code.c File Reference

Implementation of full coding & decoding process. More...

#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include "utils.h"
#include "code.h"
#include "firecode.h"
#include "const_code.h"
#include "convolution.h"
#include "interleaving.h"

Functions
void	processFullEncodingGMatrix (byte G[FIRE_SOURCE_LENGTH][INTERLEAVING_LENGTH])
	Calculates the encoding matrix corresponding to all encoding steps (Fire code, Convolution and Interleaving)
void	processFullEncodingGSystematicMatrix (byte G[FIRE_SOURCE_LENGTH][INTERLEAVING_LENGTH], byte L[FIRE_SOURCE_LENGTH][FIRE_SOURCE_LENGTH], byte P[INTERLEAVING_LENGTH][INTERLEAVING_LENGTH])
	Calculates the encoding matrix corresponding to all encoding steps (Fire code, Convolution and Interleaving) in systematic form.
void	processFullEncodingHSystematicMatrix (byte G[FIRE_SOURCE_LENGTH][INTERLEAVING_LENGTH], byte H[INTERLEAVING_LENGTH-FIRE_SOURCE_LENGTH][INTERLEAVING_LENGTH])
	Calculates the systematic parity-check matrix H associated to the code matrix G in systematic form.
void	processFullEncodingHMatrix (byte G[FIRE_SOURCE_LENGTH][INTERLEAVING_LENGTH], byte H[INTERLEAVING_LENGTH-FIRE_SOURCE_LENGTH][INTERLEAVING_LENGTH])
	Calculates the real parity-check matrix H associated to the code matrix G. Thus, H×g=0 iff g is a codeword.
void	InvertMatrixL (byte L[FIRE_SOURCE_LENGTH][FIRE_SOURCE_LENGTH], byte L_I[FIRE_SOURCE_LENGTH][FIRE_SOURCE_LENGTH])
	Inverts the provided L matrix (peculiar case of Gauss elimination when L is a square matrix of size FIRE_SOURCE_LENGTH)
void	processFullDecoding (byte codeword[CODEWORD_LENGTH], byte sourceword[SOURCEWORD_LENGTH])
	Decodes a previously encoded message.
int	code_test ()
	Autotests the encoding and decoding on a random set of problem/solution.

---

Detailed Description

Implementation of full coding & decoding process.

Author:

Nicolas Paglieri & Olivier Benjamin

Version:

File Revision #17

Date:

01/12/2011

---

Function Documentation

int code_test

(

)

Autotests the encoding and decoding on a random set of problem/solution.

Returns:

0 if the test is successfull, non-zero otherwise

References BINPRODUCT_VECTOR_MATRIX, CODEWORD_LENGTH, DEBUG, DUMP_CHAR_VECTOR, processFullDecoding(), processFullEncodingGMatrix(), and SOURCEWORD_LENGTH.

Referenced by main().

void InvertMatrixL	(	byte	L[FIRE_SOURCE_LENGTH][FIRE_SOURCE_LENGTH],
		byte	L_I[FIRE_SOURCE_LENGTH][FIRE_SOURCE_LENGTH]
	)

Inverts the provided L matrix (peculiar case of Gauss elimination when L is a square matrix of size FIRE_SOURCE_LENGTH)

Parameters:

[in,out]	L	Invertible matrix, modified by the function to become Identity Matrix
[out]	L_I	inverse of the initial L matrix

References CHAR_IDENTITY, and FIRE_SOURCE_LENGTH.

void processFullDecoding	(	byte	codeword[CODEWORD_LENGTH],
		byte	sourceword[SOURCEWORD_LENGTH]
	)

Decodes a previously encoded message.

Parameters:

[in]	codeword	Data to decode
[out]	sourceword	Decoded data

References CONVOLUTION_SOURCE_LENGTH, FIRE_CODE_LENGTH, INTERLEAVING_LENGTH, reverseConvolution(), reverseFire(), and reverseInterleaving().

Referenced by code_test(), and main().

void processFullEncodingGMatrix

(

byte

G[FIRE_SOURCE_LENGTH][INTERLEAVING_LENGTH]

)

Calculates the encoding matrix corresponding to all encoding steps (Fire code, Convolution and Interleaving)

Parameters:

[out]

G

Full encoding matrix

References CONVOLUTION_CODE_LENGTH, CONVOLUTION_SOURCE_LENGTH, FIRE_CODE_LENGTH, FIRE_SOURCE_LENGTH, INTERLEAVING_LENGTH, processConvolutionGMatrix(), processFireGMatrix(), and processInterleavingGMatrix().

Referenced by attack_decipherSecretKey(), attack_test(), code_test(), main(), and matrices_generation_exportMatrices().

void processFullEncodingGSystematicMatrix	(	byte	G[FIRE_SOURCE_LENGTH][INTERLEAVING_LENGTH],
		byte	L[FIRE_SOURCE_LENGTH][FIRE_SOURCE_LENGTH],
		byte	P[INTERLEAVING_LENGTH][INTERLEAVING_LENGTH]
	)

Calculates the encoding matrix corresponding to all encoding steps (Fire code, Convolution and Interleaving) in systematic form.

Parameters:

[out]	G	Full encoding matrix in systematic form
[out]	L	Invertible matrix
[out]	P	Permutation matrix

References CHAR_IDENTITY, FIRE_SOURCE_LENGTH, and INTERLEAVING_LENGTH.

Referenced by processFullEncodingHMatrix().

void processFullEncodingHMatrix	(	byte	G[FIRE_SOURCE_LENGTH][INTERLEAVING_LENGTH],
		byte	H[INTERLEAVING_LENGTH-FIRE_SOURCE_LENGTH][INTERLEAVING_LENGTH]
	)

Calculates the real parity-check matrix H associated to the code matrix G. Thus, H×g=0 iff g is a codeword.

Parameters:

[in]	G	Full encoding matrix
[out]	H	Parity-check matrix

References BINPRODUCT_MATRIX_MATRIX, FIRE_SOURCE_LENGTH, INTERLEAVING_LENGTH, processFullEncodingGSystematicMatrix(), and processFullEncodingHSystematicMatrix().

Referenced by attack_decipherSecretKey(), and matrices_generation_exportMatrices().

void processFullEncodingHSystematicMatrix	(	byte	G[FIRE_SOURCE_LENGTH][INTERLEAVING_LENGTH],
		byte	H[INTERLEAVING_LENGTH-FIRE_SOURCE_LENGTH][INTERLEAVING_LENGTH]
	)

Calculates the systematic parity-check matrix H associated to the code matrix G in systematic form.

Parameters:

[in]	G	Full encoding matrix in systematic form
[out]	H	Parity-check matrix in systematic form

References FIRE_SOURCE_LENGTH.

Referenced by processFullEncodingHMatrix().