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/*
* Copyright (c) 2009-2011, The Regents of the University of California,
* through Lawrence Berkeley National Laboratory (subject to receipt of any
* required approvals from the U.S. Dept. of Energy). All rights reserved.
*
* This code is distributed under a BSD style license, see the LICENSE file
* for complete information.
*
* Based on timers.c by Jef Poskanzer. Used with permission.
*/
#include <sys/types.h>
#include <stdlib.h>
#include "timer.h"
static Timer* timers = NULL;
static Timer* free_timers = NULL;
TimerClientData JunkClientData;
/* This is an efficiency tweak. All the routines that need to know the
** current time get passed a pointer to a struct timeval. If it's non-NULL
** it gets used, otherwise we do our own gettimeofday() to fill it in.
** This lets the caller avoid extraneous gettimeofday()s when efficiency
** is needed, and not bother with the extra code when efficiency doesn't
** matter too much.
*/
static void
getnow( struct timeval* nowP, struct timeval* nowP2 )
{
if ( nowP != NULL )
*nowP2 = *nowP;
else
(void) gettimeofday( nowP2, NULL );
}
static void
list_add( Timer* t )
{
Timer* t2;
Timer* t2prev;
if ( timers == NULL ) {
/* The list is empty. */
timers = t;
t->prev = t->next = NULL;
} else {
if ( t->time.tv_sec < timers->time.tv_sec ||
( t->time.tv_sec == timers->time.tv_sec &&
t->time.tv_usec < timers->time.tv_usec ) ) {
/* The new timer goes at the head of the list. */
t->prev = NULL;
t->next = timers;
timers->prev = t;
timers = t;
} else {
/* Walk the list to find the insertion point. */
for ( t2prev = timers, t2 = timers->next; t2 != NULL;
t2prev = t2, t2 = t2->next ) {
if ( t->time.tv_sec < t2->time.tv_sec ||
( t->time.tv_sec == t2->time.tv_sec &&
t->time.tv_usec < t2->time.tv_usec ) ) {
/* Found it. */
t2prev->next = t;
t->prev = t2prev;
t->next = t2;
t2->prev = t;
return;
}
}
/* Oops, got to the end of the list. Add to tail. */
t2prev->next = t;
t->prev = t2prev;
t->next = NULL;
}
}
}
static void
list_remove( Timer* t )
{
if ( t->prev == NULL )
timers = t->next;
else
t->prev->next = t->next;
if ( t->next != NULL )
t->next->prev = t->prev;
}
static void
list_resort( Timer* t )
{
/* Remove the timer from the list. */
list_remove( t );
/* And add it back in, sorted correctly. */
list_add( t );
}
static void
add_usecs( struct timeval* t, int64_t usecs )
{
t->tv_sec += usecs / 1000000L;
t->tv_usec += usecs % 1000000L;
if ( t->tv_usec >= 1000000L ) {
t->tv_sec += t->tv_usec / 1000000L;
t->tv_usec %= 1000000L;
}
}
Timer*
tmr_create(
struct timeval* nowP, TimerProc* timer_proc, TimerClientData client_data,
int64_t usecs, int periodic )
{
struct timeval now;
Timer* t;
getnow( nowP, &now );
if ( free_timers != NULL ) {
t = free_timers;
free_timers = t->next;
} else {
t = (Timer*) malloc( sizeof(Timer) );
if ( t == NULL )
return NULL;
}
t->timer_proc = timer_proc;
t->client_data = client_data;
t->usecs = usecs;
t->periodic = periodic;
t->time = now;
add_usecs( &t->time, usecs );
/* Add the new timer to the active list. */
list_add( t );
return t;
}
struct timeval*
tmr_timeout( struct timeval* nowP )
{
struct timeval now;
int64_t usecs;
static struct timeval timeout;
getnow( nowP, &now );
/* Since the list is sorted, we only need to look at the first timer. */
if ( timers == NULL )
return NULL;
usecs = ( timers->time.tv_sec - now.tv_sec ) * 1000000LL +
( timers->time.tv_usec - now.tv_usec );
if ( usecs <= 0 )
usecs = 0;
timeout.tv_sec = usecs / 1000000LL;
timeout.tv_usec = usecs % 1000000LL;
return &timeout;
}
void
tmr_run( struct timeval* nowP )
{
struct timeval now;
Timer* t;
Timer* next;
getnow( nowP, &now );
for ( t = timers; t != NULL; t = next ) {
next = t->next;
/* Since the list is sorted, as soon as we find a timer
** that isn't ready yet, we are done.
*/
if ( t->time.tv_sec > now.tv_sec ||
( t->time.tv_sec == now.tv_sec &&
t->time.tv_usec > now.tv_usec ) )
break;
(t->timer_proc)( t->client_data, &now );
if ( t->periodic ) {
/* Reschedule. */
add_usecs( &t->time, t->usecs );
list_resort( t );
} else
tmr_cancel( t );
}
}
void
tmr_reset( struct timeval* nowP, Timer* t )
{
struct timeval now;
getnow( nowP, &now );
t->time = now;
add_usecs( &t->time, t->usecs );
list_resort( t );
}
void
tmr_cancel( Timer* t )
{
/* Remove it from the active list. */
list_remove( t );
/* And put it on the free list. */
t->next = free_timers;
free_timers = t;
t->prev = NULL;
}
void
tmr_cleanup( void )
{
Timer* t;
while ( free_timers != NULL ) {
t = free_timers;
free_timers = t->next;
free( (void*) t );
}
}
void
tmr_destroy( void )
{
while ( timers != NULL )
tmr_cancel( timers );
tmr_cleanup();
}
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