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/**
* Copyright Amazon.com, Inc. or its affiliates. All Rights Reserved.
* SPDX-License-Identifier: Apache-2.0.
*/
#include <aws/common/clock.h>
#include <windows.h>
static const uint64_t FILE_TIME_TO_NS = 100;
static const uint64_t EC_TO_UNIX_EPOCH = 11644473600LL;
static const uint64_t WINDOWS_TICK = 10000000;
static INIT_ONCE s_timefunc_init_once = INIT_ONCE_STATIC_INIT;
typedef VOID WINAPI timefunc_t(LPFILETIME);
static VOID WINAPI s_get_system_time_func_lazy_init(LPFILETIME filetime_p);
static timefunc_t *volatile s_p_time_func = s_get_system_time_func_lazy_init;
/* Convert a string from a macro to a wide string */
#define WIDEN2(s) L## #s
#define WIDEN(s) WIDEN2(s)
static BOOL CALLBACK s_get_system_time_init_once(PINIT_ONCE init_once, PVOID param, PVOID *context) {
(void)init_once;
(void)param;
(void)context;
HMODULE kernel = GetModuleHandleW(WIDEN(WINDOWS_KERNEL_LIB) L".dll");
timefunc_t *time_func = (timefunc_t *)GetProcAddress(kernel, "GetSystemTimePreciseAsFileTime");
if (time_func == NULL) {
time_func = GetSystemTimeAsFileTime;
}
s_p_time_func = time_func;
return TRUE;
}
static VOID WINAPI s_get_system_time_func_lazy_init(LPFILETIME filetime_p) {
BOOL status = InitOnceExecuteOnce(&s_timefunc_init_once, s_get_system_time_init_once, NULL, NULL);
if (status) {
(*s_p_time_func)(filetime_p);
} else {
/* Something went wrong in static initialization? Should never happen, but deal with it somehow...*/
GetSystemTimeAsFileTime(filetime_p);
}
}
int aws_high_res_clock_get_ticks(uint64_t *timestamp) {
LARGE_INTEGER ticks, frequency;
/* QPC runs on sub-microsecond precision, convert to nanoseconds */
if (QueryPerformanceFrequency(&frequency) && QueryPerformanceCounter(&ticks)) {
*timestamp = aws_timestamp_convert_u64(
(uint64_t)ticks.QuadPart, (uint64_t)frequency.QuadPart, AWS_TIMESTAMP_NANOS, NULL);
return AWS_OP_SUCCESS;
}
return aws_raise_error(AWS_ERROR_CLOCK_FAILURE);
}
int aws_sys_clock_get_ticks(uint64_t *timestamp) {
FILETIME ticks;
/*GetSystemTimePreciseAsFileTime() returns 100 nanosecond precision. Convert to nanoseconds.
*Also, this function returns a different epoch than unix, so we add a conversion to handle that as well. */
(*s_p_time_func)(&ticks);
/*if this looks unnecessary, see:
* https://msdn.microsoft.com/en-us/library/windows/desktop/ms724284(v=vs.85).aspx
*/
ULARGE_INTEGER int_conv;
int_conv.LowPart = ticks.dwLowDateTime;
int_conv.HighPart = ticks.dwHighDateTime;
*timestamp = (int_conv.QuadPart - (WINDOWS_TICK * EC_TO_UNIX_EPOCH)) * FILE_TIME_TO_NS;
return AWS_OP_SUCCESS;
}
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