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 
// 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.
//
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// accordance with the terms of the Agreement is a violation of copyright law.
//

#pragma once

#include <cassert>

#include <OnixS/CboeCFE/MarketData/Pitch/Export.h>
#include <OnixS/CboeCFE/MarketData/Pitch/Memory.h>
#include <OnixS/CboeCFE/MarketData/Pitch/Defines.h>
#include <OnixS/CboeCFE/MarketData/Pitch/String.h>
#include <OnixS/CboeCFE/MarketData/Pitch/Compiler.h>

namespace OnixS
{
    namespace CboeCFE
    {
        namespace MarketData
        {
            namespace Pitch
            {
                /// Value extractor helper
                template <class FieldValue>
                struct OrdinaryExtractor
                {
                    static FieldValue extract(const void* p) ONIXS_BATS_PITCH_NOTHROW
                    {
                        return unalignedCopy<FieldValue>(p);
                    }
                };

                template<class MantissaType, class ExponentType>
                struct OrdinaryExtractor<FixedPointDecimal<MantissaType, ExponentType> >
                {
                    static FixedPointDecimal<MantissaType, ExponentType> extract(const void* p) ONIXS_BATS_PITCH_NOTHROW
                    {
                        return FixedPointDecimal<MantissaType, ExponentType>(
                            unalignedCopy<typename FixedPointDecimal<MantissaType, ExponentType>::Mantissa>(p));
                    }
                };

                /// 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 <class Block, class BlockSize> 
                class BinaryFields
                {
                    /// Instance of block providing 
                    /// actual access to encoded data.
                    const Block& block() const
                    ONIXS_BATS_PITCH_NOTHROW
                    {
                        return *static_cast<const Block*>(this);
                    }

                protected:
                    /// Returns sub message.
                    template <class SubMessage>
                    const SubMessage submessage(BlockSize offset, BlockSize size) const
                    ONIXS_BATS_PITCH_NOTHROW
                    {
                        assert(block().binarySize() >= (offset + size));

                        return
                            SubMessage(advanceByBytes(block().binary(), offset), size);
                    }

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

                        return OrdinaryExtractor<FieldValue>::extract(advanceByBytes(block().binary(), offset));
                    }

                    /// Returns value of a field by its offset.
                    template <class FieldValue>
                    const FieldValue& ordinaryRef(BlockSize offset) const
                    ONIXS_BATS_PITCH_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_BATS_PITCH_NOTHROW
                    {
                        typedef typename Enumeration::Base Base;

                        typedef typename Enumeration::Enum Enum;

                        return static_cast<Enum>(ordinary<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_BATS_PITCH_NOTHROW
                    {
                        typedef Char Str[Size];

                        const Str& str = ordinaryRef<Str>(offset);
                        
                        return StrRef(str, strnlen(str, Size));
                    }
                };

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

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

                    /// Initializes blank instance referencing to nothing.
                    BinaryMessage()
                    ONIXS_BATS_PITCH_NOTHROW
                        : data_(ONIXS_BATS_PITCH_NULLPTR)
                        , size_(0)
                    {
                    }

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

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

                    /// Indicates whether instance refers to a valid message.
                    ONIXS_BATS_PITCH_EXPLICIT
                    operator bool() const
                    ONIXS_BATS_PITCH_NOTHROW
                    {
                        return (ONIXS_BATS_PITCH_NULLPTR != data_);
                    }

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

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

                    /// Re-initializes instance as a copy of the other one.
                    BinaryMessage&
                        operator =(
                            const BinaryMessage& other)
                        ONIXS_BATS_PITCH_NOTHROW
                    {
                        if (this == &other)
                            return *this;

                        data_ = other.data_;
                        size_ = other.size_;

                        return *this;
                    }

#if defined(ONIXS_BATS_PITCH_COMPILER_CXX_RVALUE_REFERENCES) && ONIXS_BATS_PITCH_COMPILER_CXX_RVALUE_REFERENCES

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

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

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

                        return *this;
                    }
#endif

                };

                ONIXS_CBOECFE_PITCH_API
                ONIXS_BATS_PITCH_COLDPATH
                ONIXS_BATS_PITCH_NORETURN
                void throwIncorrectSize(const std::string& messageName, MessageSize receivedSize, MessageSize expectedSize);

            }
        }
    }
}