| // Copyright (c) 2012 The Chromium Authors. All rights reserved. |
| // Use of this source code is governed by a BSD-style license that can be |
| // found in the LICENSE file. |
| |
| #ifndef COBALT_SPEECH_CHUNKED_BYTE_BUFFER_H_ |
| #define COBALT_SPEECH_CHUNKED_BYTE_BUFFER_H_ |
| |
| #include <memory> |
| #include <string> |
| #include <vector> |
| |
| #include "base/memory/scoped_ptr.h" |
| #include "base/memory/scoped_vector.h" |
| |
| namespace cobalt { |
| namespace speech { |
| |
| // Models a chunk-oriented byte buffer. The term chunk is herein defined as an |
| // arbitrary sequence of bytes that is preceeded by N header bytes, indicating |
| // its size. Data may be appended to the buffer with no particular respect of |
| // chunks boundaries. However, chunks can be extracted (FIFO) only when their |
| // content (according to their header) is fully available in the buffer. |
| // The current implementation support only 4 byte Big Endian headers. |
| // Empty chunks (i.e. the sequence 00 00 00 00) are NOT allowed. |
| // |
| // E.g. 00 00 00 04 xx xx xx xx 00 00 00 02 yy yy 00 00 00 04 zz zz zz zz |
| // [----- CHUNK 1 -------] [--- CHUNK 2 ---] [------ CHUNK 3 ------] |
| class ChunkedByteBuffer { |
| public: |
| ChunkedByteBuffer(); |
| ~ChunkedByteBuffer(); |
| |
| // Appends |length| bytes starting from |start| to the buffer. |
| void Append(const uint8_t* start, size_t length); |
| |
| // Appends bytes contained in the |string| to the buffer. |
| void Append(const std::string& string); |
| |
| // Checks whether one or more complete chunks are available in the buffer. |
| bool HasChunks() const; |
| |
| // If enough data is available, reads and removes the first complete chunk |
| // from the buffer. Returns a NULL pointer if no complete chunk is available. |
| scoped_ptr<std::vector<uint8_t> > PopChunk(); |
| |
| // Clears all the content of the buffer. |
| void Clear(); |
| |
| // Returns the number of raw bytes (including headers) present. |
| size_t GetTotalLength() const { return total_bytes_stored_; } |
| |
| private: |
| struct Chunk { |
| Chunk(); |
| ~Chunk(); |
| |
| std::vector<uint8_t> header; |
| scoped_ptr<std::vector<uint8_t> > content; |
| size_t ExpectedContentLength() const; |
| |
| private: |
| DISALLOW_COPY_AND_ASSIGN(Chunk); |
| }; |
| |
| ScopedVector<Chunk> chunks_; |
| scoped_ptr<Chunk> partial_chunk_; |
| size_t total_bytes_stored_; |
| |
| DISALLOW_COPY_AND_ASSIGN(ChunkedByteBuffer); |
| }; |
| |
| } // namespace speech |
| } // namespace cobalt |
| |
| #endif // COBALT_SPEECH_CHUNKED_BYTE_BUFFER_H_ |