mirror of
https://github.com/portapack-mayhem/mayhem-firmware.git
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58 lines
1.6 KiB
C++
58 lines
1.6 KiB
C++
/*
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* Copyright (C) 2014 Jared Boone, ShareBrained Technology, Inc.
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*
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* This file is part of PortaPack.
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*
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* This program 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 2, or (at your option)
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* any later version.
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*
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* This program 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 this program; see the file COPYING. If not, write to
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* the Free Software Foundation, Inc., 51 Franklin Street,
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* Boston, MA 02110-1301, USA.
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*/
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#ifndef __ACCESS_CODE_CORRELATOR_H__
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#define __ACCESS_CODE_CORRELATOR_H__
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#include <cstdint>
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#include <cstddef>
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class AccessCodeCorrelator {
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public:
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void configure(
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const uint32_t new_code,
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const size_t new_code_length,
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const size_t new_maximum_hamming_distance
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);
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bool operator()(
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const uint_fast8_t in
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) {
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history = (history << 1) | (in & 1);
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const auto delta_bits = (history ^ code) & mask;
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//const size_t count = __builtin_popcountll(delta_bits);
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const size_t count = __builtin_popcountl(delta_bits);
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return (count <= maximum_hamming_distance);
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}
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private:
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uint32_t code { 0 };
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uint32_t mask { 0 };
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uint32_t history { 0 };
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size_t maximum_hamming_distance { 0 };
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static constexpr uint32_t mask_value(const size_t n) {
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return static_cast<uint32_t>((1ULL << n) - 1ULL);
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}
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};
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#endif/*__ACCESS_CODE_CORRELATOR_H__*/
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