80 lines
2.1 KiB
C
80 lines
2.1 KiB
C
/*-
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* See the file LICENSE for redistribution information.
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*
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* Copyright (c) 2001,2008 Oracle. All rights reserved.
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*
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* $Id: os_clock.c 63573 2008-05-23 21:43:21Z trent.nelson $
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*/
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#include "db_config.h"
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#include "db_int.h"
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/*
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* __os_gettime --
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* Return the current time-of-day clock in seconds and nanoseconds.
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*/
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void
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__os_gettime(env, tp, monotonic)
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ENV *env;
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db_timespec *tp;
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int monotonic;
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{
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if (monotonic) {
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/*
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* The elapsed time is stored as a DWORD value, so time wraps
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* around to zero if the system runs for 49.7 days. Initialize
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* a base value with 50 days worth of seconds, and add 50 more
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* days every time the counter wraps. That ensures we always
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* move forward.
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*
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* It's possible this code could race, but the danger is we
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* would increment base_seconds more than once per wrap and
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* eventually overflow, which is a pretty remote possibility.
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*/
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#define TIMER_WRAP_SECONDS (50 * 24 * 60 * 60)
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static DWORD last_ticks;
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static time_t base_seconds;
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DWORD ticks;
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ticks = GetTickCount();
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if (ticks < last_ticks)
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base_seconds += TIMER_WRAP_SECONDS;
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last_ticks = ticks;
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tp->tv_sec = base_seconds + (u_int32_t)(ticks / 1000);
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tp->tv_nsec = (u_int32_t)((ticks % 1000) * NS_PER_MS);
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} else {
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#ifdef DB_WINCE
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FILETIME ft;
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LARGE_INTEGER large_int;
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LONGLONG ns_since_epoch, utc1970;
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SYSTEMTIME st;
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(void)GetSystemTime(&st);
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(void)SystemTimeToFileTime(&st, &ft);
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/*
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* A FILETIME expresses time as 100 nanosecond chunks from
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* Jan 1, 1601; convert to a timespec where the time is
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* is expressed in seconds and nanoseconds from Jan 1, 1970.
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*
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* UTC_1970 is the number of 100-nano-second chunks from
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* 1601 to 1970.
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*/
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#define NS100_PER_SEC (NS_PER_SEC / 100)
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#define UTC_1970 (((LONGLONG)27111902 << 32) + (LONGLONG)3577643008)
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memcpy(&large_int, &ft, sizeof(large_int));
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utc1970 = UTC_1970;
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ns_since_epoch = (large_int.QuadPart - utc1970);
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tp->tv_sec = (time_t)(ns_since_epoch / NS100_PER_SEC);
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tp->tv_nsec = (long)(ns_since_epoch % NS100_PER_SEC);
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#else
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struct _timeb now;
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_ftime(&now);
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tp->tv_sec = now.time;
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tp->tv_nsec = now.millitm * NS_PER_MS;
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#endif
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}
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}
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