ncsqueeze.c File Reference

#include "config.h"
#include "ncsqueeze.h"
#include <hdf5.h>
#include <H5DSpublic.h>
#include <stdlib.h>

Functions
int	nc_def_var_bzip2 (int ncid, int varid, int level)
int	nc_inq_var_bzip2 (int ncid, int varid, int *bzip2p, int *levelp)
int	nc_def_var_lz4 (int ncid, int varid, int level)
int	nc_inq_var_lz4 (int ncid, int varid, int *lz4p, int *levelp)

Detailed Description

This is the code file for ncsqueeze.

Author

Edward Hartnett

Date

Nov 13, 2025

Copyright

Intelligent Data Design, Inc. All rights reserved.

Function Documentation

nc_def_var_bzip2()

int nc_def_var_bzip2	(	int	ncid,
		int	varid,
		int	level
	)

ncsqueeze supports compression filters for netCDF/HDF5 files which are not natively supported by the netCDF C library.

BZIP2

Bzip2 is a free and open-source file compression program that uses the Burrows–Wheeler algorithm. For more information see https://www.sourceware.org/bzip2/ and https://en.wikipedia.org/wiki/Bzip2.

In C:

• nc_def_var_bzip2()
• nc_inq_var_bzip2()

In Fortran:

• nf90_def_var_bzip2()
• nf90_inq_var_bzip2() Turn on bzip2 compression for a variable.

Parameters

ncid	File ID.
varid	Variable ID.
level	From 1 to 9. Set the block size to 100k, 200k ... 900k when compressing. (bzip2 default level is 9).

Returns

0 for success, error code otherwise.

Author

Edward Hartnett

nc_def_var_lz4()

int nc_def_var_lz4	(	int	ncid,
		int	varid,
		int	level
	)

Turn on lz4 compression for a variable.

Parameters

ncid	File ID.
varid	Variable ID.
level	From 1 to 9. Set the block size to 100k, 200k ... 900k when compressing. (lz4 default level is 9).

Returns

0 for success, error code otherwise.

Author

Edward Hartnett

nc_inq_var_bzip2()

int nc_inq_var_bzip2	(	int	ncid,
		int	varid,
		int *	bzip2p,
		int *	levelp
	)

Learn whether bzip2 compression is on for a variable, and, if so, the level setting.

Parameters

ncid	File ID.
varid	Variable ID.
bzip2p	Pointer that gets a 0 if bzip2 is not in use for this var, and a 1 if it is. Ignored if NULL.
levelp	Pointer that gets the level setting (from 1 to 9), if bzip2 is in use. Ignored if NULL.

Returns

0 for success, error code otherwise.

Author

Edward Hartnett

nc_inq_var_lz4()

int nc_inq_var_lz4	(	int	ncid,
		int	varid,
		int *	lz4p,
		int *	levelp
	)

Learn whether lz4 compression is on for a variable, and, if so, the level setting.

Parameters

ncid	File ID.
varid	Variable ID.
lz4p	Pointer that gets a 0 if lz4 is not in use for this var, and a 1 if it is. Ignored if NULL.
levelp	Pointer that gets the acceleration setting (from 1 to 9). Ignored if NULL.

Returns

0 for success, error code otherwise.

Author

Edward Hartnett