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GLAST / LAT > DAQ and FSW > FSW > Doxygen Index> LSEC / V7-1-0 > 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"
#include "LDT/HDE.h"

Functions
static __inline void	LSEC_compress (LSEC_compression *cpr, void *ctx, unsigned int sym)
static __inline unsigned	LSEC_compressH (LSEC_compression *cpr, int sym, unsigned int *buf, unsigned int pos)
	Encode a symbol using the Huffman table supplied by a compression.
static __inline void	LSEC_histogram (LSEC_compression *cpr, int sym)
	Increment the bin of a histogram.
static __inline void	LSEC_histogramH (LSEC_compression *cpr, int sym)
	Increment the bin of a Huffman histogram.
void	LSEC_compress (LSEC_compression *cpr, void *ctx, unsigned sym)
	Encode a symbol using the frequency and lookup table supplied by a compression.

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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 1.8 2010/08/12 21:10:28 saxton Exp $

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Function Documentation

void LSEC_compress	(	LSEC_compression *	cpr,
		void *	ctx,
		unsigned	sym
	)

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

unsigned LSEC_compressH	(	LSEC_compression *	cpr,
		int	sym,
		unsigned int *	buf,
		unsigned int	pos
	)			[static]

Encode a symbol using the Huffman table supplied by a compression.

This function does not check for errors since only a programming error could cause one, and speed is of the essence.

Parameters:

	cpr	Pointer to an initialsed, populated and processed compression structure
	sym	Symbol to compress
	buf	The address of the buffer to hold the encoded value.
	pos	The current bit position within the buffer.

Returns:

The updated bit position within buf.

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

Increment the bin of a histogram.

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.

void LSEC_histogramH	(	LSEC_compression *	cpr,
		int	sym
	)			[static]

Increment the bin of a Huffman histogram.

Parameters:

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

This function does not check for errors.

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