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cleanup low-level time handling

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Glenn Maynard
2004-08-15 22:41:46 +00:00
parent 3776d4a13f
commit 445d8a6cf2
1 changed files with 1 additions and 51 deletions
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stepmania/src/RageTimer.cpp
+1 -51
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@@ -11,60 +11,10 @@ const RageTimer RageZeroTimer(0,0);
static void GetTime( unsigned &secs, unsigned &us )
{
/*
* Ticks may be less than last for at least two reasons. The underlying timer may
* be 32-bit and use millisecs internally, or the system clock may have moved backwards.
* If the system clock moves backwards, we can't just clamp the time; if it moved back
* an hour, we'll sit around for an hour until it catches up.
*
* Keep track of an offset: the amount of time to add to the result of GetMicrosecondsSinceStart.
* If we move back by 100ms, the offset will be increased by 100ms. If we loop, the
* offset will be increased by the duration 2^32 ticks. This is stored in the same
* notation as RageTimer: one 32-bit int for seconds and another for microseconds, so
* wrapping isn't a problem.
*/
static uint64_t last = 0;
static uint32_t offset_secs = 0, offset_us = 0;
const uint64_t usecs = ArchHooks::GetMicrosecondsSinceStart( true );
/* The time has wrapped if the last time was very high and the current time is very low. */
const uint64_t one_day = uint64_t(24*60*60)*1000000;
if( last > (0-one_day) && usecs < one_day )
{
const uint32_t wraparound_secs = 4294967; /* (2^32 / 1000) */
const uint32_t wraparound_us = 296000; /* (2^32 % 1000) * 1000 */
offset_secs += wraparound_secs;
offset_us += wraparound_us;
}
else if( usecs < last )
{
/* The time has moved backwards. Increase the offset by the amount we moved. */
const uint64_t offset_us_diff = last - usecs;
offset_secs += unsigned(offset_us_diff/1000000);
offset_us += unsigned(offset_us_diff%1000000);
}
if( offset_us >= TIMESTAMP_RESOLUTION )
{
offset_us -= TIMESTAMP_RESOLUTION;
++offset_secs;
}
last = usecs;
uint64_t usecs = ArchHooks::GetMicrosecondsSinceStart( true );
secs = unsigned(usecs / 1000000);
us = unsigned(usecs % 1000000);
secs += offset_secs;
us += offset_us;
if( us >= TIMESTAMP_RESOLUTION )
{
us -= TIMESTAMP_RESOLUTION;
++secs;
}
}
float RageTimer::GetTimeSinceStart()