#ifdef __cplusplus
extern "C" {
#endif

#include "stdafx.h"
#include "..\..\hdf5\hdf5\hdf5-1.6.5_PC\src\hdf5.h"

#include <stdlib.h>
#include <stdio.h>
#include <memory.h>


#define FILE        "matrix.h5"
#define DATASETNAME  "OBJ" 


struct obj
{
double mat[4][4];
int id;
};


hid_t CreateObjType()
{
	unsigned int  dtsize=sizeof(obj);
	hsize_t  arr_dims[]={4,4}; //!2 dimensional array
	hid_t matrix= H5Tarray_create (H5T_STD_U32LE, 2, arr_dims, NULL);
	hid_t objtype=H5Tcreate(H5T_COMPOUND,dtsize);
	H5Tinsert(objtype,"Matrix",HOFFSET(obj,mat),matrix);
	H5Tinsert(objtype,"Id",HOFFSET(obj,id),H5T_NATIVE_UINT);
    return objtype;

}

herr_t CreateAndInitializeAttribute(hid_t& dataset)
{
	hsize_t dims[1]={1};
	hid_t space = H5Screate_simple(1, dims, NULL); 
	unsigned int totalElem=0;
	hid_t attr = H5Acreate(dataset,"Element Total", H5T_NATIVE_UINT, space, H5P_DEFAULT);
	herr_t status=H5Awrite(attr, H5T_NATIVE_UINT,&totalElem);
	H5Aclose(attr);
	H5Sclose(space);
	return status;
}


void CreateDataset(hid_t file_id, char * dataset_name, hid_t datatype)
{
	hsize_t  dim[] = {15};   //!Initial dimension of Dataspace
	hsize_t dims[1]={1};
	hsize_t  maxdims[] = {H5S_UNLIMITED}; //! to specify maximum dimension
	hid_t space = H5Screate_simple(1, dim, maxdims); //! rank = 1 and dimension = unlimited 
	hid_t cparms = H5Pcreate (H5P_DATASET_CREATE); //! dataset creation property to enable chunking
	hsize_t chunkDims[] ={1};  //! chunk dimension is 5 elements
	H5Pset_chunk ( cparms, 1, chunkDims);
	H5Pset_deflate( cparms, 8);  //! For compression
	
	//!Create the dataset with creation params
	hid_t dataset = H5Dcreate(file_id, dataset_name , datatype, space, cparms);
	//!Create attribute for total elements
	CreateAndInitializeAttribute(dataset);

	H5Sclose(space);
	H5Pclose(cparms);
	H5Dclose(dataset);
}


//!Write Header 
herr_t WriteObj(hid_t file_id, char* dataset_name , unsigned int id)
{
	herr_t status;				//!error status returned by the hdf5 library
	hsize_t  dims[]={1};		//!dimensions for memory dataspace
	hsize_t  offset[]={0};      //!offset for selecting appropriate dataset region
	unsigned int numOfElements=0;
	int i,j;

	hid_t type= CreateObjType();
	//! Create simple dataspace with rank = 1 and dimension = 1 
	hid_t memspace = H5Screate_simple(1, dims, NULL);
	//!Open the header dataset
	hid_t dataset_id = H5Dopen(file_id,dataset_name);
	//! Get the dataspace of the dataset
	hid_t dspace = H5Dget_space (dataset_id);
    //!Read the attribute to locate the position for writing
	hid_t attr=H5Aopen_idx(dataset_id,0);
	status=H5Aread(attr, H5T_NATIVE_UINT,&numOfElements);
	offset[0]=offset[0]+(hsize_t)numOfElements;

	//! Select the dataspace to which the information has to be written
	status = H5Sselect_elements (dspace, H5S_SELECT_SET, 1, (const hsize_t  **)offset); 

	obj s1;
    //! Write Header
	s1.id = id;
	for(i=0; i<4 ; i++)
	{
		for(j=0 ; j<4 ;  j++)
		{
			if(i == j) s1.mat[i][j]=20;
			else s1.mat[i][j]=0;
		}
	}

	status = H5Dwrite(dataset_id,type,memspace,dspace,H5P_DEFAULT,&s1);


	if(status >= 0)
	{
		//!Update the number of elements written
		numOfElements=numOfElements+1;
		status=H5Awrite(attr, H5T_NATIVE_UINT,&numOfElements);
	}

	//!close all resources
	H5Tclose(type);
	H5Aclose(attr);
	H5Sclose(dspace);
	H5Sclose(memspace);
	H5Dclose(dataset_id);
	return status;
}


int main()
{
    hid_t fileid=H5Fcreate(FILE, H5F_ACC_TRUNC, H5P_DEFAULT, H5P_DEFAULT);
	hid_t type= CreateObjType();
	CreateDataset(fileid, DATASETNAME, type);
    unsigned int id =12;
   WriteObj(fileid, DATASETNAME, id);
   H5Fclose(fileid);
	return 0;
}