---

GLAST/LAT > DAQ and FSW > FSW > Doxygen Index > LDT / V0-3-2

Constituent: test_huff     Tag: linux-gcc

---

         

---

HUFF.h File Reference

Huffman Encode/Decode, interface file. More...

#include "LDT/BA.h"
#include "PBI/Endianness.h"

Include dependency graph for HUFF.h:

This graph shows which files directly or indirectly include this file:

Data Structures
struct	_HUFF_code
	Structure to contain the Huffman code, both the bit pattern and its length. More...
struct	_HUFF_symbol_bf
	The information associate with a decoded symbol. More...
union	_HUFF_symbol
Defines
#define	HUFF_N_WA(_cnt)   (HUFF_N_HEAP(_cnt) + HUFF_N_PARENTS(_cnt))
	Gives the number of elements needed by the temporary wa array based of the number of elements in the frequency table.
#define	HUFF_ENCODE(_out, _buffer, _togo, _codes, _sym)
	Macro to encode one symbol using the specified code table.
Typedefs
typedef _HUFF_dtable	HUFF_dtable
typedef _HUFF_code	HUFF_code
	Typedef for struct _HUFF_code.
typedef _HUFF_symbol_bf	HUFF_symbol_bf
typedef _HUFF_symbol	HUFF_symbol
Functions
int	HUFF_build (HUFF_code *codes, const unsigned int *freqs, int count, unsigned int *wa)
int	HUFF_buildDense (HUFF_code *codes, const unsigned int *freq, const unsigned int *valid, int nvalid, unsigned int *wa)
int	HUFF_buildSparse (HUFF_code *codes, const unsigned int *freq, const unsigned int *valid, int nvalid, unsigned int *wa)
int	HUFF_bcompress (void *out, unsigned int boff, void *max, const HUFF_code *codes, const unsigned char *in, int cnt, int *unencoded)
int	HUFF_size (const HUFF_code *codes, const unsigned int *freqs, int count)
int	HUFF_sizeDense (const HUFF_code *codes, const unsigned int *freq, const unsigned int *valid, int nvalid)
int	HUFF_sizeSparse (const HUFF_code *codes, const unsigned int *freq, const unsigned int *valid, int nvalid)
int	HUFF_dtableSizeof (int nsymbols)
void	HUFF_dtableBuild (HUFF_dtable *dtable, const unsigned char *sym_lens, int nsymbols)
void	HUFF_dtableBiase (HUFF_dtable *dtable, int biase)
void	HUFF_dtablePrint (const HUFF_dtable *dtable)
unsigned int	HUFF_decode (const HUFF_dtable *dtable, const unsigned int *src, unsigned int boff)
int	HUFF_decompressBytes (unsigned char *dst, int cnt, const void *src, unsigned int boff, const HUFF_dtable *dtable)
int	HUFF_decompressShorts (unsigned short int *dst, int cnt, const void *src, unsigned int boff, const HUFF_dtable *dtable)
int	HUFF_decompressLongs (unsigned int *dst, int cnt, const void *src, unsigned int boff, const HUFF_dtable *dtable)
void	HUFF_codesPrint (const HUFF_code *codes, int ncodes)

---

Detailed Description

Huffman Encode/Decode, interface file.

Author:

JJRussell - russell@slac.stanford.edu

CVS $Id

Warning:

In their current state, these routines are not fit for Flight use. They can be used to determine compression factors and, in general, study the properties of Huffman encoding/decoding. However, they malloc all over the place and involve recursive calling techniques, neither of is appropriate for Flight code.

---

Define Documentation

#define HUFF_ENCODE (  _out, _buffer, _togo, _codes, _sym   )

Value: { \ HUFF_code code = _codes[_sym]; \ int len = code.len; \ unsigned int pat = code.pat; \ BA_WRITE_R(_out, _buffer, _togo, pat, len); \ } Macro to encode one symbol using the specified code table. Parameters: _out  The output buffer _buffer  The temporary 32-bit staging buffer _togo  The number of bits available in the staging buffer _codes  The list of codes _sym  The symbol/index into the list of codes This would be much nicer as an inline, but 3 values are potentially modified, _out, _buffer and _togo, possibly making it inefficient since one of more of these values would have to be passed by address.

#define HUFF_N_WA (  _cnt   )     (HUFF_N_HEAP(_cnt) + HUFF_N_PARENTS(_cnt))

Gives the number of elements needed by the temporary wa array based of the number of elements in the frequency table. Returns: The number of elements needed by the temporary wa array Parameters: _cnt  The number of elements in the frequency table.

---