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// Copyright 2012 The Chromium Authors
// 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 <stddef.h>
#include <stdint.h>
#include <memory>
#include <string_view>
#include <vector>
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 bytes contained in the |string| to the buffer.
void Append(std::string_view 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<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(const Chunk&) = delete;
Chunk& operator=(const Chunk&) = delete;
~Chunk();
std::vector<uint8_t> header;
std::unique_ptr<std::vector<uint8_t>> content;
size_t ExpectedContentLength() const;
};
std::vector<std::unique_ptr<Chunk>> chunks_;
std::unique_ptr<Chunk> partial_chunk_;
size_t total_bytes_stored_;
};
} // namespace speech
#endif // COMPONENTS_SPEECH_CHUNKED_BYTE_BUFFER_H_
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