lib/libhgfs/time.c

   1 /* Part of libhgfs - (c) 2009, D.C. van Moolenbroek */
   2
   3 #include "inc.h"
   4
   5 static u64_t time_offset;
   6
   7 /*===========================================================================*
   8  *                              time_init                                    *
   9  *===========================================================================*/
  10 void time_init(void)
  11 {
  12 /* Initialize the time conversion module.
  13  */
  14
  15   /* Generate a 64-bit value for the offset to use in time conversion. The
  16    * HGFS time format uses Windows' FILETIME standard, expressing time in
  17    * 100ns-units since Jan 1, 1601 UTC. The value that is generated is
  18    * the difference between that time and the UNIX epoch, in 100ns units.
  19    */
  20   /* FIXME: we currently do not take into account timezones. */
  21   time_offset = mul64u(116444736, 1000000000);
  22 }
  23
  24 /*===========================================================================*
  25  *                              time_put                                     *
  26  *===========================================================================*/
  27 void time_put(struct timespec *tsp)
  28 {
  29 /* Store a POSIX timestamp pointed to by the given pointer onto the RPC buffer,
  30  * in HGFS timestamp format. If a NULL pointer is given, store a timestamp of
  31  * zero instead.
  32  */
  33   u64_t hgfstime;
  34
  35   if (tsp != NULL) {
  36         hgfstime = add64ul(mul64u(tsp->tv_sec, 10000000), tsp->tv_nsec / 100);
  37         hgfstime = add64(hgfstime, time_offset);
  38
  39         RPC_NEXT32 = ex64lo(hgfstime);
  40         RPC_NEXT32 = ex64hi(hgfstime);
  41   } else {
  42         RPC_NEXT32 = 0;
  43         RPC_NEXT32 = 0;
  44   }
  45 }
  46
  47 /*===========================================================================*
  48  *                              time_get                                     *
  49  *===========================================================================*/
  50 void time_get(struct timespec *tsp)
  51 {
  52 /* Get a HGFS timestamp from the RPC buffer, convert it into a POSIX timestamp,
  53  * and store the result in the given time pointer. If the given pointer is
  54  * NULL, however, simply skip over the timestamp in the RPC buffer.
  55  */
  56   u64_t hgfstime;
  57   u32_t time_lo, time_hi;
  58
  59   if (tsp != NULL) {
  60         time_lo = RPC_NEXT32;
  61         time_hi = RPC_NEXT32;
  62
  63         hgfstime = sub64(make64(time_lo, time_hi), time_offset);
  64
  65         tsp->tv_sec = div64u(hgfstime, 10000000);
  66         tsp->tv_nsec = rem64u(hgfstime, 10000000) * 100;
  67   }
  68   else RPC_ADVANCE(sizeof(u32_t) * 2);
  69 }