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 16 namespace 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 ------] 28 class 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
