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/*
****************************************************************************
* Copyright IBM Corporation 1988, 1989 - All Rights Reserved *
* *
* Permission to use, copy, modify, and distribute this software and its *
* documentation for any purpose and without fee is hereby granted, *
* provided that the above copyright notice appear in all copies and *
* that both that copyright notice and this permission notice appear in *
* supporting documentation, and that the name of IBM not be used in *
* advertising or publicity pertaining to distribution of the software *
* without specific, written prior permission. *
* *
* IBM DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE, INCLUDING ALL *
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS, IN NO EVENT SHALL IBM *
* BE LIABLE FOR ANY SPECIAL, INDIRECT OR CONSEQUENTIAL DAMAGES OR ANY *
* DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER *
* IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING *
* OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. *
****************************************************************************
*/
/*
* fasttime.c -- Get the time of day quickly by mapping the kernel's
* time of day variable.
*
* David Nichols
* 6 January 1986
*
* Modification History
* 3/21/86: Added FT_ApproxTime which returns the last time
* in seconds returned by RT_FastTime. The intent is to give
* routines which aren't too concerned about the exact time
* fast access to the time, even on kernels without mmap.
* - Bob Sidebotham.
* 4/2/86: Fixed my previous mod and fixed FT_Init so it doesn't initialize
* a second time if explicitly called after being implicitly called.
* This saves a (precious) file descriptor.
*/
#ifdef HAVE_CONFIG_H
#include <config.h>
RCSID("$arla: fasttime.c,v 1.10 2002/12/20 12:54:55 lha Exp $");
#endif
#include <stdio.h>
#include <sys/types.h>
#include <sys/time.h>
#include <sys/file.h>
#ifdef HAVE_SYS_MMAN_H
#include <sys/mman.h>
#endif
#ifdef HAVE_NLIST_H
#include <nlist.h>
#else
#ifdef HAVE_LIBELF_NLIST_H
#include <libelf/nlist.h>
#endif
#endif
#include "timer.h"
#define TRUE 1
#define FALSE 0
static enum InitState {
notTried, tried, done
} initState = notTried;
/* last time returned by RT_FastTime. Used to implement FT_ApproxTime */
struct timeval FT_LastTime;
/*
* Call this to get the memory mapped. It will return -1 if anything went
* wrong. In that case, calls to FT_GetTimeOfDay will call gettimeofday
* instead. If printErrors is true, errors in initialization will cause
* error messages to be printed on stderr. If notReally is true, then
* things are set up so that all calls to FT_GetTimeOfDay call gettimeofday.
* You might want this if your program won't run too long and the nlist
* call is too expensive. Yeah, it's pretty horrible.
*/
int
FT_Init(int printErrors, int notReally)
{
/*
* This is in case explicit initialization occurs after automatic
* initialization
*/
if (initState != notTried && !notReally)
return (initState == done ? 0 : -1);
initState = tried;
if (notReally)
return 0; /* fake success, but leave initState
* wrong. */
return (-1);
}
/*
* Call this to get the time of day. It will automatically initialize the
* first time you call it. If you want error messages when you initialize,
* call FT_Init yourself. If the initialization failed, this will just
* call gettimeofday. If you ask for the timezone info, this routine will
* punt to gettimeofday.
*/
int
FT_GetTimeOfDay(struct timeval * tv, struct timezone * tz)
{
int ret;
ret = gettimeofday(tv, tz);
if (!ret) {
/*
* need to bounds check 'cause Unix can fail these checks, (esp on
* Suns) and time package can generate invalid (to select syscall)
* values for the time until the next interesting event if it
* encounters out of range microsecond fields
*/
if (tv->tv_usec < 0)
tv->tv_usec = 0;
if (tv->tv_usec > 999999)
tv->tv_usec = 999999;
FT_LastTime.tv_sec = tv->tv_sec;
FT_LastTime.tv_usec = tv->tv_usec;
}
return ret;
}
/* For compatibility. Should go away. */
int
TM_GetTimeOfDay(struct timeval * tv, struct timezone * tz)
{
return FT_GetTimeOfDay(tv, tz);
}
int
FT_AGetTimeOfDay(struct timeval * tv, struct timezone * tz)
{
if (FT_LastTime.tv_sec) {
tv->tv_sec = FT_LastTime.tv_sec;
tv->tv_usec = FT_LastTime.tv_usec;
return 0;
}
return FT_GetTimeOfDay(tv, tz);
}
unsigned int
FT_ApproxTime(void)
{
if (!FT_LastTime.tv_sec) {
FT_GetTimeOfDay(&FT_LastTime, 0);
}
return FT_LastTime.tv_sec;
}
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