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diff --git a/src/H5Zdevelop.h b/src/H5Zdevelop.h new file mode 100644 index 0000000..328e221 --- /dev/null +++ b/src/H5Zdevelop.h @@ -0,0 +1,421 @@ +/* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * + * Copyright by The HDF Group. * + * All rights reserved. * + * * + * This file is part of HDF5. The full HDF5 copyright notice, including * + * terms governing use, modification, and redistribution, is contained in * + * the COPYING file, which can be found at the root of the source code * + * distribution tree, or in https://support.hdfgroup.org/ftp/HDF5/releases. * + * If you do not have access to either file, you may request a copy from * + * help@hdfgroup.org. * + * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * */ + +/* + * This file contains public declarations for the H5Z (data filter) developer + * support routines. + */ + +#ifndef _H5Zdevelop_H +#define _H5Zdevelop_H + +/* Include package's public header */ +#include "H5Zpublic.h" + +/*****************/ +/* Public Macros */ +/*****************/ + +/** + * Current version of the H5Z_class_t struct + */ +#define H5Z_CLASS_T_VERS (1) + +/*******************/ +/* Public Typedefs */ +/*******************/ + +/** + * Structure for filter callback property + */ +typedef struct H5Z_cb_t { + H5Z_filter_func_t func; + void * op_data; +} H5Z_cb_t; + +/** + * \brief This callback determines if a filter can be applied to the dataset + * with the characteristics provided + * + * \dcpl_id + * \type_id + * \space_id + * + * \return \htri_t + * + * \details Before a dataset gets created, the \ref H5Z_can_apply_func_t + * callbacks for any filters used in the dataset creation property list + * are called with the dataset's dataset creation property list, the + * dataset's datatype and a dataspace describing a chunk (for chunked + * dataset storage). + * + * The \ref H5Z_can_apply_func_t callback must determine if the + * combination of the dataset creation property list setting, the + * datatype and the dataspace represent a valid combination to apply + * this filter to. For example, some cases of invalid combinations may + * involve the filter not operating correctly on certain datatypes (or + * certain datatype sizes), or certain sizes of the chunk dataspace. + * + * The \ref H5Z_can_apply_func_t callback can be the NULL pointer, in + * which case, the library will assume that it can apply to any + * combination of dataset creation property list values, datatypes and + * dataspaces. + * + * The \ref H5Z_can_apply_func_t callback returns positive a valid + * combination, zero for an invalid combination and negative for an + * error. + */ +//! <!-- [H5Z_can_apply_func_t_snip] --> +typedef htri_t (*H5Z_can_apply_func_t)(hid_t dcpl_id, hid_t type_id, hid_t space_id); +//! <!-- [H5Z_can_apply_func_t_snip] --> + +/** + * \brief The filter operation callback function, defining a filter's operation + * on data + * + * \dcpl_id + * \type_id + * \space_id + * + * \return \herr_t + * + * \details After the \ref H5Z_can_apply_func_t callbacks are checked for new + * datasets, the \ref H5Z_set_local_func_t callbacks for any filters + * used in the dataset creation property list are called. These + * callbacks receive the dataset's private copy of the dataset creation + * property list passed in to H5Dcreate() (i.e. not the actual property + * list passed in to H5Dcreate()) and the datatype ID passed in to + * H5Dcreate() (which is not copied and should not be modified) and a + * dataspace describing the chunk (for chunked dataset storage) (which + * should also not be modified). + * + * The \ref H5Z_set_local_func_t callback must set any parameters that + * are specific to this dataset, based on the combination of the + * dataset creation property list values, the datatype and the + * dataspace. For example, some filters perform different actions based + * on different datatypes (or datatype sizes) or different number of + * dimensions or dataspace sizes. + * + * The \ref H5Z_set_local_func_t callback can be the NULL pointer, in + * which case, the library will assume that there are no + * dataset-specific settings for this filter. + * + * The \ref H5Z_set_local_func_t callback must return non-negative on + * success and negative for an error. + */ +//! <!-- [H5Z_set_local_func_t_snip] --> +typedef herr_t (*H5Z_set_local_func_t)(hid_t dcpl_id, hid_t type_id, hid_t space_id); +//! <!-- [H5Z_set_local_func_t_snip] --> + +/** + * \brief The filter operation callback function, defining a filter's operation + * on data + * + * \param[in] flags Bit vector specifying certain general properties of the filter + * \param[in] cd_nelmts Number of elements in \p cd_values + * \param[in] cd_values Auxiliary data for the filter + * \param[in] nbytes The number of valid bytes in \p buf to be filtered + * \param[in,out] buf_size The size of \p buf + * \param[in,out] buf The filter buffer + * + * \return Returns the number of valid bytes of data contained in \p buf. In the + * case of failure, the return value is 0 (zero) and all pointer + * arguments are left unchanged. + * + * \details A filter gets definition flags and invocation flags (defined + * above), the client data array and size defined when the filter was + * added to the pipeline, the size in bytes of the data on which to + * operate, and pointers to a buffer and its allocated size. + * + * The filter should store the result in the supplied buffer if + * possible, otherwise it can allocate a new buffer, freeing the + * original. The allocated size of the new buffer should be returned + * through the \p buf_size pointer and the new buffer through the \p + * buf pointer. + * + * The return value from the filter is the number of bytes in the + * output buffer. If an error occurs then the function should return + * zero and leave all pointer arguments unchanged. + */ +//! <!-- [H5Z_func_t_snip] --> +typedef size_t (*H5Z_func_t)(unsigned int flags, size_t cd_nelmts, const unsigned int cd_values[], + size_t nbytes, size_t *buf_size, void **buf); +//! <!-- [H5Z_func_t_snip] --> + +/** + * The filter table maps filter identification numbers to structs that + * contain a pointers to the filter function and timing statistics. + */ +//! <!-- [H5Z_class2_t_snip] --> +typedef struct H5Z_class2_t { + int version; /**< Version number of the H5Z_class_t struct */ + H5Z_filter_t id; /**< Filter ID number */ + unsigned encoder_present; /**< Does this filter have an encoder? */ + unsigned decoder_present; /**< Does this filter have a decoder? */ + const char * name; /**< Comment for debugging */ + H5Z_can_apply_func_t can_apply; /**< The "can apply" callback for a filter */ + H5Z_set_local_func_t set_local; /**< The "set local" callback for a filter */ + H5Z_func_t filter; /**< The actual filter function */ +} H5Z_class2_t; +//! <!-- [H5Z_class2_t_snip] --> + +/********************/ +/* Public Variables */ +/********************/ + +/*********************/ +/* Public Prototypes */ +/*********************/ + +#ifdef __cplusplus +extern "C" { +#endif + +/** + * \ingroup H5Z + * + * \brief Registers a new filter with the HDF5 library + * + * \param[in] cls A pointer to a buffer for the struct containing the + * filter-definition + * + * \return \herr_t + * + * \details H5Zregister() registers a new filter with the HDF5 library. + * + * \details Making a new filter available to an application is a two-step + * process. The first step is to write the three filter callback + * functions described below: \c can_apply, \c set_local, and \c + * filter. This call to H5Zregister(), registering the filter with the + * library, is the second step. The can_apply and set_local fields can + * be set to NULL if they are not required for the filter being + * registered. + * + * H5Zregister() accepts a single parameter, a pointer to a buffer for + * the \p cls data structure. That data structure must conform to one + * of the following definitions: + * \snippet this H5Z_class1_t_snip + * or + * \snippet this H5Z_class2_t_snip + * + * \c version is a library-defined value reporting the version number + * of the #H5Z_class_t struct. This currently must be set to + * #H5Z_CLASS_T_VERS. + * + * \c id is the identifier for the new filter. This is a user-defined + * value between #H5Z_FILTER_RESERVED and #H5Z_FILTER_MAX. These + * values are defined in the HDF5 source file H5Zpublic.h, but the + * symbols #H5Z_FILTER_RESERVED and #H5Z_FILTER_MAX should always be + * used instead of the literal values. + * + * \c encoder_present is a library-defined value indicating whether + * the filter’s encoding capability is available to the application. + * + * \c decoder_present is a library-defined value indicating whether + * the filter’s encoding capability is available to the application. + * + * \c name is a descriptive comment used for debugging, may contain a + * descriptive name for the filter, and may be the null pointer. + * + * \c can_apply, described in detail below, is a user-defined callback + * function which determines whether the combination of the dataset + * creation property list values, the datatype, and the dataspace + * represent a valid combination to apply this filter to. + * + * \c set_local, described in detail below, is a user-defined callback + * function which sets any parameters that are specific to this + * dataset, based on the combination of the dataset creation property + * list values, the datatype, and the dataspace. + * + * \c filter, described in detail below, is a user-defined callback + * function which performs the action of the filter. + * + * The statistics associated with a filter are not reset by this + * function; they accumulate over the life of the library. + * + * #H5Z_class_t is a macro which maps to either H5Z_class1_t or + * H5Z_class2_t, depending on the needs of the application. To affect + * only this macro, H5Z_class_t_vers may be defined to either 1 or 2. + * Otherwise, it will behave in the same manner as other API + * compatibility macros. See API Compatibility Macros in HDF5 for more + * information. H5Z_class1_t matches the #H5Z_class_t structure that is + * used in the 1.6.x versions of the HDF5 library. + * + * H5Zregister() will automatically detect which structure type has + * been passed in, regardless of the mapping of the #H5Z_class_t macro. + * However, the application must make sure that the fields are filled + * in according to the correct structure definition if the macro is + * used to declare the structure. + * + * \Bold{The callback functions:}\n Before H5Zregister() can link a + * filter into an application, three callback functions must be + * defined as described in the HDF5 library header file H5Zpublic.h. + * + * When a filter is applied to the fractal heap for a group (e.g., + * when compressing group metadata) and if the can apply and set local + * callback functions have been defined for that filter, HDF5 passes + * the value -1 for all parameters for those callback functions. This + * is done to ensure that the filter will not be applied to groups if + * it relies on these parameters, as they are not applicable to group + * fractal heaps; to operate on group fractal heaps, a filter must be + * capable of operating on an opaque block of binary data. + * + * The \Emph{can apply} callback function must return a positive value + * for a valid combination, zero for an invalid combination, and a + * negative value for an error. + * \snippet this H5Z_can_apply_func_t_snip + * + * Before a dataset is created, the \Emph{can apply} callbacks for any + * filters used in the dataset creation property list are called with + * the dataset's dataset creation property list, \c dcpl_id, the + * dataset's datatype, \p type_id, and a dataspace describing a chunk, + * \p space_id, (for chunked dataset storage). + * + * This callback must determine whether the combination of the dataset + * creation property list settings, the datatype, and the dataspace + * represent a valid combination to which to apply this filter. For + * example, an invalid combination may involve the filter not + * operating correctly on certain datatypes, on certain datatype + * sizes, or on certain sizes of the chunk dataspace. If this filter + * is enabled through H5Pset_filter() as optional and the can apply + * function returns 0, the library will skip the filter in the filter + * pipeline. + * + * This callback can be the NULL pointer, in which case the library + * will assume that the filter can be applied to a dataset with any + * combination of dataset creation property list values, datatypes, + * and dataspaces. + * + * The \Emph{set local} callback function is defined as follows: + * \snippet this H5Z_set_local_func_t_snip + * + * After the can apply callbacks are checked for a new dataset, the + * \Emph{set local} callback functions for any filters used in the + * dataset creation property list are called. These callbacks receive + * \c dcpl_id, the dataset's private copy of the dataset creation + * property list passed in to H5Dcreate() (i.e. not the actual + * property list passed in to H5Dcreate()); \c type_id, the datatype + * identifier passed in to H5Dcreate(), which is not copied and should + * not be modified; and \c space_id, a dataspace describing the chunk + * (for chunked dataset storage), which should also not be modified. + * + * The set local callback must set any filter parameters that are + * specific to this dataset, based on the combination of the dataset + * creation property list values, the datatype, and the dataspace. For + * example, some filters perform different actions based on different + * datatypes, datatype sizes, numbers of dimensions, or dataspace + * sizes. + * + * The \Emph{set local} callback may be the NULL pointer, in which + * case, the library will assume that there are no dataset-specific + * settings for this filter. + * + * The \Emph{set local} callback function must return a non-negative + * value on success and a negative value for an error. + * + * The \Emph{filter operation} callback function, defining the + * filter's operation on the data, is defined as follows: + * \snippet this H5Z_func_t_snip + * + * The parameters \c flags, \c cd_nelmts, and \c cd_values are the + * same as for the function H5Pset_filter(). The one exception is that + * an additional flag, #H5Z_FLAG_REVERSE, is set when the filter is + * called as part of the input pipeline. + * + * The parameter \c buf points to the input buffer which has a size of + * \c buf_size bytes, \c nbytes of which are valid data. + * + * The filter should perform the transformation in place if possible. + * If the transformation cannot be done in place, then the filter + * should allocate a new buffer with malloc() and assign it to \c buf, + * assigning the allocated size of that buffer to \c buf_size. The old + * buffer should be freed by calling free(). + * + * If successful, the \Emph{filter operation} callback function + * returns the number of valid bytes of data contained in \c buf. In + * the case of failure, the return value is 0 (zero) and all pointer + * arguments are left unchanged. + * + * \version 1.8.6 Return type for the \Emph{can apply} callback function, + * \ref H5Z_can_apply_func_t, changed to \ref htri_t. + * \version 1.8.5 Semantics of the \Emph{can apply} and \Emph{set local} + * callback functions changed to accommodate the use of filters + * with group fractal heaps. + * \version 1.8.3 #H5Z_class_t renamed to H5Z_class2_t, H5Z_class1_t structure + * introduced for backwards compatibility with release 1.6.x, + * and #H5Z_class_t macro introduced in this release. Function + * modified to accept either structure type. + * \version 1.8.0 The fields \c version, \c encoder_present, and + * \c decoder_present were added to the #H5Z_class_t \c struct + * in this release. + * \version 1.6.0 This function was substantially revised in Release 1.6.0 with + * a new #H5Z_class_t struct and new set local and can apply + * callback functions. + * + */ +H5_DLL herr_t H5Zregister(const void *cls); +/** + * \ingroup H5Z + * + * \brief Unregisters a filter. + * + * \param[in] id Identifier of the filter to be unregistered. + * \return \herr_t + * + * \details H5Zunregister() unregisters the filter specified in \p id. + * + * \details This function first iterates through all opened datasets and + * groups. If an open object that uses this filter is found, the + * function will fail with a message indicating that an object using + * the filter is still open. All open files are then flushed to make + * sure that all cached data that may use this filter are written out. + * + * If the application is a parallel program, all processes that + * participate in collective data write should call this function to + * ensure that all data is flushed. + * + * After a call to H5Zunregister(), the filter specified in filter + * will no longer be available to the application. + * + * \version 1.8.12 Function modified to check for open objects using the + * filter. + * \since 1.6.0 + */ +H5_DLL herr_t H5Zunregister(H5Z_filter_t id); + +#ifdef __cplusplus +} +#endif + +/* Symbols defined for compatibility with previous versions of the HDF5 API. + * + * Use of these symbols is deprecated. + */ +#ifndef H5_NO_DEPRECATED_SYMBOLS + +/** + * The filter table maps filter identification numbers to structs that + * contain a pointers to the filter function and timing statistics. + */ +//! <!-- [H5Z_class1_t_snip] --> +typedef struct H5Z_class1_t { + H5Z_filter_t id; /**< Filter ID number */ + const char * name; /**< Comment for debugging */ + H5Z_can_apply_func_t can_apply; /**< The "can apply" callback for a filter */ + H5Z_set_local_func_t set_local; /**< The "set local" callback for a filter */ + H5Z_func_t filter; /**< The actual filter function */ +} H5Z_class1_t; +//! <!-- [H5Z_class1_t_snip] --> + +#endif /* H5_NO_DEPRECATED_SYMBOLS */ + +#endif /* _H5Zdevelop_H */ |