programmer	Binh-Minh Ribler - Jul, 2004
//--------------------------------------------------------------------------
H5std_string Attribute::getFileName() const
{
   try {
      return(p_get_file_name());
   }
   catch (IdComponentException E) {
      throw FileIException("Attribute::getFileName", E.getDetailMsg());
   }
}

//--------------------------------------------------------------------------
// Function:	Attribute::getName
///\brief	Gets the name of this attribute, returning its length.
///\param	buf_size  -  IN: Desired length of the name
///\param	attr_name - OUT: Buffer for the name string
///\return	Length of the attribute name
///\exception	H5::AttributeIException
// Programmer	Binh-Minh Ribler - Nov, 2001
//--------------------------------------------------------------------------
ssize_t Attribute::getName( size_t buf_size, H5std_string& attr_name ) const
{
   char* name_C = new char[buf_size+1];  // temporary C-string for C API

   // Calls C routine H5Aget_name to get the name of the attribute
   ssize_t name_size = H5Aget_name( id, buf_size, name_C );

   // If H5Aget_name returns a negative value, raise an exception,
   if( name_size < 0 )
   {
      throw AttributeIException("Attribute::getName", "H5Aget_name failed");
   }
   // otherwise, convert the C attribute name and return
   attr_name = name_C;
   delete []name_C;
   return( name_size );
}

//--------------------------------------------------------------------------
// Function:	Attribute::getName
///\brief	This is an overloaded member function, provided for convenience.
///		It differs from the above function in that it returns the
///		attribute's name, not the length.
///\return	Name of the attribute
///\param	buf_size  -  IN: Desired length of the name
///\exception	H5::AttributeIException
// Programmer	Binh-Minh Ribler - 2000
//--------------------------------------------------------------------------
H5std_string Attribute::getName( size_t buf_size ) const
{
   H5std_string attr_name;
   ssize_t name_size = getName( buf_size, attr_name );
   return( attr_name );
   // let caller catch exception if any
}

//--------------------------------------------------------------------------
// Function:	Attribute::getName
///\brief	This is an overloaded member function, provided for convenience.
///		It differs from the above functions in that it doesn't take
///		any arguments and returns the attribute's name.
///\return	Name of the attribute
///\exception	H5::AttributeIException
// Programmer	Binh-Minh Ribler - May, 2004
//--------------------------------------------------------------------------
H5std_string Attribute::getName() const
{
   // Try with 256 characters for the name first, if the name's length
   // returned is more than that then, read the name again with the
   // appropriate space allocation
   char* name_C = new char[256];  // temporary C-string for C API
   ssize_t name_size = H5Aget_name(id, 255, name_C);

   H5std_string attr_name;
   if (name_size >= 256)
      name_size = getName(name_size, attr_name);

   // otherwise, convert the C attribute name and return
   else
      attr_name = name_C;

   delete []name_C;
   return( attr_name );
}

//--------------------------------------------------------------------------
// Function:	Attribute::getStorageSize
///\brief	Returns the amount of storage size required for this attribute.
///\return	Size of the storage or 0, for no data
///\exception	H5::AttributeIException
// Note:	H5Dget_storage_size returns 0 when there is no data.  This
//		function should have no failure. (from SLU)
// Programmer	Binh-Minh Ribler - Mar, 2005
//--------------------------------------------------------------------------
hsize_t Attribute::getStorageSize() const
{
   hsize_t storage_size = H5Aget_storage_size(id);
   return (storage_size);
}

//--------------------------------------------------------------------------
// Function:    Attribute::getId
// Purpose:     Get the id of this attribute
// Description:
//		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 Attribute::getId() const
{
   return(id);
}

//--------------------------------------------------------------------------
// Function:	Attribute::p_get_type (private)
// Purpose	Gets the datatype of this attribute.
// Return	Id of the datatype
// Exception	H5::AttributeIException
// Description
// 		This private function is used in AbstractDs.
// Programmer	Binh-Minh Ribler - 2000
//--------------------------------------------------------------------------
hid_t Attribute::p_get_type() const
{
   hid_t type_id = H5Aget_type( id );
   if( type_id > 0 )
      return( type_id );
   else
   {
      throw AttributeIException("", "H5Aget_type failed");
   }
}

//--------------------------------------------------------------------------
// Function:	Attribute::p_read_fixed_len (private)
// brief	Reads a fixed length \a H5std_string from an attribute.
// param	mem_type  - IN: Attribute datatype (in memory)
// param	strg      - IN: Buffer for read string
// exception	H5::AttributeIException
// Programmer	Binh-Minh Ribler - Jul, 2009
// Modification
//	Jul 2009
//		Separated the fixed length case from the original
//		Attribute::read
//--------------------------------------------------------------------------
void Attribute::p_read_fixed_len(const DataType& mem_type, H5std_string& strg) const
{
    // Only allocate for fixed-len string.

    // Get the size of the attribute's data
    size_t attr_size = getInMemDataSize();

    // If there is data, allocate buffer and read it.
    if (attr_size > 0)
    {
	char *strg_C = NULL;

	strg_C = new char [(size_t)attr_size+1];
	herr_t ret_value = H5Aread(id, mem_type.getId(), strg_C);

	if( ret_value < 0 )
	{
	    delete []strg_C;	// de-allocate for fixed-len string
	    throw AttributeIException("Attribute::read", "H5Aread failed");
	}

	// Get string from the C char* and release resource allocated locally
	strg = strg_C;
	delete []strg_C;
    }
}

//--------------------------------------------------------------------------
// Function:	Attribute::p_read_variable_len (private)
// brief	Reads a variable length \a H5std_string from an attribute.
// param	mem_type  - IN: Attribute datatype (in memory)
// param	strg      - IN: Buffer for read string
// exception	H5::AttributeIException
// Programmer	Binh-Minh Ribler - Jul, 2009
// Modification
//	Jul 2009
//		Separated the variable length case from the original
//		Attribute::read
//--------------------------------------------------------------------------
void Attribute::p_read_variable_len(const DataType& mem_type, H5std_string& strg) const
{

    // Prepare and call C API to read attribute.
    char *strg_C;

    // Read attribute, no allocation for variable-len string; C library will
    herr_t ret_value = H5Aread(id, mem_type.getId(), &strg_C);

    if( ret_value < 0 )
    {
	throw AttributeIException("Attribute::read", "H5Aread failed");
    }

    // Get string from the C char* and release resource allocated by C API
    strg = strg_C;
    HDfree(strg_C);
}

//--------------------------------------------------------------------------
// Function:    Attribute::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 Attribute::p_setId(const hid_t new_id)
{
    // handling references to this old id
    try {
	close();
    }
    catch (Exception close_error) {
	throw AttributeIException("Attribute::p_setId", close_error.getDetailMsg());
    }
   // reset object's id to the given id
   id = new_id;
}

//--------------------------------------------------------------------------
// Function:	Attribute::close
///\brief	Closes this attribute.
///
///\exception	H5::AttributeIException
// Programmer	Binh-Minh Ribler - Mar 9, 2005
//--------------------------------------------------------------------------
void Attribute::close()
{
    if (p_valid_id(id))
    {
	herr_t ret_value = H5Aclose(id);
	if( ret_value < 0 )
	{
	    throw AttributeIException("Attribute::close", "H5Aclose failed");
	}
	// reset the id when the attribute that it represents is no longer
	// referenced
	if (getCounter() == 0)
	    id = 0;
    }
}

//--------------------------------------------------------------------------
// Function:	Attribute destructor
///\brief	Properly terminates access to this attribute.
// 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
//--------------------------------------------------------------------------
Attribute::~Attribute()
{
    try {
	close();
    }
    catch (Exception close_error) {
	cerr << "Attribute::~Attribute - " << close_error.getDetailMsg() << endl;
    }
}

#ifndef H5_NO_NAMESPACE
} // end namespace
#endif