NetworkMessage.h

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// Copyright Onix Solutions Limited [OnixS]. All rights reserved.
//
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// in the Agreement.
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#pragma once

#include <OnixS/CME/iLink3/messaging/SimpleOpenFramingHeader.h>
#include <OnixS/CME/iLink3/messaging/ExceptionHelpers.h>
#include <OnixS/CME/iLink3/messaging/SbeMessage.h>

ONIXS_ILINK3_MESSAGING_NAMESPACE_BEGIN

/// A network iLink3 message.

/// https://www.cmegroup.com/confluence/display/EPICSANDBOX/iLink+3+-+Simple+Binary+Encoding
ONIXS_ILINK3_LTWT_CLASS NetworkMessage
{
public:
    /// Constructs an empty instance.
    NetworkMessage() ONIXS_ILINK3_NOTHROW
        : data_(ONIXS_ILINK3_NULLPTR)
        , size_(0)
    {}

    /// Constructs NetworkMessage from a data block. Performs no checks.
    NetworkMessage(const void* data, ONIXS_ILINK3_UNUSED size_t size, SbeMessage::NoCheck) ONIXS_ILINK3_NOTHROW
        : data_(ONIXS_ILINK3_NULLPTR)
        , size_(0)
    {
        assert(size >= sizeof(SimpleOpenFramingHeader));

        const SimpleOpenFramingHeader* const header = reinterpret_cast<const SimpleOpenFramingHeader*>(data);

        assert(header->encoding() == CmeSbeEncodingType);
        assert(header->size() <= size);

#ifndef NDEBUG
        SbeMessage(toByteBlock(toMutable(data)) + sizeof(SimpleOpenFramingHeader), header->size() - sizeof(SimpleOpenFramingHeader));
#endif

        data_ = data;
        size_ = header->size();
    }

    /// Constructs NetworkMessage from a data block.
    NetworkMessage(const void* data, size_t size)
        : data_(ONIXS_ILINK3_NULLPTR)
        , size_(0)
    {
         if ONIXS_ILINK3_UNLIKELY(size < sizeof(SimpleOpenFramingHeader))
             throwBinaryBlockIsTooSmall(static_cast<MessageSize>(size), sizeof(SimpleOpenFramingHeader), "SimpleOpenFramingHeader");

        const SimpleOpenFramingHeader* const header = reinterpret_cast<const SimpleOpenFramingHeader*>(data);

        if ONIXS_ILINK3_UNLIKELY(header->encoding() != CmeSbeEncodingType)
            throwIncorrectEncoding(header->encoding(), data, static_cast<MessageSize>(size));

        if ONIXS_ILINK3_UNLIKELY(header->size() > size)
            throwNetPacketIsTooSmall(static_cast<MessageSize>(size), header->size());

        SbeMessage(toByteBlock(toMutable(data)) + sizeof(SimpleOpenFramingHeader), header->size() - sizeof(SimpleOpenFramingHeader));

        data_ = data;
        size_ = header->size();
    }

    ///
    const void* data() const ONIXS_ILINK3_NOTHROW
    {
        return data_;
    }

    ///
    MessageSize size() const ONIXS_ILINK3_NOTHROW
    {
        return size_;
    }

    /// Blank the instance.
    void clear() ONIXS_ILINK3_NOTHROW
    {
        *this = NetworkMessage();
        assert(!valid());
    }

    /// \return `true` if the instance refers to a valid packet, otherwise - `false`.

    bool valid() const ONIXS_ILINK3_NOTHROW
    {
        return (ONIXS_ILINK3_NULLPTR != data_);
    }

    /// Retrieves the underlying SBE message.

    SbeMessage message() const ONIXS_ILINK3_NOTHROW
    {
        assert(valid());

#ifndef NDEBUG
        SbeMessage(toByteBlock(toMutable(data_)) + sizeof(SimpleOpenFramingHeader), size_ - sizeof(SimpleOpenFramingHeader));
#endif

        return SbeMessage(
            toByteBlock(toMutable(data_)) + sizeof(SimpleOpenFramingHeader),
            size_ - sizeof(SimpleOpenFramingHeader), SbeMessage::NoCheck());
    }

private:
    const void* data_;
    MessageSize size_;
};

/// Serializes into a string.
ONIXS_ILINK3_EXPORTED
void toStr(std::string&, const NetworkMessage&);

inline
std::string toStr(const NetworkMessage& message)
{
    std::string res;
    toStr(res, message);
    return res;
}

ONIXS_ILINK3_MESSAGING_NAMESPACE_END