src/add-ons/kernel/file_systems/ramfs/BlockAllocator.h

   1 // BlockAllocator.h
   2
   3 #ifndef BLOCK_ALLOCATOR_H
   4 #define BLOCK_ALLOCATOR_H
   5
   6 #include <OS.h>
   7
   8 #include "Block.h"
   9 #include "BlockReferenceManager.h"
  10 #include "Debug.h"
  11 #include "List.h"
  12
  13 #define ENABLE_BA_PANIC 1
  14 #if ENABLE_BA_PANIC
  15 #define BA_PANIC(x)     { PANIC(x); BlockAllocator::fPanic = true; }
  16 #endif
  17
  18 class AllocationInfo;
  19
  20 // BlockAllocator
  21 class BlockAllocator {
  22 public:
  23         BlockAllocator(size_t areaSize);
  24         ~BlockAllocator();
  25
  26         status_t InitCheck() const;
  27
  28         BlockReference *AllocateBlock(size_t usableSize);
  29         void FreeBlock(BlockReference *block);
  30         BlockReference *ResizeBlock(BlockReference *block, size_t usableSize);
  31
  32         size_t GetAvailableBytes() const        { return fAreaCount * fAreaSize; }
  33         size_t GetFreeBytes() const                     { return fFreeBytes; }
  34         size_t GetUsedBytes() const                     { return fAreaCount * fAreaSize
  35                                                                                                  - fFreeBytes; }
  36
  37 public:
  38         class Area;
  39         class AreaBucket;
  40
  41         // debugging only
  42         bool SanityCheck(bool deep = false) const;
  43         bool CheckArea(Area *area);
  44         bool CheckBlock(Block *block, size_t minSize = 0);
  45         bool CheckBlock(BlockReference *reference, size_t minSize = 0);
  46         void GetAllocationInfo(AllocationInfo &info);
  47
  48 private:
  49         inline Area *_AreaForBlock(Block *block);
  50         Block *_AllocateBlock(size_t usableSize, bool dontCreateArea = false);
  51         void _FreeBlock(Area *area, Block *block, bool freeReference);
  52         inline void _RethinkAreaBucket(Area *area, AreaBucket *bucket,
  53                                                                    bool needsDefragmenting);
  54         inline bool _DefragmentingRecommended();
  55         bool _Defragment();
  56
  57 private:
  58         BlockReferenceManager           fReferenceManager;
  59         AreaBucket                                      *fBuckets;
  60         int32                                           fBucketCount;
  61         size_t                                          fAreaSize;
  62         int32                                           fAreaCount;
  63         size_t                                          fFreeBytes;
  64 #if ENABLE_BA_PANIC
  65 public:
  66         static bool                                     fPanic;
  67 #endif
  68 };
  69
  70 #endif  // BLOCK_ALLOCATOR_H