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.
4
5#ifndef CONTENT_BROWSER_SPEECH_CHUNKED_BYTE_BUFFER_H_
6#define CONTENT_BROWSER_SPEECH_CHUNKED_BYTE_BUFFER_H_
7
8#include <string>
9#include <vector>
10
11#include "base/basictypes.h"
12#include "base/memory/scoped_ptr.h"
13#include "base/memory/scoped_vector.h"
14#include "content/common/content_export.h"
15
16namespace content {
17
18// Models a chunk-oriented byte buffer. The term chunk is herein defined as an
19// arbitrary sequence of bytes that is preceeded by N header bytes, indicating
20// its size. Data may be appended to the buffer with no particular respect of
21// chunks boundaries. However, chunks can be extracted (FIFO) only when their
22// content (according to their header) is fully available in the buffer.
23// The current implementation support only 4 byte Big Endian headers.
24// Empty chunks (i.e. the sequence 00 00 00 00) are NOT allowed.
25//
26// E.g. 00 00 00 04 xx xx xx xx 00 00 00 02 yy yy 00 00 00 04 zz zz zz zz
27//      [----- CHUNK 1 -------] [--- CHUNK 2 ---] [------ CHUNK 3 ------]
28class CONTENT_EXPORT ChunkedByteBuffer {
29 public:
30  ChunkedByteBuffer();
31  ~ChunkedByteBuffer();
32
33  // Appends |length| bytes starting from |start| to the buffer.
34  void Append(const uint8* start, size_t length);
35
36  // Appends bytes contained in the |string| to the buffer.
37  void Append(const std::string& string);
38
39  // Checks whether one or more complete chunks are available in the buffer.
40  bool HasChunks() const;
41
42  // If enough data is available, reads and removes the first complete chunk
43  // from the buffer. Returns a NULL pointer if no complete chunk is available.
44  scoped_ptr< std::vector<uint8> > PopChunk();
45
46  // Clears all the content of the buffer.
47  void Clear();
48
49  // Returns the number of raw bytes (including headers) present.
50  size_t GetTotalLength() const { return total_bytes_stored_; }
51
52 private:
53  struct Chunk {
54    Chunk();
55    ~Chunk();
56
57    std::vector<uint8> header;
58    scoped_ptr< std::vector<uint8> > content;
59    size_t ExpectedContentLength() const;
60
61   private:
62    DISALLOW_COPY_AND_ASSIGN(Chunk);
63  };
64
65  ScopedVector<Chunk> chunks_;
66  scoped_ptr<Chunk> partial_chunk_;
67  size_t total_bytes_stored_;
68
69  DISALLOW_COPY_AND_ASSIGN(ChunkedByteBuffer);
70};
71
72
73}  // namespace content
74
75#endif  // CONTENT_BROWSER_SPEECH_CHUNKED_BYTE_BUFFER_H_
76