Roll src/third_party/WebKit d9c6159:8139f33 (svn 201974:201975)
[chromium-blink-merge.git] / remoting / base / compound_buffer.h
blob50d3efb8b1a35c0cddcfea157ee072e41224a5a0
1 // Copyright (c) 2011 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 // CompoundBuffer implements a data buffer that is composed of several pieces,
6 // each stored in a refcounted IOBuffer. It is needed for encoding/decoding
7 // video pipeline to represent data packet and minimize data copying.
8 // It is particularly useful for splitting data between multiple RTP packets
9 // and assembling them into one buffer on the receiving side.
11 // CompoundBufferInputStream implements ZeroCopyInputStream interface
12 // to be used by protobuf to decode data stored in CompoundBuffer into
13 // a protocol buffer message.
15 // Mutations to the buffer are not thread-safe. Immutability can be ensured
16 // with the Lock() method.
18 #ifndef REMOTING_BASE_COMPOUND_BUFFER_H_
19 #define REMOTING_BASE_COMPOUND_BUFFER_H_
21 #include <deque>
23 #include "base/basictypes.h"
24 #include "base/memory/ref_counted.h"
25 #include "google/protobuf/io/zero_copy_stream.h"
27 namespace net {
28 class IOBuffer;
29 class IOBufferWithSize;
30 } // namespace net
32 namespace remoting {
34 class CompoundBuffer {
35 public:
36 CompoundBuffer();
37 ~CompoundBuffer();
39 void Clear();
41 // Adds new chunk to the buffer. |start| defines position of the chunk
42 // within the |buffer|. |size| is the size of the chunk that is being
43 // added, not size of the |buffer|.
44 void Append(net::IOBuffer* buffer, int size);
45 void Append(net::IOBuffer* buffer, const char* start, int size);
46 void Append(const CompoundBuffer& buffer);
47 void Prepend(net::IOBuffer* buffer, int size);
48 void Prepend(net::IOBuffer* buffer, const char* start, int size);
49 void Prepend(const CompoundBuffer& buffer);
51 // Same as above, but creates new IOBuffer and copies the data.
52 void AppendCopyOf(const char* data, int data_size);
53 void PrependCopyOf(const char* data, int data_size);
55 // Drop |bytes| bytes from the beginning or the end of the buffer.
56 void CropFront(int bytes);
57 void CropBack(int bytes);
59 // Current size of the buffer.
60 int total_bytes() const { return total_bytes_; }
62 // Locks the buffer. After the buffer is locked, no data can be
63 // added or removed (content can still be changed if some other
64 // object holds reference to the IOBuffer objects).
65 void Lock();
67 // Returns true if content is locked.
68 bool locked() const { return locked_; }
70 // Creates new IOBufferWithSize object and copies all data into it.
71 // Ownership of the result is given to the caller.
72 net::IOBufferWithSize* ToIOBufferWithSize() const;
74 // Copies all data into given location.
75 void CopyTo(char* data, int data_size) const;
77 // Clears the buffer, and initializes it with the interval from |buffer|
78 // starting at |start| and ending at |end|. The data itself isn't copied.
79 void CopyFrom(const CompoundBuffer& source, int start, int end);
81 private:
82 friend class CompoundBufferInputStream;
84 struct DataChunk {
85 DataChunk(net::IOBuffer* buffer, const char* start, int size);
86 ~DataChunk();
88 scoped_refptr<net::IOBuffer> buffer;
89 const char* start;
90 int size;
92 typedef std::deque<DataChunk> DataChunkList;
94 DataChunkList chunks_;
95 int total_bytes_;
96 bool locked_;
98 DISALLOW_COPY_AND_ASSIGN(CompoundBuffer);
101 class CompoundBufferInputStream
102 : public google::protobuf::io::ZeroCopyInputStream {
103 public:
104 // Caller keeps ownership of |buffer|. |buffer| must be locked.
105 explicit CompoundBufferInputStream(const CompoundBuffer* buffer);
106 ~CompoundBufferInputStream() override;
108 int position() const { return position_; }
110 // google::protobuf::io::ZeroCopyInputStream interface.
111 bool Next(const void** data, int* size) override;
112 void BackUp(int count) override;
113 bool Skip(int count) override;
114 int64 ByteCount() const override;
116 private:
117 const CompoundBuffer* buffer_;
119 size_t current_chunk_;
120 int current_chunk_position_;
121 int position_;
122 int last_returned_size_;
125 } // namespace remoting
127 #endif // REMOTING_BASE_COMPOUND_BUFFER_H_