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xahaud/modules/beast_basics/memory/beast_MemoryAlignment.h
2013-06-17 09:28:43 -07:00

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2.1 KiB
C++

//------------------------------------------------------------------------------
/*
This file is part of Beast: https://github.com/vinniefalco/Beast
Copyright 2013, Vinnie Falco <vinnie.falco@gmail.com>
Permission to use, copy, modify, and/or distribute this software for any
purpose with or without fee is hereby granted, provided that the above
copyright notice and this permission notice appear in all copies.
THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
ANY SPECIAL , DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
*/
//==============================================================================
#ifndef BEAST_MEMORYALIGNMENT_BEASTHEADER
#define BEAST_MEMORYALIGNMENT_BEASTHEADER
namespace Memory
{
// Constants
const int cacheLineAlignBits = 6; // 64 bytes
const int cacheLineAlignBytes = 1 << cacheLineAlignBits;
const int cacheLineAlignMask = cacheLineAlignBytes - 1;
const int allocAlignBits = 3; // 8 bytes
const int allocAlignBytes = 1 << allocAlignBits;
const int allocAlignMask = allocAlignBytes - 1;
// Returns the number of bytes needed to advance p to the correct alignment
template <typename P>
inline size_t bytesNeededForAlignment (P const* const p)
{
return (allocAlignBytes - (uintptr_t (p) & allocAlignMask))
& allocAlignMask;
}
// Returns the number of bytes to make "bytes" an aligned size
inline size_t sizeAdjustedForAlignment (const size_t bytes)
{
return (bytes + allocAlignMask) & ~allocAlignMask;
}
// Returns a pointer with alignment added.
template <typename P>
inline P* pointerAdjustedForAlignment (P* const p)
{
return reinterpret_cast <P*> (reinterpret_cast <char*> (p) +
bytesNeededForAlignment (p));
}
}
#endif