endianness.inl

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/** @file
 *  @author Bram de Greve (bram@cocamware.com)
 *  @author Tom De Muer (tom@cocamware.com)
 *
 *  *** BEGIN LICENSE INFORMATION ***
 *  
 *  The contents of this file are subject to the Common Public Attribution License 
 *  Version 1.0 (the "License"); you may not use this file except in compliance with 
 *  the License. You may obtain a copy of the License at 
 *  http://lass.sourceforge.net/cpal-license. The License is based on the 
 *  Mozilla Public License Version 1.1 but Sections 14 and 15 have been added to cover 
 *  use of software over a computer network and provide for limited attribution for 
 *  the Original Developer. In addition, Exhibit A has been modified to be consistent 
 *  with Exhibit B.
 *  
 *  Software distributed under the License is distributed on an "AS IS" basis, WITHOUT 
 *  WARRANTY OF ANY KIND, either express or implied. See the License for the specific 
 *  language governing rights and limitations under the License.
 *  
 *  The Original Code is LASS - Library of Assembled Shared Sources.
 *  
 *  The Initial Developer of the Original Code is Bram de Greve and Tom De Muer.
 *  The Original Developer is the Initial Developer.
 *  
 *  All portions of the code written by the Initial Developer are:
 *  Copyright (C) 2004-2011 the Initial Developer.
 *  All Rights Reserved.
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 *  GNU General Public License Version 2 or later (the GPL), in which case the 
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 *  *** END LICENSE INFORMATION ***
 */
 
 
 
#ifndef LASS_GUARDIAN_OF_INCLUSION_NUM_ENDIANNESS_INL
#define LASS_GUARDIAN_OF_INCLUSION_NUM_ENDIANNESS_INL
 
namespace lass
{
namespace num
{
 
// --- implementation ------------------------------------------------------------------------------
 
namespace impl
{
 
template <size_t numOfBytes>
struct Revertor
{
 
    static void revert(void* ioIn) 
    { 
        std::reverse(static_cast<Tuint8*>(ioIn), static_cast<Tuint8*>(ioIn) + numOfBytes); 
    }
};
 
template <>
struct Revertor<0>
{
    static void revert(void* /*ioIn*/)
    {
    }
};
 
template <>
struct Revertor<1>
{
    static void revert(void* /* ioIn */)
    {
    }
};
 
template <>
struct Revertor<2>
{
    static void revert(void* ioIn)
    {
        Tuint16& temp = *static_cast<Tuint16*>(ioIn);
        temp = static_cast<Tuint16>(((temp & 0x00ff) << 8) | (temp >> 8));
    }
};
 
template <>
struct Revertor<4>
{
    static void revert(void* ioIn)
    {
        Tuint32& temp = *static_cast<Tuint32*>(ioIn);
        temp = ((temp & 0x000000ff) << 24) | ((temp & 0x0000ff00) << 8) |
            ((temp & 0x00ff0000) >> 8) | (temp >> 24);
    }
};
 
 
 
template <size_t numOfBytes, Endianness outEndian, Endianness inEndian>
struct EndianCaster
{
    inline static void cast(void* ioIn) 
    {
        Revertor<numOfBytes>::revert(ioIn);
    }
};
 
template <size_t numOfBytes, Endianness endian>
struct EndianCaster<numOfBytes, endian, endian>
{
    inline static void cast(void* /*ioIn*/)
    {
    }
};
 
}
 
// --- free ----------------------------------------------------------------------------------------
 
template <Endianness outEndian, Endianness inEndian, typename T> 
inline T endianCast(T iIn)
{
    impl::EndianCaster<sizeof(T), outEndian, inEndian>::cast(reinterpret_cast<void*>(&iIn));
    return iIn;
}
 
template <typename T>
inline T fixEndianness(T iIn, Endianness iEndianness)
{
    return iEndianness == systemEndian ? iIn : endianCast<bigEndian, littleEndian>(iIn);
}
 
}
 
}
 
#endif
 
// EOF