X-Git-Url: https://diplodocus.org/git/nmh/blobdiff_plain/a3724ed395f47e90d887c6b172ef20b9441e5ca9..94187a80bd60baab4b9c4b949ad820d730578123:/sbr/dtime.c

diff --git a/sbr/dtime.c b/sbr/dtime.c
index d52662bc..5e0fdc0a 100644
--- a/sbr/dtime.c
+++ b/sbr/dtime.c
@@ -7,6 +7,7 @@
 
 #include <h/mh.h>   /* for snprintf() */
 #include <h/nmh.h>
+#include <h/utils.h>
 #include <h/tws.h>
 #include <time.h>
 
@@ -117,7 +118,7 @@ dlocaltime (time_t *clock)
 
     tw.tw_clock = *clock;
 
-    return (&tw);
+    return &tw;
 }
 
 
@@ -164,7 +165,7 @@ dgmtime (time_t *clock)
 
     tw.tw_clock = *clock;
 
-    return (&tw);
+    return &tw;
 }
 
 
@@ -178,15 +179,15 @@ dgmtime (time_t *clock)
 char *
 dctime (struct tws *tw)
 {
-    static char buffer[64];
+    static char buffer[26];
 
     if (!tw)
 	return NULL;
 
-    snprintf (buffer, sizeof(buffer), "%.3s %.3s %02d %02d:%02d:%02d %.4d\n",
+    snprintf (buffer, sizeof(buffer), "%.3s %.3s %02d %02d:%02d:%02d %s\n",
 	    tw_dotw[tw->tw_wday], tw_moty[tw->tw_mon], tw->tw_mday,
 	    tw->tw_hour, tw->tw_min, tw->tw_sec,
-	    tw->tw_year < 100 ? tw->tw_year + 1900 : tw->tw_year);
+	    m_strn(tw->tw_year < 100 ? tw->tw_year + 1900 : tw->tw_year, 4));
 
     return buffer;
 }
@@ -284,24 +285,23 @@ dasctime (struct tws *tw, int flags)
  * return the string representation of the numeric offset.
  */
 
-char *
-dtimezone (int offset, int flags)
+char *dtimezone(int offset, int flags)
 {
-    int hours, mins;
-    static char buffer[64];
-
-    if (offset < 0) {
-	mins = -((-offset) % 60);
-	hours = -((-offset) / 60);
-    } else {
-	mins = offset % 60;
-	hours = offset / 60;
-    }
+    static char buffer[sizeof "+3579139459"]; /* 2,147,483,648 / 60 = 35,791,394 */
+    bool pos;
+    unsigned os, hours, mins;
+
+    pos = offset >= 0;
+    os = pos ? offset : ~offset + 1; /* abs(3) undefined on INT_MIN. */
+    hours = os / 60;
+    mins = os % 60;
+
+    if (flags & TW_DST) /* Shift towards +infinity. */
+        hours += pos ? 1 : -1;
+
+    snprintf(buffer, sizeof(buffer), "%c%02u%02u",
+        pos ? '+' : '-', hours, mins);
 
-    if (flags & TW_DST)
-	hours++;
-    snprintf (buffer, sizeof(buffer), "%s%02d%02d",
-		offset < 0 ? "-" : "+", abs (hours), abs (mins));
     return buffer;
 }
 
@@ -345,14 +345,17 @@ dmktime (struct tws *tw)
     while (--mon)
 	result += dmsize[mon - 1];
     result += mday - 1;
-    result = 24 * result + hour;
-    result = 60 * result + min;
-    result = 60 * result + sec;
+    result *= 24; /* Days to hours. */
+    result += hour;
+    result *= 60; /* Hours to minutes. */
+    result += min;
+    result *= 60; /* Minutes to seconds. */
+    result += sec;
     result -= 60 * tw->tw_zone;
     if (tw->tw_flags & TW_DST)
-	result -= 60 * 60;
+	result -= 60 * 60; /* One hour. */
 
-    return (tw->tw_clock = result);
+    return tw->tw_clock = result;
 }
 
 
@@ -405,6 +408,6 @@ twsort (struct tws *tw1, struct tws *tw2)
     if (tw2->tw_clock == 0)
 	dmktime (tw2);
 
-    return ((c1 = tw1->tw_clock) > (c2 = tw2->tw_clock) ? 1
-	    : c1 == c2 ? 0 : -1);
+    return (c1 = tw1->tw_clock) > (c2 = tw2->tw_clock) ? 1
+	    : c1 == c2 ? 0 : -1;
 }