MutableBinaryMessage.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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#pragma once

#include <OnixS/SgxTitan/Trading/OUCH/Bootstrap.h>
#include <OnixS/SgxTitan/Trading/OUCH/BinaryMessage.h>

ONIXS_SGXTITAN_OUCH_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 MutableBinaryFields : public BinaryFields<Block, FieldAccessor>
{
    typedef MessageSize BlockSize;

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

protected:
    /// Assigns value of a field by its offset.
    template<class FieldValue>
    void setOrdinary(BlockSize offset, FieldValue value)
    ONIXS_SGX_OUCH_NOTHROW
    {
        assert(block().binarySize() >= (offset + sizeof(FieldValue)));

        void* const fieldPos = advanceByBytes(block().binary(), offset);

        FieldAccessor::set(fieldPos, value);
    }

    /// Assigns value of a field by its offset.
    template <class FieldValue>
    void setOrdinaryRef(BlockSize offset, FieldValue value)
    ONIXS_SGX_OUCH_NOTHROW
    {
        assert(block().binarySize() >= (offset + sizeof(FieldValue)));
        assert(sizeof(FieldValue) == 1);

        *static_cast <FieldValue*>(advanceByBytes(block().binary(), offset)) = value;
    }

    /// Returns value of a field by its offset.
    template<class Enumeration>
    void setEnumeration(BlockSize offset, typename Enumeration::Enum value)
    ONIXS_SGX_OUCH_NOTHROW
    {
        typedef typename Enumeration::Base Base;
        setOrdinaryRef<Base>(offset, static_cast<Base>(value));
    }

    template<BlockSize Size>
    void setFixedStr(BlockSize offset, const StrRef& value)
    ONIXS_SGX_OUCH_NOTHROW
    {
        assert(block().binarySize() >= (offset + Size));

        void* const fieldPos = advanceByBytes(block().binary(), offset);

        const BlockSize size = std::min(Size, static_cast<BlockSize>(value.size()));

        memcpy(fieldPos, value.items(), size);
        memset(advanceByBytes(fieldPos, size), ' ', Size - size);
    }
};

/// Encapsulates services for manipulating little endian encoded messages.
template <typename Accessor>
class MutableBinaryMessage
    : public MutableBinaryFields<MutableBinaryMessage, Accessor>
{
    void* data_;
    MessageSize size_;

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

    typedef Accessor FieldAccessor;

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

    void* binary()
    ONIXS_SGX_OUCH_NOTHROW
    {
        return data_;
    }

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

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

        return *this;
    }

protected:
    /// Initializes instance over given memory block.
    MutableBinaryMessage(
            void* data,
            MessageSize size)
    ONIXS_SGX_OUCH_NOTHROW
        : data_(data)
        , size_(size)
    {
    }

#if defined(ONIXS_SGX_OUCH_COMPILER_CXX_RVALUE_REFERENCES) && ONIXS_SGX_OUCH_COMPILER_CXX_RVALUE_REFERENCES

private:
    MutableBinaryMessage(MutableBinaryMessage&&)
    {}

    MutableBinaryMessage& operator=(MutableBinaryMessage&&)
    {
        return *this; 
    };
    
#endif
};

ONIXS_SGXTITAN_OUCH_NAMESPACE_END