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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);
allocThrow(size_t bytes)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 
totalCapacity()44     size_t totalCapacity() const { return fTotalCapacity; }
totalUsed()45     size_t totalUsed() const { return fTotalUsed; }
blockCount()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