nel/src/misc/contiguous_block_allocator.cpp

   1 // NeL - MMORPG Framework <http://dev.ryzom.com/projects/nel/>
   2 // Copyright (C) 2010  Winch Gate Property Limited
   3 //
   4 // This program is free software: you can redistribute it and/or modify
   5 // it under the terms of the GNU Affero General Public License as
   6 // published by the Free Software Foundation, either version 3 of the
   7 // License, or (at your option) any later version.
   8 //
   9 // This program is distributed in the hope that it will be useful,
  10 // but WITHOUT ANY WARRANTY; without even the implied warranty of
  11 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12 // GNU Affero General Public License for more details.
  13 //
  14 // You should have received a copy of the GNU Affero General Public License
  15 // along with this program.  If not, see <http://www.gnu.org/licenses/>.
  16
  17 #include "stdmisc.h"
  18
  19 #include "nel/misc/contiguous_block_allocator.h"
  20
  21 #ifdef DEBUG_NEW
  22         #define new DEBUG_NEW
  23 #endif
  24
  25 namespace NLMISC
  26 {
  27
  28 // *********************************************************************************************************
  29 CContiguousBlockAllocator::CContiguousBlockAllocator()
  30 {
  31         _BlockStart = NULL;
  32         _NextAvailablePos = NULL;
  33         _BlockEnd = 0;
  34         _NumAllocatedBytes = 0;
  35         #ifdef NL_DEBUG
  36                 _NumAlloc = 0;
  37                 _NumFree = 0;
  38         #endif
  39 }
  40
  41 // *********************************************************************************************************
  42 CContiguousBlockAllocator::~CContiguousBlockAllocator()
  43 {
  44         init(0);
  45 }
  46
  47 // *********************************************************************************************************
  48 void CContiguousBlockAllocator::init(uint numBytes /*=0*/)
  49 {
  50         if (_BlockStart) _DefaultAlloc.deallocate(_BlockStart, _BlockEnd - _BlockStart);
  51         _BlockEnd =  NULL;
  52         _BlockStart = NULL;
  53         _NumAllocatedBytes = 0;
  54         _NextAvailablePos = NULL;
  55         if (numBytes != 0)
  56         {
  57                 _BlockStart = _DefaultAlloc.allocate(numBytes);
  58                 _NextAvailablePos = _BlockStart;
  59                 _BlockEnd = _BlockStart + numBytes;
  60                 _NumAllocatedBytes = 0;
  61         }
  62         #ifdef NL_DEBUG
  63                 _NumAlloc = 0;
  64                 _NumFree = 0;
  65         #endif
  66 }
  67
  68 // *********************************************************************************************************
  69 void *CContiguousBlockAllocator::alloc(uint numBytes)
  70 {
  71         if (numBytes == 0) return NULL;
  72         _NumAllocatedBytes += numBytes;
  73         if (_BlockStart)
  74         {
  75                 if (_NextAvailablePos + numBytes <= _BlockEnd)
  76                 {
  77                         uint8 *block = _NextAvailablePos;
  78                         _NextAvailablePos += numBytes;
  79                         #ifdef NL_DEBUG
  80                                 ++ _NumAlloc;
  81                         #endif
  82                         return block;
  83                 }
  84         }
  85         // just uses standard new
  86         #ifdef NL_DEBUG
  87                 ++ _NumAlloc;
  88         #endif
  89         return _DefaultAlloc.allocate(numBytes);
  90 }
  91
  92 // *********************************************************************************************************
  93 void CContiguousBlockAllocator::freeBlock(void *block, uint numBytes)
  94 {
  95         if (!block) return;
  96         #ifdef NL_DEBUG
  97                 ++ _NumFree;
  98         #endif
  99         // no-op if block not inside the big block (sub-block are never deallocated until init(0) is encountered)
 100         if (block < _BlockStart || block >= _BlockEnd)
 101         {
 102                 // the block was allocated with std allocator
 103                 _DefaultAlloc.deallocate((uint8 *) block, numBytes);
 104         }
 105 }
 106
 107 } // NLMISC