Memory.h

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#pragma once

#include <cstddef>

#include <OnixS/eSpeed/MarketData/Itch/Integral.h>

ONIXS_ESPEED_ITCH_NAMESPACE_BEGIN

/// Alias for Byte. 
typedef UInt8 Byte;

/// Makes pointer as opaque one. 
template
    <
    typename Type
    >
    inline
    void*
    toOpaquePtr(Type* ptr)
{
    return static_cast<void*>(ptr);
}

/// Makes pointer as opaque one. 
template
    <
    typename Type
    >
    inline
    const void*
    toOpaquePtr(
        const Type* ptr)
{
    return static_cast<const void*>(ptr);
}

/// Reinterprets pointer to one 
/// referencing to byte block. 
template
    <
    typename Type
    >
    inline
    Byte*
    toByteBlock(
        Type* ptr)
{
    return
        static_cast
        <Byte*>
        (toOpaquePtr(ptr));
}

/// Reinterprets pointer to one 
/// referencing to byte block. 
template
    <
    typename Type
    >
    inline
    const Byte*
    toByteBlock(
        const Type* ptr)
{
    return
        static_cast
        <const Byte*>
        (toOpaquePtr(ptr));
}

/// Advances given pointer to a given offset (distance) in bytes. 
template
    <
    typename Type
    >
    inline
    Type*
    advanceByBytes(
        Type* pointer,
        ptrdiff_t distance)
{
    return
        reinterpret_cast<Type*>
        (
            toByteBlock(pointer) + distance
            );
}

/// Returns pointer which is lower than 
/// given one to a given number of bytes. 
template
    <
    typename Type
    >
    inline
    Type*
    advanceBackByBytes(
        Type* pointer,
        ptrdiff_t distance)
{
    return
        reinterpret_cast<Type*>
        (
            toByteBlock(pointer) - distance
            );
}

/// Returns distance in bytes between two pointers. 
template
    <
    typename Left,
    typename Right
    >
    inline
    ptrdiff_t
    byteDistance(
        Left* left,
        Right* right)
{
    return (
        toByteBlock(left) -
        toByteBlock(right)
        );
}

ONIXS_ESPEED_ITCH_NAMESPACE_END