Narayan Kamath | fc74cb4 | 2017-09-13 12:53:52 +0100 | [diff] [blame^] | 1 | /* |
| 2 | * Copyright (c) 2007-2012 Niels Provos and Nick Mathewson |
| 3 | * |
| 4 | * Redistribution and use in source and binary forms, with or without |
| 5 | * modification, are permitted provided that the following conditions |
| 6 | * are met: |
| 7 | * 1. Redistributions of source code must retain the above copyright |
| 8 | * notice, this list of conditions and the following disclaimer. |
| 9 | * 2. Redistributions in binary form must reproduce the above copyright |
| 10 | * notice, this list of conditions and the following disclaimer in the |
| 11 | * documentation and/or other materials provided with the distribution. |
| 12 | * 3. The name of the author may not be used to endorse or promote products |
| 13 | * derived from this software without specific prior written permission. |
| 14 | * |
| 15 | * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR |
| 16 | * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES |
| 17 | * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. |
| 18 | * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, |
| 19 | * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT |
| 20 | * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, |
| 21 | * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY |
| 22 | * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT |
| 23 | * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF |
| 24 | * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. |
| 25 | */ |
| 26 | |
| 27 | #include "event2/event-config.h" |
| 28 | #include "evconfig-private.h" |
| 29 | |
| 30 | #ifdef _WIN32 |
| 31 | #include <winsock2.h> |
| 32 | #define WIN32_LEAN_AND_MEAN |
| 33 | #include <windows.h> |
| 34 | #undef WIN32_LEAN_AND_MEAN |
| 35 | #endif |
| 36 | |
| 37 | #include <sys/types.h> |
| 38 | #ifdef EVENT__HAVE_STDLIB_H |
| 39 | #include <stdlib.h> |
| 40 | #endif |
| 41 | #include <errno.h> |
| 42 | #include <limits.h> |
| 43 | #ifndef EVENT__HAVE_GETTIMEOFDAY |
| 44 | #include <sys/timeb.h> |
| 45 | #endif |
| 46 | #if !defined(EVENT__HAVE_NANOSLEEP) && !defined(EVENT_HAVE_USLEEP) && \ |
| 47 | !defined(_WIN32) |
| 48 | #include <sys/select.h> |
| 49 | #endif |
| 50 | #include <time.h> |
| 51 | #include <sys/stat.h> |
| 52 | #include <string.h> |
| 53 | |
| 54 | /** evutil_usleep_() */ |
| 55 | #if defined(_WIN32) |
| 56 | #elif defined(EVENT__HAVE_NANOSLEEP) |
| 57 | #elif defined(EVENT__HAVE_USLEEP) |
| 58 | #include <unistd.h> |
| 59 | #endif |
| 60 | |
| 61 | #include "event2/util.h" |
| 62 | #include "util-internal.h" |
| 63 | #include "log-internal.h" |
| 64 | #include "mm-internal.h" |
| 65 | |
| 66 | #ifndef EVENT__HAVE_GETTIMEOFDAY |
| 67 | /* No gettimeofday; this must be windows. */ |
| 68 | int |
| 69 | evutil_gettimeofday(struct timeval *tv, struct timezone *tz) |
| 70 | { |
| 71 | #ifdef _MSC_VER |
| 72 | #define U64_LITERAL(n) n##ui64 |
| 73 | #else |
| 74 | #define U64_LITERAL(n) n##llu |
| 75 | #endif |
| 76 | |
| 77 | /* Conversion logic taken from Tor, which in turn took it |
| 78 | * from Perl. GetSystemTimeAsFileTime returns its value as |
| 79 | * an unaligned (!) 64-bit value containing the number of |
| 80 | * 100-nanosecond intervals since 1 January 1601 UTC. */ |
| 81 | #define EPOCH_BIAS U64_LITERAL(116444736000000000) |
| 82 | #define UNITS_PER_SEC U64_LITERAL(10000000) |
| 83 | #define USEC_PER_SEC U64_LITERAL(1000000) |
| 84 | #define UNITS_PER_USEC U64_LITERAL(10) |
| 85 | union { |
| 86 | FILETIME ft_ft; |
| 87 | ev_uint64_t ft_64; |
| 88 | } ft; |
| 89 | |
| 90 | if (tv == NULL) |
| 91 | return -1; |
| 92 | |
| 93 | GetSystemTimeAsFileTime(&ft.ft_ft); |
| 94 | |
| 95 | if (EVUTIL_UNLIKELY(ft.ft_64 < EPOCH_BIAS)) { |
| 96 | /* Time before the unix epoch. */ |
| 97 | return -1; |
| 98 | } |
| 99 | ft.ft_64 -= EPOCH_BIAS; |
| 100 | tv->tv_sec = (long) (ft.ft_64 / UNITS_PER_SEC); |
| 101 | tv->tv_usec = (long) ((ft.ft_64 / UNITS_PER_USEC) % USEC_PER_SEC); |
| 102 | return 0; |
| 103 | } |
| 104 | #endif |
| 105 | |
| 106 | #define MAX_SECONDS_IN_MSEC_LONG \ |
| 107 | (((LONG_MAX) - 999) / 1000) |
| 108 | |
| 109 | long |
| 110 | evutil_tv_to_msec_(const struct timeval *tv) |
| 111 | { |
| 112 | if (tv->tv_usec > 1000000 || tv->tv_sec > MAX_SECONDS_IN_MSEC_LONG) |
| 113 | return -1; |
| 114 | |
| 115 | return (tv->tv_sec * 1000) + ((tv->tv_usec + 999) / 1000); |
| 116 | } |
| 117 | |
| 118 | /* |
| 119 | Replacement for usleep on platforms that don't have one. Not guaranteed to |
| 120 | be any more finegrained than 1 msec. |
| 121 | */ |
| 122 | void |
| 123 | evutil_usleep_(const struct timeval *tv) |
| 124 | { |
| 125 | if (!tv) |
| 126 | return; |
| 127 | #if defined(_WIN32) |
| 128 | { |
| 129 | long msec = evutil_tv_to_msec_(tv); |
| 130 | Sleep((DWORD)msec); |
| 131 | } |
| 132 | #elif defined(EVENT__HAVE_NANOSLEEP) |
| 133 | { |
| 134 | struct timespec ts; |
| 135 | ts.tv_sec = tv->tv_sec; |
| 136 | ts.tv_nsec = tv->tv_usec*1000; |
| 137 | nanosleep(&ts, NULL); |
| 138 | } |
| 139 | #elif defined(EVENT__HAVE_USLEEP) |
| 140 | /* Some systems don't like to usleep more than 999999 usec */ |
| 141 | sleep(tv->tv_sec); |
| 142 | usleep(tv->tv_usec); |
| 143 | #else |
| 144 | select(0, NULL, NULL, NULL, tv); |
| 145 | #endif |
| 146 | } |
| 147 | |
| 148 | int |
| 149 | evutil_date_rfc1123(char *date, const size_t datelen, const struct tm *tm) |
| 150 | { |
| 151 | static const char *DAYS[] = |
| 152 | { "Sun", "Mon", "Tue", "Wed", "Thu", "Fri", "Sat" }; |
| 153 | static const char *MONTHS[] = |
| 154 | { "Jan", "Feb", "Mar", "Apr", "May", "Jun", "Jul", "Aug", "Sep", "Oct", "Nov", "Dec" }; |
| 155 | |
| 156 | time_t t = time(NULL); |
| 157 | |
| 158 | #ifndef _WIN32 |
| 159 | struct tm sys; |
| 160 | #endif |
| 161 | |
| 162 | /* If `tm` is null, set system's current time. */ |
| 163 | if (tm == NULL) { |
| 164 | #ifdef _WIN32 |
| 165 | /** TODO: detect _gmtime64()/_gmtime64_s() */ |
| 166 | tm = gmtime(&t); |
| 167 | #else |
| 168 | gmtime_r(&t, &sys); |
| 169 | tm = &sys; |
| 170 | #endif |
| 171 | } |
| 172 | |
| 173 | return evutil_snprintf( |
| 174 | date, datelen, "%s, %02d %s %4d %02d:%02d:%02d GMT", |
| 175 | DAYS[tm->tm_wday], tm->tm_mday, MONTHS[tm->tm_mon], |
| 176 | 1900 + tm->tm_year, tm->tm_hour, tm->tm_min, tm->tm_sec); |
| 177 | } |
| 178 | |
| 179 | /* |
| 180 | This function assumes it's called repeatedly with a |
| 181 | not-actually-so-monotonic time source whose outputs are in 'tv'. It |
| 182 | implements a trivial ratcheting mechanism so that the values never go |
| 183 | backwards. |
| 184 | */ |
| 185 | static void |
| 186 | adjust_monotonic_time(struct evutil_monotonic_timer *base, |
| 187 | struct timeval *tv) |
| 188 | { |
| 189 | evutil_timeradd(tv, &base->adjust_monotonic_clock, tv); |
| 190 | |
| 191 | if (evutil_timercmp(tv, &base->last_time, <)) { |
| 192 | /* Guess it wasn't monotonic after all. */ |
| 193 | struct timeval adjust; |
| 194 | evutil_timersub(&base->last_time, tv, &adjust); |
| 195 | evutil_timeradd(&adjust, &base->adjust_monotonic_clock, |
| 196 | &base->adjust_monotonic_clock); |
| 197 | *tv = base->last_time; |
| 198 | } |
| 199 | base->last_time = *tv; |
| 200 | } |
| 201 | |
| 202 | /* |
| 203 | Allocate a new struct evutil_monotonic_timer |
| 204 | */ |
| 205 | struct evutil_monotonic_timer * |
| 206 | evutil_monotonic_timer_new(void) |
| 207 | { |
| 208 | struct evutil_monotonic_timer *p = NULL; |
| 209 | |
| 210 | p = mm_malloc(sizeof(*p)); |
| 211 | if (!p) goto done; |
| 212 | |
| 213 | memset(p, 0, sizeof(*p)); |
| 214 | |
| 215 | done: |
| 216 | return p; |
| 217 | } |
| 218 | |
| 219 | /* |
| 220 | Free a struct evutil_monotonic_timer |
| 221 | */ |
| 222 | void |
| 223 | evutil_monotonic_timer_free(struct evutil_monotonic_timer *timer) |
| 224 | { |
| 225 | if (timer) { |
| 226 | mm_free(timer); |
| 227 | } |
| 228 | } |
| 229 | |
| 230 | /* |
| 231 | Set up a struct evutil_monotonic_timer for initial use |
| 232 | */ |
| 233 | int |
| 234 | evutil_configure_monotonic_time(struct evutil_monotonic_timer *timer, |
| 235 | int flags) |
| 236 | { |
| 237 | return evutil_configure_monotonic_time_(timer, flags); |
| 238 | } |
| 239 | |
| 240 | /* |
| 241 | Query the current monotonic time |
| 242 | */ |
| 243 | int |
| 244 | evutil_gettime_monotonic(struct evutil_monotonic_timer *timer, |
| 245 | struct timeval *tp) |
| 246 | { |
| 247 | return evutil_gettime_monotonic_(timer, tp); |
| 248 | } |
| 249 | |
| 250 | |
| 251 | #if defined(HAVE_POSIX_MONOTONIC) |
| 252 | /* ===== |
| 253 | The POSIX clock_gettime() interface provides a few ways to get at a |
| 254 | monotonic clock. CLOCK_MONOTONIC is most widely supported. Linux also |
| 255 | provides a CLOCK_MONOTONIC_COARSE with accuracy of about 1-4 msec. |
| 256 | |
| 257 | On all platforms I'm aware of, CLOCK_MONOTONIC really is monotonic. |
| 258 | Platforms don't agree about whether it should jump on a sleep/resume. |
| 259 | */ |
| 260 | |
| 261 | int |
| 262 | evutil_configure_monotonic_time_(struct evutil_monotonic_timer *base, |
| 263 | int flags) |
| 264 | { |
| 265 | /* CLOCK_MONOTONIC exists on FreeBSD, Linux, and Solaris. You need to |
| 266 | * check for it at runtime, because some older kernel versions won't |
| 267 | * have it working. */ |
| 268 | #ifdef CLOCK_MONOTONIC_COARSE |
| 269 | const int precise = flags & EV_MONOT_PRECISE; |
| 270 | #endif |
| 271 | const int fallback = flags & EV_MONOT_FALLBACK; |
| 272 | struct timespec ts; |
| 273 | |
| 274 | #ifdef CLOCK_MONOTONIC_COARSE |
| 275 | if (CLOCK_MONOTONIC_COARSE < 0) { |
| 276 | /* Technically speaking, nothing keeps CLOCK_* from being |
| 277 | * negative (as far as I know). This check and the one below |
| 278 | * make sure that it's safe for us to use -1 as an "unset" |
| 279 | * value. */ |
| 280 | event_errx(1,"I didn't expect CLOCK_MONOTONIC_COARSE to be < 0"); |
| 281 | } |
| 282 | if (! precise && ! fallback) { |
| 283 | if (clock_gettime(CLOCK_MONOTONIC_COARSE, &ts) == 0) { |
| 284 | base->monotonic_clock = CLOCK_MONOTONIC_COARSE; |
| 285 | return 0; |
| 286 | } |
| 287 | } |
| 288 | #endif |
| 289 | if (!fallback && clock_gettime(CLOCK_MONOTONIC, &ts) == 0) { |
| 290 | base->monotonic_clock = CLOCK_MONOTONIC; |
| 291 | return 0; |
| 292 | } |
| 293 | |
| 294 | if (CLOCK_MONOTONIC < 0) { |
| 295 | event_errx(1,"I didn't expect CLOCK_MONOTONIC to be < 0"); |
| 296 | } |
| 297 | |
| 298 | base->monotonic_clock = -1; |
| 299 | return 0; |
| 300 | } |
| 301 | |
| 302 | int |
| 303 | evutil_gettime_monotonic_(struct evutil_monotonic_timer *base, |
| 304 | struct timeval *tp) |
| 305 | { |
| 306 | struct timespec ts; |
| 307 | |
| 308 | if (base->monotonic_clock < 0) { |
| 309 | if (evutil_gettimeofday(tp, NULL) < 0) |
| 310 | return -1; |
| 311 | adjust_monotonic_time(base, tp); |
| 312 | return 0; |
| 313 | } |
| 314 | |
| 315 | if (clock_gettime(base->monotonic_clock, &ts) == -1) |
| 316 | return -1; |
| 317 | tp->tv_sec = ts.tv_sec; |
| 318 | tp->tv_usec = ts.tv_nsec / 1000; |
| 319 | |
| 320 | return 0; |
| 321 | } |
| 322 | #endif |
| 323 | |
| 324 | #if defined(HAVE_MACH_MONOTONIC) |
| 325 | /* ====== |
| 326 | Apple is a little late to the POSIX party. And why not? Instead of |
| 327 | clock_gettime(), they provide mach_absolute_time(). Its units are not |
| 328 | fixed; we need to use mach_timebase_info() to get the right functions to |
| 329 | convert its units into nanoseconds. |
| 330 | |
| 331 | To all appearances, mach_absolute_time() seems to be honest-to-goodness |
| 332 | monotonic. Whether it stops during sleep or not is unspecified in |
| 333 | principle, and dependent on CPU architecture in practice. |
| 334 | */ |
| 335 | |
| 336 | int |
| 337 | evutil_configure_monotonic_time_(struct evutil_monotonic_timer *base, |
| 338 | int flags) |
| 339 | { |
| 340 | const int fallback = flags & EV_MONOT_FALLBACK; |
| 341 | struct mach_timebase_info mi; |
| 342 | memset(base, 0, sizeof(*base)); |
| 343 | /* OSX has mach_absolute_time() */ |
| 344 | if (!fallback && |
| 345 | mach_timebase_info(&mi) == 0 && |
| 346 | mach_absolute_time() != 0) { |
| 347 | /* mach_timebase_info tells us how to convert |
| 348 | * mach_absolute_time() into nanoseconds, but we |
| 349 | * want to use microseconds instead. */ |
| 350 | mi.denom *= 1000; |
| 351 | memcpy(&base->mach_timebase_units, &mi, sizeof(mi)); |
| 352 | } else { |
| 353 | base->mach_timebase_units.numer = 0; |
| 354 | } |
| 355 | return 0; |
| 356 | } |
| 357 | |
| 358 | int |
| 359 | evutil_gettime_monotonic_(struct evutil_monotonic_timer *base, |
| 360 | struct timeval *tp) |
| 361 | { |
| 362 | ev_uint64_t abstime, usec; |
| 363 | if (base->mach_timebase_units.numer == 0) { |
| 364 | if (evutil_gettimeofday(tp, NULL) < 0) |
| 365 | return -1; |
| 366 | adjust_monotonic_time(base, tp); |
| 367 | return 0; |
| 368 | } |
| 369 | |
| 370 | abstime = mach_absolute_time(); |
| 371 | usec = (abstime * base->mach_timebase_units.numer) |
| 372 | / (base->mach_timebase_units.denom); |
| 373 | tp->tv_sec = usec / 1000000; |
| 374 | tp->tv_usec = usec % 1000000; |
| 375 | |
| 376 | return 0; |
| 377 | } |
| 378 | #endif |
| 379 | |
| 380 | #if defined(HAVE_WIN32_MONOTONIC) |
| 381 | /* ===== |
| 382 | Turn we now to Windows. Want monontonic time on Windows? |
| 383 | |
| 384 | Windows has QueryPerformanceCounter(), which gives time most high- |
| 385 | resolution time. It's a pity it's not so monotonic in practice; it's |
| 386 | also got some fun bugs, especially: with older Windowses, under |
| 387 | virtualizations, with funny hardware, on multiprocessor systems, and so |
| 388 | on. PEP418 [1] has a nice roundup of the issues here. |
| 389 | |
| 390 | There's GetTickCount64() on Vista and later, which gives a number of 1-msec |
| 391 | ticks since startup. The accuracy here might be as bad as 10-20 msec, I |
| 392 | hear. There's an undocumented function (NtSetTimerResolution) that |
| 393 | allegedly increases the accuracy. Good luck! |
| 394 | |
| 395 | There's also GetTickCount(), which is only 32 bits, but seems to be |
| 396 | supported on pre-Vista versions of Windows. Apparently, you can coax |
| 397 | another 14 bits out of it, giving you 2231 years before rollover. |
| 398 | |
| 399 | The less said about timeGetTime() the better. |
| 400 | |
| 401 | "We don't care. We don't have to. We're the Phone Company." |
| 402 | -- Lily Tomlin, SNL |
| 403 | |
| 404 | Our strategy, if precise timers are turned off, is to just use the best |
| 405 | GetTickCount equivalent available. If we've been asked for precise timing, |
| 406 | then we mostly[2] assume that GetTickCount is monotonic, and correct |
| 407 | GetPerformanceCounter to approximate it. |
| 408 | |
| 409 | [1] http://www.python.org/dev/peps/pep-0418 |
| 410 | [2] Of course, we feed the Windows stuff into adjust_monotonic_time() |
| 411 | anyway, just in case it isn't. |
| 412 | |
| 413 | */ |
| 414 | /* |
| 415 | Parts of our logic in the win32 timer code here are closely based on |
| 416 | BitTorrent's libUTP library. That code is subject to the following |
| 417 | license: |
| 418 | |
| 419 | Copyright (c) 2010 BitTorrent, Inc. |
| 420 | |
| 421 | Permission is hereby granted, free of charge, to any person obtaining a |
| 422 | copy of this software and associated documentation files (the |
| 423 | "Software"), to deal in the Software without restriction, including |
| 424 | without limitation the rights to use, copy, modify, merge, publish, |
| 425 | distribute, sublicense, and/or sell copies of the Software, and to |
| 426 | permit persons to whom the Software is furnished to do so, subject to |
| 427 | the following conditions: |
| 428 | |
| 429 | The above copyright notice and this permission notice shall be included |
| 430 | in all copies or substantial portions of the Software. |
| 431 | |
| 432 | THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS |
| 433 | OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF |
| 434 | MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND |
| 435 | NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE |
| 436 | LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION |
| 437 | OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION |
| 438 | WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE. |
| 439 | */ |
| 440 | |
| 441 | static ev_uint64_t |
| 442 | evutil_GetTickCount_(struct evutil_monotonic_timer *base) |
| 443 | { |
| 444 | if (base->GetTickCount64_fn) { |
| 445 | /* Let's just use GetTickCount64 if we can. */ |
| 446 | return base->GetTickCount64_fn(); |
| 447 | } else if (base->GetTickCount_fn) { |
| 448 | /* Greg Hazel assures me that this works, that BitTorrent has |
| 449 | * done it for years, and this it won't turn around and |
| 450 | * bite us. He says they found it on some game programmers' |
| 451 | * forum some time around 2007. |
| 452 | */ |
| 453 | ev_uint64_t v = base->GetTickCount_fn(); |
| 454 | return (DWORD)v | ((v >> 18) & 0xFFFFFFFF00000000); |
| 455 | } else { |
| 456 | /* Here's the fallback implementation. We have to use |
| 457 | * GetTickCount() with its given signature, so we only get |
| 458 | * 32 bits worth of milliseconds, which will roll ove every |
| 459 | * 49 days or so. */ |
| 460 | DWORD ticks = GetTickCount(); |
| 461 | if (ticks < base->last_tick_count) { |
| 462 | base->adjust_tick_count += ((ev_uint64_t)1) << 32; |
| 463 | } |
| 464 | base->last_tick_count = ticks; |
| 465 | return ticks + base->adjust_tick_count; |
| 466 | } |
| 467 | } |
| 468 | |
| 469 | int |
| 470 | evutil_configure_monotonic_time_(struct evutil_monotonic_timer *base, |
| 471 | int flags) |
| 472 | { |
| 473 | const int precise = flags & EV_MONOT_PRECISE; |
| 474 | const int fallback = flags & EV_MONOT_FALLBACK; |
| 475 | HANDLE h; |
| 476 | memset(base, 0, sizeof(*base)); |
| 477 | |
| 478 | h = evutil_load_windows_system_library_(TEXT("kernel32.dll")); |
| 479 | if (h != NULL && !fallback) { |
| 480 | base->GetTickCount64_fn = (ev_GetTickCount_func)GetProcAddress(h, "GetTickCount64"); |
| 481 | base->GetTickCount_fn = (ev_GetTickCount_func)GetProcAddress(h, "GetTickCount"); |
| 482 | } |
| 483 | |
| 484 | base->first_tick = base->last_tick_count = evutil_GetTickCount_(base); |
| 485 | if (precise && !fallback) { |
| 486 | LARGE_INTEGER freq; |
| 487 | if (QueryPerformanceFrequency(&freq)) { |
| 488 | LARGE_INTEGER counter; |
| 489 | QueryPerformanceCounter(&counter); |
| 490 | base->first_counter = counter.QuadPart; |
| 491 | base->usec_per_count = 1.0e6 / freq.QuadPart; |
| 492 | base->use_performance_counter = 1; |
| 493 | } |
| 494 | } |
| 495 | |
| 496 | return 0; |
| 497 | } |
| 498 | |
| 499 | static inline ev_int64_t |
| 500 | abs64(ev_int64_t i) |
| 501 | { |
| 502 | return i < 0 ? -i : i; |
| 503 | } |
| 504 | |
| 505 | |
| 506 | int |
| 507 | evutil_gettime_monotonic_(struct evutil_monotonic_timer *base, |
| 508 | struct timeval *tp) |
| 509 | { |
| 510 | ev_uint64_t ticks = evutil_GetTickCount_(base); |
| 511 | if (base->use_performance_counter) { |
| 512 | /* Here's a trick we took from BitTorrent's libutp, at Greg |
| 513 | * Hazel's recommendation. We use QueryPerformanceCounter for |
| 514 | * our high-resolution timer, but use GetTickCount*() to keep |
| 515 | * it sane, and adjust_monotonic_time() to keep it monotonic. |
| 516 | */ |
| 517 | LARGE_INTEGER counter; |
| 518 | ev_int64_t counter_elapsed, counter_usec_elapsed, ticks_elapsed; |
| 519 | QueryPerformanceCounter(&counter); |
| 520 | counter_elapsed = (ev_int64_t) |
| 521 | (counter.QuadPart - base->first_counter); |
| 522 | ticks_elapsed = ticks - base->first_tick; |
| 523 | /* TODO: This may upset VC6. If you need this to work with |
| 524 | * VC6, please supply an appropriate patch. */ |
| 525 | counter_usec_elapsed = (ev_int64_t) |
| 526 | (counter_elapsed * base->usec_per_count); |
| 527 | |
| 528 | if (abs64(ticks_elapsed*1000 - counter_usec_elapsed) > 1000000) { |
| 529 | /* It appears that the QueryPerformanceCounter() |
| 530 | * result is more than 1 second away from |
| 531 | * GetTickCount() result. Let's adjust it to be as |
| 532 | * accurate as we can; adjust_monotnonic_time() below |
| 533 | * will keep it monotonic. */ |
| 534 | counter_usec_elapsed = ticks_elapsed * 1000; |
| 535 | base->first_counter = (ev_uint64_t) (counter.QuadPart - counter_usec_elapsed / base->usec_per_count); |
| 536 | } |
| 537 | tp->tv_sec = (time_t) (counter_usec_elapsed / 1000000); |
| 538 | tp->tv_usec = counter_usec_elapsed % 1000000; |
| 539 | |
| 540 | } else { |
| 541 | /* We're just using GetTickCount(). */ |
| 542 | tp->tv_sec = (time_t) (ticks / 1000); |
| 543 | tp->tv_usec = (ticks % 1000) * 1000; |
| 544 | } |
| 545 | adjust_monotonic_time(base, tp); |
| 546 | |
| 547 | return 0; |
| 548 | } |
| 549 | #endif |
| 550 | |
| 551 | #if defined(HAVE_FALLBACK_MONOTONIC) |
| 552 | /* ===== |
| 553 | And if none of the other options work, let's just use gettimeofday(), and |
| 554 | ratchet it forward so that it acts like a monotonic timer, whether it |
| 555 | wants to or not. |
| 556 | */ |
| 557 | |
| 558 | int |
| 559 | evutil_configure_monotonic_time_(struct evutil_monotonic_timer *base, |
| 560 | int precise) |
| 561 | { |
| 562 | memset(base, 0, sizeof(*base)); |
| 563 | return 0; |
| 564 | } |
| 565 | |
| 566 | int |
| 567 | evutil_gettime_monotonic_(struct evutil_monotonic_timer *base, |
| 568 | struct timeval *tp) |
| 569 | { |
| 570 | if (evutil_gettimeofday(tp, NULL) < 0) |
| 571 | return -1; |
| 572 | adjust_monotonic_time(base, tp); |
| 573 | return 0; |
| 574 | |
| 575 | } |
| 576 | #endif |