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130 lines
3.5 KiB
C
130 lines
3.5 KiB
C
/************************************************************
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This example shows how to read and write float datatypes
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to a dataset. The program first writes floats to a
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dataset with a dataspace of DIM0xDIM1, then closes the
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file. Next, it reopens the file, reads back the data, and
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outputs it to the screen.
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************************************************************/
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#include "hdf5.h"
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#include <stdio.h>
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#include <stdlib.h>
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#define FILENAME "h5ex_t_float.h5"
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#define DATASET "DS1"
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#define DIM0 4
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#define DIM1 7
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int
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main(void)
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{
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hid_t file, space, dset; /* Handles */
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herr_t status;
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hsize_t dims[2] = {DIM0, DIM1};
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double wdata[DIM0][DIM1], /* Write buffer */
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**rdata; /* Read buffer */
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int ndims;
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hsize_t i, j;
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/*
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* Initialize data.
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*/
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for (i = 0; i < DIM0; i++)
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for (j = 0; j < DIM1; j++)
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wdata[i][j] = (double)i / (j + 0.5) + j;
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/*
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* Create a new file using the default properties.
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*/
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file = H5Fcreate(FILENAME, H5F_ACC_TRUNC, H5P_DEFAULT, H5P_DEFAULT);
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/*
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* Create dataspace. Setting maximum size to NULL sets the maximum
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* size to be the current size.
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*/
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space = H5Screate_simple(2, dims, NULL);
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/*
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* Create the dataset and write the floating point data to it. In
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* this example we will save the data as 64 bit little endian IEEE
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* floating point numbers, regardless of the native type. The HDF5
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* library automatically converts between different floating point
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* types.
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*/
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dset = H5Dcreate(file, DATASET, H5T_IEEE_F64LE, space, H5P_DEFAULT, H5P_DEFAULT, H5P_DEFAULT);
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status = H5Dwrite(dset, H5T_NATIVE_DOUBLE, H5S_ALL, H5S_ALL, H5P_DEFAULT, wdata[0]);
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/*
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* Close and release resources.
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*/
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status = H5Dclose(dset);
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status = H5Sclose(space);
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status = H5Fclose(file);
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/*
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* Now we begin the read section of this example. Here we assume
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* the dataset has the same name and rank, but can have any size.
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* Therefore we must allocate a new array to read in data using
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* malloc().
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*/
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/*
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* Open file and dataset.
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*/
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file = H5Fopen(FILENAME, H5F_ACC_RDONLY, H5P_DEFAULT);
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dset = H5Dopen(file, DATASET, H5P_DEFAULT);
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/*
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* Get dataspace and allocate memory for read buffer. This is a
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* two dimensional dataset so the dynamic allocation must be done
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* in steps.
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*/
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space = H5Dget_space(dset);
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ndims = H5Sget_simple_extent_dims(space, dims, NULL);
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/*
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* Allocate array of pointers to rows.
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*/
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rdata = (double **)malloc(dims[0] * sizeof(double *));
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/*
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* Allocate space for floating point data.
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*/
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rdata[0] = (double *)malloc(dims[0] * dims[1] * sizeof(double));
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/*
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* Set the rest of the pointers to rows to the correct addresses.
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*/
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for (i = 1; i < dims[0]; i++)
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rdata[i] = rdata[0] + i * dims[1];
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/*
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* Read the data.
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*/
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status = H5Dread(dset, H5T_NATIVE_DOUBLE, H5S_ALL, H5S_ALL, H5P_DEFAULT, rdata[0]);
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/*
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* Output the data to the screen.
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*/
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printf("%s:\n", DATASET);
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for (i = 0; i < dims[0]; i++) {
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printf(" [");
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for (j = 0; j < dims[1]; j++)
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printf(" %6.4f", rdata[i][j]);
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printf("]\n");
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}
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/*
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* Close and release resources.
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*/
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free(rdata[0]);
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free(rdata);
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status = H5Dclose(dset);
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status = H5Sclose(space);
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status = H5Fclose(file);
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return 0;
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}
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