diff options
Diffstat (limited to 'hl/src/H5DOpublic.h')
| -rw-r--r-- | hl/src/H5DOpublic.h | 199 |
1 files changed, 199 insertions, 0 deletions
diff --git a/hl/src/H5DOpublic.h b/hl/src/H5DOpublic.h index 88616a3..99358b3 100644 --- a/hl/src/H5DOpublic.h +++ b/hl/src/H5DOpublic.h @@ -18,6 +18,29 @@ extern "C" { #endif +/**\defgroup H5DO Optimizations + * + * <em>Bypassing default HDF5 behavior in order to optimize for specific + * use cases (H5DO)</em> + * + * HDF5 functions described is this section are implemented in the HDF5 High-level + * library as optimized functions. These functions generally require careful setup + * and testing as they enable an application to bypass portions of the HDF5 + * library’s I/O pipeline for performance purposes. + * + * These functions are distributed in the standard HDF5 distribution and are + * available any time the HDF5 High-level library is available. + * + * - \ref H5DOappend + * \n Appends data to a dataset along a specified dimension. + * - \ref H5DOread_chunk + * \n Reads a raw data chunk directly from a dataset in a file into a buffer (DEPRECATED) + * - \ref H5DOwrite_chunk + * \n Writes a raw data chunk from a buffer directly to a dataset in a file (DEPRECATED) + * . + * + */ + /*------------------------------------------------------------------------- * * "Optimized dataset" routines. @@ -25,6 +48,48 @@ extern "C" { *------------------------------------------------------------------------- */ +/** + * -------------------------------------------------------------------------- + * \ingroup H5DO + * + * \brief Appends data to a dataset along a specified dimension. + * + * \param[in] dset_id Dataset identifier + * \param[in] dxpl_id Dataset transfer property list identifier + * \param[in] axis Dataset Dimension (0-based) for the append + * \param[in] extension Number of elements to append for the + * axis-th dimension + * \param[in] memtype The memory datatype identifier + * \param[in] buf Buffer with data for the append + * + * \return \herr_t + * + * \details The H5DOappend() routine extends a dataset by \p extension + * number of elements along a dimension specified by a + * dimension \p axis and writes \p buf of elements to the + * dataset. Dimension \p axis is 0-based. Elements’ type + * is described by \p memtype. + * + * This routine combines calling H5Dset_extent(), + * H5Sselect_hyperslab(), and H5Dwrite() into a single routine + * that simplifies application development for the common case + * of appending elements to an existing dataset. + * + * For a multi-dimensional dataset, appending to one dimension + * will write a contiguous hyperslab over the other dimensions. + * For example, if a 3-D dataset has dimension sizes (3, 5, 8), + * extending the 0th dimension (currently of size 3) by 3 will + * append 3*5*8 = 120 elements (which must be pointed to by the + * \p buffer parameter) to the dataset, making its final + * dimension sizes (6, 5, 8). + * + * If a dataset has more than one unlimited dimension, any of + * those dimensions may be appended to, although only along + * one dimension per call to H5DOappend(). + * + * \since 1.10.0 + * + */ H5_HLDLL herr_t H5DOappend(hid_t dset_id, hid_t dxpl_id, unsigned axis, size_t extension, hid_t memtype, const void *buf); @@ -35,8 +100,142 @@ H5_HLDLL herr_t H5DOappend(hid_t dset_id, hid_t dxpl_id, unsigned axis, size_t e #ifndef H5_NO_DEPRECATED_SYMBOLS /* Compatibility wrappers for functionality moved to H5D */ + +/** + * -------------------------------------------------------------------------- + * \ingroup H5DO + * + * \brief Writes a raw data chunk from a buffer directly to a dataset in a file. + * + * \param[in] dset_id Identifier for the dataset to write to + * \param[in] dxpl_id Transfer property list identifier for + * this I/O operation + * \param[in] filters Mask for identifying the filters in use + * \param[in] offset Logical position of the chunk’s first element + * in the dataspace + * \param[in] data_size Size of the actual data to be written in bytes + * \param[in] buf Buffer containing data to be written to the chunk + * + * \return \herr_t + * + * \deprecated This function was deprecated in favor of the function + * H5Dwrite_chunk() of HDF5-1.10.3. + * The functionality of H5DOwrite_chunk() was moved + * to H5Dwrite_chunk(). + * \deprecated For compatibility, this API call has been left as a stub which + * simply calls H5Dwrite_chunk(). New code should use H5Dwrite_chunk(). + * + * \details The H5DOwrite_chunk() writes a raw data chunk as specified by its + * logical \p offset in a chunked dataset \p dset_id from the application + * memory buffer \p buf to the dataset in the file. Typically, the data + * in \p buf is preprocessed in memory by a custom transformation, such as + * compression. The chunk will bypass the library’s internal data + * transfer pipeline, including filters, and will be written directly to the file. + * + * \p dxpl_id is a data transfer property list identifier. + * + * \p filters is a mask providing a record of which filters are used + * with the chunk. The default value of the mask is zero (\c 0), + * indicating that all enabled filters are applied. A filter is skipped + * if the bit corresponding to the filter’s position in the pipeline + * (<tt>0 ≤ position < 32</tt>) is turned on. This mask is saved + * with the chunk in the file. + * + * \p offset is an array specifying the logical position of the first + * element of the chunk in the dataset’s dataspace. The length of the + * offset array must equal the number of dimensions, or rank, of the + * dataspace. The values in \p offset must not exceed the dimension limits + * and must specify a point that falls on a dataset chunk boundary. + * + * \p data_size is the size in bytes of the chunk, representing the number of + * bytes to be read from the buffer \p buf. If the data chunk has been + * precompressed, \p data_size should be the size of the compressed data. + * + * \p buf is the memory buffer containing data to be written to the chunk in the file. + * + * \attention Exercise caution when using H5DOread_chunk() and H5DOwrite_chunk(), + * as they read and write data chunks directly in a file. + * H5DOwrite_chunk() bypasses hyperslab selection, the conversion of data + * from one datatype to another, and the filter pipeline to write the chunk. + * Developers should have experience with these processes before + * using this function. Please see + * <a href="https://portal.hdfgroup.org/display/HDF5/Using+the+Direct+Chunk+Write+Function"> + * Using the Direct Chunk Write Function</a> + * for more information. + * + * \note H5DOread_chunk() and H5DOwrite_chunk() are not + * supported under parallel and do not support variable length types. + * + * \par Example + * The following code illustrates the use of H5DOwrite_chunk to write + * an entire dataset, chunk by chunk: + * \snippet H5DO_examples.c H5DOwrite + * + * \version 1.10.3 Function deprecated in favor of H5Dwrite_chunk. + * + * \since 1.8.11 + */ H5_HLDLL herr_t H5DOwrite_chunk(hid_t dset_id, hid_t dxpl_id, uint32_t filters, const hsize_t *offset, size_t data_size, const void *buf); + +/** + * -------------------------------------------------------------------------- + * \ingroup H5DO + * + * \brief Reads a raw data chunk directly from a dataset in a file into a buffer. + * + * \param[in] dset_id Identifier for the dataset to be read + * \param[in] dxpl_id Transfer property list identifier for + * this I/O operation + * \param[in] offset Logical position of the chunk’s first + element in the dataspace + * \param[in,out] filters Mask for identifying the filters used + * with the chunk + * \param[in] buf Buffer containing the chunk read from + * the dataset + * + * \return \herr_t + * + * \deprecated This function was deprecated in favor of the function + * H5Dread_chunk() as of HDF5-1.10.3. + * In HDF5 1.10.3, the functionality of H5DOread_chunk() + * was moved to H5Dread_chunk(). + * \deprecated For compatibility, this API call has been left as a stub which + * simply calls H5Dread_chunk(). New code should use H5Dread_chunk(). + * + * \details The H5DOread_chunk() reads a raw data chunk as specified + * by its logical \p offset in a chunked dataset \p dset_id + * from the dataset in the file into the application memory + * buffer \p buf. The data in \p buf is read directly from the file + * bypassing the library’s internal data transfer pipeline, + * including filters. + * + * \p dxpl_id is a data transfer property list identifier. + * + * The mask \p filters indicates which filters are used with the + * chunk when written. A zero value indicates that all enabled filters + * are applied on the chunk. A filter is skipped if the bit corresponding + * to the filter’s position in the pipeline + * (<tt>0 ≤ position < 32</tt>) is turned on. + * + * \p offset is an array specifying the logical position of the first + * element of the chunk in the dataset’s dataspace. The length of the + * offset array must equal the number of dimensions, or rank, of the + * dataspace. The values in \p offset must not exceed the dimension + * limits and must specify a point that falls on a dataset chunk boundary. + * + * \p buf is the memory buffer containing the chunk read from the dataset + * in the file. + * + * \par Example + * The following code illustrates the use of H5DOread_chunk() + * to read a chunk from a dataset: + * \snippet H5DO_examples.c H5DOread + * + * \version 1.10.3 Function deprecated in favor of H5Dread_chunk. + * + * \since 1.10.2, 1.8.19 + */ H5_HLDLL herr_t H5DOread_chunk(hid_t dset_id, hid_t dxpl_id, const hsize_t *offset, uint32_t *filters /*out*/, void *buf /*out*/); |