diff options
| author | Tom Rondeau <trondeau@vt.edu> | 2013-01-06 18:49:07 -0500 |
|---|---|---|
| committer | Tom Rondeau <trondeau@vt.edu> | 2013-01-06 21:54:13 -0500 |
| commit | 7bee8dfbe234c8caf0c1033ebd71040355fcb838 (patch) | |
| tree | 7f1a477681fc1e7dd37567b4c19c307e44cf89e0 /gr-vocoder/lib/cvsd_decode_bs_impl.cc | |
| parent | 9293a3863ae6fb1287e42185e4a7d8073375b65b (diff) | |
vocoder: converting to private impl format.
Diffstat (limited to 'gr-vocoder/lib/cvsd_decode_bs_impl.cc')
| -rw-r--r-- | gr-vocoder/lib/cvsd_decode_bs_impl.cc | 192 |
1 files changed, 192 insertions, 0 deletions
diff --git a/gr-vocoder/lib/cvsd_decode_bs_impl.cc b/gr-vocoder/lib/cvsd_decode_bs_impl.cc new file mode 100644 index 0000000000..e7f284adda --- /dev/null +++ b/gr-vocoder/lib/cvsd_decode_bs_impl.cc @@ -0,0 +1,192 @@ +/* -*- c++ -*- */ +/* + * Copyright 2007,2010,2011,2013 Free Software Foundation, Inc. + * + * This file is part of GNU Radio + * + * GNU Radio 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 3, or (at your option) + * any later version. + * + * GNU Radio 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 GNU Radio; see the file COPYING. If not, write to + * the Free Software Foundation, Inc., 51 Franklin Street, + * Boston, MA 02110-1301, USA. + */ + +#ifdef HAVE_CONFIG_H +#include "config.h" +#endif + +#include "cvsd_decode_bs_impl.h" +#include <gr_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) + : gr_sync_interpolator("vocoder_cvsd_decode_bs", + gr_make_io_signature(1, 1, sizeof(unsigned char)), + gr_make_io_signature(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\n"); + + if(d_J > d_K) + throw std::runtime_error("cvsd_decode_bs_impl: J must be <= K\n"); + } + + 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]; + // Initiliaze 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 */ |