* time.c (find_time_t): always outerpolate from past.

  [ruby-core:30672] reported by Benoit Daloze.
  backport r28238 from trunk.

* time.c (calc_tm_yday): extracted from timegmw_noleapsecond.
  backport r28236 from trunk.


git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/branches/ruby_1_9_2@28254 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

1 files changed, 44 insertions, 21 deletions

diff --git a/time.c b/time.c
index ddad3d8948..890b0c9a11 100644
--- a/time.c
+++ b/time.c
@@ -30,6 +30,7 @@ static ID id_eq, id_ne, id_quo, id_div, id_cmp, id_lshift;
 #define NDIV(x,y) (-(-((x)+1)/(y))-1)
 #define NMOD(x,y) ((y)-(-((x)+1)%(y))-1)
 #define DIV(n,d) ((n)<0 ? NDIV((n),(d)) : (n)/(d))
+#define MOD(n,d) ((n)<0 ? NMOD((n),(d)) : (n)%(d))
 
 static int
 eq(VALUE x, VALUE y)
@@ -933,13 +934,29 @@ static const int leap_year_days_in_month[] = {
     31, 29, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31
 };
 
+static int
+calc_tm_yday(long tm_year, int tm_mon, int tm_mday)
+{
+    int tm_year_mod400;
+    int tm_yday = tm_mday;
+
+    tm_year_mod400 = MOD(tm_year, 400);
+
+    if (leap_year_p(tm_year_mod400 + 1900))
+	tm_yday += leap_year_yday_offset[tm_mon];
+    else
+	tm_yday += common_year_yday_offset[tm_mon];
+
+    return tm_yday;
+}
+
 static wideval_t
 timegmw_noleapsecond(struct vtm *vtm)
 {
     VALUE year1900;
     VALUE q400, r400;
     int year_mod400;
-    int yday = vtm->mday;
+    int yday;
     long days_in400;
     VALUE vdays, ret;
     wideval_t wret;
@@ -949,10 +966,7 @@ timegmw_noleapsecond(struct vtm *vtm)
     divmodv(year1900, INT2FIX(400), &q400, &r400);
     year_mod400 = NUM2INT(r400);
 
-    if (leap_year_p(year_mod400 + 1900))
-	yday += leap_year_yday_offset[vtm->mon-1];
-    else
-	yday += common_year_yday_offset[vtm->mon-1];
+    yday = calc_tm_yday(year_mod400, vtm->mon-1, vtm->mday);
 
     /*
      *  `Seconds Since the Epoch' in SUSv3:
@@ -2660,6 +2674,7 @@ find_time_t(struct tm *tptr, int utc_p, time_t *tp)
     int find_dst;
     struct tm result;
     int status;
+    int tptr_tm_yday;
 
 #define GUESS(p) (DEBUG_FIND_TIME_NUMGUESS_INC (utc_p ? gmtime_with_leapsecond(p, &result) : LOCALTIME(p, result)))
 
@@ -2887,22 +2902,30 @@ find_time_t(struct tm *tptr, int utc_p, time_t *tp)
 	}
     }
     /* Given argument has no corresponding time_t. Let's outerpolation. */
-    if (tm_lo.tm_year == tptr->tm_year && tm_lo.tm_mon == tptr->tm_mon) {
-	*tp = guess_lo +
-	      (tptr->tm_mday - tm_lo.tm_mday) * 24 * 60 * 60 +
-	      (tptr->tm_hour - tm_lo.tm_hour) * 60 * 60 +
-	      (tptr->tm_min - tm_lo.tm_min) * 60 +
-	      (tptr->tm_sec - tm_lo.tm_sec);
-        return NULL;
-    }
-    else if (tm_hi.tm_year == tptr->tm_year && tm_hi.tm_mon == tptr->tm_mon) {
-	*tp = guess_hi +
-	      (tptr->tm_mday - tm_hi.tm_mday) * 24 * 60 * 60 +
-	      (tptr->tm_hour - tm_hi.tm_hour) * 60 * 60 +
-	      (tptr->tm_min - tm_hi.tm_min) * 60 +
-	      (tptr->tm_sec - tm_hi.tm_sec);
-        return NULL;
-    }
+    /*
+     *  `Seconds Since the Epoch' in SUSv3:
+     *  tm_sec + tm_min*60 + tm_hour*3600 + tm_yday*86400 +
+     *  (tm_year-70)*31536000 + ((tm_year-69)/4)*86400 -
+     *  ((tm_year-1)/100)*86400 + ((tm_year+299)/400)*86400
+     */
+
+    tptr_tm_yday = calc_tm_yday(tptr->tm_year, tptr->tm_mon, tptr->tm_mday);
+
+    *tp = guess_lo +
+          ((tptr->tm_year - tm_lo.tm_year) * 365 +
+           ((tptr->tm_year-69)/4) -
+           ((tptr->tm_year-1)/100) +
+           ((tptr->tm_year+299)/400) -
+           ((tm_lo.tm_year-69)/4) +
+           ((tm_lo.tm_year-1)/100) -
+           ((tm_lo.tm_year+299)/400) +
+           tptr_tm_yday -
+           tm_lo.tm_yday) * 86400 +
+          (tptr->tm_hour - tm_lo.tm_hour) * 3600 +
+          (tptr->tm_min - tm_lo.tm_min) * 60 +
+          (tptr->tm_sec - tm_lo.tm_sec);
+
+    return NULL;
 
   out_of_range:
     return "time out of range";