From a30d9e99bbb225ba5c99d684a86fceb65a1d2615 Mon Sep 17 00:00:00 2001 From: charlet Date: Wed, 26 Sep 2007 10:41:35 +0000 Subject: 2007-09-26 Hristian Kirtchev * a-calend-vms.adb, a-calend.adb: Add a section on leap seconds control along with two entities used to enable and disable leap seconds support. The array Leap_Second_Times is now constant and contains hard time values pre-generated. Remove all elaboration code used to populate the table of leap seconds. * bindgen.adb: Add entity Leap_Seconds_Support to the list of global run-time variables along with a comment on its usage and values. (Gen_Adainit_Ada): Add code to generate the declaration and import of Integer variable Leap_Seconds_Support. Set its value to zero (disabled) or one (enabled) depending on the presence of binder switch "-y". (Gen_Adainit_C): Add code to generate the declaration of external int __gl_leap_seconds_support. Set is value to zero (disabled) or one (enabled) depending on the presence of binder switch "-y". * init.c: Add __gl_leap_seconds_support to the list of global values computed by the binder. git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@128780 138bc75d-0d04-0410-961f-82ee72b054a4 --- gcc/ada/a-calend.adb | 122 +++++++++++++++++++-------------------------------- 1 file changed, 44 insertions(+), 78 deletions(-) (limited to 'gcc/ada/a-calend.adb') diff --git a/gcc/ada/a-calend.adb b/gcc/ada/a-calend.adb index 9acac9bf6d7..eb77eac37b2 100644 --- a/gcc/ada/a-calend.adb +++ b/gcc/ada/a-calend.adb @@ -127,17 +127,27 @@ package body Ada.Calendar is type Time_Dur is range 0 .. 2 ** 63 - 1; - --------------------- - -- Local Constants -- - --------------------- + -------------------------- + -- Leap seconds control -- + -------------------------- + + Flag : Integer; + pragma Import (C, Flag, "__gl_leap_seconds_support"); + -- This imported value is used to determine whether the compilation had + -- binder flag "-y" present which enables leap seconds. A value of zero + -- signifies no leap seconds support while a value of one enables the + -- support. - -- Currently none of the GNAT targets support leap seconds. At some point - -- it might be necessary to query a C function to determine if the target - -- supports leap seconds, but for now this is deemed unnecessary. + Leap_Support : constant Boolean := Flag = 1; + -- The above flag controls the usage of leap seconds in all Ada.Calendar + -- routines. - Leap_Support : constant Boolean := False; Leap_Seconds_Count : constant Natural := 23; + --------------------- + -- Local Constants -- + --------------------- + Ada_Min_Year : constant Year_Number := Year_Number'First; Secs_In_Four_Years : constant := (3 * 365 + 366) * Secs_In_Day; Secs_In_Non_Leap_Year : constant := 365 * Secs_In_Day; @@ -174,10 +184,33 @@ package body Ada.Calendar is constant array (Month_Number) of Natural := (0, 31, 59, 90, 120, 151, 181, 212, 243, 273, 304, 334); - Leap_Second_Times : array (1 .. Leap_Seconds_Count) of Time_Rep; - -- Each value represents a time value which is one second before a leap - -- second occurence. This table is populated during the elaboration of - -- Ada.Calendar. + -- The following table contains the hard time values of all existing leap + -- seconds. The values are produced by the utility program xleaps.adb. + + Leap_Second_Times : constant array (1 .. Leap_Seconds_Count) of Time_Rep := + (-5601484800000000000, + -5585587199000000000, + -5554051198000000000, + -5522515197000000000, + -5490979196000000000, + -5459356795000000000, + -5427820794000000000, + -5396284793000000000, + -5364748792000000000, + -5317487991000000000, + -5285951990000000000, + -5254415989000000000, + -5191257588000000000, + -5112287987000000000, + -5049129586000000000, + -5017593585000000000, + -4970332784000000000, + -4938796783000000000, + -4907260782000000000, + -4859827181000000000, + -4812566380000000000, + -4765132779000000000, + -4544207978000000000); --------- -- "+" -- @@ -1318,71 +1351,4 @@ package body Ada.Calendar is begin System.OS_Primitives.Initialize; - - -- Population of the leap seconds table - - if Leap_Support then - declare - type Leap_Second_Date is record - Year : Year_Number; - Month : Month_Number; - Day : Day_Number; - end record; - - Leap_Second_Dates : - constant array (1 .. Leap_Seconds_Count) of Leap_Second_Date := - ((1972, 6, 30), (1972, 12, 31), (1973, 12, 31), (1974, 12, 31), - (1975, 12, 31), (1976, 12, 31), (1977, 12, 31), (1978, 12, 31), - (1979, 12, 31), (1981, 6, 30), (1982, 6, 30), (1983, 6, 30), - (1985, 6, 30), (1987, 12, 31), (1989, 12, 31), (1990, 12, 31), - (1992, 6, 30), (1993, 6, 30), (1994, 6, 30), (1995, 12, 31), - (1997, 6, 30), (1998, 12, 31), (2005, 12, 31)); - - Days_In_Four_Years : constant := 365 * 3 + 366; - - Days : Natural; - Leap : Leap_Second_Date; - Years : Natural; - - begin - for Index in 1 .. Leap_Seconds_Count loop - Leap := Leap_Second_Dates (Index); - - -- Calculate the number of days from the start of Ada time until - -- the current leap second occurence. Non-leap centenial years - -- are not accounted for in these calculations since there are - -- no leap seconds after 2100 yet. - - Years := Leap.Year - Ada_Min_Year; - Days := (Years / 4) * Days_In_Four_Years; - Years := Years mod 4; - - if Years = 1 then - Days := Days + 365; - - elsif Years = 2 then - Days := Days + 365 * 2; - - elsif Years = 3 then - Days := Days + 365 * 3; - end if; - - Days := Days + Cumulative_Days_Before_Month (Leap.Month); - - if Is_Leap (Leap.Year) - and then Leap.Month > 2 - then - Days := Days + 1; - end if; - - Days := Days + Leap.Day; - - -- Index - 1 previous leap seconds are added to Time (Index) as - -- well as the lower buffer for time zones. - - Leap_Second_Times (Index) := Ada_Low + - (Time_Rep (Days) * Secs_In_Day + Time_Rep (Index - 1)) * Nano; - end loop; - end; - end if; end Ada.Calendar; -- cgit v1.2.1