H5Zpublic.h File Reference

#include "H5public.h"

Data Structures
struct	H5Z_cb_t
struct	H5Z_class2_t
struct	H5Z_class1_t

Macros
#define	H5Z_FILTER_ERROR   (-1)
#define	H5Z_FILTER_NONE   0
#define	H5Z_FILTER_DEFLATE   1
#define	H5Z_FILTER_SHUFFLE   2
#define	H5Z_FILTER_FLETCHER32   3
#define	H5Z_FILTER_SZIP   4
#define	H5Z_FILTER_NBIT   5
#define	H5Z_FILTER_SCALEOFFSET   6
#define	H5Z_FILTER_RESERVED   256
#define	H5Z_FILTER_MAX   65535
#define	H5Z_FILTER_ALL   0
#define	H5Z_MAX_NFILTERS   32
#define	H5Z_FLAG_DEFMASK   0x00ff
#define	H5Z_FLAG_MANDATORY   0x0000
#define	H5Z_FLAG_OPTIONAL   0x0001
#define	H5Z_FLAG_INVMASK   0xff00
#define	H5Z_FLAG_REVERSE   0x0100
#define	H5Z_FLAG_SKIP_EDC   0x0200
#define	H5_SZIP_ALLOW_K13_OPTION_MASK   1
#define	H5_SZIP_CHIP_OPTION_MASK   2
#define	H5_SZIP_EC_OPTION_MASK   4
#define	H5_SZIP_NN_OPTION_MASK   32
#define	H5_SZIP_MAX_PIXELS_PER_BLOCK   32
#define	H5Z_SHUFFLE_USER_NPARMS   0
#define	H5Z_SHUFFLE_TOTAL_NPARMS   1
#define	H5Z_SZIP_USER_NPARMS   2
#define	H5Z_SZIP_TOTAL_NPARMS   4
#define	H5Z_SZIP_PARM_MASK   0
#define	H5Z_SZIP_PARM_PPB   1
#define	H5Z_SZIP_PARM_BPP   2
#define	H5Z_SZIP_PARM_PPS   3
#define	H5Z_NBIT_USER_NPARMS   0 /* Number of parameters that users can set */
#define	H5Z_SCALEOFFSET_USER_NPARMS   2
#define	H5Z_SO_INT_MINBITS_DEFAULT   0
#define	H5Z_CLASS_T_VERS   (1)
#define	H5Z_FILTER_CONFIG_ENCODE_ENABLED   (0x0001)
#define	H5Z_FILTER_CONFIG_DECODE_ENABLED   (0x0002)

Typedefs
typedef int	H5Z_filter_t
	Filter identifiers. More...
typedef H5Z_cb_return_t(*	H5Z_filter_func_t) (H5Z_filter_t filter, void *buf, size_t buf_size, void *op_data)
typedef htri_t(*	H5Z_can_apply_func_t) (hid_t dcpl_id, hid_t type_id, hid_t space_id)
	This callback determines if a filter can be applied to the dataset with the characteristics provided. More...
typedef herr_t(*	H5Z_set_local_func_t) (hid_t dcpl_id, hid_t type_id, hid_t space_id)
	The filter operation callback function, defining a filter's operation on data. More...
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)
	The filter operation callback function, defining a filter's operation on data. More...

Enumerations
enum	H5Z_SO_scale_type_t { H5Z_SO_FLOAT_DSCALE = 0 , H5Z_SO_FLOAT_ESCALE = 1 , H5Z_SO_INT = 2 }
enum	H5Z_EDC_t { H5Z_ERROR_EDC = -1 , H5Z_DISABLE_EDC = 0 , H5Z_ENABLE_EDC = 1 , H5Z_NO_EDC = 2 }
enum	H5Z_cb_return_t { H5Z_CB_ERROR = -1 , H5Z_CB_FAIL = 0 , H5Z_CB_CONT = 1 , H5Z_CB_NO = 2 }

Functions
herr_t	H5Zregister (const void *cls)
	Registers a new filter with the HDF5 library. More...
herr_t	H5Zunregister (H5Z_filter_t id)
	Unregisters a filter. More...
htri_t	H5Zfilter_avail (H5Z_filter_t id)
	Determines whether a filter is available. More...
herr_t	H5Zget_filter_info (H5Z_filter_t filter, unsigned int *filter_config_flags)
	Retrieves information about a filter. More...

Macro Definition Documentation

H5Z_CLASS_T_VERS

#define H5Z_CLASS_T_VERS   (1)

Current version of the H5Z_class_t struct

H5Z_FILTER_ALL

#define H5Z_FILTER_ALL   0

Symbol to remove all filters in H5Premove_filter()

H5Z_FILTER_CONFIG_DECODE_ENABLED

#define H5Z_FILTER_CONFIG_DECODE_ENABLED   (0x0002)

H5Z_FILTER_CONFIG_ENCODE_ENABLED

#define H5Z_FILTER_CONFIG_ENCODE_ENABLED   (0x0001)

H5Z_FILTER_DEFLATE

#define H5Z_FILTER_DEFLATE   1

deflation like gzip

H5Z_FILTER_ERROR

#define H5Z_FILTER_ERROR   (-1)

no filter

H5Z_FILTER_FLETCHER32

#define H5Z_FILTER_FLETCHER32   3

fletcher32 checksum of EDC

H5Z_FILTER_MAX

#define H5Z_FILTER_MAX   65535

maximum filter id

H5Z_FILTER_NBIT

#define H5Z_FILTER_NBIT   5

nbit compression

H5Z_FILTER_NONE

#define H5Z_FILTER_NONE   0

reserved indefinitely

H5Z_FILTER_RESERVED

#define H5Z_FILTER_RESERVED   256

filter ids below this value are reserved for library use

H5Z_FILTER_SCALEOFFSET

#define H5Z_FILTER_SCALEOFFSET   6

scale+offset compression

H5Z_FILTER_SHUFFLE

#define H5Z_FILTER_SHUFFLE   2

shuffle the data

H5Z_FILTER_SZIP

#define H5Z_FILTER_SZIP   4

szip compression

H5Z_FLAG_DEFMASK

#define H5Z_FLAG_DEFMASK   0x00ff

definition flag mask

H5Z_FLAG_INVMASK

#define H5Z_FLAG_INVMASK   0xff00

invocation flag mask

H5Z_FLAG_MANDATORY

#define H5Z_FLAG_MANDATORY   0x0000

filter is mandatory

H5Z_FLAG_OPTIONAL

#define H5Z_FLAG_OPTIONAL   0x0001

filter is optional

H5Z_FLAG_REVERSE

#define H5Z_FLAG_REVERSE   0x0100

reverse direction; read

H5Z_FLAG_SKIP_EDC

#define H5Z_FLAG_SKIP_EDC   0x0200

skip EDC filters for read

H5Z_MAX_NFILTERS

#define H5Z_MAX_NFILTERS   32

Maximum number of filters allowed in a pipeline

H5Z_NBIT_USER_NPARMS

#define H5Z_NBIT_USER_NPARMS   0 /* Number of parameters that users can set */

Number of parameters that users can set for the N-bit filter

Typedef Documentation

H5Z_can_apply_func_t

typedef htri_t(* H5Z_can_apply_func_t) (hid_t dcpl_id, hid_t type_id, hid_t space_id)

This callback determines if a filter can be applied to the dataset with the characteristics provided.

Parameters

[in]	dcpl_id	Dataset creation property list identifier
[in]	type_id	Datatype identifier
[in]	space_id	Dataspace identifier

Returns

Returns zero (false), a positive (true) or a negative (failure) value.

Before a dataset gets created, the 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 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 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 H5Z_can_apply_func_t callback returns positive a valid combination, zero for an invalid combination and negative for an error.

H5Z_filter_func_t

typedef H5Z_cb_return_t(* H5Z_filter_func_t) (H5Z_filter_t filter, void *buf, size_t buf_size, void *op_data)

Filter callback function definition

H5Z_filter_t

typedef int H5Z_filter_t

Filter identifiers.

Values 0 through 255 are for filters defined by the HDF5 library. Values 256 through 511 are available for testing new filters. Subsequent values should be obtained from the HDF5 development team at help@.nosp@m.hdfg.nosp@m.roup..nosp@m.org. These values will never change because they appear in the HDF5 files.

H5Z_func_t

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)

The filter operation callback function, defining a filter's operation on data.

Parameters

[in]	flags	Bit vector specifying certain general properties of the filter
[in]	cd_nelmts	Number of elements in cd_values
[in]	cd_values	Auxiliary data for the filter
[in]	nbytes	The number of valid bytes in buf to be filtered
[in,out]	buf_size	The size of buf
[in,out]	buf	The filter buffer

Returns

Returns the number of valid bytes of data contained in buf. In the case of failure, the return value is 0 (zero) and all pointer arguments are left unchanged.

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 buf_size pointer and the new buffer through the 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_set_local_func_t

typedef herr_t(* H5Z_set_local_func_t) (hid_t dcpl_id, hid_t type_id, hid_t space_id)

The filter operation callback function, defining a filter's operation on data.

Parameters

[in]	dcpl_id	Dataset creation property list identifier
[in]	type_id	Datatype identifier
[in]	space_id	Dataspace identifier

Returns

Returns a non-negative value if successful; otherwise returns a negative value.

After the H5Z_can_apply_func_t callbacks are checked for new datasets, the 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 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 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 H5Z_set_local_func_t callback must return non-negative on success and negative for an error.

Enumeration Type Documentation

H5Z_cb_return_t

enum H5Z_cb_return_t

Return values for filter callback function

Enumerator
H5Z_CB_ERROR	error value
H5Z_CB_FAIL	I/O should fail if filter fails.
H5Z_CB_CONT	I/O continues if filter fails.
H5Z_CB_NO	sentinel