1 // Copyright 2015 The Android Open Source Project
2 //
3 // Licensed under the Apache License, Version 2.0 (the "License");
4 // you may not use this file except in compliance with the License.
5 // You may obtain a copy of the License at
6 //
7 // http://www.apache.org/licenses/LICENSE-2.0
8 //
9 // Unless required by applicable law or agreed to in writing, software
10 // distributed under the License is distributed on an "AS IS" BASIS,
11 // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
12 // See the License for the specific language governing permissions and
13 // limitations under the License.
14 
15 #pragma once
16 
17 #include "android/base/Compiler.h"
18 #include "android/base/files/Stream.h"
19 
20 #include <vector>
21 
22 namespace android {
23 namespace base {
24 
25 // An implementation of the Stream interface on top of a vector.
26 class MemStream : public Stream {
27 public:
28     using Buffer = std::vector<char>;
29 
30     MemStream(int reserveSize = 512);
31     MemStream(Buffer&& data);
32 
33     MemStream(MemStream&& other) = default;
34     MemStream& operator=(MemStream&& other) = default;
35 
36     int writtenSize() const;
37     int readPos() const;
38     int readSize() const;
39 
40     // Stream interface implementation.
41     ssize_t read(void* buffer, size_t size) override;
42     ssize_t write(const void* buffer, size_t size) override;
43 
44     // Snapshot support.
45     void save(Stream* stream) const;
46     void load(Stream* stream);
47 
buffer()48     const Buffer& buffer() const { return mData; }
49 
50 private:
51     DISALLOW_COPY_AND_ASSIGN(MemStream);
52 
53     Buffer mData;
54     int mReadPos = 0;
55 };
56 
57 }  // namespace base
58 }  // namespace android
59