/*****************************************************************************
* mtime.c: high resolution time management functions
- * Functions are prototyped in mtime.h.
+ * Functions are prototyped in vlc_mtime.h.
*****************************************************************************
- * Copyright (C) 1998-2001, 2003 VideoLAN
- * $Id: mtime.c,v 1.41 2003/12/11 10:44:32 gbazin Exp $
+ * Copyright (C) 1998-2007 VLC authors and VideoLAN
+ * Copyright © 2006-2007 Rémi Denis-Courmont
+ * $Id$
*
* Authors: Vincent Seguin <seguin@via.ecp.fr>
+ * Rémi Denis-Courmont <rem$videolan,org>
+ * Gisle Vanem
*
- * This program is free software; you can redistribute it and/or modify
- * it under the terms of the GNU General Public License as published by
- * the Free Software Foundation; either version 2 of the License, or
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU Lesser General Public License as published by
+ * the Free Software Foundation; either version 2.1 of the License, or
* (at your option) any later version.
- *
+ *
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
- * GNU General Public License for more details.
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU Lesser General Public License for more details.
*
- * You should have received a copy of the GNU General Public License
- * along with this program; if not, write to the Free Software
- * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111, USA.
+ * You should have received a copy of the GNU Lesser General Public License
+ * along with this program; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin Street, Fifth Floor, Boston MA 02110-1301, USA.
*****************************************************************************/
-/*
- * TODO:
- * see if using Linux real-time extensions is possible and profitable
- */
-
/*****************************************************************************
* Preamble
*****************************************************************************/
-#include <stdio.h> /* sprintf() */
-
-#include <vlc/vlc.h>
-#if defined( PTH_INIT_IN_PTH_H ) /* GNU Pth */
-# include <pth.h>
+#ifdef HAVE_CONFIG_H
+# include "config.h"
#endif
+#include <vlc_common.h>
+#include <assert.h>
+
#ifdef HAVE_UNISTD_H
-# include <unistd.h> /* select() */
+# include <unistd.h>
#endif
-
-#ifdef HAVE_KERNEL_OS_H
-# include <kernel/OS.h>
+#if !defined (_POSIX_TIMERS) || defined (_WIN32)
+# define _POSIX_TIMERS (-1)
#endif
-
-#if defined( WIN32 ) || defined( UNDER_CE )
-# include <windows.h>
+#if (_POSIX_TIMERS > 0)
+# include <time.h> /* clock_gettime() */
#else
-# include <sys/time.h>
-#endif
-
-#if defined(HAVE_NANOSLEEP) && !defined(HAVE_STRUCT_TIMESPEC)
-struct timespec
-{
- time_t tv_sec;
- int32_t tv_nsec;
-};
-#endif
-
-#if defined(HAVE_NANOSLEEP) && !defined(HAVE_DECL_NANOSLEEP)
-int nanosleep(struct timespec *, struct timespec *);
+# include <sys/time.h>
#endif
/**
*
* This function converts a mtime date into a string.
* psz_buffer should be a buffer long enough to store the formatted
- * date.
+ * date.
* \param date to be converted
* \param psz_buffer should be a buffer at least MSTRTIME_MAX_SIZE characters
* \return psz_buffer is returned so this can be used as printf parameter.
*/
char *mstrtime( char *psz_buffer, mtime_t date )
{
- static mtime_t ll1000 = 1000, ll60 = 60, ll24 = 24;
+ static const mtime_t ll1000 = 1000, ll60 = 60, ll24 = 24;
snprintf( psz_buffer, MSTRTIME_MAX_SIZE, "%02d:%02d:%02d-%03d.%03d",
(int) (date / (ll1000 * ll1000 * ll60 * ll60) % ll24),
* \param psz_buffer should be a buffer at least MSTRTIME_MAX_SIZE characters
* \return psz_buffer is returned so this can be used as printf parameter.
*/
-char *secstotimestr( char *psz_buffer, int i_seconds )
+char *secstotimestr( char *psz_buffer, int32_t i_seconds )
{
- snprintf( psz_buffer, MSTRTIME_MAX_SIZE, "%d:%2.2d:%2.2d",
- (int) (i_seconds / (60 *60)),
- (int) ((i_seconds / 60) % 60),
- (int) (i_seconds % 60) );
- return( psz_buffer );
-}
-
-/**
- * Return high precision date
- *
- * Uses the gettimeofday() function when possible (1 MHz resolution) or the
- * ftime() function (1 kHz resolution).
- */
-mtime_t mdate( void )
-{
-#if defined( HAVE_KERNEL_OS_H )
- return( real_time_clock_usecs() );
-
-#elif defined( WIN32 ) || defined( UNDER_CE )
- /* We don't need the real date, just the value of a high precision timer */
- static mtime_t freq = I64C(-1);
- mtime_t usec_time;
-
- if( freq == I64C(-1) )
+ if( unlikely(i_seconds < 0) )
{
- /* Extract from the Tcl source code:
- * (http://www.cs.man.ac.uk/fellowsd-bin/TIP/7.html)
- *
- * Some hardware abstraction layers use the CPU clock
- * in place of the real-time clock as a performance counter
- * reference. This results in:
- * - inconsistent results among the processors on
- * multi-processor systems.
- * - unpredictable changes in performance counter frequency
- * on "gearshift" processors such as Transmeta and
- * SpeedStep.
- * There seems to be no way to test whether the performance
- * counter is reliable, but a useful heuristic is that
- * if its frequency is 1.193182 MHz or 3.579545 MHz, it's
- * derived from a colorburst crystal and is therefore
- * the RTC rather than the TSC. If it's anything else, we
- * presume that the performance counter is unreliable.
- */
-
- freq = ( QueryPerformanceFrequency( (LARGE_INTEGER *)&freq ) &&
- (freq == I64C(1193182) || freq == I64C(3579545) ) )
- ? freq : 0;
+ secstotimestr( psz_buffer + 1, -i_seconds );
+ *psz_buffer = '-';
+ return psz_buffer;
}
- if( freq != 0 )
- {
- /* Microsecond resolution */
- QueryPerformanceCounter( (LARGE_INTEGER *)&usec_time );
- return ( usec_time * 1000000 ) / freq;
- }
+ div_t d;
+
+ d = div( i_seconds, 60 );
+ i_seconds = d.rem;
+ d = div( d.quot, 60 );
+
+ if( d.quot )
+ snprintf( psz_buffer, MSTRTIME_MAX_SIZE, "%u:%02u:%02u",
+ d.quot, d.rem, i_seconds );
else
- {
- /* Fallback on GetTickCount() which has a milisecond resolution
- * (actually, best case is about 10 ms resolution)
- * GetTickCount() only returns a DWORD thus will wrap after
- * about 49.7 days so we try to detect the wrapping. */
-
- static CRITICAL_SECTION date_lock;
- static mtime_t i_previous_time = I64C(-1);
- static int i_wrap_counts = -1;
-
- if( i_wrap_counts == -1 )
- {
- /* Initialization */
- i_previous_time = I64C(1000) * GetTickCount();
- InitializeCriticalSection( &date_lock );
- i_wrap_counts = 0;
- }
-
- EnterCriticalSection( &date_lock );
- usec_time = I64C(1000) *
- (i_wrap_counts * I64C(0x100000000) + GetTickCount());
- if( i_previous_time > usec_time )
- {
- /* Counter wrapped */
- i_wrap_counts++;
- usec_time += I64C(0x100000000000);
- }
- i_previous_time = usec_time;
- LeaveCriticalSection( &date_lock );
-
- return usec_time;
- }
+ snprintf( psz_buffer, MSTRTIME_MAX_SIZE, "%02u:%02u",
+ d.rem, i_seconds );
+ return psz_buffer;
+}
-#else
- struct timeval tv_date;
+/*
+ * Date management (internal and external)
+ */
- /* gettimeofday() could return an error, and should be tested. However, the
- * only possible error, according to 'man', is EFAULT, which can not happen
- * here, since tv is a local variable. */
- gettimeofday( &tv_date, NULL );
- return( (mtime_t) tv_date.tv_sec * 1000000 + (mtime_t) tv_date.tv_usec );
+/**
+ * Initialize a date_t.
+ *
+ * \param date to initialize
+ * \param divider (sample rate) numerator
+ * \param divider (sample rate) denominator
+ */
-#endif
+void date_Init( date_t *p_date, uint32_t i_divider_n, uint32_t i_divider_d )
+{
+ p_date->date = 0;
+ p_date->i_divider_num = i_divider_n;
+ p_date->i_divider_den = i_divider_d;
+ p_date->i_remainder = 0;
}
/**
- * Wait for a date
+ * Change a date_t.
*
- * This function uses select() and an system date function to wake up at a
- * precise date. It should be used for process synchronization. If current date
- * is posterior to wished date, the function returns immediately.
- * \param date The date to wake up at
+ * \param date to change
+ * \param divider (sample rate) numerator
+ * \param divider (sample rate) denominator
*/
-void mwait( mtime_t date )
-{
-#if defined( HAVE_KERNEL_OS_H )
- mtime_t delay;
-
- delay = date - real_time_clock_usecs();
- if( delay <= 0 )
- {
- return;
- }
- snooze( delay );
-#elif defined( WIN32 ) || defined( UNDER_CE )
- mtime_t usec_time, delay;
+void date_Change( date_t *p_date, uint32_t i_divider_n, uint32_t i_divider_d )
+{
+ /* change time scale of remainder */
+ p_date->i_remainder = p_date->i_remainder * i_divider_n / p_date->i_divider_num;
+ p_date->i_divider_num = i_divider_n;
+ p_date->i_divider_den = i_divider_d;
+}
- usec_time = mdate();
- delay = date - usec_time;
- if( delay <= 0 )
- {
- return;
- }
- msleep( delay );
+/**
+ * Set the date value of a date_t.
+ *
+ * \param date to set
+ * \param date value
+ */
+void date_Set( date_t *p_date, mtime_t i_new_date )
+{
+ p_date->date = i_new_date;
+ p_date->i_remainder = 0;
+}
-#else
+/**
+ * Get the date of a date_t
+ *
+ * \param date to get
+ * \return date value
+ */
+mtime_t date_Get( const date_t *p_date )
+{
+ return p_date->date;
+}
- struct timeval tv_date;
- mtime_t delay; /* delay in msec, signed to detect errors */
+/**
+ * Move forwards or backwards the date of a date_t.
+ *
+ * \param date to move
+ * \param difference value
+ */
+void date_Move( date_t *p_date, mtime_t i_difference )
+{
+ p_date->date += i_difference;
+}
- /* see mdate() about gettimeofday() possible errors */
- gettimeofday( &tv_date, NULL );
+/**
+ * Increment the date and return the result, taking into account
+ * rounding errors.
+ *
+ * \param date to increment
+ * \param incrementation in number of samples
+ * \return date value
+ */
+mtime_t date_Increment( date_t *p_date, uint32_t i_nb_samples )
+{
+ mtime_t i_dividend = i_nb_samples * CLOCK_FREQ * p_date->i_divider_den;
+ lldiv_t d = lldiv( i_dividend, p_date->i_divider_num );
- /* calculate delay and check if current date is before wished date */
- delay = date - (mtime_t) tv_date.tv_sec * 1000000
- - (mtime_t) tv_date.tv_usec
- - 10000;
+ p_date->date += d.quot;
+ p_date->i_remainder += (int)d.rem;
- /* Linux/i386 has a granularity of 10 ms. It's better to be in advance
- * than to be late. */
- if( delay <= 0 ) /* wished date is now or already passed */
+ if( p_date->i_remainder >= p_date->i_divider_num )
{
- return;
+ /* This is Bresenham algorithm. */
+ assert( p_date->i_remainder < 2*p_date->i_divider_num);
+ p_date->date += 1;
+ p_date->i_remainder -= p_date->i_divider_num;
}
-# if defined( PTH_INIT_IN_PTH_H )
- pth_usleep( delay );
-
-# elif defined( ST_INIT_IN_ST_H )
- st_usleep( delay );
+ return p_date->date;
+}
-# else
+/**
+ * Decrement the date and return the result, taking into account
+ * rounding errors.
+ *
+ * \param date to decrement
+ * \param decrementation in number of samples
+ * \return date value
+ */
+mtime_t date_Decrement( date_t *p_date, uint32_t i_nb_samples )
+{
+ mtime_t i_dividend = (mtime_t)i_nb_samples * 1000000 * p_date->i_divider_den;
+ p_date->date -= i_dividend / p_date->i_divider_num;
+ unsigned i_rem_adjust = i_dividend % p_date->i_divider_num;
-# if defined( HAVE_NANOSLEEP )
+ if( p_date->i_remainder < i_rem_adjust )
{
- struct timespec ts_delay;
- ts_delay.tv_sec = delay / 1000000;
- ts_delay.tv_nsec = (delay % 1000000) * 1000;
-
- nanosleep( &ts_delay, NULL );
+ /* This is Bresenham algorithm. */
+ assert( p_date->i_remainder > -p_date->i_divider_num);
+ p_date->date -= 1;
+ p_date->i_remainder += p_date->i_divider_num;
}
-# else
- tv_date.tv_sec = delay / 1000000;
- tv_date.tv_usec = delay % 1000000;
- /* see msleep() about select() errors */
- select( 0, NULL, NULL, NULL, &tv_date );
-# endif
-
-# endif
+ p_date->i_remainder -= i_rem_adjust;
-#endif
+ return p_date->date;
}
/**
- * More precise sleep()
- *
- * Portable usleep() function.
- * \param delay the amount of time to sleep
+ * @return NTP 64-bits timestamp in host byte order.
*/
-void msleep( mtime_t delay )
+uint64_t NTPtime64 (void)
{
-#if defined( HAVE_KERNEL_OS_H )
- snooze( delay );
-
-#elif defined( PTH_INIT_IN_PTH_H )
- pth_usleep( delay );
-
-#elif defined( ST_INIT_IN_ST_H )
- st_usleep( delay );
-
-#elif defined( WIN32 ) || defined( UNDER_CE )
- Sleep( (int) (delay / 1000) );
-
-#elif defined( HAVE_NANOSLEEP )
- struct timespec ts_delay;
-
- ts_delay.tv_sec = delay / 1000000;
- ts_delay.tv_nsec = (delay % 1000000) * 1000;
-
- nanosleep( &ts_delay, NULL );
+#if (_POSIX_TIMERS > 0)
+ struct timespec ts;
+ clock_gettime (CLOCK_REALTIME, &ts);
#else
- struct timeval tv_delay;
+ struct timeval tv;
+ struct
+ {
+ uint32_t tv_sec;
+ uint32_t tv_nsec;
+ } ts;
- tv_delay.tv_sec = delay / 1000000;
- tv_delay.tv_usec = delay % 1000000;
+ gettimeofday (&tv, NULL);
+ ts.tv_sec = tv.tv_sec;
+ ts.tv_nsec = tv.tv_usec * 1000;
+#endif
- /* select() return value should be tested, since several possible errors
- * can occur. However, they should only happen in very particular occasions
- * (i.e. when a signal is sent to the thread, or when memory is full), and
- * can be ignored. */
- select( 0, NULL, NULL, NULL, &tv_delay );
+ /* Convert nanoseconds to 32-bits fraction (232 picosecond units) */
+ uint64_t t = (uint64_t)(ts.tv_nsec) << 32;
+ t /= 1000000000;
-#endif
+
+ /* There is 70 years (incl. 17 leap ones) offset to the Unix Epoch.
+ * No leap seconds during that period since they were not invented yet.
+ */
+ assert (t < 0x100000000);
+ t |= ((70LL * 365 + 17) * 24 * 60 * 60 + ts.tv_sec) << 32;
+ return t;
}
projects / vlc / blobdiff