mysql5/mysql-5.7.27/mysys/my_getsystime.c

157 lines
4.1 KiB
C

/* Copyright (c) 2004, 2017, Oracle and/or its affiliates. All rights reserved.
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; version 2 of the License.
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.
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., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA */
/* get time since epoc in 100 nanosec units */
/* thus to get the current time we should use the system function
with the highest possible resolution */
#include "mysys_priv.h"
#include "my_static.h"
#if HAVE_SYS_TIME_H
#include <sys/time.h>
#endif
#if defined(_WIN32)
#include "my_sys.h" /* for my_printf_error */
typedef VOID(WINAPI *time_fn)(LPFILETIME);
static time_fn my_get_system_time_as_file_time= GetSystemTimeAsFileTime;
/**
Initialise highest available time resolution API on Windows
@return Initialization result
@retval FALSE Success
@retval TRUE Error. Couldn't initialize environment
*/
my_bool win_init_get_system_time_as_file_time()
{
DWORD error;
HMODULE h;
h= LoadLibrary("kernel32.dll");
if (h != NULL)
{
time_fn pfn= (time_fn) GetProcAddress(h, "GetSystemTimePreciseAsFileTime");
if (pfn)
my_get_system_time_as_file_time= pfn;
return FALSE;
}
error= GetLastError();
my_printf_error(0,
"LoadLibrary(\"kernel32.dll\") failed: GetLastError returns %lu",
MYF(0),
error);
return TRUE;
}
#endif
/**
Get high-resolution time.
@remark For windows platforms we need the frequency value of
the CPU. This is initialized in my_init.c through
QueryPerformanceFrequency(). If the Windows platform
doesn't support QueryPerformanceFrequency(), zero is
returned.
@retval current high-resolution time.
*/
ulonglong my_getsystime()
{
#ifdef HAVE_CLOCK_GETTIME
struct timespec tp;
clock_gettime(CLOCK_REALTIME, &tp);
return (ulonglong)tp.tv_sec*10000000+(ulonglong)tp.tv_nsec/100;
#elif defined(_WIN32)
LARGE_INTEGER t_cnt;
if (query_performance_frequency)
{
QueryPerformanceCounter(&t_cnt);
return ((t_cnt.QuadPart / query_performance_frequency * 10000000) +
((t_cnt.QuadPart % query_performance_frequency) * 10000000 /
query_performance_frequency) + query_performance_offset);
}
return 0;
#else
/* TODO: check for other possibilities for hi-res timestamping */
struct timeval tv;
gettimeofday(&tv,NULL);
return (ulonglong)tv.tv_sec*10000000+(ulonglong)tv.tv_usec*10;
#endif
}
/**
Return current time.
@param flags If MY_WME is set, write error if time call fails.
@retval current time.
*/
time_t my_time(myf flags)
{
time_t t;
/*
The following loop is here beacuse time() may fail on some systems.
We're using a hardcoded my_message_stderr() here rather than going
through the hook in my_message_local() because it's far too easy to
come full circle with any logging function that writes timestamps ...
*/
while ((t= time(0)) == (time_t) -1)
{
if (flags & MY_WME)
my_message_stderr(0, "time() call failed", MYF(0));
}
return t;
}
#define OFFSET_TO_EPOCH 116444736000000000ULL
/**
Return time in microseconds.
@remark This function is to be used to measure performance in
micro seconds.
@retval Number of microseconds since the Epoch, 1970-01-01 00:00:00 +0000 (UTC)
*/
ulonglong my_micro_time()
{
#ifdef _WIN32
ulonglong newtime;
my_get_system_time_as_file_time((FILETIME*)&newtime);
newtime-= OFFSET_TO_EPOCH;
return (newtime/10);
#else
ulonglong newtime;
struct timeval t;
/*
The following loop is here because gettimeofday may fail on some systems
*/
while (gettimeofday(&t, NULL) != 0)
{}
newtime= (ulonglong)t.tv_sec * 1000000 + t.tv_usec;
return newtime;
#endif
}