/************************************************************************
*
*	FILENAME		:	cdecoder.c
*
*	DESCRIPTION		:	Main program for speech channel decoding
*
************************************************************************
*
*	USAGE			:	cdecoder input_file output_file
*					(Executable_File Input1 Output1)
*
*	INPUT FILE(S)		:	
*
*		INPUT1	:	- Description : channel encoded serial stream 
*					- Format : binary file 16 bit-samples
*					  each 16 bit-sample represents one encoded bit
*					- 1 channel frame = 432 bits
*
*	OUTPUT FILE(S)	:	
*
*		OUTPUT1	:	- Description :  serial stream output file
*					- Format : binary file 16 bit-samples
*					  each 16 bit-sample represents one encoded bit
*					- 1 output frame includes 2 speech frames with BFI
*					   = 2 * (137 + 1) = 276 bits
*  
*	COMMENTS		:	- Values of channel encoded samples are 
*					either -127 or +127
*
************************************************************************
*
*	INCLUDED FILES	:	channel.h
*					stdlib.h
*
************************************************************************/

/* LIBRARIES USED */
#include <stdlib.h>
#include "channel.h"
		       
#ifndef TRUE
# define TRUE   (1==1)
# define FALSE  (1==0)
#endif

static short   first_pass = TRUE;


static Word16 Frame_stealing = 0;	/* Frame Stealing Flag :
					0 = Inactive, 
					!0 = First Frame in time-slot stolen
					This flag is set/reset by external world */
void csdec(Word16 audio[], Word16 Interleaved_coded_array[]) /* 480 432 */
{
	Word16  i;    
	Word16  bfi1 = 0;            
	Word16  bfi2 = 0;               /* Reset Bad Frame Indicator :
					0 = correct data, 1 = Corrupted frame */
	
	Word16  Reordered_array[286];   /* 2 frames vocoder + 8 + 4 */
	Word16  Coded_array[432];
        Word16  Reordered_bfi[138];
	
/* read Input_array (1 TETRA frame = 2 speech frames) from input file */

	if (Frame_stealing) 
	{
		Desinterleaving_Signalling(Interleaved_coded_array + 216,
			Coded_array + 216);
/* When Frame Stealing occurs, recopy first half slot : */
		for (i = 0; i < 216; i++) Coded_array[i] = 
			Interleaved_coded_array[i];
	}
	else
		Desinterleaving_Speech(Interleaved_coded_array, Coded_array);
        bfi1 = Frame_stealing;

/* "Interleaved_coded_array" has been desinterleaved and result put
in "Coded_array" */

/* Message in case the Frame was stolen */
/*
		if (bfi1) fprintf(stderr,"Frame Nb %ld was stolen\n",Loop_counter+1);
*/
/* Channel Decoding */
	bfi2 = Channel_Decoding(first_pass,Frame_stealing,
				Coded_array,Reordered_array);
	first_pass = FALSE;
	if ((Frame_stealing==0) && (bfi2==1)) bfi1=1;
/* Increment Loop counter */

/* Message in case the Bad Frame Indicator was set */
/*
		if (bfi2) fprintf(stderr,"Frame Nb %ld Bfi active\n\n",Loop_counter);
*/
/* writing  Reordered_array to output file */
        Reordered_bfi[0] = bfi1;  
        for (i = 1; i < 138; i++) Reordered_bfi[i] = Reordered_array[i-1];
        sdec(&audio[0], Reordered_bfi);

        Reordered_bfi[0] = bfi2;
        for (i = 1; i < 138; i++) Reordered_bfi[i] = Reordered_array[i+136];
        sdec(&audio[240], Reordered_bfi);
}