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/* ptmacosx.c -- portable timer implementation for mac os x */
#include <stdlib.h>
#include <stdio.h>
#include <CoreAudio/HostTime.h>
#import <mach/mach.h>
#import <mach/mach_error.h>
#import <mach/mach_time.h>
#import <mach/clock.h>
#include "porttime.h"
#include "sys/time.h"
#include "pthread.h"
#define NSEC_PER_MSEC 1000000
#define THREAD_IMPORTANCE 30
static int time_started_flag = FALSE;
static UInt64 start_time;
static pthread_t pt_thread_pid;
/* note that this is static data -- we only need one copy */
typedef struct {
int id;
int resolution;
PtCallback *callback;
void *userData;
} pt_callback_parameters;
static int pt_callback_proc_id = 0;
static void *Pt_CallbackProc(void *p)
{
pt_callback_parameters *parameters = (pt_callback_parameters *) p;
int mytime = 1;
kern_return_t error;
thread_extended_policy_data_t extendedPolicy;
thread_precedence_policy_data_t precedencePolicy;
extendedPolicy.timeshare = 0;
error = thread_policy_set(mach_thread_self(), THREAD_EXTENDED_POLICY,
(thread_policy_t)&extendedPolicy,
THREAD_EXTENDED_POLICY_COUNT);
if (error != KERN_SUCCESS) {
mach_error("Couldn't set thread timeshare policy", error);
}
precedencePolicy.importance = THREAD_IMPORTANCE;
error = thread_policy_set(mach_thread_self(), THREAD_PRECEDENCE_POLICY,
(thread_policy_t)&precedencePolicy,
THREAD_PRECEDENCE_POLICY_COUNT);
if (error != KERN_SUCCESS) {
mach_error("Couldn't set thread precedence policy", error);
}
/* to kill a process, just increment the pt_callback_proc_id */
/* printf("pt_callback_proc_id %d, id %d\n", pt_callback_proc_id, parameters->id); */
while (pt_callback_proc_id == parameters->id) {
/* wait for a multiple of resolution ms */
UInt64 wait_time;
int delay = mytime++ * parameters->resolution - Pt_Time();
long timestamp;
if (delay < 0) delay = 0;
wait_time = AudioConvertNanosToHostTime((UInt64)delay * NSEC_PER_MSEC);
wait_time += AudioGetCurrentHostTime();
error = mach_wait_until(wait_time);
timestamp = Pt_Time();
(*(parameters->callback))(timestamp, parameters->userData);
}
free(parameters);
return NULL;
}
PtError Pt_Start(int resolution, PtCallback *callback, void *userData)
{
if (time_started_flag) return ptAlreadyStarted;
start_time = AudioGetCurrentHostTime();
if (callback) {
int res;
pt_callback_parameters *parms;
parms = (pt_callback_parameters *) malloc(sizeof(pt_callback_parameters));
if (!parms) return ptInsufficientMemory;
parms->id = pt_callback_proc_id;
parms->resolution = resolution;
parms->callback = callback;
parms->userData = userData;
res = pthread_create(&pt_thread_pid, NULL, Pt_CallbackProc, parms);
if (res != 0) return ptHostError;
}
time_started_flag = TRUE;
return ptNoError;
}
PtError Pt_Stop()
{
/* printf("Pt_Stop called\n"); */
pt_callback_proc_id++;
time_started_flag = FALSE;
return ptNoError;
}
int Pt_Started()
{
return time_started_flag;
}
PtTimestamp Pt_Time()
{
UInt64 clock_time, nsec_time;
clock_time = AudioGetCurrentHostTime() - start_time;
nsec_time = AudioConvertHostTimeToNanos(clock_time);
return (PtTimestamp)(nsec_time / NSEC_PER_MSEC);
}
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