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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     /** Free up all allocated blocks. This invalidates all returned
21         pointers.
22     */
23     void reset();
24 
25     /** Reuse all allocated blocks. This invalidates all returned
26         pointers (like reset) but doesn't necessarily free up all
27         of the privately allocated blocks. This is more efficient
28         if you plan to reuse the allocator multiple times.
29     */
30     void reuse();
31 
32     enum AllocFailType {
33         kReturnNil_AllocFailType,
34         kThrow_AllocFailType
35     };
36 
37     void* alloc(size_t bytes, AllocFailType);
allocThrow(size_t bytes)38     void* allocThrow(size_t bytes) {
39         return this->alloc(bytes, kThrow_AllocFailType);
40     }
41 
42     /** Call this to unalloc the most-recently allocated ptr by alloc(). On
43         success, the number of bytes freed is returned, or 0 if the block could
44         not be unallocated. This is a hint to the underlying allocator that
45         the previous allocation may be reused, but the implementation is free
46         to ignore this call (and return 0).
47      */
48     size_t unalloc(void* ptr);
49 
totalCapacity()50     size_t totalCapacity() const { return fTotalCapacity; }
51 
52     /**
53      *  Returns true if the specified address is within one of the chunks, and
54      *  has at least 1-byte following the address (i.e. if addr points to the
55      *  end of a chunk, then contains() will return false).
56      */
57     bool contains(const void* addr) const;
58 
59 private:
60     struct Block;
61     Block*  fBlock;
62     size_t  fMinSize;
63     Block*  fPool;
64     size_t  fTotalCapacity;
65 
66     Block* newBlock(size_t bytes, AllocFailType ftype);
67 };
68 
69 #endif
70