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#pragma once
#include "../Buffer.h"
#include "Stream.h"
#include <condition_variable>
#include <list>
#include <mutex>
#include <thread>
namespace cru::io {
struct AutoReadStreamOptions {
/**
* @brief The size of a single buffer allocated each time new space is needed.
* Use default value if <= 0.
*
* When current buffer is full and there is no space for following data, a new
* buffer will be allocated and appended to the buffer list. Note if sum size
* of all buffers reaches the total_buffer_size, no more buffer will be
* allocated but wait.
*/
int buffer_block_size = 0;
/**
* @brief Total size limit of saved data in buffer. Use default value if < 0.
* No limit if == 0.
*
* When the buffer is filled, it will block and wait for user to read to get
* free space of buffer to continue read.
*/
int total_buffer_size = 0;
};
/**
* @brief A stream that wraps another stream and auto read it into a buffer in a
* background thread.
*/
class CRU_BASE_API AutoReadStream : public Stream {
private:
class BufferBlock {};
public:
/**
* @brief Wrap a stream and auto read it in background.
* @param stream The stream to auto read.
* @param auto_delete Whether to delete the stream object in destructor.
* @param options Options to modify the behavior.
*/
AutoReadStream(
Stream* stream, bool auto_delete,
const AutoReadStreamOptions& options = AutoReadStreamOptions());
~AutoReadStream() override;
public:
bool CanSeek() override;
Index Seek(Index offset, SeekOrigin origin = SeekOrigin::Current) override;
bool CanRead() = 0;
virtual Index Read(std::byte* buffer, Index offset, Index size) = 0;
bool CanWrite() override;
Index Write(const std::byte* buffer, Index offset, Index size) override;
void Flush() override;
void Close() = 0;
private:
void BackgroundThreadRun();
private:
Stream* stream_;
bool auto_delete_;
int buffer_block_size_;
int total_buffer_size_;
std::mutex buffer_mutex_;
std::condition_variable buffer_condition_variable_;
std::list<Buffer> buffer_list_;
std::thread background_thread_;
};
} // namespace cru::io
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