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libtgvoip/webrtc_dsp/rtc_base/timeutils.cc
2020-01-22 12:55:03 +01:00

247 lines
7.3 KiB
C++

/*
* Copyright 2004 The WebRTC Project Authors. All rights reserved.
*
* Use of this source code is governed by a BSD-style license
* that can be found in the LICENSE file in the root of the source
* tree. An additional intellectual property rights grant can be found
* in the file PATENTS. All contributing project authors may
* be found in the AUTHORS file in the root of the source tree.
*/
#include <stdint.h>
#if defined(WEBRTC_POSIX)
#include <sys/time.h>
#if defined(WEBRTC_MAC)
#include <mach/mach_time.h>
#include "rtc_base/numerics/safe_conversions.h"
#endif
#endif
#if defined(WEBRTC_WIN)
// clang-format off
// clang formatting would put <windows.h> last,
// which leads to compilation failure.
#include <windows.h>
#include <mmsystem.h>
#include <sys/timeb.h>
// clang-format on
#endif
#include "rtc_base/checks.h"
#include "rtc_base/timeutils.h"
namespace rtc {
ClockInterface* g_clock = nullptr;
ClockInterface* SetClockForTesting(ClockInterface* clock) {
ClockInterface* prev = g_clock;
g_clock = clock;
return prev;
}
ClockInterface* GetClockForTesting() {
return g_clock;
}
int64_t SystemTimeNanos() {
int64_t ticks;
#if defined(WEBRTC_MAC)
static mach_timebase_info_data_t timebase;
if (timebase.denom == 0) {
// Get the timebase if this is the first time we run.
// Recommended by Apple's QA1398.
if (mach_timebase_info(&timebase) != KERN_SUCCESS) {
RTC_NOTREACHED();
}
}
// Use timebase to convert absolute time tick units into nanoseconds.
const auto mul = [](uint64_t a, uint32_t b) -> int64_t {
RTC_DCHECK_NE(b, 0);
RTC_DCHECK_LE(a, std::numeric_limits<int64_t>::max() / b)
<< "The multiplication " << a << " * " << b << " overflows";
return rtc::dchecked_cast<int64_t>(a * b);
};
ticks = mul(mach_absolute_time(), timebase.numer) / timebase.denom;
#elif defined(WEBRTC_POSIX)
struct timespec ts;
// TODO(deadbeef): Do we need to handle the case when CLOCK_MONOTONIC is not
// supported?
clock_gettime(CLOCK_MONOTONIC, &ts);
ticks = kNumNanosecsPerSec * static_cast<int64_t>(ts.tv_sec) +
static_cast<int64_t>(ts.tv_nsec);
#elif defined(WEBRTC_UWP)
static volatile ULONGLONG last_timegettime = 0;
static volatile int64_t num_wrap_timegettime = 0;
volatile ULONGLONG* last_timegettime_ptr = &last_timegettime;
ULONGLONG now = GetTickCount64();
// Atomically update the last gotten time
ULONGLONG old = InterlockedExchange(last_timegettime_ptr, now);
if (now < old) {
// If now is earlier than old, there may have been a race between threads.
// 0x0fffffff ~3.1 days, the code will not take that long to execute
// so it must have been a wrap around.
if (old > 0xf0000000 && now < 0x0fffffff) {
num_wrap_timegettime++;
}
}
ticks = now + (num_wrap_timegettime << 32);
// TODO(deadbeef): Calculate with nanosecond precision. Otherwise, we're
// just wasting a multiply and divide when doing Time() on Windows.
ticks = ticks * kNumNanosecsPerMillisec;
#elif defined(WEBRTC_WIN)
static volatile LONG last_timegettime = 0;
static volatile int64_t num_wrap_timegettime = 0;
volatile LONG* last_timegettime_ptr = &last_timegettime;
DWORD now = timeGetTime();
// Atomically update the last gotten time
DWORD old = InterlockedExchange(last_timegettime_ptr, now);
if (now < old) {
// If now is earlier than old, there may have been a race between threads.
// 0x0fffffff ~3.1 days, the code will not take that long to execute
// so it must have been a wrap around.
if (old > 0xf0000000 && now < 0x0fffffff) {
num_wrap_timegettime++;
}
}
ticks = now + (num_wrap_timegettime << 32);
// TODO(deadbeef): Calculate with nanosecond precision. Otherwise, we're
// just wasting a multiply and divide when doing Time() on Windows.
ticks = ticks * kNumNanosecsPerMillisec;
#else
#error Unsupported platform.
#endif
return ticks;
}
int64_t SystemTimeMillis() {
return static_cast<int64_t>(SystemTimeNanos() / kNumNanosecsPerMillisec);
}
int64_t TimeNanos() {
if (g_clock) {
return g_clock->TimeNanos();
}
return SystemTimeNanos();
}
uint32_t Time32() {
return static_cast<uint32_t>(TimeNanos() / kNumNanosecsPerMillisec);
}
int64_t TimeMillis() {
return TimeNanos() / kNumNanosecsPerMillisec;
}
int64_t TimeMicros() {
return TimeNanos() / kNumNanosecsPerMicrosec;
}
int64_t TimeAfter(int64_t elapsed) {
RTC_DCHECK_GE(elapsed, 0);
return TimeMillis() + elapsed;
}
int32_t TimeDiff32(uint32_t later, uint32_t earlier) {
return later - earlier;
}
int64_t TimeDiff(int64_t later, int64_t earlier) {
return later - earlier;
}
TimestampWrapAroundHandler::TimestampWrapAroundHandler()
: last_ts_(0), num_wrap_(-1) {}
int64_t TimestampWrapAroundHandler::Unwrap(uint32_t ts) {
if (num_wrap_ == -1) {
last_ts_ = ts;
num_wrap_ = 0;
return ts;
}
if (ts < last_ts_) {
if (last_ts_ >= 0xf0000000 && ts < 0x0fffffff)
++num_wrap_;
} else if ((ts - last_ts_) > 0xf0000000) {
// Backwards wrap. Unwrap with last wrap count and don't update last_ts_.
return ts + ((num_wrap_ - 1) << 32);
}
last_ts_ = ts;
return ts + (num_wrap_ << 32);
}
int64_t TmToSeconds(const tm& tm) {
static short int mdays[12] = {31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31};
static short int cumul_mdays[12] = {0, 31, 59, 90, 120, 151,
181, 212, 243, 273, 304, 334};
int year = tm.tm_year + 1900;
int month = tm.tm_mon;
int day = tm.tm_mday - 1; // Make 0-based like the rest.
int hour = tm.tm_hour;
int min = tm.tm_min;
int sec = tm.tm_sec;
bool expiry_in_leap_year =
(year % 4 == 0 && (year % 100 != 0 || year % 400 == 0));
if (year < 1970)
return -1;
if (month < 0 || month > 11)
return -1;
if (day < 0 || day >= mdays[month] + (expiry_in_leap_year && month == 2 - 1))
return -1;
if (hour < 0 || hour > 23)
return -1;
if (min < 0 || min > 59)
return -1;
if (sec < 0 || sec > 59)
return -1;
day += cumul_mdays[month];
// Add number of leap days between 1970 and the expiration year, inclusive.
day += ((year / 4 - 1970 / 4) - (year / 100 - 1970 / 100) +
(year / 400 - 1970 / 400));
// We will have added one day too much above if expiration is during a leap
// year, and expiration is in January or February.
if (expiry_in_leap_year && month <= 2 - 1) // |month| is zero based.
day -= 1;
// Combine all variables into seconds from 1970-01-01 00:00 (except |month|
// which was accumulated into |day| above).
return (((static_cast<int64_t>(year - 1970) * 365 + day) * 24 + hour) * 60 +
min) *
60 +
sec;
}
int64_t TimeUTCMicros() {
if (g_clock) {
return g_clock->TimeNanos() / kNumNanosecsPerMicrosec;
}
#if defined(WEBRTC_POSIX)
struct timeval time;
gettimeofday(&time, nullptr);
// Convert from second (1.0) and microsecond (1e-6).
return (static_cast<int64_t>(time.tv_sec) * rtc::kNumMicrosecsPerSec +
time.tv_usec);
#elif defined(WEBRTC_WIN)
struct _timeb time;
_ftime(&time);
// Convert from second (1.0) and milliseconds (1e-3).
return (static_cast<int64_t>(time.time) * rtc::kNumMicrosecsPerSec +
static_cast<int64_t>(time.millitm) * rtc::kNumMicrosecsPerMillisec);
#endif
}
int64_t TimeUTCMillis() {
return TimeUTCMicros() / kNumMicrosecsPerMillisec;
}
} // namespace rtc