khanat-opennel-code/code/nel/src/misc/contiguous_block_allocator.cpp

102 lines
3 KiB
C++

// NeL - MMORPG Framework <http://dev.ryzom.com/projects/nel/>
// Copyright (C) 2010 Winch Gate Property Limited
//
// This program is free software: you can redistribute it and/or modify
// it under the terms of the GNU Affero General Public License as
// published by the Free Software Foundation, either version 3 of the
// License, or (at your option) any later version.
//
// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU Affero General Public License for more details.
//
// You should have received a copy of the GNU Affero General Public License
// along with this program. If not, see <http://www.gnu.org/licenses/>.
#include "stdmisc.h"
#include "nel/misc/contiguous_block_allocator.h"
namespace NLMISC
{
// *********************************************************************************************************
CContiguousBlockAllocator::CContiguousBlockAllocator()
{
_BlockStart = NULL;
_NextAvailablePos = NULL;
_BlockEnd = 0;
_NumAllocatedBytes = 0;
#ifdef NL_DEBUG
_NumAlloc = 0;
_NumFree = 0;
#endif
}
// *********************************************************************************************************
CContiguousBlockAllocator::~CContiguousBlockAllocator()
{
init(0);
}
// *********************************************************************************************************
void CContiguousBlockAllocator::init(uint numBytes /*=0*/)
{
if (_BlockStart) _DefaultAlloc.deallocate(_BlockStart, _BlockEnd - _BlockStart);
_BlockEnd = NULL;
_BlockStart = NULL;
_NumAllocatedBytes = 0;
_NextAvailablePos = NULL;
if (numBytes != 0)
{
_BlockStart = _DefaultAlloc.allocate(numBytes);
_NextAvailablePos = _BlockStart;
_BlockEnd = _BlockStart + numBytes;
_NumAllocatedBytes = 0;
}
#ifdef NL_DEBUG
_NumAlloc = 0;
_NumFree = 0;
#endif
}
// *********************************************************************************************************
void *CContiguousBlockAllocator::alloc(uint numBytes)
{
if (numBytes == 0) return NULL;
_NumAllocatedBytes += numBytes;
if (_BlockStart)
{
if (_NextAvailablePos + numBytes <= _BlockEnd)
{
uint8 *block = _NextAvailablePos;
_NextAvailablePos += numBytes;
#ifdef NL_DEBUG
++ _NumAlloc;
#endif
return block;
}
}
// just uses standard new
#ifdef NL_DEBUG
++ _NumAlloc;
#endif
return _DefaultAlloc.allocate(numBytes);
}
// *********************************************************************************************************
void CContiguousBlockAllocator::free(void *block, uint numBytes)
{
if (!block) return;
#ifdef NL_DEBUG
++ _NumFree;
#endif
// no-op if block not inside the big block (sub-block are never deallocated until init(0) is encountered)
if (block < _BlockStart || block >= _BlockEnd)
{
// the block was allocated with std allocator
_DefaultAlloc.deallocate((uint8 *) block, numBytes);
}
}
} // NLMISC