hdf5/doc/html/h5s.examples
1998-07-08 09:54:54 -05:00

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Example 1: Create a simple fixed size 3-D dataspace in memory and on disk and
copy the entire dataset to disk.
{
hid_t file; /* File ID */
hid_t dataset; /* Dataset ID */
hid_t mem_space, file_space; /* Dataspaces for memory and the file */
uint8 *buf; /* Buffer for data */
hsize_t curr_dims[3]={3,4,5}; /* Dimensions of the dataset */
/* Create file */
file = H5Fcreate("example1.h5", H5F_ACC_TRUNC, H5P_DEFAULT, H5P_DEFAULT);
/* Create dataspace for dataset in the file */
/* Selection for dataspace defaults to entire space */
file_space=H5Screate(H5S_SIMPLE);
/* Set the extent & type of the dataset's dataspace */
H5Sset_extent_simple(file_space,3,curr_dims,curr_dims);
/* Create the dataspace for the dataset in memory */
/* Selection for dataspace defaults to entire space */
mem_space=H5Screate(H5S_SIMPLE);
/* Set the extent & type of the memory dataspace */
H5Sset_extent_simple(mem_space,3,curr_dims,curr_dims);
/* Create the dataset on disk */
dataset=H5Dcreate(file,"Dataset",H5T_NATIVE_UINT8,file_space,H5P_DEFAULT);
/* Write the dataset to the file */
H5Dwrite(dataset,H5T_NATIVE_UINT8,mem_space,file_space,H5P_DEFAULT,buf);
/* Close dataspaces */
H5Sclose(mem_space);
H5Sclose(file_space);
/* Close dataset & file */
H5Dclose(dataset);
H5Fclose(file);
}
Example 2: Create a simple fixed size 3-D dataspace in memory and on disk and
copy a hyperslab to disk. The hyperslab blocks are packed and
contiguous in memory, but are scattered when written to the dataset
on disk.
{
hid_t file; /* File ID */
hid_t dataset; /* Dataset ID */
hid_t mem_space, file_space; /* Dataspaces for memory and the file */
uint8 *buf; /* Buffer for data */
hssize_t start[3]={3,4,5}; /* Start of hyperslab */
hsize_t stride[3]={1,2,2}; /* Stride for hyperslab */
hsize_t count[3]={3,3,3}; /* Hyperslab block count in each dimension */
hsize_t block[3]={2,2,2}; /* Hyperslab block size in each dimension */
hsize_t curr_dims[3]={13,14,15}; /* Dimensions of the dataset */
/* Create file */
file = H5Fcreate("example2.h5", H5F_ACC_TRUNC, H5P_DEFAULT, H5P_DEFAULT);
/* Create dataspace for dataset in the file */
/* Selection for dataspace defaults to entire space */
file_space=H5Screate(H5S_SIMPLE);
/* Set the extent & type of the dataset's dataspace */
H5Sset_extent_simple(file_space,3,curr_dims,curr_dims);
/* Set the hyperslab selection for a file dataspace */
H5Sselect_hyperslab(file_space,H5S_SELECT_SET,start,stride,count,block);
/* Create the dataspace for the dataset in memory */
/* Selection for dataspace defaults to entire space */
mem_space=H5Screate(H5S_SIMPLE);
/* Set the extent & type of the memory dataspace */
/* Compute the memory dimensions based on the hyperslab blocks to write */
for(i=0; i<3; i++)
curr_dims[i]=count[i]*block[i];
H5Sset_extent_simple(mem_space,3,curr_dims,curr_dims);
/* Create the dataset on disk */
dataset=H5Dcreate(file,"Dataset",H5T_NATIVE_UINT8,file_space,H5P_DEFAULT);
/* Write the hyperslab to the file */
H5Dwrite(dataset,H5T_NATIVE_UINT8,mem_space,file_space,H5P_DEFAULT,buf);
/* Close dataspaces */
H5Sclose(mem_space);
H5Sclose(file_space);
/* Close dataset & file */
H5Dclose(dataset);
H5Fclose(file);
}
Example 3: Create a simple fixed size 3-D dataspace in memory and on disk and
copy a specific selection of points (with a particular order) to
disk. The memory and file dataspaces are different sizes, but the number
of points selected are the same.
{
hid_t file; /* File ID */
hid_t dataset; /* Dataset ID */
hid_t mem_space, file_space; /* Dataspaces for memory and the file */
uint8 *buf; /* Buffer for data */
hsize_t elements[5][3]; /* Dataspace elements selected */
hsize_t curr_dims[3]={13,14,15}; /* Dimensions of the dataset */
/* Create file */
file = H5Fcreate("example3.h5", H5F_ACC_TRUNC, H5P_DEFAULT, H5P_DEFAULT);
/* Create dataspace for dataset in the file */
/* Selection for dataspace defaults to entire space */
file_space=H5Screate(H5S_SIMPLE);
/* Set the extent & type of the dataset's dataspace */
H5Sset_extent_simple(file_space,3,curr_dims,curr_dims);
/* Set the elements for the selection in the file dataspace */
elements[0]={0,2,4}; /* Yes, I know this won't compile.. :-) */
elements[1]={3,4,1};
elements[2]={9,8,3};
elements[3]={7,2,0};
elements[4]={6,5,8};
H5Sselect_elements(file_space,H5S_SELECT_SET,5,elements);
/* Create the dataspace for the dataset in memory */
/* Selection for dataspace defaults to entire space */
mem_space=H5Screate(H5S_SIMPLE);
/* Set the extent & type of the memory dataspace */
curr_dims={23,15,18}; /* This won't compile either :-) */
H5Sset_extent_simple(mem_space,3,curr_dims,curr_dims);
/* Set the elements for the selection in the file dataspace */
elements[0]={9,2,1};
elements[1]={13,1,12};
elements[2]={4,1,7};
elements[3]={0,12,0};
elements[4]={20,10,17};
H5Sselect_elements(mem_space,H5S_SELECT_SET,5,elements);
/* Create the dataset on disk */
dataset=H5Dcreate(file,"Dataset",H5T_NATIVE_UINT8,file_space,H5P_DEFAULT);
/* Write the hyperslab to the file */
H5Dwrite(dataset,H5T_NATIVE_UINT8,mem_space,file_space,H5P_DEFAULT,buf);
/* Close dataspaces */
H5Sclose(mem_space);
H5Sclose(file_space);
/* Close dataset & file */
H5Dclose(dataset);
H5Fclose(file);
}
Example 4: Create a simple fixed size 3-D dataspace in memory and on disk and
build up selection hyperslab selections to copy from memory to disk. The
selection is the same for both dataspaces, but a different offset is used,
to illustrate the selection offsets.
{
hid_t file; /* File ID */
hid_t dataset; /* Dataset ID */
hid_t mem_space, file_space; /* Dataspaces for memory and the file */
uint8 *buf; /* Buffer for data */
hssize_t start[3]; /* Start of hyperslab */
hsize_t stride[3]; /* Stride for hyperslab */
hsize_t count[3]; /* Hyperslab block count in each dimension */
hsize_t block[3]; /* Hyperslab block size in each dimension */
hssize_t offset[3]; /* Selection offset */
hsize_t curr_dims[3]={13,14,15}; /* Dimensions of the dataset */
/* Create file */
file = H5Fcreate("example4.h5", H5F_ACC_TRUNC, H5P_DEFAULT, H5P_DEFAULT);
/* Create dataspace for dataset in the file */
/* Selection for dataspace defaults to entire space */
file_space=H5Screate(H5S_SIMPLE);
/* Set the extent & type of the dataset's dataspace */
H5Sset_extent_simple(file_space,3,curr_dims,curr_dims);
/* Build up the selection with a series of hyperslab selections */
start={0,2,4}; /* Again, this won't compile.. :-) */
stride={1,1,1};
count={6,5,8};
block={1,1,1};
/* Set the first selection, union the rest in */
H5Sselect_hyperslab(file_space,H5S_SELECT_SET,start,stride,count,block);
/* initialize the second hyperslab */
start={10,9,1}; /* Again, this won't compile.. :-) */
stride={1,1,1};
count={2,3,10};
block={1,1,1};
/* Union the second hyperslab into the file dataspace's selection */
H5Sselect_hyperslab(file_space,H5S_SELECT_UNION,start,stride,count,block);
/* initialize the third hyperslab */
start={3,10,5}; /* Again, this won't compile.. :-) */
stride={1,1,1};
count={8,2,6};
block={1,1,1};
/* Union the final hyperslab into the file dataspace's selection */
H5Sselect_hyperslab(file_space,H5S_SELECT_UNION,start,stride,count,block);
/* Create the dataspace for the dataset in memory */
/* Selection for dataspace defaults to entire space */
mem_space=H5Screate(H5S_SIMPLE);
/* Set the extent & type of the memory dataspace */
curr_dims={23,15,18}; /* This won't compile either :-) */
H5Sset_extent_simple(mem_space,3,curr_dims,curr_dims);
/* Copy the selection from the file dataspace */
H5Sselect_op(mem_space,H5S_SELECT_COPY,file_space);
/* Adjust the offset of the selection in the memory dataspace */
offset={1,1,1};
H5Soffset_simple(mem_space,offset);
/* Create the dataset on disk */
dataset=H5Dcreate(file,"Dataset",H5T_NATIVE_UINT8,file_space,H5P_DEFAULT);
/* Write the hyperslab to the file */
H5Dwrite(dataset,H5T_NATIVE_UINT8,mem_space,file_space,H5P_DEFAULT,buf);
/* Close dataspaces */
H5Sclose(mem_space);
H5Sclose(file_space);
/* Close dataset & file */
H5Dclose(dataset);
H5Fclose(file);
}
Example 5: Same as example 1 (create a simple fixed size 3-D dataspace in memory and on disk and
copy the entire dataset to disk), except that the selection order is changed
for the memory dataspace, to change between FORTRAN and C array ordering.
{
hid_t file; /* File ID */
hid_t dataset; /* Dataset ID */
hid_t mem_space, file_space; /* Dataspaces for memory and the file */
uint8 *buf; /* Buffer for data */
hsize_t order[3]; /* Dimension ordering for selection */
hsize_t curr_dims[3]={3,4,5}; /* Dimensions of the dataset */
/* Create file */
file = H5Fcreate("example5.h5", H5F_ACC_TRUNC, H5P_DEFAULT, H5P_DEFAULT);
/* Create dataspace for dataset in the file */
/* Selection for dataspace defaults to entire space and C array order */
file_space=H5Screate(H5S_SIMPLE);
/* Set the extent & type of the dataset's dataspace */
H5Sset_extent_simple(file_space,3,curr_dims,curr_dims);
/* Create the dataspace for the dataset in memory */
/* Selection for dataspace defaults to entire space and C array order */
mem_space=H5Screate(H5S_SIMPLE);
/* Set the extent & type of the memory dataspace */
H5Sset_extent_simple(mem_space,3,curr_dims,curr_dims);
/* Change selection ordering to FORTRAN order for memory dataspace */
order={0,1,2};
H5Sselect_order(mem_space,order);
/* Create the dataset on disk */
dataset=H5Dcreate(file,"Dataset",H5T_NATIVE_UINT8,file_space,H5P_DEFAULT);
/* Write the dataset to the file */
H5Dwrite(dataset,H5T_NATIVE_UINT8,mem_space,file_space,H5P_DEFAULT,buf);
/* Close dataspaces */
H5Sclose(mem_space);
H5Sclose(file_space);
/* Close dataset & file */
H5Dclose(dataset);
H5Fclose(file);
}
Example 6: Create a stored dataspace on disk and use the H5Ssubspace function
create a dataspace located within that space.
{
hid_t file; /* File ID */
hid_t space1, space2; /* Dataspace IDs */
hssize_t start[3]; /* Start of hyperslab */
hsize_t count[3]; /* Hyperslab block count in each dimension */
hsize_t curr_dims[3]={13,14,15};/* Dimensions of the dataset */
/* Create file */
file = H5Fcreate("example6.h5", H5F_ACC_TRUNC, H5P_DEFAULT, H5P_DEFAULT);
/* Create dataspace #1 */
space1=H5Screate(H5S_SIMPLE);
/* Set the extent & type of dataspace #1 */
H5Sset_extent_simple(space1,3,curr_dims,curr_dims);
/* Store dataspace #1 on disk */
H5Scommit(file,"/Dataspaces/Dataspace #1",space1);
/* Select a contiguous hyperslab in dataspace #1 to create dataspace #2 with */
start={0,2,4};
count={6,5,8};
/*
* Use stride and block set to NULL to get contiguous, single element sized
* hyperslab. The stride and block parameters could also be set to all
* 1's, but this is simpler and easier.
*/
H5Sselect_hyperslab(space1,H5S_SELECT_SET,start,NULL,count,NULL);
/* Create dataspace #2 as a dataspace located within dataspace #1 */
space2=H5Ssubspace(space1);
/* Store dataspace #2 on disk also */
H5Scommit(file,"/Dataspaces/Dataspace #2",space2);
/*
* space1 & space2 can be used to create datasets, etc. Any datasets
* created with space2 can have their dataspace queried to find the parent
* dataspace and the location within the parent dataspace
*/
/* Close dataspaces */
H5Sclose(space1);
H5Sclose(space2);
/* Close file */
H5Fclose(file);
}