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* $Id: pa_win_util.c 1410 2009-04-07 10:08:48Z rossb $
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* Portable Audio I/O Library
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* Win32 platform-specific support functions
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* Based on the Open Source API proposed by Ross Bencina
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* Copyright (c) 1999-2008 Ross Bencina
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* Permission is hereby granted, free of charge, to any person obtaining
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* a copy of this software and associated documentation files
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* (the "Software"), to deal in the Software without restriction,
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* including without limitation the rights to use, copy, modify, merge,
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* publish, distribute, sublicense, and/or sell copies of the Software,
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* and to permit persons to whom the Software is furnished to do so,
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* subject to the following conditions:
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* The above copyright notice and this permission notice shall be
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* included in all copies or substantial portions of the Software.
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* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
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* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
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* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
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* IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR
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* ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF
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* CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
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* WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
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* The text above constitutes the entire PortAudio license; however,
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* the PortAudio community also makes the following non-binding requests:
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* Any person wishing to distribute modifications to the Software is
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* requested to send the modifications to the original developer so that
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* they can be incorporated into the canonical version. It is also
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* requested that these non-binding requests be included along with the
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@brief Win32 implementation of platform-specific PaUtil support functions.
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@todo Implement workaround for QueryPerformanceCounter() skipping forward
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bug. (see msdn kb Q274323).
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#include <mmsystem.h> /* for timeGetTime() */
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#if (defined(WIN32) && (defined(_MSC_VER) && (_MSC_VER >= 1200))) /* MSC version 6 and above */
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#pragma comment( lib, "winmm.lib" )
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Track memory allocations to avoid leaks.
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static int numAllocations_ = 0;
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void *PaUtil_AllocateMemory( long size )
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void *result = GlobalAlloc( GPTR, size );
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if( result != NULL ) numAllocations_ += 1;
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void PaUtil_FreeMemory( void *block )
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int PaUtil_CountCurrentlyAllocatedBlocks( void )
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return numAllocations_;
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void Pa_Sleep( long msec )
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static int usePerformanceCounter_;
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static double secondsPerTick_;
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void PaUtil_InitializeClock( void )
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LARGE_INTEGER ticksPerSecond;
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if( QueryPerformanceFrequency( &ticksPerSecond ) != 0 )
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usePerformanceCounter_ = 1;
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secondsPerTick_ = 1.0 / (double)ticksPerSecond.QuadPart;
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usePerformanceCounter_ = 0;
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double PaUtil_GetTime( void )
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if( usePerformanceCounter_ )
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according to this knowledge-base article, QueryPerformanceCounter
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can skip forward by seconds!
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http://support.microsoft.com/default.aspx?scid=KB;EN-US;Q274323&
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it may be better to use the rtdsc instruction using inline asm,
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however then a method is needed to calculate a ticks/seconds ratio.
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QueryPerformanceCounter( &time );
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return time.QuadPart * secondsPerTick_;
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return timeGetTime() * .001;
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return GetTickCount() * .001;