BinaryMessage.h

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// Copyright Onix Solutions Limited [OnixS]. All rights reserved.
//
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// protected by copyright law and international copyright treaties.
//
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// agreements granting a non-assignable, non-transferable and non-exclusive license 
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// in the Agreement.
//
// Except as otherwise granted within the terms of the Agreement, copying or 
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// amendments to this copyright notice, are expressly prohibited.
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//
#pragma once

#include <cassert>

#include <OnixS/eSpeed/MarketData/Itch/Compiler.h>
#include <OnixS/eSpeed/MarketData/Itch/Defines.h>
#include <OnixS/eSpeed/MarketData/Itch/String.h>

ONIXS_ESPEED_ITCH_NAMESPACE_BEGIN


/// Exposes base services to access fields stored in
/// little Endian block of memory. Class represents an
/// abstraction, instance construction available through
/// descendants implementing actual access to encoded data.

template <template<class> class Block, class FieldAccessor>
class BinaryFields
{
    typedef MessageSize BlockSize;

    /// Instance of block providing
    /// actual access to encoded data.
    const Block<FieldAccessor>& block() const
    ONIXS_ESPEED_ITCH_NOTHROW
    {
        return *static_cast<const Block<FieldAccessor>*>(this);
    }

protected:
    /// Returns value of a field by its offset.
    template <class FieldValue>
    FieldValue ordinary(BlockSize offset) const
    ONIXS_ESPEED_ITCH_NOTHROW
    {
        assert(block().binarySize() >= (offset + sizeof(FieldValue)));

        return FieldAccessor::get(FieldValue(), advanceByBytes(block().binary(), offset));
    }

    /// Returns value of a field by its offset.
    template <class FieldValue>
    const FieldValue& ordinaryRef(BlockSize offset) const
    ONIXS_ESPEED_ITCH_NOTHROW
    {
        assert(block().binarySize() >= (offset + sizeof(FieldValue)));

        return *static_cast <const FieldValue*>(advanceByBytes(block().binary(), offset));
    }

    /// Returns value of a field by its offset.
    ///
    /// Given function serves as specialization of
    /// general case for fields of enumeration type.
    template <class Enumeration>
    typename Enumeration::Enum enumeration(BlockSize offset) const
    ONIXS_ESPEED_ITCH_NOTHROW
    {
        typedef typename Enumeration::Base Base;

        typedef typename Enumeration::Enum Enum;

        return static_cast<Enum>(ordinaryRef<Base>(offset));
    }

    /// Provides access to string field by its offset.
    ///
    /// Given function serves as specialization
    /// of general case for fields of string type.
    template <BlockSize Size>
    StrRef fixedStr(BlockSize offset) const
    ONIXS_ESPEED_ITCH_NOTHROW
    {
        typedef Char Str[Size];

        assert(block().binarySize() >= (offset + Size));

        return
            StrRef(ordinaryRef<Str>(offset), strnlen(ordinaryRef<Str>(offset), Size));
    }
};

/// Encapsulates services for manipulating encoded messages.
template <class Accessor>
class BinaryMessage
    : public BinaryFields<BinaryMessage, Accessor>
{
    const void* data_;
    MessageSize size_;

public:
    /// Length of message binary data.
    typedef MessageSize BinarySize;

    /// Initializes instance over given memory block.
    BinaryMessage(
        const void* data,
        MessageSize size)
    ONIXS_ESPEED_ITCH_NOTHROW
        : data_(data)
        , size_(size)
    {
    }

    /// Initializes instance as copy of the other one.
    ONIXS_ESPEED_ITCH_CONSTEXPR
    BinaryMessage(
        const BinaryMessage& other)
    ONIXS_ESPEED_ITCH_NOTHROW
        : data_(other.data_)
        , size_(other.size_)
    {
    }

    /// Message content.
    const void* binary() const
    ONIXS_ESPEED_ITCH_NOTHROW
    {
        return data_;
    }

    /// Size of message.
    MessageSize binarySize() const
    ONIXS_ESPEED_ITCH_NOTHROW
    {
        return size_;
    }

    /// Re-initializes instance as a copy of the other one.
    BinaryMessage&
        operator =(
            const BinaryMessage& other)
    ONIXS_ESPEED_ITCH_NOTHROW
    {
        data_ = other.data_;
        size_ = other.size_;

        return *this;
    }

#if defined(ONIXS_ESPEED_ITCH_COMPILER_CXX_RVALUE_REFERENCES) && ONIXS_ESPEED_ITCH_COMPILER_CXX_RVALUE_REFERENCES

    BinaryMessage(BinaryMessage&& other)
    ONIXS_ESPEED_ITCH_NOTHROW
        : data_(std::move(other.data_))
        , size_(std::move(other.size_))
    {
    }

    BinaryMessage&
        operator=(
                BinaryMessage&& other)
    ONIXS_ESPEED_ITCH_NOTHROW
    {
        if (this == &other)
            return *this;

        data_ = std::move(other.data_);
        size_ = std::move(other.size_);

        return *this;
    }
    
#endif
};

ONIXS_ESPEED_ITCH_API
void throwIncorrectSize(const std::string& messageName, MessageSize receivedSize, MessageSize expectedSize);


ONIXS_ESPEED_ITCH_NAMESPACE_END