ConversationPart.hpp

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/*
 * This file is part of the DUDS project. It is subject to the BSD-style
 * license terms in the LICENSE file found in the top-level directory of this
 * distribution and at https://github.com/jjackowski/duds/blob/master/LICENSE.
 * No part of DUDS, including this file, may be copied, modified, propagated,
 * or distributed except according to the terms contained in the LICENSE file.
 *
 * Copyright (C) 2017  Jeff Jackowski
 */
#ifndef CONVERSATIONPART_HPP
#define CONVERSATIONPART_HPP

#include <cstdint>
#include <duds/general/BitFlags.hpp>
#include <boost/exception/info.hpp>

namespace duds { namespace hardware { namespace interface {

struct ConversationError : virtual std::exception, virtual boost::exception { };

class ConversationPart {
public:
    typedef duds::general::BitFlags<struct ConversationPartFlags, std::uint16_t>
        Flags;
    static constexpr Flags MpfInput = Flags::Bit(0);
    static constexpr Flags MpfExtract = Flags::Bit(1);
    static constexpr Flags MpfVarlen = Flags::Bit(2);
    static constexpr Flags MpfBigendian = Flags::Bit(3);
    static constexpr Flags MpfBreak = Flags::Bit(4);
private:
    Flags mpf;  // message part flags, but message was changed to conversation
protected:
    std::int16_t val16;
    ConversationPart(Flags f) : mpf(f) { }
    ConversationPart(Flags f, std::int16_t v) : mpf(f), val16(v) { }
public:
    ConversationPart(const ConversationPart &) = default;
    virtual ~ConversationPart();
    Flags flags() const {
        return mpf;
    }
    bool input() const {
        return mpf & MpfInput;
    }
    bool output() const {
        return !(mpf & MpfInput);
    }
    bool extract() const {
        return mpf & MpfExtract;
    }
    ConversationPart &extract(bool ex) {
        mpf.setTo(MpfExtract, ex);
        return *this;
    }
    bool varyingLength() const {
        return (mpf & MpfVarlen) && (mpf & MpfInput);
    }
    bool bigEndian() const {
        return mpf & MpfBigendian;
    }
    ConversationPart &bigEndian(bool big) {
        mpf.setTo(MpfBigendian, big);
        return *this;
    }
    bool littleEndian() const {
        return !(mpf & MpfBigendian);
    }
    ConversationPart &littleEndian(bool little) {
        mpf.setTo(MpfBigendian, !little);
        return *this;
    }
    ConversationPart &breakBefore() {
        mpf |= MpfBreak;
        return *this;
    }
    virtual char *start() const = 0;
    virtual std::size_t length() const = 0;
};

} } }

#endif        //  #ifndef CONVERSATIONPART_HPP