g-catiio.adb (Image): For the case of %s...

2007-08-14  Hristian Kirtchev  <kirtchev@adacore.com>

	* g-catiio.adb (Image): For the case of %s, use Ada.Calendar.Time
	values to compute the number of seconds since the Unix Epoc in order to
	account for Daylight Savings Time. Perform special processing for dates
	that are earlier than the Unix Epoc to obtain a negative number.

From-SVN: r127450

gcc/ada/g-catiio.adb

@@ -306,15 +306,33 @@ package body GNAT.Calendar.Time_IO is
 
                when 's' =>
                   declare
-                     Sec : constant Sec_Number :=
-                             Sec_Number (Julian_Day (Year, Month, Day)
-                                          - Julian_Day (1970, 1, 1)) * 86_400
-                                          + Sec_Number (Hour) * 3_600
-                                          + Sec_Number (Minute) * 60
-                                          + Sec_Number (Second);
+                     --  Compute the number of seconds using Ada.Calendar.Time
+                     --  values rather than Julian days to account for Daylight
+                     --  Savings Time.
+
+                     Neg : Boolean  := False;
+                     Sec : Duration := Date - Time_Of (1970, 1, 1, 0.0);
 
                   begin
-                     Result := Result & Image (Sec, None);
+                     --  Avoid rounding errors and perform special processing
+                     --  for dates earlier than the Unix Epoc.
+
+                     if Sec > 0.0 then
+                        Sec := Sec - 0.5;
+                     elsif Sec < 0.0 then
+                        Neg := True;
+                        Sec := abs (Sec + 0.5);
+                     end if;
+
+                     --  Prepend a minus sign to the result since Sec_Number
+                     --  cannot handle negative numbers.
+
+                     if Neg then
+                        Result :=
+                          Result & "-" & Image (Sec_Number (Sec), None);
+                     else
+                        Result := Result & Image (Sec_Number (Sec), None);
+                     end if;
                   end;
 
                --  Second (00..59)