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/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/*
* The contents of this file are subject to the Mozilla Public
* License Version 1.1 (the "License"); you may not use this file
* except in compliance with the License. You may obtain a copy of
* the License at http://www.mozilla.org/MPL/
*
* Software distributed under the License is distributed on an "AS
* IS" basis, WITHOUT WARRANTY OF ANY KIND, either express or
* implied. See the License for the specific language governing
* rights and limitations under the License.
*
* The Original Code is the Netscape Portable Runtime (NSPR).
*
* The Initial Developer of the Original Code is Netscape
* Communications Corporation. Portions created by Netscape are
* Copyright (C) 1998-2000 Netscape Communications Corporation. All
* Rights Reserved.
*
* Contributor(s):
*
* Alternatively, the contents of this file may be used under the
* terms of the GNU General Public License Version 2 or later (the
* "GPL"), in which case the provisions of the GPL are applicable
* instead of those above. If you wish to allow use of your
* version of this file only under the terms of the GPL and not to
* allow others to use your version of this file under the MPL,
* indicate your decision by deleting the provisions above and
* replace them with the notice and other provisions required by
* the GPL. If you do not delete the provisions above, a recipient
* may use your version of this file under either the MPL or the
* GPL.
*/
/*
* NT interval timers
*
*/
#include "primpl.h"
#if defined(WIN16)
#include <win/compobj.h>
#define QueryPerformanceFrequency(x) FALSE
#define QueryPerformanceCounter(x) FALSE
#endif
static PRIntn _nt_bitShift = 0;
static PRInt32 _nt_ticksPerSec = -1;
void
_PR_MD_INTERVAL_INIT()
{
LARGE_INTEGER count;
if (QueryPerformanceFrequency(&count)) {
/*
* HighPart is signed (LONG). Assert that its sign bit is 0
* because we will be right shifting it. LowPart is unsigned
* (DWORD).
*/
PR_ASSERT(count.HighPart >= 0);
while(count.HighPart) {
count.LowPart = (count.HighPart << 31) + (count.LowPart >> 1);
count.HighPart >>= 1;
_nt_bitShift++;
}
while(count.LowPart > PR_INTERVAL_MAX) {
count.LowPart >>= 1;
_nt_bitShift++;
}
/*
* We can't use the performance counter if after
* normalization we are left with fewer than 32 bits.
*/
if (_nt_bitShift <= 32) {
_nt_ticksPerSec = count.LowPart;
PR_ASSERT(_nt_ticksPerSec > PR_INTERVAL_MIN);
return;
}
}
_nt_ticksPerSec = -1;
}
PRIntervalTime
_PR_MD_GET_INTERVAL()
{
LARGE_INTEGER count;
/* Sadly; nspr requires the interval to range from 1000 ticks per second
* to only 100000 ticks per second; QueryPerformanceCounter is too high
* resolution...
*/
if (_nt_ticksPerSec != -1) {
(void)QueryPerformanceCounter(&count);
PR_ASSERT(_nt_bitShift <= 32);
if (_nt_bitShift == 32) {
return (PRUint32)count.HighPart;
} else {
return (PRUint32)((count.HighPart << (32 - _nt_bitShift))
+ (count.LowPart >> _nt_bitShift));
}
} else
#if defined(__MINGW32__)
return time();
#elif defined(WIN16)
return clock(); /* milliseconds since application start */
#else
return GetTickCount(); /* milliseconds since system start */
#endif
}
PRIntervalTime
_PR_MD_INTERVAL_PER_SEC()
{
if (_nt_ticksPerSec != -1)
return _nt_ticksPerSec;
else
return 1000;
}
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