not, write to the Free Software Foundation, Inc., 675 Mass Ave,
Cambridge, MA 02139, USA. */
+/* #define DEBUG */ /* Define this to have a standalone shell to test
+ * this implementation of mktime
+ */
+
#ifdef HAVE_CONFIG_H
#if defined (CONFIG_BROKETS)
/* We use <config.h> instead of "config.h" so that a compilation
};
+static int times_through_search; /* This library routine should never
+ hang -- make sure we always return
+ when we're searching for a value */
+
/* After testing this, the maximum number of iterations that I had on
any number that I tried was 3! Not bad.
#ifdef DEBUG
+#include <stdio.h>
+#include <ctype.h>
+
int debugging_enabled = 0;
-/* Print the values in a `struct tm'. */
+/* Print the values in a `struct tm'. */
static void
printtm (it)
struct tm *it;
}
#endif
+
static time_t
dist_tm (t1, t2)
struct tm *t1;
v1 = v2 = 0;
-#define doit(x, secs) \
- v1 += t1->x * secs; \
- v2 += t2->x * secs; \
- if (!diff_flag) \
- { \
- if (t1->x < t2->x) \
- diff_flag = -1; \
- else if (t1->x > t2->x) \
- diff_flag = 1; \
+#define doit(x, secs) \
+ v1 += t1->x * secs; \
+ v2 += t2->x * secs; \
+ if (!diff_flag) \
+ { \
+ if (t1->x < t2->x) \
+ diff_flag = -1; \
+ else if (t1->x > t2->x) \
+ diff_flag = 1; \
}
-
- doit (tm_year, 31536000); /* Okay, not all years have 365 days. */
- doit (tm_mon, 2592000); /* Okay, not all months have 30 days. */
+
+ doit (tm_year, 31536000); /* Okay, not all years have 365 days. */
+ doit (tm_mon, 2592000); /* Okay, not all months have 30 days. */
doit (tm_mday, 86400);
doit (tm_hour, 3600);
doit (tm_min, 60);
doit (tm_sec, 1);
-
+
#undef doit
+
+ /* We should also make sure that the sign of DISTANCE is correct --
+ * if DIFF_FLAG is positive, the distance should be positive and
+ * vice versa. */
+
+ distance = (v1 > v2) ? (v1 - v2) : (v2 - v1);
+ if (diff_flag < 0)
+ distance = -distance;
+
+ if (times_through_search > 20) /* Arbitrary # of calls, but makes
+ sure we never hang if there's a
+ problem with this algorithm */
+ {
+ distance = diff_flag;
+ }
- distance = v1 - v2;
-
- /* We need this DIFF_FLAG business because it is forseeable that the
- distance may be zero when, in actuality, the two structures are
- different. This is usually the case when the dates are 366 days
- apart and one of the years is a leap year. */
+ /* We need this DIFF_FLAG business because it is forseeable that
+ * the distance may be zero when, in actuality, the two structures
+ * are different. This is usually the case when the dates are
+ * 366 days apart and one of the years is a leap year. */
- if (distance == 0 && diff_flag)
+ if ((distance == 0) && diff_flag)
distance = 86400 * diff_flag;
return distance;
}
-
-
-/* Modified binary search -- make intelligent guesses as to where the time
- might lie along the timeline, assuming that our target time lies a
- linear distance (w/o considering time jumps of a particular region).
-
- Assume that time does not fluctuate at all along the timeline -- e.g.,
- assume that a day will always take 86400 seconds, etc. -- and come up
- with a hypothetical value for the time_t representation of the struct tm
- TARGET, in relation to the guess variable -- it should be pretty close! */
+
+
+/* Modified b-search -- make intelligent guesses as to where the time
+ * might lie along the timeline, assuming that our target time lies a
+ * linear distance (w/o considering time jumps of a particular region).
+ *
+ * Assume that time does not fluctuate at all along the timeline --
+ * e.g., assume that a day will always take 86400 seconds, etc. -- and
+ * come up with a hypothetical value for the time_t representation of
+ * the struct tm TARGET, in relation to the guess variable -- it should
+ * be pretty close! */
static time_t
search (target)
time_t guess = 0;
time_t distance = 0;
+ times_through_search = 0;
+
do
{
guess += distance;
+ times_through_search++;
+
guess_tm = localtime (&guess);
-
+
#ifdef DEBUG
if (debugging_enabled)
{
- printf ("guess %d == ", guess);
+ printf ("guess %d == ", (int) guess);
printtm (guess_tm);
puts ("");
}
#endif
-
- /* Are we on the money? */
+
+ /* Are we on the money? */
distance = dist_tm (target, guess_tm);
-
+
} while (distance != 0);
return guess;
}
/* Since this function will call localtime many times (and the user might
- be passing their `struct tm *' right from localtime, let's make a copy
- for ourselves and run the search on the copy.
-
- Also, we have to normalize the timeptr because it's possible to call mktime
- with values that are out of range for a specific item (like 30th Feb). */
-
+ * be passing their `struct tm *' right from localtime, let's make a copy
+ * for ourselves and run the search on the copy.
+ *
+ * Also, we have to normalize the timeptr because it's possible to call mktime
+ * with values that are out of range for a specific item (like 30th Feb). */
time_t
mktime (timeptr)
struct tm *timeptr;
{
- struct tm private_mktime_struct_tm; /* Yes, users can get a ptr to this. */
+ struct tm private_mktime_struct_tm; /* Yes, users can get a ptr to this. */
struct tm *me;
time_t result;
me = &private_mktime_struct_tm;
-
+
*me = *timeptr;
#define normalize(foo,x,y,bar); \
me->bar++; \
me->foo = (x + (me->foo - y)); \
}
-
+
normalize (tm_sec, 0, 59, tm_min);
normalize (tm_min, 0, 59, tm_hour);
normalize (tm_hour, 0, 23, tm_mday);
-
- /* Do the month first, so day range can be found. */
+
+ /* Do the month first, so day range can be found. */
normalize (tm_mon, 0, 11, tm_year);
normalize (tm_mday, 1,
__mon_lengths[__isleap (me->tm_year)][me->tm_mon],
tm_mon);
- /* Do the month again, because the day may have pushed it out of range. */
+ /* Do the month again, because the day may have pushed it out of range. */
normalize (tm_mon, 0, 11, tm_year);
- /* Do day again, because month may have changed the range. */
+ /* Do the day again, because the month may have changed the range. */
normalize (tm_mday, 1,
__mon_lengths[__isleap (me->tm_year)][me->tm_mon],
tm_mon);
-
+
#ifdef DEBUG
if (debugging_enabled)
{
int time;
int result_time;
struct tm *tmptr;
-
+
if (argc == 1)
{
long q;
-
+
printf ("starting long test...\n");
for (q = 10000000; q < 1000000000; q++)
{
struct tm *tm = localtime (&q);
if ((q % 10000) == 0) { printf ("%ld\n", q); fflush (stdout); }
- if (q != my_mktime (tm))
+ if (q != mktime (tm))
{ printf ("failed for %ld\n", q); fflush (stdout); }
}
-
+
printf ("test finished\n");
exit (0);
}
-
+
if (argc != 2)
{
printf ("wrong # of args\n");
exit (0);
}
-
- debugging_enabled = 1; /* we want to see the info */
+
+ debugging_enabled = 1; /* We want to see the info */
++argv;
time = atoi (*argv);
+
+ printf ("Time: %d %s\n", time, ctime ((time_t *) &time));
- printf ("Time: %d %s\n", time, ctime (&time));
-
- tmptr = localtime (&time);
+ tmptr = localtime ((time_t *) &time);
printf ("localtime returns: ");
printtm (tmptr);
printf ("\n");
- printf ("mktime: %d\n\n", mktime (tmptr));
+ printf ("mktime: %d\n\n", (int) mktime (tmptr));
tmptr->tm_sec -= 20;
tmptr->tm_min -= 20;
tmptr->tm_mday -= 20;
tmptr->tm_mon -= 20;
tmptr->tm_year -= 20;
- tmptr->tm_gmtoff -= 20000; /* this has no effect! */
- tmptr->tm_zone = NULL; /* nor does this! */
+ tmptr->tm_gmtoff -= 20000; /* This has no effect! */
+ tmptr->tm_zone = NULL; /* Nor does this! */
tmptr->tm_isdst = -1;
printf ("changed ranges: ");
printf ("\n\n");
result_time = mktime (tmptr);
- printf ("\n mine: %d\n", result_time);
+ printf ("\nmktime: %d\n", result_time);
}
#endif /* DEBUG */
projects / gnulib.git / blobdiff