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      1 
      2 /*
      3  * Copyright 2006 The Android Open Source Project
      4  *
      5  * Use of this source code is governed by a BSD-style license that can be
      6  * found in the LICENSE file.
      7  */
      8 
      9 
     10 #ifndef SkChunkAlloc_DEFINED
     11 #define SkChunkAlloc_DEFINED
     12 
     13 #include "SkTypes.h"
     14 
     15 class SkChunkAlloc : SkNoncopyable {
     16 public:
     17     SkChunkAlloc(size_t minSize);
     18     ~SkChunkAlloc();
     19 
     20     /**
     21      *  Free up all allocated blocks. This invalidates all returned
     22      *  pointers.
     23      */
     24     void reset();
     25 
     26     enum AllocFailType {
     27         kReturnNil_AllocFailType,
     28         kThrow_AllocFailType
     29     };
     30 
     31     void* alloc(size_t bytes, AllocFailType);
     32     void* allocThrow(size_t bytes) {
     33         return this->alloc(bytes, kThrow_AllocFailType);
     34     }
     35 
     36     /** Call this to unalloc the most-recently allocated ptr by alloc(). On
     37         success, the number of bytes freed is returned, or 0 if the block could
     38         not be unallocated. This is a hint to the underlying allocator that
     39         the previous allocation may be reused, but the implementation is free
     40         to ignore this call (and return 0).
     41      */
     42     size_t unalloc(void* ptr);
     43 
     44     size_t totalCapacity() const { return fTotalCapacity; }
     45     size_t totalUsed() const { return fTotalUsed; }
     46     int blockCount() const { return fBlockCount; }
     47 
     48     /**
     49      *  Returns true if the specified address is within one of the chunks, and
     50      *  has at least 1-byte following the address (i.e. if addr points to the
     51      *  end of a chunk, then contains() will return false).
     52      */
     53     bool contains(const void* addr) const;
     54 
     55 private:
     56     struct Block;
     57 
     58     Block*  fBlock;
     59     size_t  fMinSize;
     60     size_t  fChunkSize;
     61     size_t  fTotalCapacity;
     62     size_t  fTotalUsed;     // will be <= fTotalCapacity
     63     int     fBlockCount;
     64 
     65     Block* newBlock(size_t bytes, AllocFailType ftype);
     66 };
     67 
     68 #endif
     69