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/** @file
*
* VirtualBox console event handling
*/
/*
* Copyright (C) 2006-2010 Oracle Corporation
*
* This file is part of VirtualBox Open Source Edition (OSE), as
* available from http://www.virtualbox.org. This file is free software;
* you can redistribute it and/or modify it under the terms of the GNU
* General Public License (GPL) as published by the Free Software
* Foundation, in version 2 as it comes in the "COPYING" file of the
* VirtualBox OSE distribution. VirtualBox OSE is distributed in the
* hope that it will be useful, but WITHOUT ANY WARRANTY of any kind.
*/
#ifndef ____H_CONSOLEEVENTS
#define ____H_CONSOLEEVENTS
#include <iprt/semaphore.h>
template<class C> class ConsoleEventBuffer
{
public:
/**
* Constructor
*
* @param size FIFO size in elements.
*/
ConsoleEventBuffer(size_t size) :
sz(size), buf(new C[size]), curg(0), curp(0), full(false)
{
RTSemMutexCreate(&mutex);
}
/**
* Destructor
*
*/
virtual ~ConsoleEventBuffer()
{
RTSemMutexDestroy(mutex);
delete buf;
}
/**
* Opens the buffer for extraction of elements. Must be called before #get().
*/
void open()
{
lock();
}
/**
* Closes the buffer previously opened by #open(). Must be called after #get().
*/
void close()
{
unlock();
}
/**
* Gets the element from the buffer. Requires #open() before and #close()
* after. Returns the first element and removes it from the buffer. If
* the buffer is empty, returns an empty element (constructed with the
* default constructor).
*/
C get()
{
C c;
if (full || curg != curp)
{
c = buf[curg];
++curg %= sz;
full = false;
}
return c;
}
/**
* Puts the element to the end of the buffer. #open()/#close() must not
* be used. Returns 1 if successful, or 0 if the buffer is full, or 2
* if the element is invalid.
*/
size_t put(C c)
{
if (!c.isValid())
return 2; // invalid element
lock();
size_t i = 0;
if (!full)
{
buf[curp] = c;
++curp %= sz;
i++;
full = curg == curp;
}
unlock();
return i;
}
/**
* Puts the number of elements to the buffer. #open()/#close() must not
* be used. Returns the count of elements placed. If it is less than
* the count passed as an argument then the buffer is full. If it is
* greater (special case) then the invalid element is encountered and
* its index is return value munis count minus 1.
*/
size_t put(C *codes, size_t count)
{
lock();
size_t i = 0;
while (i < count && !full)
{
if (!codes[i].isValid())
{
i += count + 1; // invalid code
break;
}
buf[curp] = codes[i++];
++curp %= sz;
full = curg == curp;
}
unlock();
return i;
}
private:
/**
* Acquire the local mutex
*/
void lock()
{
RTSemMutexRequest(mutex, RT_INDEFINITE_WAIT);
}
/**
* Release the local mutex
*/
void unlock()
{
RTSemMutexRelease(mutex);
}
private:
size_t sz;
C *buf;
size_t curg, curp;
bool full;
RTSEMMUTEX mutex;
};
#endif // ____H_CONSOLEEVENTS
/* vi: set tabstop=4 shiftwidth=4 expandtab: */
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