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GLAST / LAT > DAQ and FSW > FSW > Doxygen Index> LSEC / V7-0-0 > lsec / mv2304

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compress.ic File Reference

The histogram and compress functions, as static inlines for efficiency. More...

#include "compress.h"
#include "LSEC_p.h"
#include "LDT/APE.h"

Defines
#define	LSEC_N_ENCODE   32
Functions
static __inline void	LSEC_compress (LSEC_compression *cpr, void *ctx, unsigned sym)
	Encode a symbol using the frequency and lookup table supplied by a compression.
static __inline void	LSEC_compressD (LSEC_compression *cpr, void *ctx, unsigned int sym, const unsigned int **tables, unsigned short *syms, int *nsyms)
	Encode a symbol using the frequency and lookup table supplied by a compression.
static __inline void	LSEC_histogram (LSEC_compression *cpr, unsigned sym)
	Increment the bin of the histogram corresponding.

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Detailed Description

The histogram and compress functions, as static inlines for efficiency.

Author:

James Swain & Owen Saxton

$Id: compress.ic,v 1.7 2010/05/25 19:16:36 saxton Exp $

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Function Documentation

void LSEC_compress	(	LSEC_compression *	cpr,
		void *	ctx,
		unsigned	sym
	)			[static]

Encode a symbol using the frequency and lookup table supplied by a compression.

This function does not return errors since propogation of those errors to a point in LSEC where reasonable decisions about error handling can be made is problematic. Instead, errors are latched and can be checked using LSEC_checkCompression.

Parameters:

	cpr	Pointer to an initialsed, populated and processed compression structure
	ctx	Context, pointer to the arithmetic encoder context
	sym	Symbol to compress

void LSEC_compressD	(	LSEC_compression *	cpr,
		void *	ctx,
		unsigned int	sym,
		const unsigned int **	tables,
		unsigned short *	syms,
		int *	nsyms
	)			[static]

Encode a symbol using the frequency and lookup table supplied by a compression.

This function does not do the encoding immediately. It instead collects the table and symbol to be used into a pair of supplied arrays, and encodes the arrays when they become full.

This function does not return errors since propogation of those errors to a point in LSEC where reasonable decisions about error handling can be made is problematic. Instead, errors are latched and can be checked using LSEC_checkCompression.

Parameters:

	cpr	Pointer to an initialsed, populated and processed compression structure
	ctx	Context, pointer to the arithmetic encoder context
	sym	Symbol to encode.
	tables	Pointer to an array of size LSEC_N_ENCODE to hold the table pointers for deferred encoding.
	syms	Pointer to an array of size LSEC_N_ENCODE to hold the symbols for deferred encoding.
	nsyms	Pointer to an integer to hold the number of symbols to be encoded.

void LSEC_histogram	(	LSEC_compression *	cpr,
		unsigned	sym
	)			[static]

Increment the bin of the histogram corresponding.

Parameters:

	cpr	Pointer to an allocated, initialised, compression structure
	sym	Symbol to add to the histogram

This function does not return errors since propogation of those errors to a point in LSEC where reasonable decisions about error handling can be made is problematic. Instead, errors are latched and can be checked using LSEC_checkCompression.

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