function h5ex_t_opaque %************************************************************************** % % This example shows how to read and write opaque datatypes % to a dataset. The program first writes opaque data to a % dataset with a dataspace of DIM0, then closes the file. % Next, it reopens the file, reads back the data, and % outputs it to the screen. % % This file is intended for use with HDF5 Library version 1.8 %************************************************************************** fileName = 'h5ex_t_opaque.h5'; DATASET = 'DS1'; DIM0 = 4; LEN = 7; dims =DIM0; wdata =uint8(zeros(LEN,DIM0)); str ='OPAQUE'; % % Initialize data. % for i=1: DIM0 wdata(:,i)=[str,num2str(i)]; end % %% Create a new file using the default properties. % file = H5F.create (fileName, 'H5F_ACC_TRUNC', 'H5P_DEFAULT', 'H5P_DEFAULT'); % % Create opaque datatype and set the tag to something appropriate. % For this example we will write and view the data as a character % array. % dtype = H5T.create ('H5T_OPAQUE', LEN); H5T.set_tag (dtype, 'Character array'); % % Create dataspace. Setting maximum size to [] sets the maximum % size to be the current size. % space = H5S.create_simple (1,fliplr( dims), []); % % Create the dataset and write the opaque data to it. % dset = H5D.create (file, DATASET, dtype, space, 'H5P_DEFAULT'); H5D.write (dset, dtype, 'H5S_ALL', 'H5S_ALL', 'H5P_DEFAULT', wdata); % % Close and release resources. % H5D.close (dset); H5S.close (space); H5T.close (dtype); H5F.close (file); % %% Now we begin the read section of this example. Here we assume % the dataset has the same name and rank, but can have any size. % % % Open file and dataset. % file = H5F.open (fileName, 'H5F_ACC_RDONLY', 'H5P_DEFAULT'); dset = H5D.open (file, DATASET); % % Get datatype and properties for the datatype. % dtype = H5D.get_type (dset); %len = H5T.get_size (dtype); tag = H5T.get_tag (dtype); % % Get dataspace % space = H5D.get_space (dset); [~, dims, ~] = H5S.get_simple_extent_dims (space); dims=fliplr(dims); % % Read the data. % rdata = H5D.read (dset, dtype, 'H5S_ALL', 'H5S_ALL', 'H5P_DEFAULT'); % % Output the data to the screen. % fprintf ('Datatype tag for %s is: "%s"\n', DATASET, tag); for i=1: dims(1) fprintf ('%s[%u]: ', DATASET, i); fprintf ('%s',char(rdata(:,i))); fprintf ('\n'); end % % Close and release resources. % H5D.close (dset); H5S.close (space); H5T.close (dtype); H5F.close (file);