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- #include <stdint.h>
- #include <assert.h>
- #include <time.h>
-
- #if defined(OS_WINDOWS)
- #include <Windows.h>
- #else
- #include <sys/time.h>
-
- #if defined(OS_MAC)
- #include <sys/param.h>
- #include <sys/sysctl.h>
- #include <mach/mach_time.h>
- #endif
-
- #endif
-
- /// same as system_time except ms -> us
- /// @return microseconds since the Epoch(1970-01-01 00:00:00 +0000 (UTC))
- uint64_t rtpclock()
- {
- #if defined(OS_WINDOWS)
- uint64_t t;
- FILETIME ft;
- GetSystemTimeAsFileTime(&ft);
- t = (uint64_t)ft.dwHighDateTime << 32 | ft.dwLowDateTime;
- return t / 10 - 11644473600000000; /* Jan 1, 1601 */
- #elif defined(OS_MAC)
- uint64_t tick;
- mach_timebase_info_data_t timebase;
- tick = mach_absolute_time();
- mach_timebase_info(&timebase);
- return tick * timebase.numer / timebase.denom / 1000;
- #else
- #if defined(CLOCK_MONOTONIC)
- struct timespec tp;
- clock_gettime(CLOCK_MONOTONIC, &tp);
- return (uint64_t)tp.tv_sec * 1000000 + tp.tv_nsec / 1000;
- #else
- // POSIX.1-2008 marks gettimeofday() as obsolete, recommending the use of clock_gettime(2) instead.
- struct timeval tv;
- gettimeofday(&tv, NULL);
- return (uint64_t)tv.tv_sec * 1000000 + tv.tv_usec;
- #endif
- #endif
- }
-
- /// us(microsecond) -> ntp
- uint64_t clock2ntp(uint64_t clock)
- {
- uint64_t ntp;
-
- // high 32 bits in seconds
- ntp = ((clock/1000000)+0x83AA7E80) << 32; // 1/1/1970 -> 1/1/1900
-
- // low 32 bits in picosecond
- // us * 2^32 / 10^6
- // 10^6 = 2^6 * 15625
- // => us * 2^26 / 15625
- ntp |= (uint32_t)(((clock % 1000000) << 26) / 15625);
-
- return ntp;
- }
-
- /// ntp -> us(microsecond)
- uint64_t ntp2clock(uint64_t ntp)
- {
- uint64_t clock;
-
- // high 32 bits in seconds
- clock = ((uint64_t)((unsigned int)(ntp >> 32) - 0x83AA7E80)) * 1000000; // 1/1/1900 -> 1/1/1970
-
- // low 32 bits in picosecond
- clock += ((ntp & 0xFFFFFFFF) * 15625) >> 26;
-
- return clock;
- }
-
- #if defined(_DEBUG) || defined(DEBUG)
- void rtp_time_test(void)
- {
- const uint64_t ntp = 0xe2e1d897e9c38b05ULL;
- uint64_t clock;
- struct tm* tm;
- time_t t;
-
- clock = ntp2clock(ntp);
- t = (time_t)(clock / 1000000);
- tm = gmtime(&t);
- assert(tm->tm_year + 1900 == 2020 && tm->tm_mon == 7 && tm->tm_mday == 15 && tm->tm_hour == 3 && tm->tm_min == 44 && tm->tm_sec == 23);
- assert(clock2ntp(clock) == 0xe2e1d897e9c38b04ULL);
- }
- #endif
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