dist/ntp/libntp/prettydate.c

   1 /*      $NetBSD: prettydate.c,v 1.2 2003/12/04 16:23:37 drochner Exp $  */
   2
   3 /*
   4  * prettydate - convert a time stamp to something readable
   5  */
   6 #include <stdio.h>
   7
   8 #include "ntp_fp.h"
   9 #include "ntp_unixtime.h"       /* includes <sys/time.h> */
  10 #include "lib_strbuf.h"
  11 #include "ntp_stdlib.h"
  12
  13 static const char *months[] = {
  14   "Jan", "Feb", "Mar", "Apr", "May", "Jun",
  15   "Jul", "Aug", "Sep", "Oct", "Nov", "Dec"
  16 };
  17
  18 static const char *days[] = {
  19   "Sun", "Mon", "Tue", "Wed", "Thu", "Fri", "Sat"
  20 };
  21
  22 /* Helper function to handle possible wraparound of the ntp epoch.
  23
  24    Works by assuming that the localtime/gmtime library functions
  25    have been updated so that they work
  26 */
  27
  28 #define MAX_EPOCH_NR 1000
  29
  30 struct tm *
  31 ntp2unix_tm(
  32         u_long ntp, int local
  33         )
  34 {
  35         time_t t, curr;
  36         struct tm *tm;
  37         int curr_year, epoch_nr;
  38
  39         /* First get the current year: */
  40         curr = time(NULL);
  41         tm = local ? localtime(&curr) : gmtime(&curr);
  42         if (!tm) return NULL;
  43
  44         curr_year = 1900 + tm->tm_year;
  45
  46         /* Convert the ntp timestamp to a unix utc seconds count: */
  47         t = (time_t) ntp - JAN_1970;
  48
  49         /* Check that the ntp timestamp is not before a 136 year window centered
  50            around the current year:
  51
  52            Failsafe in case of an infinite loop:
  53        Allow up to 1000 epochs of 136 years each!
  54         */
  55     for (epoch_nr = 0; epoch_nr < MAX_EPOCH_NR; epoch_nr++) {
  56                 tm = local ? localtime(&t) : gmtime(&t);
  57
  58 #if SIZEOF_TIME_T < 4
  59 # include "Bletch: sizeof(time_t) < 4!"
  60 #endif
  61
  62 #if SIZEOF_TIME_T == 4
  63                 /* If 32 bits, then year is 1970-2038, so no sense looking */
  64                 epoch_nr = MAX_EPOCH_NR;
  65 #else   /* SIZEOF_TIME_T > 4 */
  66                 /* Check that the resulting year is in the correct epoch: */
  67                 if (1900 + tm->tm_year > curr_year - 68) break;
  68
  69                 /* Epoch wraparound: Add 2^32 seconds! */
  70                 t += (time_t) 65536 << 16;
  71 #endif /* SIZEOF_TIME_T > 4 */
  72         }
  73         return tm;
  74 }
  75
  76 char *
  77 prettydate(
  78         l_fp *ts
  79         )
  80 {
  81         char *bp;
  82         struct tm *tm;
  83         time_t sec;
  84         u_long msec;
  85
  86         LIB_GETBUF(bp);
  87
  88         sec = ts->l_ui;
  89         msec = ts->l_uf / 4294967;      /* fract / (2 ** 32 / 1000) */
  90
  91         tm = ntp2unix_tm(sec, 1);
  92         if (!tm) {
  93                 (void) sprintf(bp, "%08lx.%08lx  --- --- -- ---- --:--:--",
  94                        (u_long)ts->l_ui, (u_long)ts->l_uf);
  95         }
  96         else {
  97                 (void) sprintf(bp, "%08lx.%08lx  %s, %s %2d %4d %2d:%02d:%02d.%03lu",
  98                        (u_long)ts->l_ui, (u_long)ts->l_uf, days[tm->tm_wday],
  99                        months[tm->tm_mon], tm->tm_mday, 1900 + tm->tm_year,
 100                        tm->tm_hour,tm->tm_min, tm->tm_sec, msec);
 101         }
 102
 103         return bp;
 104 }
 105
 106 char *
 107 gmprettydate(
 108         l_fp *ts
 109         )
 110 {
 111         char *bp;
 112         struct tm *tm;
 113         time_t sec;
 114         u_long msec;
 115
 116         LIB_GETBUF(bp);
 117
 118         sec = ts->l_ui;
 119         msec = ts->l_uf / 4294967;      /* fract / (2 ** 32 / 1000) */
 120
 121         tm = ntp2unix_tm(sec, 0);
 122         if (!tm) {
 123                 (void) sprintf(bp, "%08lx.%08lx  --- --- -- ---- --:--:--",
 124                        (u_long)ts->l_ui, (u_long)ts->l_uf);
 125         }
 126         else {
 127                 (void) sprintf(bp, "%08lx.%08lx  %s, %s %2d %4d %2d:%02d:%02d.%03lu",
 128                        (u_long)ts->l_ui, (u_long)ts->l_uf, days[tm->tm_wday],
 129                        months[tm->tm_mon], tm->tm_mday, 1900 + tm->tm_year,
 130                        tm->tm_hour,tm->tm_min, tm->tm_sec, msec);
 131         }
 132
 133         return bp;
 134 }