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1 // Copyright 2016 The Chromium Authors. All rights reserved.
2 // Use of this source code is governed by a BSD-style license that can be
3 // found in the LICENSE file.
4 
5 #ifndef QUICHE_SPDY_CORE_SPDY_SIMPLE_ARENA_H_
6 #define QUICHE_SPDY_CORE_SPDY_SIMPLE_ARENA_H_
7 
8 #include <memory>
9 #include <vector>
10 
11 #include "quiche/common/platform/api/quiche_export.h"
12 
13 namespace spdy {
14 
15 // Allocates large blocks of memory, and doles them out in smaller chunks.
16 // Not thread-safe.
17 class QUICHE_EXPORT SpdySimpleArena {
18  public:
19   class QUICHE_EXPORT Status {
20    private:
21     friend class SpdySimpleArena;
22     size_t bytes_allocated_;
23 
24    public:
Status()25     Status() : bytes_allocated_(0) {}
bytes_allocated()26     size_t bytes_allocated() const { return bytes_allocated_; }
27   };
28 
29   // Blocks allocated by this arena will be at least |block_size| bytes.
30   explicit SpdySimpleArena(size_t block_size);
31   ~SpdySimpleArena();
32 
33   // Copy and assign are not allowed.
34   SpdySimpleArena() = delete;
35   SpdySimpleArena(const SpdySimpleArena&) = delete;
36   SpdySimpleArena& operator=(const SpdySimpleArena&) = delete;
37 
38   // Move is allowed.
39   SpdySimpleArena(SpdySimpleArena&& other);
40   SpdySimpleArena& operator=(SpdySimpleArena&& other);
41 
42   char* Alloc(size_t size);
43   char* Realloc(char* original, size_t oldsize, size_t newsize);
44   char* Memdup(const char* data, size_t size);
45 
46   // If |data| and |size| describe the most recent allocation made from this
47   // arena, the memory is reclaimed. Otherwise, this method is a no-op.
48   void Free(char* data, size_t size);
49 
50   void Reset();
51 
status()52   Status status() const { return status_; }
53 
54  private:
55   struct QUICHE_EXPORT Block {
56     std::unique_ptr<char[]> data;
57     size_t size = 0;
58     size_t used = 0;
59 
60     explicit Block(size_t s);
61     ~Block();
62 
63     Block(Block&& other);
64     Block& operator=(Block&& other);
65   };
66 
67   void Reserve(size_t additional_space);
68   void AllocBlock(size_t size);
69 
70   size_t block_size_;
71   std::vector<Block> blocks_;
72   Status status_;
73 };
74 
75 }  // namespace spdy
76 
77 #endif  // QUICHE_SPDY_CORE_SPDY_SIMPLE_ARENA_H_
78