src/misc/mtime.c

   1 /*****************************************************************************
   2  * mtime.c: high resolution time management functions
   3  * Functions are prototyped in vlc_mtime.h.
   4  *****************************************************************************
   5  * Copyright (C) 1998-2007 the VideoLAN team
   6  * Copyright © 2006-2007 Rémi Denis-Courmont
   7  * $Id$
   8  *
   9  * Authors: Vincent Seguin <seguin@via.ecp.fr>
  10  *          Rémi Denis-Courmont <rem$videolan,org>
  11  *          Gisle Vanem
  12  *
  13  * This program is free software; you can redistribute it and/or modify
  14  * it under the terms of the GNU General Public License as published by
  15  * the Free Software Foundation; either version 2 of the License, or
  16  * (at your option) any later version.
  17  *
  18  * This program is distributed in the hope that it will be useful,
  19  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  20  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  21  * GNU General Public License for more details.
  22  *
  23  * You should have received a copy of the GNU General Public License
  24  * along with this program; if not, write to the Free Software
  25  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston MA 02110-1301, USA.
  26  *****************************************************************************/
  27
  28 /*****************************************************************************
  29  * Preamble
  30  *****************************************************************************/
  31
  32 #ifdef HAVE_CONFIG_H
  33 # include "config.h"
  34 #endif
  35
  36 #include <vlc_common.h>
  37
  38 #include <time.h>                      /* clock_gettime(), clock_nanosleep() */
  39 #include <assert.h>
  40 #include <errno.h>
  41
  42 #ifdef HAVE_UNISTD_H
  43 #   include <unistd.h>                                           /* select() */
  44 #endif
  45
  46 #ifdef HAVE_KERNEL_OS_H
  47 #   include <kernel/OS.h>
  48 #endif
  49
  50 #if defined( WIN32 ) || defined( UNDER_CE )
  51 #   include <windows.h>
  52 #   include <mmsystem.h>
  53 #endif
  54
  55 #if defined(HAVE_SYS_TIME_H)
  56 #   include <sys/time.h>
  57 #endif
  58
  59 #if defined(__APPLE__) && !defined(__powerpc__) && !defined(__ppc__) && !defined(__ppc64__)
  60 #define USE_APPLE_MACH 1
  61 #   include <mach/mach.h>
  62 #   include <mach/mach_time.h>
  63 #endif
  64
  65 #if !defined(HAVE_STRUCT_TIMESPEC)
  66 struct timespec
  67 {
  68     time_t  tv_sec;
  69     int32_t tv_nsec;
  70 };
  71 #endif
  72
  73 #if defined(HAVE_NANOSLEEP) && !defined(HAVE_DECL_NANOSLEEP)
  74 int nanosleep(struct timespec *, struct timespec *);
  75 #endif
  76
  77 #if !defined (_POSIX_CLOCK_SELECTION)
  78 #  define _POSIX_CLOCK_SELECTION (-1)
  79 #endif
  80
  81 # if (_POSIX_CLOCK_SELECTION < 0)
  82 /*
  83  * We cannot use the monotonic clock if clock selection is not available,
  84  * as it would screw vlc_cond_timedwait() completely. Instead, we have to
  85  * stick to the realtime clock. Nevermind it screws everything up when ntpdate
  86  * warps the wall clock.
  87  */
  88 #  undef CLOCK_MONOTONIC
  89 #  define CLOCK_MONOTONIC CLOCK_REALTIME
  90 #elif !defined (HAVE_CLOCK_NANOSLEEP)
  91 /* Clock selection without clock in the first place, I don't think so. */
  92 #  error We have quite a situation here! Fix me if it ever happens.
  93 #endif
  94
  95 /**
  96  * Return a date in a readable format
  97  *
  98  * This function converts a mtime date into a string.
  99  * psz_buffer should be a buffer long enough to store the formatted
 100  * date.
 101  * \param date to be converted
 102  * \param psz_buffer should be a buffer at least MSTRTIME_MAX_SIZE characters
 103  * \return psz_buffer is returned so this can be used as printf parameter.
 104  */
 105 char *mstrtime( char *psz_buffer, mtime_t date )
 106 {
 107     static const mtime_t ll1000 = 1000, ll60 = 60, ll24 = 24;
 108
 109     snprintf( psz_buffer, MSTRTIME_MAX_SIZE, "%02d:%02d:%02d-%03d.%03d",
 110              (int) (date / (ll1000 * ll1000 * ll60 * ll60) % ll24),
 111              (int) (date / (ll1000 * ll1000 * ll60) % ll60),
 112              (int) (date / (ll1000 * ll1000) % ll60),
 113              (int) (date / ll1000 % ll1000),
 114              (int) (date % ll1000) );
 115     return( psz_buffer );
 116 }
 117
 118 /**
 119  * Convert seconds to a time in the format h:mm:ss.
 120  *
 121  * This function is provided for any interface function which need to print a
 122  * time string in the format h:mm:ss
 123  * date.
 124  * \param secs  the date to be converted
 125  * \param psz_buffer should be a buffer at least MSTRTIME_MAX_SIZE characters
 126  * \return psz_buffer is returned so this can be used as printf parameter.
 127  */
 128 char *secstotimestr( char *psz_buffer, int32_t i_seconds )
 129 {
 130     if( unlikely(i_seconds < 0) )
 131     {
 132         secstotimestr( psz_buffer + 1, -i_seconds );
 133         *psz_buffer = '-';
 134         return psz_buffer;
 135     }
 136
 137     div_t d;
 138
 139     d = div( i_seconds, 60 );
 140     i_seconds = d.rem;
 141     d = div( d.quot, 60 );
 142
 143     if( d.quot )
 144         snprintf( psz_buffer, MSTRTIME_MAX_SIZE, "%u:%02u:%02u",
 145                  d.quot, d.rem, i_seconds );
 146     else
 147         snprintf( psz_buffer, MSTRTIME_MAX_SIZE, "%02u:%02u",
 148                   d.rem, i_seconds );
 149     return psz_buffer;
 150 }
 151
 152 #if defined (HAVE_CLOCK_NANOSLEEP)
 153 static unsigned prec = 0;
 154
 155 static void mprec_once( void )
 156 {
 157     struct timespec ts;
 158     if( clock_getres( CLOCK_MONOTONIC, &ts ))
 159         clock_getres( CLOCK_REALTIME, &ts );
 160
 161     prec = ts.tv_nsec / 1000;
 162 }
 163 #endif
 164
 165 /**
 166  * Return a value that is no bigger than the clock precision
 167  * (possibly zero).
 168  */
 169 static inline unsigned mprec( void )
 170 {
 171 #if defined (HAVE_CLOCK_NANOSLEEP)
 172     static pthread_once_t once = PTHREAD_ONCE_INIT;
 173     pthread_once( &once, mprec_once );
 174     return prec;
 175 #else
 176     return 0;
 177 #endif
 178 }
 179
 180 #ifdef USE_APPLE_MACH
 181 static mach_timebase_info_data_t mtime_timebase_info;
 182 static pthread_once_t mtime_timebase_info_once = PTHREAD_ONCE_INIT;
 183 static void mtime_init_timebase(void)
 184 {
 185     mach_timebase_info(&mtime_timebase_info);
 186 }
 187 #endif
 188
 189 /**
 190  * Return high precision date
 191  *
 192  * Use a 1 MHz clock when possible, or 1 kHz
 193  *
 194  * Beware ! It doesn't reflect the actual date (since epoch), but can be the machine's uptime or anything (when monotonic clock is used)
 195  */
 196 mtime_t mdate( void )
 197 {
 198     mtime_t res;
 199
 200 #if defined (HAVE_CLOCK_NANOSLEEP)
 201     struct timespec ts;
 202
 203     /* Try to use POSIX monotonic clock if available */
 204     if( clock_gettime( CLOCK_MONOTONIC, &ts ) == EINVAL )
 205         /* Run-time fallback to real-time clock (always available) */
 206         (void)clock_gettime( CLOCK_REALTIME, &ts );
 207
 208     res = ((mtime_t)ts.tv_sec * (mtime_t)1000000)
 209            + (mtime_t)(ts.tv_nsec / 1000);
 210
 211 #elif defined( HAVE_KERNEL_OS_H )
 212     res = real_time_clock_usecs();
 213
 214 #elif defined( USE_APPLE_MACH )
 215     pthread_once(&mtime_timebase_info_once, mtime_init_timebase);
 216     uint64_t date = mach_absolute_time();
 217
 218     /* Convert to nanoseconds */
 219     date *= mtime_timebase_info.numer;
 220     date /= mtime_timebase_info.denom;
 221
 222     /* Convert to microseconds */
 223     res = date / 1000;
 224 #elif defined( WIN32 ) || defined( UNDER_CE )
 225     /* We don't need the real date, just the value of a high precision timer */
 226     static mtime_t freq = INT64_C(-1);
 227
 228     if( freq == INT64_C(-1) )
 229     {
 230         /* Extract from the Tcl source code:
 231          * (http://www.cs.man.ac.uk/fellowsd-bin/TIP/7.html)
 232          *
 233          * Some hardware abstraction layers use the CPU clock
 234          * in place of the real-time clock as a performance counter
 235          * reference.  This results in:
 236          *    - inconsistent results among the processors on
 237          *      multi-processor systems.
 238          *    - unpredictable changes in performance counter frequency
 239          *      on "gearshift" processors such as Transmeta and
 240          *      SpeedStep.
 241          * There seems to be no way to test whether the performance
 242          * counter is reliable, but a useful heuristic is that
 243          * if its frequency is 1.193182 MHz or 3.579545 MHz, it's
 244          * derived from a colorburst crystal and is therefore
 245          * the RTC rather than the TSC.  If it's anything else, we
 246          * presume that the performance counter is unreliable.
 247          */
 248         LARGE_INTEGER buf;
 249
 250         freq = ( QueryPerformanceFrequency( &buf ) &&
 251                  (buf.QuadPart == INT64_C(1193182) || buf.QuadPart == INT64_C(3579545) ) )
 252                ? buf.QuadPart : 0;
 253
 254 #if defined( WIN32 )
 255         /* on windows 2000, XP and Vista detect if there are two
 256            cores there - that makes QueryPerformanceFrequency in
 257            any case not trustable?
 258            (may also be true, for single cores with adaptive
 259             CPU frequency and active power management?)
 260         */
 261         HINSTANCE h_Kernel32 = LoadLibrary(_T("kernel32.dll"));
 262         if(h_Kernel32)
 263         {
 264             void WINAPI (*pf_GetSystemInfo)(LPSYSTEM_INFO);
 265             pf_GetSystemInfo = (void WINAPI (*)(LPSYSTEM_INFO))
 266                                 GetProcAddress(h_Kernel32, _T("GetSystemInfo"));
 267             if(pf_GetSystemInfo)
 268             {
 269                SYSTEM_INFO system_info;
 270                pf_GetSystemInfo(&system_info);
 271                if(system_info.dwNumberOfProcessors > 1)
 272                   freq = 0;
 273             }
 274             FreeLibrary(h_Kernel32);
 275         }
 276 #endif
 277     }
 278
 279     if( freq != 0 )
 280     {
 281         LARGE_INTEGER counter;
 282         QueryPerformanceCounter (&counter);
 283
 284         /* Convert to from (1/freq) to microsecond resolution */
 285         /* We need to split the division to avoid 63-bits overflow */
 286         lldiv_t d = lldiv (counter.QuadPart, freq);
 287
 288         res = (d.quot * 1000000) + ((d.rem * 1000000) / freq);
 289     }
 290     else
 291     {
 292         /* Fallback on timeGetTime() which has a millisecond resolution
 293          * (actually, best case is about 5 ms resolution)
 294          * timeGetTime() only returns a DWORD thus will wrap after
 295          * about 49.7 days so we try to detect the wrapping. */
 296
 297         static CRITICAL_SECTION date_lock;
 298         static mtime_t i_previous_time = INT64_C(-1);
 299         static int i_wrap_counts = -1;
 300
 301         if( i_wrap_counts == -1 )
 302         {
 303             /* Initialization */
 304 #if defined( WIN32 )
 305             i_previous_time = INT64_C(1000) * timeGetTime();
 306 #else
 307             i_previous_time = INT64_C(1000) * GetTickCount();
 308 #endif
 309             InitializeCriticalSection( &date_lock );
 310             i_wrap_counts = 0;
 311         }
 312
 313         EnterCriticalSection( &date_lock );
 314 #if defined( WIN32 )
 315         res = INT64_C(1000) *
 316             (i_wrap_counts * INT64_C(0x100000000) + timeGetTime());
 317 #else
 318         res = INT64_C(1000) *
 319             (i_wrap_counts * INT64_C(0x100000000) + GetTickCount());
 320 #endif
 321         if( i_previous_time > res )
 322         {
 323             /* Counter wrapped */
 324             i_wrap_counts++;
 325             res += INT64_C(0x100000000) * 1000;
 326         }
 327         i_previous_time = res;
 328         LeaveCriticalSection( &date_lock );
 329     }
 330 #elif defined(USE_APPLE_MACH)
 331     /* The version that should be used, if it was cancelable */
 332     pthread_once(&mtime_timebase_info_once, mtime_init_timebase);
 333     uint64_t mach_time = date * 1000 * mtime_timebase_info.denom / mtime_timebase_info.numer;
 334     mach_wait_until(mach_time);
 335
 336 #else
 337     struct timeval tv_date;
 338
 339     /* gettimeofday() cannot fail given &tv_date is a valid address */
 340     (void)gettimeofday( &tv_date, NULL );
 341     res = (mtime_t) tv_date.tv_sec * 1000000 + (mtime_t) tv_date.tv_usec;
 342 #endif
 343
 344     return res;
 345 }
 346
 347 #undef mwait
 348 /**
 349  * Wait for a date
 350  *
 351  * This function uses select() and an system date function to wake up at a
 352  * precise date. It should be used for process synchronization. If current date
 353  * is posterior to wished date, the function returns immediately.
 354  * \param date The date to wake up at
 355  */
 356 void mwait( mtime_t date )
 357 {
 358     /* If the deadline is already elapsed, or within the clock precision,
 359      * do not even bother the system timer. */
 360     date -= mprec();
 361
 362 #if defined (HAVE_CLOCK_NANOSLEEP)
 363     lldiv_t d = lldiv( date, 1000000 );
 364     struct timespec ts = { d.quot, d.rem * 1000 };
 365
 366     int val;
 367     while( ( val = clock_nanosleep( CLOCK_MONOTONIC, TIMER_ABSTIME, &ts,
 368                                     NULL ) ) == EINTR );
 369     if( val == EINVAL )
 370     {
 371         ts.tv_sec = d.quot; ts.tv_nsec = d.rem * 1000;
 372         while( clock_nanosleep( CLOCK_REALTIME, 0, &ts, NULL ) == EINTR );
 373     }
 374
 375 #elif defined (WIN32)
 376     mtime_t i_total;
 377
 378     while( (i_total = (date - mdate())) > 0 )
 379     {
 380         const mtime_t i_sleep = i_total / 1000;
 381         DWORD i_delay = (i_sleep > 0x7fffffff) ? 0x7fffffff : i_sleep;
 382         vlc_testcancel();
 383         SleepEx( i_delay, TRUE );
 384     }
 385     vlc_testcancel();
 386
 387 #else
 388     mtime_t delay = date - mdate();
 389     if( delay > 0 )
 390         msleep( delay );
 391
 392 #endif
 393 }
 394
 395
 396 #include "libvlc.h" /* vlc_backtrace() */
 397 #undef msleep
 398
 399 /**
 400  * Portable usleep(). Cancellation point.
 401  *
 402  * \param delay the amount of time to sleep
 403  */
 404 void msleep( mtime_t delay )
 405 {
 406 #if defined( HAVE_CLOCK_NANOSLEEP )
 407     lldiv_t d = lldiv( delay, 1000000 );
 408     struct timespec ts = { d.quot, d.rem * 1000 };
 409
 410     int val;
 411     while( ( val = clock_nanosleep( CLOCK_MONOTONIC, 0, &ts, &ts ) ) == EINTR );
 412     if( val == EINVAL )
 413     {
 414         ts.tv_sec = d.quot; ts.tv_nsec = d.rem * 1000;
 415         while( clock_nanosleep( CLOCK_REALTIME, 0, &ts, &ts ) == EINTR );
 416     }
 417
 418 #elif defined( HAVE_KERNEL_OS_H )
 419     snooze( delay );
 420
 421 #elif defined( WIN32 ) || defined( UNDER_CE )
 422     mwait (mdate () + delay);
 423
 424 #elif defined( HAVE_NANOSLEEP )
 425     struct timespec ts_delay;
 426
 427     ts_delay.tv_sec = delay / 1000000;
 428     ts_delay.tv_nsec = (delay % 1000000) * 1000;
 429
 430     while( nanosleep( &ts_delay, &ts_delay ) && ( errno == EINTR ) );
 431
 432 #elif defined (USE_APPLE_MACH)
 433     /* The version that should be used, if it was cancelable */
 434     pthread_once(&mtime_timebase_info_once, mtime_init_timebase);
 435     uint64_t mach_time = delay * 1000 * mtime_timebase_info.denom / mtime_timebase_info.numer;
 436     mach_wait_until(mach_time + mach_absolute_time());
 437
 438 #else
 439     struct timeval tv_delay;
 440
 441     tv_delay.tv_sec = delay / 1000000;
 442     tv_delay.tv_usec = delay % 1000000;
 443
 444     /* If a signal is caught, you are screwed. Update your OS to nanosleep()
 445      * or clock_nanosleep() if this is an issue. */
 446     select( 0, NULL, NULL, NULL, &tv_delay );
 447 #endif
 448 }
 449
 450 /*
 451  * Date management (internal and external)
 452  */
 453
 454 /**
 455  * Initialize a date_t.
 456  *
 457  * \param date to initialize
 458  * \param divider (sample rate) numerator
 459  * \param divider (sample rate) denominator
 460  */
 461
 462 void date_Init( date_t *p_date, uint32_t i_divider_n, uint32_t i_divider_d )
 463 {
 464     p_date->date = 0;
 465     p_date->i_divider_num = i_divider_n;
 466     p_date->i_divider_den = i_divider_d;
 467     p_date->i_remainder = 0;
 468 }
 469
 470 /**
 471  * Change a date_t.
 472  *
 473  * \param date to change
 474  * \param divider (sample rate) numerator
 475  * \param divider (sample rate) denominator
 476  */
 477
 478 void date_Change( date_t *p_date, uint32_t i_divider_n, uint32_t i_divider_d )
 479 {
 480     /* change time scale of remainder */
 481     p_date->i_remainder = p_date->i_remainder * i_divider_n / p_date->i_divider_num;
 482     p_date->i_divider_num = i_divider_n;
 483     p_date->i_divider_den = i_divider_d;
 484 }
 485
 486 /**
 487  * Set the date value of a date_t.
 488  *
 489  * \param date to set
 490  * \param date value
 491  */
 492 void date_Set( date_t *p_date, mtime_t i_new_date )
 493 {
 494     p_date->date = i_new_date;
 495     p_date->i_remainder = 0;
 496 }
 497
 498 /**
 499  * Get the date of a date_t
 500  *
 501  * \param date to get
 502  * \return date value
 503  */
 504 mtime_t date_Get( const date_t *p_date )
 505 {
 506     return p_date->date;
 507 }
 508
 509 /**
 510  * Move forwards or backwards the date of a date_t.
 511  *
 512  * \param date to move
 513  * \param difference value
 514  */
 515 void date_Move( date_t *p_date, mtime_t i_difference )
 516 {
 517     p_date->date += i_difference;
 518 }
 519
 520 /**
 521  * Increment the date and return the result, taking into account
 522  * rounding errors.
 523  *
 524  * \param date to increment
 525  * \param incrementation in number of samples
 526  * \return date value
 527  */
 528 mtime_t date_Increment( date_t *p_date, uint32_t i_nb_samples )
 529 {
 530     mtime_t i_dividend = (mtime_t)i_nb_samples * 1000000 * p_date->i_divider_den;
 531     p_date->date += i_dividend / p_date->i_divider_num;
 532     p_date->i_remainder += (int)(i_dividend % p_date->i_divider_num);
 533
 534     if( p_date->i_remainder >= p_date->i_divider_num )
 535     {
 536         /* This is Bresenham algorithm. */
 537         assert( p_date->i_remainder < 2*p_date->i_divider_num);
 538         p_date->date += 1;
 539         p_date->i_remainder -= p_date->i_divider_num;
 540     }
 541
 542     return p_date->date;
 543 }
 544
 545 /**
 546  * Decrement the date and return the result, taking into account
 547  * rounding errors.
 548  *
 549  * \param date to decrement
 550  * \param decrementation in number of samples
 551  * \return date value
 552  */
 553 mtime_t date_Decrement( date_t *p_date, uint32_t i_nb_samples )
 554 {
 555     mtime_t i_dividend = (mtime_t)i_nb_samples * 1000000 * p_date->i_divider_den;
 556     p_date->date -= i_dividend / p_date->i_divider_num;
 557     unsigned i_rem_adjust = i_dividend % p_date->i_divider_num;
 558
 559     if( p_date->i_remainder < i_rem_adjust )
 560     {
 561         /* This is Bresenham algorithm. */
 562         assert( p_date->i_remainder > -p_date->i_divider_num);
 563         p_date->date -= 1;
 564         p_date->i_remainder += p_date->i_divider_num;
 565     }
 566
 567     p_date->i_remainder -= i_rem_adjust;
 568
 569     return p_date->date;
 570 }
 571
 572 #ifndef HAVE_GETTIMEOFDAY
 573
 574 #ifdef WIN32
 575
 576 /*
 577  * Number of micro-seconds between the beginning of the Windows epoch
 578  * (Jan. 1, 1601) and the Unix epoch (Jan. 1, 1970).
 579  *
 580  * This assumes all Win32 compilers have 64-bit support.
 581  */
 582 #if defined(_MSC_VER) || defined(_MSC_EXTENSIONS) || defined(__WATCOMC__)
 583 #   define DELTA_EPOCH_IN_USEC  11644473600000000Ui64
 584 #else
 585 #   define DELTA_EPOCH_IN_USEC  11644473600000000ULL
 586 #endif
 587
 588 static uint64_t filetime_to_unix_epoch (const FILETIME *ft)
 589 {
 590     uint64_t res = (uint64_t) ft->dwHighDateTime << 32;
 591
 592     res |= ft->dwLowDateTime;
 593     res /= 10;                   /* from 100 nano-sec periods to usec */
 594     res -= DELTA_EPOCH_IN_USEC;  /* from Win epoch to Unix epoch */
 595     return (res);
 596 }
 597
 598 static int gettimeofday (struct timeval *tv, void *tz )
 599 {
 600     FILETIME  ft;
 601     uint64_t tim;
 602
 603     if (!tv) {
 604         return VLC_EGENERIC;
 605     }
 606     GetSystemTimeAsFileTime (&ft);
 607     tim = filetime_to_unix_epoch (&ft);
 608     tv->tv_sec  = (long) (tim / 1000000L);
 609     tv->tv_usec = (long) (tim % 1000000L);
 610     return (0);
 611 }
 612
 613 #endif
 614
 615 #endif
 616
 617 /**
 618  * @return NTP 64-bits timestamp in host byte order.
 619  */
 620 uint64_t NTPtime64 (void)
 621 {
 622     struct timespec ts;
 623 #if defined (CLOCK_REALTIME)
 624     clock_gettime (CLOCK_REALTIME, &ts);
 625 #else
 626     {
 627         struct timeval tv;
 628         gettimeofday (&tv, NULL);
 629         ts.tv_sec = tv.tv_sec;
 630         ts.tv_nsec = tv.tv_usec * 1000;
 631     }
 632 #endif
 633
 634     /* Convert nanoseconds to 32-bits fraction (232 picosecond units) */
 635     uint64_t t = (uint64_t)(ts.tv_nsec) << 32;
 636     t /= 1000000000;
 637
 638
 639     /* There is 70 years (incl. 17 leap ones) offset to the Unix Epoch.
 640      * No leap seconds during that period since they were not invented yet.
 641      */
 642     assert (t < 0x100000000);
 643     t |= ((70LL * 365 + 17) * 24 * 60 * 60 + ts.tv_sec) << 32;
 644     return t;
 645 }
 646