mirror of
https://github.com/gnss-sdr/gnss-sdr
synced 2024-09-20 19:29:48 +00:00
85 lines
2.8 KiB
C++
85 lines
2.8 KiB
C++
/*!
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* \file unpack_byte_2bit_samples.cc
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*
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* \brief Unpacks byte samples to NSR 2 bits samples
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* \author Javier Arribas jarribas (at) cttc.es
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* -------------------------------------------------------------------------
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*
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* Copyright (C) 2010-2018 (see AUTHORS file for a list of contributors)
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*
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* GNSS-SDR is a software defined Global Navigation
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* Satellite Systems receiver
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*
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* This file is part of GNSS-SDR.
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*
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* GNSS-SDR is free software: you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation, either version 3 of the License, or
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* (at your option) any later version.
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*
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* GNSS-SDR is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with GNSS-SDR. If not, see <https://www.gnu.org/licenses/>.
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*
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* -------------------------------------------------------------------------
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*/
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#include "unpack_byte_2bit_samples.h"
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#include <gnuradio/io_signature.h>
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struct byte_2bit_struct
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{
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signed two_bit_sample : 2; // <- 2 bits wide only
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};
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unpack_byte_2bit_samples_sptr make_unpack_byte_2bit_samples()
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{
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return unpack_byte_2bit_samples_sptr(new unpack_byte_2bit_samples());
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}
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unpack_byte_2bit_samples::unpack_byte_2bit_samples() : sync_interpolator("unpack_byte_2bit_samples",
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gr::io_signature::make(1, 1, sizeof(signed char)),
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gr::io_signature::make(1, 1, sizeof(float)),
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4)
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{
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}
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unpack_byte_2bit_samples::~unpack_byte_2bit_samples() = default;
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int unpack_byte_2bit_samples::work(int noutput_items,
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gr_vector_const_void_star &input_items,
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gr_vector_void_star &output_items)
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{
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const signed char *in = reinterpret_cast<const signed char *>(input_items[0]);
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float *out = reinterpret_cast<float *>(output_items[0]);
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byte_2bit_struct sample;
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int n = 0;
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for (int i = 0; i < noutput_items / 4; i++)
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{
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// Read packed input sample (1 byte = 4 samples)
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signed char c = in[i];
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sample.two_bit_sample = c & 3;
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out[n++] = static_cast<float>(sample.two_bit_sample);
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sample.two_bit_sample = (c >> 2) & 3;
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out[n++] = static_cast<float>(sample.two_bit_sample);
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sample.two_bit_sample = (c >> 4) & 3;
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out[n++] = static_cast<float>(sample.two_bit_sample);
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sample.two_bit_sample = (c >> 6) & 3;
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out[n++] = static_cast<float>(sample.two_bit_sample);
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}
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return noutput_items;
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}
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