常用数据类型转换(不断更新中)

    在程序开发过程中不断会碰到不同的数据间的转换,在这里做一个总结:
一.时间类型间的转换:
1.time_t 转 FILETIME
 FILETIME ft;
 LONGLONG ll = Int32x32To64(t, 10000000) + 116444736000000000;
 ft.dwLowDateTime = (DWORD) ll;
 ft.dwHighDateTime = (DWORD)(ll >> 32);

2.FILETIME 转 time_t 
 FILETIME ft;
  LONGLONG llTime;
time_t t;
 llTime = (ft.dwHighDateTime << 32) + ft.dwLowDateTime;

 t = (DWORD)((LONGLONG)(llTime - 116444736000000000) / 10000000);

3.SYSTEMTIME 转 FILETIME
FILETIME ft;
SYSTEMTIME st;
 SystemTimeToFileTime( &st, &ft );

4. FILETIME 转 SYSTEMTIME
FILETIME ft;
SYSTEMTIME st;
FileTimeToSystemTime( &ft, &st);

5.DATE 转 SYSTEMTIME
DATE pst;
SYSTEMTIME st;
  VariantTimeToSystemTime(pst,&st);
6. SYSTEMTIME 转 DATE
DATE pst;
SYSTEMTIME st;

SystemTimeToVariantTime(st, &pst);

7. BYTE转DWORD

 #define   MAKEB2W(c0, c1, c2, c3) ((DWORD)(((BYTE)(c0)|((WORD)((BYTE)(c1))<<8))|(((DWORD)(BYTE)(c2))<<16) | (((DWORD)(BYTE)(c3))<<24)))