// 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 COMPONENTS_SPEECH_CHUNKED_BYTE_BUFFER_H_ #define COMPONENTS_SPEECH_CHUNKED_BYTE_BUFFER_H_ #include #include #include #include #include "base/strings/string_piece.h" 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(const ChunkedByteBuffer&) = delete; ChunkedByteBuffer& operator=(const ChunkedByteBuffer&) = delete; ~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(base::StringPiece 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. std::unique_ptr> 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(const Chunk&) = delete; Chunk& operator=(const Chunk&) = delete; ~Chunk(); std::vector header; std::unique_ptr> content; size_t ExpectedContentLength() const; }; std::vector> chunks_; std::unique_ptr partial_chunk_; size_t total_bytes_stored_; }; } // namespace speech #endif // COMPONENTS_SPEECH_CHUNKED_BYTE_BUFFER_H_