1 // Copyright (c) 2012 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.
5 #ifndef BASE_MEMORY_REF_COUNTED_MEMORY_H_
6 #define BASE_MEMORY_REF_COUNTED_MEMORY_H_
11 #include "base/base_export.h"
12 #include "base/compiler_specific.h"
13 #include "base/memory/ref_counted.h"
17 // A generic interface to memory. This object is reference counted because one
18 // of its two subclasses own the data they carry, and we need to have
19 // heterogeneous containers of these two types of memory.
20 class BASE_EXPORT RefCountedMemory
21 : public base::RefCountedThreadSafe<RefCountedMemory> {
23 // Retrieves a pointer to the beginning of the data we point to. If the data
24 // is empty, this will return NULL.
25 virtual const unsigned char* front() const = 0;
27 // Size of the memory pointed to.
28 virtual size_t size() const = 0;
30 // Returns true if |other| is byte for byte equal.
31 bool Equals(const scoped_refptr<RefCountedMemory>& other) const;
33 // Handy method to simplify calling front() with a reinterpret_cast.
34 template<typename T> const T* front_as() const {
35 return reinterpret_cast<const T*>(front());
39 friend class base::RefCountedThreadSafe<RefCountedMemory>;
41 virtual ~RefCountedMemory();
44 // An implementation of RefCountedMemory, where the ref counting does not
46 class BASE_EXPORT RefCountedStaticMemory : public RefCountedMemory {
48 RefCountedStaticMemory()
49 : data_(NULL), length_(0) {}
50 RefCountedStaticMemory(const void* data, size_t length)
51 : data_(static_cast<const unsigned char*>(length ? data : NULL)),
54 // Overridden from RefCountedMemory:
55 virtual const unsigned char* front() const OVERRIDE;
56 virtual size_t size() const OVERRIDE;
59 virtual ~RefCountedStaticMemory();
61 const unsigned char* data_;
64 DISALLOW_COPY_AND_ASSIGN(RefCountedStaticMemory);
67 // An implementation of RefCountedMemory, where we own our the data in a
69 class BASE_EXPORT RefCountedBytes : public RefCountedMemory {
73 // Constructs a RefCountedBytes object by _copying_ from |initializer|.
74 explicit RefCountedBytes(const std::vector<unsigned char>& initializer);
76 // Constructs a RefCountedBytes object by performing a swap. (To non
77 // destructively build a RefCountedBytes, use the constructor that takes a
79 static RefCountedBytes* TakeVector(std::vector<unsigned char>* to_destroy);
81 // Overridden from RefCountedMemory:
82 virtual const unsigned char* front() const OVERRIDE;
83 virtual size_t size() const OVERRIDE;
85 const std::vector<unsigned char>& data() const { return data_; }
86 std::vector<unsigned char>& data() { return data_; }
89 virtual ~RefCountedBytes();
91 std::vector<unsigned char> data_;
93 DISALLOW_COPY_AND_ASSIGN(RefCountedBytes);
96 // An implementation of RefCountedMemory, where the bytes are stored in an STL
97 // string. Use this if your data naturally arrives in that format.
98 class BASE_EXPORT RefCountedString : public RefCountedMemory {
102 // Constructs a RefCountedString object by performing a swap. (To non
103 // destructively build a RefCountedString, use the default constructor and
104 // copy into object->data()).
105 static RefCountedString* TakeString(std::string* to_destroy);
107 // Overridden from RefCountedMemory:
108 virtual const unsigned char* front() const OVERRIDE;
109 virtual size_t size() const OVERRIDE;
111 const std::string& data() const { return data_; }
112 std::string& data() { return data_; }
115 virtual ~RefCountedString();
119 DISALLOW_COPY_AND_ASSIGN(RefCountedString);
122 // An implementation of RefCountedMemory that holds a chunk of memory
123 // previously allocated with malloc or calloc, and that therefore must be freed
125 class BASE_EXPORT RefCountedMallocedMemory : public base::RefCountedMemory {
127 RefCountedMallocedMemory(void* data, size_t length);
129 // Overridden from RefCountedMemory:
130 virtual const unsigned char* front() const OVERRIDE;
131 virtual size_t size() const OVERRIDE;
134 virtual ~RefCountedMallocedMemory();
136 unsigned char* data_;
139 DISALLOW_COPY_AND_ASSIGN(RefCountedMallocedMemory);
144 #endif // BASE_MEMORY_REF_COUNTED_MEMORY_H_