Packet.h

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// Copyright Onix Solutions Limited [OnixS]. All rights reserved.
//
// This software owned by Onix Solutions Limited [OnixS] and is
// protected by copyright law and international copyright treaties.
//
// Access to and use of the software is governed by the terms of the applicable
// OnixS Software Services Agreement (the Agreement) and Customer end user license
// agreements granting a non-assignable, non-transferable and non-exclusive license
// to use the software for it's own data processing purposes under the terms defined
// in the Agreement.
//
// Except as otherwise granted within the terms of the Agreement, copying or
// reproduction of any part of this source code or associated reference material
// to any other location for further reproduction or redistribution, and any
// amendments to this copyright notice, are expressly prohibited.
//
// Any reproduction or redistribution for sale or hiring of the Software not in
// accordance with the terms of the Agreement is a violation of copyright law.
//
 
#pragma once
 
#include <cassert>
#include <stdexcept>
 
#include <OnixS/CME/MDH/Time.h>
#include <OnixS/CME/MDH/Integral.h>
 
#include <OnixS/CME/MDH/BinaryMessage.h>
#include <OnixS/CME/MDH/PacketTraits.h>
 
ONIXS_CMEMDH_NAMESPACE_BEGIN
ONIXS_CMEMDH_DATA_PACKING_BEGIN(1)
 
ONIXS_CMEMDH_LTWT_CLASS_DECL(NetFeed);
ONIXS_CMEMDH_LTWT_CLASS_DECL(Packet);

ONIXS_CMEMDH_EXPORTED
void throwBadMessage(const Packet* packet);

class ONIXS_CMEMDH_LTWT BinaryMessageIterator
{
public:
    // Identifies iterator category.
    typedef std::forward_iterator_tag iterator_category;

    typedef ptrdiff_t difference_type;

    typedef const BinaryMessage value_type;

    typedef value_type* pointer;

    typedef value_type& reference;

    BinaryMessageIterator(const void* dataBegin, const void* dataEnd, const Packet* packet)
        : header_(static_cast<const Header*>(dataBegin))
        , end_(dataEnd)
        , packet_(packet)
    {
        assert(dataBegin <= dataEnd);
 
        validate();
    }

    BinaryMessage message() const
    {
        assert(header_ != end_);
 
        return BinaryMessage(header_ + 1, header_->messageSize - sizeof(Header));
    }

    BinaryMessage operator*() const
    {
        return message();
    }

    BinaryMessageIterator& operator++()
    {
        header_ = advanceByBytes(header_, header_->messageSize);
 
        validate();
 
        return *this;
    }

    bool operator==(const BinaryMessageIterator& other) const
    {
        return header_ == other.header_;
    }

    bool operator!=(const BinaryMessageIterator& other) const
    {
        return header_ != other.header_;
    }
 
private:
    // Messages are prefixed with message header.
    struct Header
    {
        MessageSize messageSize;
    };
 
    const Header* header_;
    const void* end_;
    const Packet* packet_;
 
    void validate() const
    {
        const size_t availableSize = byteDistance(end_, header_);
 
        if ONIXS_CMEMDH_LIKELY(availableSize != 0)
            if ONIXS_CMEMDH_UNLIKELY(availableSize < sizeof(Header) || availableSize < header_->messageSize)
                throwBadMessage(packet_);
    }
};

class ONIXS_CMEMDH_LTWT BinaryMessages
{
public:
    BinaryMessages(const void* messagesBegin, const void* messagesEnd, const Packet* packet = ONIXS_CMEMDH_NULLPTR)
        : begin_(messagesBegin)
        , end_(messagesEnd)
        , packet_(packet)
    {
    }

    BinaryMessageIterator begin() const
    {
        return BinaryMessageIterator(begin_, end_, packet_);
    }

    BinaryMessageIterator end() const
    {
        return BinaryMessageIterator(end_, end_, packet_);
    }
 
private:
    // Memory block keeping messages.
    const void* begin_;
    const void* end_;
    const Packet* packet_;
};

ONIXS_CMEMDH_EXPORTED
void throwBadPacket(PacketSize packetSize, PacketSize minimalSize, const void* data);

struct ONIXS_CMEMDH_LTWT NoVerify
{};

class ONIXS_CMEMDH_LTWT Packet
{
public:
    Packet()
        : header_(ONIXS_CMEMDH_NULLPTR)
        , size_(0)
    {
    }

    Packet(const void* data, PacketSize size)
        : header_(static_cast<const Header*>(data))
        , size_(size)
    {
        assert(ONIXS_CMEMDH_NULLPTR != header_);
        assert(0 != size_);
 
        const PacketSize headerSize = sizeof(Header);
 
        if ONIXS_CMEMDH_UNLIKELY(size < headerSize)
            throwBadPacket(size, headerSize, data);
    }

    Packet(const void* data, PacketSize size, const NoVerify&)
        : header_(static_cast<const Header*>(data))
        , size_(size)
    {
    }

    Packet(const Packet& other)
        : header_(other.header_)
        , size_(other.size_)
    {
    }

    ~Packet() {}

    operator bool() const
    {
        return 0 != size_;
    }

    const void* data() const
    {
        assert(ONIXS_CMEMDH_NULLPTR != header_);
 
        return static_cast<const void*>(header_);
    }

    PacketSize size() const
    {
        return size_;
    }

    SequenceNumber seqNumber() const
    {
        assert(ONIXS_CMEMDH_NULLPTR != header_);
 
        return header_->seqNumber;
    }

    const Timestamp& sendingTime() const
    {
        assert(ONIXS_CMEMDH_NULLPTR != header_);
 
        return header_->sendingTime;
    }

    BinaryMessages messages() const
    {
        assert(ONIXS_CMEMDH_NULLPTR != header_);
 
        return BinaryMessages(header_ + 1, advanceByBytes(header_, size_), this);
    }

    void reset()
    {
        header_ = ONIXS_CMEMDH_NULLPTR;
        size_ = 0;
    }

    void reset(const void* data, PacketSize size)
    {
        const PacketSize headerSize = sizeof(Header);
 
        if ONIXS_CMEMDH_UNLIKELY(!data || size < headerSize)
            throwBadPacket(size, headerSize, data);
 
        header_ = static_cast<const Header*>(data);
        size_ = size;
    }

    void reset(const void* data, PacketSize size, const NoVerify&)
    {
        header_ = static_cast<const Header*>(data);
 
        size_ = size;
    }

    Packet& operator=(const Packet& other)
    {
        header_ = other.header_;
        size_ = other.size_;
 
        return *this;
    }
 
private:
    struct Header
    {
        SequenceNumber seqNumber;
        Timestamp sendingTime;
    };
 
    const Header* header_;
    PacketSize size_;
};
 
ONIXS_CMEMDH_EXPORTED
void toStr(std::string& str, const Packet& packet);
 
inline std::string toStr(const Packet& packet)
{
    std::string str;
    toStr(str, packet);
    return str;
}
 
class ONIXS_CMEMDH_LTWT NetPacket : public Packet
{
public:
    NetPacket()
        : source_(ONIXS_CMEMDH_NULLPTR)
    {
    }

    NetPacket(const void* data, PacketSize size)
        : Packet(data, size)
        , source_(ONIXS_CMEMDH_NULLPTR)
    {
    }

    NetPacket(const NetPacket& other)
        : Packet(static_cast<const Packet&>(other))
        , receiveTime_(other.receiveTime_)
        , source_(other.source_)
    {
    }

    ~NetPacket() {}

    const NetFeed& source() const
    {
        assert(ONIXS_CMEMDH_NULLPTR != source_);
 
        return *source_;
    }

    void source(const NetFeed& source)
    {
        source_ = &source;
    }

    const Timestamp& receiveTime() const
    {
        return receiveTime_;
    }

    void receiveTime(const Timestamp& receiveTime)
    {
        receiveTime_ = receiveTime;
    }

    void reset()
    {
        Packet::reset();
 
        receiveTime_ = Timestamp();
 
        source_ = ONIXS_CMEMDH_NULLPTR;
    }

    NetPacket& operator=(const NetPacket& other)
    {
        static_cast<Packet&>(*this) = static_cast<const Packet&>(other);
 
        receiveTime_ = other.receiveTime_;
 
        source_ = other.source_;
 
        return *this;
    }
 
private:
    Timestamp receiveTime_;
    const NetFeed* source_;
};

typedef NetPacket PacketArgs;
 
ONIXS_CMEMDH_DATA_PACKING_END
ONIXS_CMEMDH_NAMESPACE_END