! ************************************************************ ! ! This example shows how to read and write data to a dataset ! using the N-Bit filter. The program first checks if the ! N-Bit filter is available, then if it is it writes ! integers to a dataset using N-Bit, then closes the file. ! Next, it reopens the file, reads back the data, and ! outputs the type of filter and the maximum value in the ! dataset to the screen. ! ! This file is intended for use with HDF5 Library verion 1.8 ! ! ************************************************************ PROGRAM main USE HDF5 IMPLICIT NONE CHARACTER(LEN=14), PARAMETER :: filename = "h5ex_d_nbit.h5" CHARACTER(LEN=3) , PARAMETER :: dataset = "DS1" INTEGER , PARAMETER :: dim0 = 32 INTEGER , PARAMETER :: dim1 = 64 INTEGER , PARAMETER :: chunk0 = 4 INTEGER , PARAMETER :: chunk1 = 8 INTEGER :: hdferr INTEGER(HID_T) :: file, space, dset, dtype, dcpl ! Handles INTEGER, DIMENSION(1:1) :: cd_values INTEGER(HSIZE_T), DIMENSION(1:2) :: dims = (/dim0, dim1/), chunk = (/chunk0,chunk1/) INTEGER(HSIZE_T), DIMENSION(1:2) :: start, stride, count, block LOGICAL :: avail INTEGER :: filter_id INTEGER :: filter_info_both INTEGER(SIZE_T) :: nelmts INTEGER :: flags, filter_info INTEGER, DIMENSION(1:dim0, 1:dim1) :: wdata, & ! Write buffer rdata ! Read buffer INTEGER :: max, i, j INTEGER, PARAMETER :: MaxChrLen = 80 CHARACTER(LEN=MaxChrLen) :: name ! ! Initialize FORTRAN interface. ! CALL h5open_f(hdferr) ! Check if N-Bit compression is available and can be used for both ! compression and decompression. Normally we do not perform error ! checking in these examples for the sake of clarity, but in this ! case we will make an exception because this filter is an ! optional part of the hdf5 library. ! CALL h5zfilter_avail_f(H5Z_FILTER_NBIT_F, avail, hdferr) IF (.NOT.avail) THEN WRITE(*,'("N-Bit filter not available.",/)') STOP ENDIF CALL h5zget_filter_info_f(H5Z_FILTER_NBIT_F, filter_info, hdferr) filter_info_both=IOR(H5Z_FILTER_ENCODE_ENABLED_F,H5Z_FILTER_DECODE_ENABLED_F) IF (filter_info .NE. filter_info_both) THEN WRITE(*,'("N-Bit filter not available for encoding and decoding.",/)') STOP ENDIF ! Initialize data. DO i = 1, dim0 DO j = 1, dim1 wdata(i,j) = (i-1)*(j-1)-(j-1) ENDDO ENDDO ! ! Create a new file using the default properties. ! CALL h5fcreate_f(filename, H5F_ACC_TRUNC_F, file, hdferr) ! ! Create dataspace. Setting size to be the current size. ! CALL h5screate_simple_f(2, dims, space, hdferr) ! ! Create the datatype to use with the N-Bit filter. It has an ! uncompressed size of 32 bits, but will have a size of 16 bits ! after being packed by the N-Bit filter. ! CALL h5tcopy_f (H5T_STD_I32LE, dtype, hdferr) CALL h5tset_precision_f (dtype, 16, hdferr) CALL h5tset_offset_f (dtype, 5, hdferr) ! ! Create the dataset creation property list, add the N-Bit filter ! and set the chunk size. ! CALL h5pcreate_f(H5P_DATASET_CREATE_F, dcpl, hdferr) CALL h5pset_nbit_f(dcpl, hdferr) CALL h5pset_chunk_f(dcpl, 2, chunk, hdferr) ! ! Create the dataset. ! CALL h5dcreate_f(file, dataset, dtype, space, dset, hdferr, dcpl) ! ! Write the data to the dataset. ! CALL h5dwrite_f(dset, H5T_NATIVE_INTEGER, wdata, dims, hdferr) ! ! Close and release resources. ! CALL h5pclose_f(dcpl , hdferr) CALL h5tclose_f(dtype, hdferr) CALL h5dclose_f(dset , hdferr) CALL h5sclose_f(space, hdferr) CALL h5fclose_f(file , hdferr) ! ! Now we begin the read section of this example. ! ! Open file and dataset using the default properties. ! CALL h5fopen_f(filename, H5F_ACC_RDONLY_F, file, hdferr) CALL h5dopen_f (file, dataset, dset, hdferr) ! ! Retrieve dataset creation property list. ! CALL h5dget_create_plist_f(dset, dcpl, hdferr) ! ! Retrieve and print the filter type. Here we only retrieve the ! first filter because we know that we only added one filter. ! nelmts = 0 CALL H5Pget_filter_f(dcpl, 0, flags, nelmts, cd_values, MaxChrLen, name, filter_id, hdferr) WRITE(*,'("Filter type is: ")', ADVANCE='NO') IF(filter_id.EQ.H5Z_FILTER_DEFLATE_F)THEN WRITE(*,'(T2,"H5Z_FILTER_DEFLATE_F")') ELSE IF(filter_id.EQ.H5Z_FILTER_SHUFFLE_F)THEN WRITE(*,'(T2,"H5Z_FILTER_SHUFFLE_F")') ELSE IF(filter_id.EQ.H5Z_FILTER_FLETCHER32_F)THEN WRITE(*,'(T2,"H5Z_FILTER_FLETCHER32_F")') ELSE IF(filter_id.EQ.H5Z_FILTER_SZIP_F)THEN WRITE(*,'(T2,"H5Z_FILTER_SZIP_F")') ELSE IF(filter_id.EQ.H5Z_FILTER_NBIT_F)THEN WRITE(*,'(T2,"H5Z_FILTER_NBIT_F")') ENDIF ! ! Read the data using the default properties. ! CALL h5dread_f(dset, H5T_NATIVE_INTEGER, rdata, dims, hdferr) ! ! Find the maximum value in the dataset, to verify that it was ! read correctly. ! max = MAXVAL(rdata) ! ! Print the maximum value. ! WRITE(*,'("Maximum value in ",A," is: ",i10)') dataset, max ! ! Close and release resources. ! CALL h5pclose_f(dcpl , hdferr) CALL h5dclose_f(dset , hdferr) CALL h5fclose_f(file , hdferr) END PROGRAM main