function h5ex_d_soint %************************************************************************** % % This example shows how to read and write data to a dataset % using the Scale-Offset filter. The program first checks % if the Scale-Offset filter is available, then if it is it % writes integers to a dataset using Scale-Offset, 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 version 1.8 %************************************************************************** FILE = 'h5ex_d_soint.h5'; DATASET = 'DS1'; DIM0 = 32; DIM1 = 64; CHUNK0 = 4; CHUNK1 = 8; dims = [DIM0, DIM1]; chunk = [CHUNK0, CHUNK1]; % %% Check if Scale-Offset 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. % avail = H5Z.filter_avail('H5Z_FILTER_SCALEOFFSET'); if (~avail) disp('Scale-Offset filter not available.\n'); end filter_info=H5Z.get_filter_info ('H5Z_FILTER_SCALEOFFSET'); if ( ~(filter_info && ... H5ML.get_constant_value('H5Z_FILTER_CONFIG_ENCODE_ENABLED')) ... ||... ~(filter_info &&... H5ML.get_constant_value('H5Z_FILTER_CONFIG_DECODE_ENABLED') )) disp ('Scale-Offset filter not available for encoding and decoding'); end % % Initialize data. % wdata=zeros(dims,'int32'); for i=1:DIM0 for j=1:DIM1 ci=i-1; cj=j-1; wdata(i,j) = int32(ci*cj-cj); end end % % Find the maximum value in the dataset, to verify that it was % read correctly. % maxV = max(wdata(:)); minV = min(wdata(:)); % % Print the maximum value. % disp (['Maximum value in write buffer is: ', num2str(maxV)]); disp (['Minimum value in write buffer is: ', num2str(minV)]); % % Create a new file using the default properties. % file = H5F.create (FILE, 'H5F_ACC_TRUNC', 'H5P_DEFAULT', 'H5P_DEFAULT'); % % Create dataspace. Setting maximum size to [] sets the maximum % size to be the current size. % space = H5S.create_simple (2, fliplr(dims), []); % % Create the dataset creation property list, add the Scale-Offset % filter and set the chunk size. % dcpl = H5P.create ('H5P_DATASET_CREATE'); H5P.set_scaleoffset (dcpl, 'H5Z_SO_INT', 'H5Z_SO_INT_MINBITS_DEFAULT'); H5P.set_chunk (dcpl, fliplr(chunk)); % % Create the dataset. % dset = H5D.create (file, DATASET, 'H5T_STD_I32LE', ... space, 'H5P_DEFAULT', dcpl,'H5P_DEFAULT'); % % Write the data to the dataset. % H5D.write (dset, 'H5T_NATIVE_INT', 'H5S_ALL',... 'H5S_ALL', 'H5P_DEFAULT',wdata); % % Close and release resources. % H5P.close (dcpl); H5D.close (dset); H5S.close (space); H5F.close (file); % %% Now we begin the read section of this example. % % % Open file and dataset using the default properties. % file = H5F.open (FILE, 'H5F_ACC_RDONLY', 'H5P_DEFAULT'); dset = H5D.open (file, DATASET, 'H5P_DEFAULT'); % % Retrieve dataset creation property list. % dcpl = H5D.get_create_plist (dset); % % Retrieve and print the filter type. Here we only retrieve the % first filter because we know that we only added one filter. % filter_type = H5P.get_filter (dcpl, 0); disp ('Filter type is: '); switch (filter_type) case H5ML.get_constant_value('H5Z_FILTER_DEFLATE') disp ('H5Z_FILTER_DEFLATE'); case H5ML.get_constant_value('H5Z_FILTER_SHUFFLE') disp ('H5Z_FILTER_SHUFFLE'); case H5ML.get_constant_value('H5Z_FILTER_FLETCHER32') disp ('H5Z_FILTER_FLETCHER32'); case H5ML.get_constant_value('H5Z_FILTER_SZIP') disp ('H5Z_FILTER_SZIP'); case H5ML.get_constant_value('H5Z_FILTER_NBIT') disp ('H5Z_FILTER_NBIT'); case H5ML.get_constant_value('H5Z_FILTER_SCALEOFFSET') disp ('H5Z_FILTER_SCALEOFFSET'); end % % Read the data using the default properties. % rdata=... H5D.read (dset, 'H5T_NATIVE_INT', 'H5S_ALL',... 'H5S_ALL', 'H5P_DEFAULT'); % % Find the maximum value in the dataset, to verify that it was % read correctly. % maxV = max(rdata(:)); minV = min(rdata(:)); % % Print the maximum value. % disp (['Maximum value in ', DATASET,' is ' num2str(maxV)]); disp (['Minimum value in ', DATASET,' is ' num2str(minV)]); % % Close and release resources. % H5P.close (dcpl); H5D.close (dset); H5F.close (file);