FILETIME, SYSTEMTIME 与 time_t 相互转换
FILETIME, SYSTEMTIME 与 time_t 相互转换
//************************************************************
//FILETIME, SYSTEMTIME 与 time_t 相互转换
//#####SYSTEMTIME 与 FILETIME相互转换#####
//可以使用系统函数
//FileTimeToSystemTime(&ftcreate,&stcreate);
//参数：
//(lpFileTime As FILETIME, lpSystemTime As SYSTEMTIME)
//说明
//根据一个FILETIME结构的内容，装载一个SYSTEMTIME结构
//返回值
//Long，非零表示成功，零表示失败。会设置GetLastError
//参数表
//参数 类型及说明
//lpFileTime FILETIME，包含了文件时间的一个结构
//lpSystemTime SYSTEMTIME，用于装载系统时间信息的一个结构
//#####SYSTEMTIME 与 time_t相互转换#####
//#### Time_tToSystemTime ####
void TimetToSystemTime( time_t t, LPSYSTEMTIME pst )
{
FILETIME ft;
LONGLONG ll = Int32x32To64(t, 10000000) + 116444736000000000;
ft.dwLowDateTime = (DWORD) ll;
ft.dwHighDateTime = (DWORD)(ll >> 32);
FileTimeToSystemTime( &ft, pst );
}
//#### SystemTimeToTime_t ####
void SystemTimeToTime_t( SYSTEMTIME st, time_t *pt )
{
FILETIME ft;
SystemTimeToFileTime( &st, &ft );
LONGLONG ll;
ULARGE_INTEGER ui;
ui.LowPart = ft.dwLowDateTime;
ui.HighPart = ft.dwHighDateTime;
ll = (ft.dwHighDateTime << 32) + ft.dwLowDateTime;
*pt = (DWORD)((LONGLONG)(ui.QuadPart - 116444736000000000) / 10000000);
}
//#### FileTimeToTime_t ####
void FileTimeToTime_t( FILETIME ft, time_t *t )
{
LONGLONG ll;
ULARGE_INTEGER ui;
ui.LowPart = ft.dwLowDateTime;
ui.HighPart = ft.dwHighDateTime;
ll = ft.dwHighDateTime << 32 + ft.dwLowDateTime;
//这一步是不是多余的
*t = ((LONGLONG)(ui.QuadPart - 116444736000000000) / 10000000);
//将ui.QuadPart的数据类型ULONGLONG强制转换为time_t的LONGLONG数据类型
}
//
struct { DWORD LowPart; DWORD HighPart; }; 和ULONGLONG QuadPart;组成共用体ULARGE_INTEGER
//********************************************************************/
参见：
时间结构体2.2：
