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// StreamBinder.h
#ifndef ZIP7_INC_STREAM_BINDER_H
#define ZIP7_INC_STREAM_BINDER_H
#include "../../Windows/Synchronization.h"
#include "../IStream.h"
/*
We can use one from two code versions here: with Event or with Semaphore to unlock Writer thread
The difference for cases where Reading must be closed before Writing closing
1) Event Version: _canWrite_Event
We call _canWrite_Event.Set() without waiting _canRead_Event in CloseRead() function.
The writer thread can get (_readingWasClosed) status in one from two iterations.
It's ambiguity of processing flow. But probably it's SAFE to use, if Event functions provide memory barriers.
reader thread:
_canWrite_Event.Set();
_readingWasClosed = true;
_canWrite_Event.Set();
writer thread:
_canWrite_Event.Wait()
if (_readingWasClosed)
2) Semaphore Version: _canWrite_Semaphore
writer thread always will detect closing of reading in latest iteration after all data processing iterations
*/
class CStreamBinder
{
NWindows::NSynchronization::CAutoResetEvent _canRead_Event;
// NWindows::NSynchronization::CAutoResetEvent _canWrite_Event;
NWindows::NSynchronization::CSemaphore _canWrite_Semaphore;
// bool _readingWasClosed; // set it in reader thread and check it in write thread
bool _readingWasClosed2; // use it in writer thread
// bool WritingWasCut;
bool _waitWrite; // use it in reader thread
UInt32 _bufSize;
const void *_buf;
public:
UInt64 ProcessedSize; // the size that was read by reader thread
void CreateStreams2(CMyComPtr<ISequentialInStream> &inStream, CMyComPtr<ISequentialOutStream> &outStream);
HRESULT Create_ReInit();
HRESULT Read(void *data, UInt32 size, UInt32 *processedSize);
HRESULT Write(const void *data, UInt32 size, UInt32 *processedSize);
void CloseRead_CallOnce()
{
// call it only once: for example, in destructor
/*
_readingWasClosed = true;
_canWrite_Event.Set();
*/
/*
We must relase Semaphore only once !!!
we must release at least 2 items of Semaphore:
one item to unlock partial Write(), if Read() have read some items
then additional item to stop writing (_bufSize will be 0)
*/
_canWrite_Semaphore.Release(2);
}
void CloseWrite()
{
_buf = NULL;
_bufSize = 0;
_canRead_Event.Set();
}
};
#endif
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