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/* -*- c++ -*- */
/*
* Copyright 2007,2010,2011,2013 Free Software Foundation, Inc.
*
* This file is part of GNU Radio
*
* SPDX-License-Identifier: GPL-3.0-or-later
*
*/
#ifdef HAVE_CONFIG_H
#include "config.h"
#endif
#include "cvsd_decode_bs_impl.h"
#include <gnuradio/io_signature.h>
#include <limits.h>
namespace gr {
namespace vocoder {
cvsd_decode_bs::sptr cvsd_decode_bs::make(short min_step,
short max_step,
double step_decay,
double accum_decay,
int K,
int J,
short pos_accum_max,
short neg_accum_max)
{
return gnuradio::get_initial_sptr(new cvsd_decode_bs_impl(
min_step, max_step, step_decay, accum_decay, K, J, pos_accum_max, neg_accum_max));
}
cvsd_decode_bs_impl::cvsd_decode_bs_impl(short min_step,
short max_step,
double step_decay,
double accum_decay,
int K,
int J,
short pos_accum_max,
short neg_accum_max)
: sync_interpolator("vocoder_cvsd_decode_bs",
io_signature::make(1, 1, sizeof(unsigned char)),
io_signature::make(1, 1, sizeof(short)),
8),
d_min_step(min_step),
d_max_step(max_step),
d_step_decay(step_decay),
d_accum_decay(accum_decay),
d_K(K),
d_J(J),
d_pos_accum_max(pos_accum_max),
d_neg_accum_max(neg_accum_max),
d_accum(0),
d_loop_counter(1),
d_runner(0),
d_runner_mask(0),
d_stepsize(min_step)
{
if (d_K > 32)
throw std::runtime_error("cvsd_decode_bs_impl: K must be <= 32");
if (d_J > d_K)
throw std::runtime_error("cvsd_decode_bs_impl: J must be <= K");
}
cvsd_decode_bs_impl::~cvsd_decode_bs_impl()
{
// nothing else required in this example
}
unsigned char cvsd_decode_bs_impl::cvsd_bitwise_sum(unsigned int input)
{
unsigned int temp = input;
unsigned char bits = 0;
while (temp) {
temp = temp & (temp - 1);
bits++;
}
return bits;
}
int cvsd_decode_bs_impl::cvsd_round(double input)
{
double temp;
temp = input + 0.5;
temp = floor(temp);
return (int)temp;
}
unsigned int cvsd_decode_bs_impl::cvsd_pow(short radix, short power)
{
double d_radix = (double)radix;
int i_power = (int)power;
double output;
output = pow(d_radix, i_power);
return ((unsigned int)cvsd_round(output));
}
int cvsd_decode_bs_impl::work(int noutput_items,
gr_vector_const_void_star& input_items,
gr_vector_void_star& output_items)
{
const unsigned char* in = (const unsigned char*)input_items[0];
short* out = (short*)output_items[0];
int i = 0;
short output_short = 0; // 2 bytes 0 .. 65,535
unsigned char bit_count = 0; // 1 byte, 0 .. 255
unsigned int mask = 0; // 4 bytes, 0 .. 4,294,967,295
unsigned char input_byte = 0; // 1 bytes
unsigned char input_bit = 0; // 1 byte, 0 .. 255
// Loop through each input data point
for (i = 0; i < noutput_items / 8.0; i++) {
input_byte = in[i];
// Initialize bit counter
bit_count = 0;
while (bit_count < 8) {
// Compute the Appropriate Mask
mask = cvsd_pow(2, 7 - bit_count);
// Pull off the corresponding bit
input_bit = input_byte & mask;
// Update the bit counter
bit_count++;
// Update runner with the next input bit
// Runner is a shift-register; shift left, add on newest output bit
d_runner = (d_runner << 1) | ((unsigned int)input_bit);
// Run this only if you have >= J bits in your shift register
if (d_loop_counter >= d_J) {
// Update Step Size
d_runner_mask = (cvsd_pow(2, d_J) - 1);
if ((cvsd_bitwise_sum(d_runner & d_runner_mask) >= d_J) ||
(cvsd_bitwise_sum((~d_runner) & d_runner_mask) >= d_J)) {
// Runs of 1s and 0s
d_stepsize = std::min((short)(d_stepsize + d_min_step), d_max_step);
} else {
// No runs of 1s and 0s
d_stepsize = std::max((short)cvsd_round(d_stepsize * d_step_decay),
d_min_step);
}
}
// Update Accum (i.e. the reference value)
if (input_bit) {
d_accum = d_accum + d_stepsize;
} else {
d_accum = d_accum - d_stepsize;
}
// Multiply by Accum_Decay
d_accum = (cvsd_round(d_accum * d_accum_decay));
// Check for overflow
if (d_accum >= ((int)d_pos_accum_max)) {
d_accum = (int)d_pos_accum_max;
} else if (d_accum <= ((int)d_neg_accum_max)) {
d_accum = (int)d_neg_accum_max;
}
// Find the output short to write to the file
output_short = ((short)d_accum);
if (d_loop_counter <= d_K) {
d_loop_counter++;
}
*(out++) = output_short;
} // while ()
} // for()
return noutput_items;
}
} /* namespace vocoder */
} /* namespace gr */
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