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88 lines
4.0 KiB
88 lines
4.0 KiB
/**
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* Digital Voice Modem - Host Software
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* GPLv2 Open Source. Use is subject to license terms.
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* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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*
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* @package DVM / Host Software
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*
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*/
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//
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// Based on code from the MMDVMHost project. (https://github.com/g4klx/MMDVMHost)
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// Licensed under the GPLv2 License (https://opensource.org/licenses/GPL-2.0)
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//
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/*
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* Copyright (C) 2016,2018 by Jonathan Naylor, G4KLX
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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; version 2 of the License.
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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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#if !defined(__P25_EDAC__TRELLIS_H__)
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#define __P25_EDAC__TRELLIS_H__
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#include "Defines.h"
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namespace p25
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{
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namespace edac
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{
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// ---------------------------------------------------------------------------
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// Class Declaration
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// Implements 1/2 rate and 3/4 rate Trellis for P25.
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// ---------------------------------------------------------------------------
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class HOST_SW_API Trellis {
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public:
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/// <summary>Initializes a new instance of the Trellis class.</summary>
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Trellis();
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/// <summary>Finalizes a instance of the Trellis class.</summary>
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~Trellis();
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/// <summary>Decodes 3/4 rate Trellis.</summary>
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bool decode34(const uint8_t* data, uint8_t* payload);
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/// <summary>Encodes 3/4 rate Trellis.</summary>
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void encode34(const uint8_t* payload, uint8_t* data);
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/// <summary>Decodes 1/2 rate Trellis.</summary>
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bool decode12(const uint8_t* data, uint8_t* payload);
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/// <summary>Encodes 1/2 rate Trellis.</summary>
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void encode12(const uint8_t* payload, uint8_t* data);
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private:
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/// <summary>Helper to deinterleave the input symbols into dibits.</summary>
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void deinterleave(const uint8_t* in, int8_t* dibits) const;
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/// <summary>Helper to interleave the input dibits into symbols.</summary>
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void interleave(const int8_t* dibits, uint8_t* out) const;
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/// <summary>Helper to map dibits to C4FM constellation points.</summary>
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void dibitsToPoints(const int8_t* dibits, uint8_t* points) const;
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/// <summary>Helper to map C4FM constellation points to dibits.</summary>
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void pointsToDibits(const uint8_t* points, int8_t* dibits) const;
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/// <summary>Helper to convert a byte payload into tribits.</summary>
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void bitsToTribits(const uint8_t* payload, uint8_t* tribits) const;
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/// <summary>Helper to convert a byte payload into dibits.</summary>
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void bitsToDibits(const uint8_t* payload, uint8_t* dibits) const;
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/// <summary>Helper to convert tribits into a byte payload.</summary>
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void tribitsToBits(const uint8_t* tribits, uint8_t* payload) const;
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/// <summary>Helper to convert dibits into a byte payload.</summary>
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void dibitsToBits(const uint8_t* dibits, uint8_t* payload) const;
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/// <summary>Helper to fix errors in Trellis coding.</summary>
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bool fixCode34(uint8_t* points, uint32_t failPos, uint8_t* payload) const;
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/// <summary>Helper to detect errors in Trellis coding.</summary>
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uint32_t checkCode34(const uint8_t* points, uint8_t* tribits) const;
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/// <summary>Helper to fix errors in Trellis coding.</summary>
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bool fixCode12(uint8_t* points, uint32_t failPos, uint8_t* payload) const;
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/// <summary>Helper to detect errors in Trellis coding.</summary>
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uint32_t checkCode12(const uint8_t* points, uint8_t* dibits) const;
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};
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} // namespace edac
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} // namespace p25
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#endif // __P25_EDAC__TRELLIS_H__
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