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GLAST / LAT > DAQ and FSW > FSW > Doxygen Index> LSEC / V6-1-0 > lsec / rad750

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compress.c File Reference

Routines acting upon the compression structure. More...

#include "LSEC/LSEC_msgs.h"
#include "compress_p.h"
#include "LDT/APM.h"
#include "PBS/MBA.h"
#include "MSG/MSG_pubdefs.h"
#include <string.h>

Functions
unsigned	LSEC_checkCompression (LSEC_compression *cpr)
	Check if there were errors during the histogram or encode operations.
void	LSEC_clearCompression (LSEC_compression *cpr)
	Clear the compression structrure of any data from a previous cycle.
void	LSEC_deleteCompression (LSEC_compression *cpr)
	Free the memory associated with the compression structure.
unsigned int	LSEC_getBin (LSEC_compression *cpr, unsigned int bin)
	Return the contents of one bin of the histogram.
unsigned int	LSEC_getCount (LSEC_compression *cpr)
	Return the number of non-zero bins in the histogram.
LSEC_compression *	LSEC_newCompression (unsigned int nbits, const char *name)
	Allocate and initialise a new compression structure.
unsigned *	LSEC_pack (LSEC_compression *cpr, unsigned *buffer)
	Pack the tables of a compression structure into a buffer.
size_t	LSEC_packedSize32 (LSEC_compression *cpr)
	Calculate the size of a packed compression structure.
unsigned	LSEC_process (LSEC_compression *cpr)
	Build the lookup, frequency and probability tables required by the APE.
void	LSEC_reportCompression (LSEC_compression *cmp, FILE *fp)
	Describe the contents of a compression structure.
void	LSEC_zeroBin (LSEC_compression *cpr, unsigned int bin)
	Set the selected bin of the histogram to zero.

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Detailed Description

Routines acting upon the compression structure.

Author:

James Swain & Owen Saxton

Id

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Function Documentation

unsigned LSEC_checkCompression

(

LSEC_compression *

cpr

)

Check if there were errors during the histogram or encode operations.

Parameters:

cpr

Pointer to a compression structure

Return values:

	LSEC_SYMOOR	If any of the symbols histogrammed or encoded by this compression structure were out of range
	LSEC_AWEFAIL	If there were any error during the encoding
	LSEC_SUCCESS	If there were no errors

void LSEC_clearCompression

(

LSEC_compression *

cpr

)

Clear the compression structrure of any data from a previous cycle.

Parameters:

cpr

Pointer to an allocated, initialised, compression structure

void LSEC_deleteCompression

(

LSEC_compression *

cpr

)

Free the memory associated with the compression structure.

Parameters:

cpr

Pointer to an allocated compression structure

unsigned int LSEC_getBin	(	LSEC_compression *	cpr,
		unsigned int	bin
	)

Return the contents of one bin of the histogram.

Parameters:

	cpr	Pointer to an allocated, initialised, populated, compression structure
	bin	ID of one of the bins of the histogram

Returns:

Contents of the bin

unsigned int LSEC_getCount

(

LSEC_compression *

cpr

)

Return the number of non-zero bins in the histogram.

Parameters:

cpr

Pointer to a compression structure

Returns:

Number of non-zero bins in the histogram

LSEC_compression* LSEC_newCompression	(	unsigned int	nbits,
		const char *	name
	)

Allocate and initialise a new compression structure.

Parameters:

	name	String used in the reporting of error to identify a compression structure
	nbits	Number of symbols in the complete range of possible symbols (including excluded internal sub-ranges), hence the number of bins in the histogram and frequency tables

Returns:

Pointer to an allocated and initialised LSEC_compression structure

The order of calling the functions presented here should be LSEC_newCompression LSEC_histogram - Repeat as necessary LSEC_process LSEC_pack LSEC_compress - Repeat as necessary LSEC_clearCompression : repeat as necessary : LSEC_deleteCompression

unsigned* LSEC_pack	(	LSEC_compression *	cpr,
		unsigned *	buffer
	)

Pack the tables of a compression structure into a buffer.

This routine selects sufficient data from the tables of the compression structure to be able to recreate the tables required to decompress the data, and pack it into the consignment

Parameters:

	buffer	Pointer to the start of the buffer to place the packed structure
	cpr	Pointer to an initialised, populated and processed compression structure

Returns:

Pointer to the word after this compression structure after packing

size_t LSEC_packedSize32

(

LSEC_compression *

cpr

)

Calculate the size of a packed compression structure.

This routine calculates the number of 32-bit words required to hold the packed compression structure

Parameters:

cpr

Pointer to a compression structure

Returns:

Size of the packed compression structure

unsigned LSEC_process

(

LSEC_compression *

cpr

)

Build the lookup, frequency and probability tables required by the APE.

Parameters:

cpr

Pointer to an allocated, initialised, populated, compression structure

Return values:

LSEC_SUCCESS

If the processing goes well

void LSEC_reportCompression	(	LSEC_compression *	cmp,
		FILE *	fp
	)

Describe the contents of a compression structure.

This routine formats the compression structure as ASCII text and writes it to the specified file

Parameters:

	cmp	Pointer to the compression structure
	fp	Pointer to the file used as the destination

void LSEC_zeroBin	(	LSEC_compression *	cpr,
		unsigned int	bin
	)

Set the selected bin of the histogram to zero.

This indicates that this symbol will be selectively removed from the uncompressed data stream before encoding

Parameters:

	cpr	Pointer to an allocated, initialised, populated, compression structure
	bin	ID of one of the bins of the histogram

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