rrbb.c

//
//    This file is part of Dire Wolf, an amateur radio packet TNC.
//
//    Copyright (C) 2011, 2012, 2013  John Langner, WB2OSZ
//
//    This program is free software: you can redistribute it and/or modify
//    it under the terms of the GNU General Public License as published by
//    the Free Software Foundation, either version 2 of the License, or
//    (at your option) any later version.
//
//    This program is distributed in the hope that it will be useful,
//    but WITHOUT ANY WARRANTY; without even the implied warranty of
//    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
//    GNU General Public License for more details.
//
//    You should have received a copy of the GNU General Public License
//    along with this program.  If not, see <http://www.gnu.org/licenses/>.
//


/********************************************************************************
 *
 * File:	rrbb.c
 *
 * Purpose:	Raw Received Bit Buffer.
 *		Implementation of an array of bits used to hold data out of
 *		the demodulator before feeding it into the HLDC decoding.
 *
 * Version 1.0:	Let's try something new.
 *		Rather than storing a single bit from the demodulator
 *		output, let's store a value which we can try later
 *		comparing to threshold values besides 0.
 *
 *******************************************************************************/

#define RRBB_C

#include <stdio.h>
#include <assert.h>
#include <stdlib.h>
#include <string.h>

#include "direwolf.h"
#include "textcolor.h"
#include "ax25_pad.h"
#include "rrbb.h"




#define MAGIC1 0x12344321
#define MAGIC2 0x56788765

#ifndef SLICENDICE
static const unsigned int masks[SOI] = {
	0x00000001,
	0x00000002,
	0x00000004,
	0x00000008,
	0x00000010,
	0x00000020,
	0x00000040,
	0x00000080,
	0x00000100,
	0x00000200,
	0x00000400,
	0x00000800,
	0x00001000,
	0x00002000,
	0x00004000,
	0x00008000,
	0x00010000,
	0x00020000,
	0x00040000,
	0x00080000,
	0x00100000,
	0x00200000,
	0x00400000,
	0x00800000,
	0x01000000,
	0x02000000,
	0x04000000,
	0x08000000,
	0x10000000,
	0x20000000,
	0x40000000,
	0x80000000 };
#endif

static int new_count = 0;
static int delete_count = 0;


/***********************************************************************************
 *
 * Name:	rrbb_new	
 *
 * Purpose:	Allocate space for an array of samples.
 *
 * Inputs:	chan	- Radio channel from whence it came.
 *
 *		subchan	- Which demodulator of the channel.
 *
 *		is_scrambled - Is data scrambled? (true, false)
 *
 *		descram_state - State of data descrambler.
 *
 * Returns:	Handle to be used by other functions.
 *		
 * Description:	
 *
 ***********************************************************************************/

rrbb_t rrbb_new (int chan, int subchan, int is_scrambled, int descram_state)
{
	rrbb_t result;

	assert (SOI == 8 * sizeof(unsigned int));

	assert (chan >= 0 && chan < MAX_CHANS);
	assert (subchan >= 0 && subchan < MAX_SUBCHANS);


	result = malloc(sizeof(struct rrbb_s));

	result->magic1 = MAGIC1;
	result->chan = chan;
	result->subchan = subchan;
	result->magic2 = MAGIC2;

	new_count++;

	rrbb_clear (result, is_scrambled, descram_state);

	return (result);
}

/***********************************************************************************
 *
 * Name:	rrbb_clear	
 *
 * Purpose:	Clear by setting length to zero, etc.
 *
 * Inputs:	Handle for sample array.
 *
 ***********************************************************************************/

void rrbb_clear (rrbb_t b, int is_scrambled, int descram_state)
{
	assert (b != NULL);
	assert (b->magic1 == MAGIC1);
	assert (b->magic2 == MAGIC2);

	assert (is_scrambled == 0 || is_scrambled == 1);

	b->nextp = NULL;
	b->audio_level = 9999;
	b->len = 0;

	b->is_scrambled = is_scrambled;
	b->descram_state = descram_state;

}

/***********************************************************************************
 *
 * Name:	rrbb_append_bit	
 *
 * Purpose:	Append another bit to the end.
 *
 * Inputs:	Handle for sample array.
 *		Value for the sample.
 *
 ***********************************************************************************/

#if SLICENDICE
void rrbb2_append_bit (rrbb_t b, float val)
{
	assert (b != NULL);
	assert (b->magic1 == MAGIC1);
	assert (b->magic2 == MAGIC2);
	assert (b->len >= 0);

	if (b->len >= MAX_NUM_BITS) {
	  return;	/* Silently discard if full. */
	}

	b->data[b->len++] = (int)(val * 1000.);
}
#else
void rrbb_append_bit (rrbb_t b, int val)
{
	unsigned int di, mi;
	
	assert (b != NULL);
	assert (b->magic1 == MAGIC1);
	assert (b->magic2 == MAGIC2);

	if (b->len >= MAX_NUM_BITS) {
	  return;	/* Silently discard if full. */
	}

	di = b->len / SOI;
	mi = b->len % SOI;

	if (val) {
	  b->data[di] |= masks[mi];
	}
	else {
	  b->data[di] &= ~ masks[mi];
	}

	b->len++;
}
#endif

/***********************************************************************************
 *
 * Name:	rrbb_chop8	
 *
 * Purpose:	Remove 8 from the length.
 *
 * Inputs:	Handle for bit array.
 *		
 * Description:	Back up after appending the flag sequence.
 *
 ***********************************************************************************/

void rrbb_chop8 (rrbb_t b)
{
	
	assert (b != NULL);
	assert (b->magic1 == MAGIC1);
	assert (b->magic2 == MAGIC2);

	if (b->len >= 8) {
	  b->len -= 8;
	}
}

/***********************************************************************************
 *
 * Name:	rrbb_get_len	
 *
 * Purpose:	Get number of bits in the array.
 *
 * Inputs:	Handle for bit array.
 *		
 ***********************************************************************************/

int rrbb_get_len (rrbb_t b)
{
	assert (b != NULL);
	assert (b->magic1 == MAGIC1);
	assert (b->magic2 == MAGIC2);

	return (b->len);
}


/***********************************************************************************
 *
 * Name:	rrbb_set_slice_val	
 *
 * Purpose:	Set slicing value to determine whether a sample is bit 0 or 1.
 *
 * Inputs:	Handle for sample array.
 *		Slicing point value.
 *		
 ***********************************************************************************/

#if SLICENDICE

static int cmp_slice (slice_t *a, slice_t *b)
{
	return ( *a - *b );
}

void rrbb_set_slice_val (rrbb_t b, slice_t slice_val)
{
	slice_t sorted[MAX_NUM_BITS];
	int n, i;
	int sum, ave, median, izero;

	assert (b != NULL);
	assert (b->magic1 == MAGIC1);
	assert (b->magic2 == MAGIC2);

	b->slice_val = slice_val;

	memcpy (sorted, b->data, b->len * sizeof(slice_t));

	/* Typically takes 14 milliseconds on a reasonable PC. */
	qsort (sorted, (size_t)(b->len), sizeof(slice_t), cmp_slice);

	text_color_set (DW_COLOR_DEBUG);
	
	n = 0;
	dw_printf ("[%d..%d] ", n, n+9);
	for (i=n; i<=n+9; i++) dw_printf (" %d", sorted[i]);
	dw_printf ("\n");

	n = ( b->len / 2 ) - 10;
	dw_printf ("m[%d..%d] ", n, n+19);
	for (i=n; i<=n+19; i++) dw_printf (" %d", sorted[i]);
	dw_printf ("\n");

	n = b->len - 1 - 9;
	dw_printf ("[%d..%d] ", n, n+9);
	for (i=n; i<=n+9; i++) dw_printf (" %d", sorted[i]);
	dw_printf ("\n");

	sum = 0;
	for (i=0; i<b->len; i++) {
	  sum += sorted[i];
	}
	ave = sum / b->len;

	//b->slice_val = ave;
	//b->slice_val = sorted[b->len/2];
	 
	/* Find first one >= 0. */
	izero = -1;
	for (i=0; i<b->len; i++) {
	  if (sorted[i] >= 0) {
	    izero = i;
	    break;
	  }
	}

	if (izero >= 0) {
	  n = izero - 10;
	  dw_printf ("z[%d..%d] ", n, n+19);
	  for (i=n; i<=n+19; i++) dw_printf (" %d", sorted[i]);
	  dw_printf ("\n");

	b->slice_val = sorted[izero-1];

	}
	
	

}

#endif


/***********************************************************************************
 *
 * Name:	rrbb_get_bit	
 *
 * Purpose:	Get value of bit in specified position.
 *
 * Inputs:	Handle for sample array.
 *		Index into array.
 *		
 ***********************************************************************************/

#if SLICENDICE
int rrbb_get_bit (rrbb_t b, unsigned int ind)
{
	assert (b != NULL);
	assert (b->magic1 == MAGIC1);
	assert (b->magic2 == MAGIC2);
	assert (ind >= 0 && ind < b->len);

	if (b->data[ind] > b->slice_val) {
	  return 1;
	}
	else {
	  return 0;
	}
}
#else
int rrbb_get_bit (rrbb_t b, unsigned int ind)
{
	unsigned int di, mi;

	assert (b != NULL);
	assert (b->magic1 == MAGIC1);
	assert (b->magic2 == MAGIC2);

	assert (ind < b->len);

	di = ind / SOI;
	mi = ind % SOI;

	if (b->data[di] & masks[mi]) {
	  return 1;
	}
	else {
	  return 0;
	}
}
#endif


/***********************************************************************************
 *
 * Name:	rrbb_flip_bit	
 *
 * Purpose:	Complement the value of bit in specified position.
 *
 * Inputs:	Handle for bit array.
 *		Index into array.
 *		
 ***********************************************************************************/

//void rrbb_flip_bit (rrbb_t b, unsigned int ind)
//{
//	unsigned int di, mi;
//
//	assert (b != NULL);
//	assert (b->magic1 == MAGIC1);
//	assert (b->magic2 == MAGIC2);
//
//	assert (ind < b->len);
//
//	di = ind / SOI;
//	mi = ind % SOI;
//
//	b->data[di] ^= masks[mi];
//}

/***********************************************************************************
 *
 * Name:	rrbb_delete	
 *
 * Purpose:	Free the storage associated with the bit array.
 *
 * Inputs:	Handle for bit array.
 *		
 ***********************************************************************************/

void rrbb_delete (rrbb_t b)
{
	assert (b != NULL);
	assert (b->magic1 == MAGIC1);
	assert (b->magic2 == MAGIC2);

	b->magic1 = 0;
	b->magic2 = 0;
	
	free (b);

	delete_count++;
}


/***********************************************************************************
 *
 * Name:	rrbb_set_netxp	
 *
 * Purpose:	Set the nextp field, used to maintain a queue.
 *
 * Inputs:	b	Handle for bit array.
 *		np	New value for nextp.
 *		
 ***********************************************************************************/

void rrbb_set_nextp (rrbb_t b, rrbb_t np)
{
	assert (b != NULL);
	assert (b->magic1 == MAGIC1);
	assert (b->magic2 == MAGIC2);

	b->nextp = np;
}


/***********************************************************************************
 *
 * Name:	rrbb_get_netxp	
 *
 * Purpose:	Get value of nextp field.
 *
 * Inputs:	b	Handle for bit array.
 *		
 ***********************************************************************************/

rrbb_t rrbb_get_nextp (rrbb_t b)
{
	assert (b != NULL);
	assert (b->magic1 == MAGIC1);
	assert (b->magic2 == MAGIC2);

	return (b->nextp);
}

/***********************************************************************************
 *
 * Name:	rrbb_get_chan	
 *
 * Purpose:	Get channel from which bit buffer was received.
 *
 * Inputs:	b	Handle for bit array.
 *		
 ***********************************************************************************/

int rrbb_get_chan (rrbb_t b)
{
	assert (b != NULL);
	assert (b->magic1 == MAGIC1);
	assert (b->magic2 == MAGIC2);

	assert (b->chan >= 0 && b->chan < MAX_CHANS);

	return (b->chan);
}


/***********************************************************************************
 *
 * Name:	rrbb_get_subchan	
 *
 * Purpose:	Get subchannel from which bit buffer was received.
 *
 * Inputs:	b	Handle for bit array.
 *		
 ***********************************************************************************/

int rrbb_get_subchan (rrbb_t b)
{
	assert (b != NULL);
	assert (b->magic1 == MAGIC1);
	assert (b->magic2 == MAGIC2);

	assert (b->subchan >= 0 && b->subchan < MAX_SUBCHANS);

	return (b->subchan);
}


/***********************************************************************************
 *
 * Name:	rrbb_set_audio_level	
 *
 * Purpose:	Set audio level at time the frame was received.
 *
 * Inputs:	b	Handle for bit array.
 *		a	Audio level.
 *		
 ***********************************************************************************/

void rrbb_set_audio_level (rrbb_t b, int a)
{
	assert (b != NULL);
	assert (b->magic1 == MAGIC1);
	assert (b->magic2 == MAGIC2);

	b->audio_level = a;
}


/***********************************************************************************
 *
 * Name:	rrbb_get_audio_level	
 *
 * Purpose:	Get audio level at time the frame was received.
 *
 * Inputs:	b	Handle for bit array.
 *		
 ***********************************************************************************/

int rrbb_get_audio_level (rrbb_t b)
{
	assert (b != NULL);
	assert (b->magic1 == MAGIC1);
	assert (b->magic2 == MAGIC2);

	return (b->audio_level);
}


/***********************************************************************************
 *
 * Name:	rrbb_get_is_scrambled	
 *
 * Purpose:	Find out if using scrambled data.
 *
 * Inputs:	b	Handle for bit array.
 *
 * Returns:	True (for 9600 baud) or false (for slower AFSK).
 *		
 ***********************************************************************************/

int rrbb_get_is_scrambled (rrbb_t b)
{
	assert (b != NULL);
	assert (b->magic1 == MAGIC1);
	assert (b->magic2 == MAGIC2);

	return (b->is_scrambled);
}



/***********************************************************************************
 *
 * Name:	rrbb_get_descram_state	
 *
 * Purpose:	Get data descrambler state before first data bit of frame.
 *
 * Inputs:	b	Handle for bit array.
 *		
 ***********************************************************************************/

int rrbb_get_descram_state (rrbb_t b)
{
	assert (b != NULL);
	assert (b->magic1 == MAGIC1);
	assert (b->magic2 == MAGIC2);

	return (b->descram_state);
}


/* end rrbb.c */