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Diffstat (limited to 'gcc-4.2.1/gcc/ada/a-calend.adb')
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diff --git a/gcc-4.2.1/gcc/ada/a-calend.adb b/gcc-4.2.1/gcc/ada/a-calend.adb new file mode 100644 index 000000000..581295818 --- /dev/null +++ b/gcc-4.2.1/gcc/ada/a-calend.adb @@ -0,0 +1,481 @@ +------------------------------------------------------------------------------ +-- -- +-- GNAT RUN-TIME COMPONENTS -- +-- -- +-- A D A . C A L E N D A R -- +-- -- +-- B o d y -- +-- -- +-- Copyright (C) 1992-2005, Free Software Foundation, Inc. -- +-- -- +-- GNAT is free software; you can redistribute it and/or modify it under -- +-- terms of the GNU General Public License as published by the Free Soft- -- +-- ware Foundation; either version 2, or (at your option) any later ver- -- +-- sion. GNAT is distributed in the hope that it will be useful, but WITH- -- +-- OUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY -- +-- or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License -- +-- for more details. You should have received a copy of the GNU General -- +-- Public License distributed with GNAT; see file COPYING. If not, write -- +-- to the Free Software Foundation, 51 Franklin Street, Fifth Floor, -- +-- Boston, MA 02110-1301, USA. -- +-- -- +-- As a special exception, if other files instantiate generics from this -- +-- unit, or you link this unit with other files to produce an executable, -- +-- this unit does not by itself cause the resulting executable to be -- +-- covered by the GNU General Public License. This exception does not -- +-- however invalidate any other reasons why the executable file might be -- +-- covered by the GNU Public License. -- +-- -- +-- GNAT was originally developed by the GNAT team at New York University. -- +-- Extensive contributions were provided by Ada Core Technologies Inc. -- +-- -- +------------------------------------------------------------------------------ + +with Unchecked_Conversion; + +with System.OS_Primitives; +-- used for Clock + +package body Ada.Calendar is + + ------------------------------ + -- Use of Pragma Unsuppress -- + ------------------------------ + + -- This implementation of Calendar takes advantage of the permission in + -- Ada 95 of using arithmetic overflow checks to check for out of bounds + -- time values. This means that we must catch the constraint error that + -- results from arithmetic overflow, so we use pragma Unsuppress to make + -- sure that overflow is enabled, using software overflow checking if + -- necessary. That way, compiling Calendar with options to suppress this + -- checking will not affect its correctness. + + ------------------------ + -- Local Declarations -- + ------------------------ + + type Char_Pointer is access Character; + subtype int is Integer; + subtype long is Long_Integer; + -- Synonyms for C types. We don't want to get them from Interfaces.C + -- because there is no point in loading that unit just for calendar. + + type tm is record + tm_sec : int; -- seconds after the minute (0 .. 60) + tm_min : int; -- minutes after the hour (0 .. 59) + tm_hour : int; -- hours since midnight (0 .. 24) + tm_mday : int; -- day of the month (1 .. 31) + tm_mon : int; -- months since January (0 .. 11) + tm_year : int; -- years since 1900 + tm_wday : int; -- days since Sunday (0 .. 6) + tm_yday : int; -- days since January 1 (0 .. 365) + tm_isdst : int; -- Daylight Savings Time flag (-1 .. +1) + tm_gmtoff : long; -- offset from CUT in seconds + tm_zone : Char_Pointer; -- timezone abbreviation + end record; + + type tm_Pointer is access all tm; + + subtype time_t is long; + + type time_t_Pointer is access all time_t; + + procedure localtime_r (C : time_t_Pointer; res : tm_Pointer); + pragma Import (C, localtime_r, "__gnat_localtime_r"); + + function mktime (TM : tm_Pointer) return time_t; + pragma Import (C, mktime); + -- mktime returns -1 in case the calendar time given by components of + -- TM.all cannot be represented. + + -- The following constants are used in adjusting Ada dates so that they + -- fit into a 56 year range that can be handled by Unix (1970 included - + -- 2026 excluded). Dates that are not in this 56 year range are shifted + -- by multiples of 56 years to fit in this range. + + -- The trick is that the number of days in any four year period in the Ada + -- range of years (1901 - 2099) has a constant number of days. This is + -- because we have the special case of 2000 which, contrary to the normal + -- exception for centuries, is a leap year after all. 56 has been chosen, + -- because it is not only a multiple of 4, but also a multiple of 7. Thus + -- two dates 56 years apart fall on the same day of the week, and the + -- Daylight Saving Time change dates are usually the same for these two + -- years. + + Unix_Year_Min : constant := 1970; + Unix_Year_Max : constant := 2026; + + Ada_Year_Min : constant := 1901; + Ada_Year_Max : constant := 2099; + + -- Some basic constants used throughout + + Days_In_Month : constant array (Month_Number) of Day_Number := + (31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31); + + Days_In_4_Years : constant := 365 * 3 + 366; + Seconds_In_4_Years : constant := 86_400 * Days_In_4_Years; + Seconds_In_56_Years : constant := Seconds_In_4_Years * 14; + Seconds_In_56_YearsD : constant := Duration (Seconds_In_56_Years); + + --------- + -- "+" -- + --------- + + function "+" (Left : Time; Right : Duration) return Time is + pragma Unsuppress (Overflow_Check); + begin + return (Left + Time (Right)); + exception + when Constraint_Error => + raise Time_Error; + end "+"; + + function "+" (Left : Duration; Right : Time) return Time is + pragma Unsuppress (Overflow_Check); + begin + return (Time (Left) + Right); + exception + when Constraint_Error => + raise Time_Error; + end "+"; + + --------- + -- "-" -- + --------- + + function "-" (Left : Time; Right : Duration) return Time is + pragma Unsuppress (Overflow_Check); + begin + return Left - Time (Right); + exception + when Constraint_Error => + raise Time_Error; + end "-"; + + function "-" (Left : Time; Right : Time) return Duration is + pragma Unsuppress (Overflow_Check); + begin + return Duration (Left) - Duration (Right); + exception + when Constraint_Error => + raise Time_Error; + end "-"; + + --------- + -- "<" -- + --------- + + function "<" (Left, Right : Time) return Boolean is + begin + return Duration (Left) < Duration (Right); + end "<"; + + ---------- + -- "<=" -- + ---------- + + function "<=" (Left, Right : Time) return Boolean is + begin + return Duration (Left) <= Duration (Right); + end "<="; + + --------- + -- ">" -- + --------- + + function ">" (Left, Right : Time) return Boolean is + begin + return Duration (Left) > Duration (Right); + end ">"; + + ---------- + -- ">=" -- + ---------- + + function ">=" (Left, Right : Time) return Boolean is + begin + return Duration (Left) >= Duration (Right); + end ">="; + + ----------- + -- Clock -- + ----------- + + function Clock return Time is + begin + return Time (System.OS_Primitives.Clock); + end Clock; + + --------- + -- Day -- + --------- + + function Day (Date : Time) return Day_Number is + DY : Year_Number; + DM : Month_Number; + DD : Day_Number; + DS : Day_Duration; + begin + Split (Date, DY, DM, DD, DS); + return DD; + end Day; + + ----------- + -- Month -- + ----------- + + function Month (Date : Time) return Month_Number is + DY : Year_Number; + DM : Month_Number; + DD : Day_Number; + DS : Day_Duration; + begin + Split (Date, DY, DM, DD, DS); + return DM; + end Month; + + ------------- + -- Seconds -- + ------------- + + function Seconds (Date : Time) return Day_Duration is + DY : Year_Number; + DM : Month_Number; + DD : Day_Number; + DS : Day_Duration; + begin + Split (Date, DY, DM, DD, DS); + return DS; + end Seconds; + + ----------- + -- Split -- + ----------- + + procedure Split + (Date : Time; + Year : out Year_Number; + Month : out Month_Number; + Day : out Day_Number; + Seconds : out Day_Duration) + is + -- The following declare bounds for duration that are comfortably + -- wider than the maximum allowed output result for the Ada range + -- of representable split values. These are used for a quick check + -- that the value is not wildly out of range. + + Low : constant := (Ada_Year_Min - Unix_Year_Min - 2) * 365 * 86_400; + High : constant := (Ada_Year_Max - Unix_Year_Min + 2) * 365 * 86_400; + + LowD : constant Duration := Duration (Low); + HighD : constant Duration := Duration (High); + + -- Finally the actual variables used in the computation + + D : Duration; + Frac_Sec : Duration; + Year_Val : Integer; + Adjusted_Seconds : aliased time_t; + Tm_Val : aliased tm; + + begin + -- For us a time is simply a signed duration value, so we work with + -- this duration value directly. Note that it can be negative. + + D := Duration (Date); + + -- First of all, filter out completely ludicrous values. Remember that + -- we use the full stored range of duration values, which may be + -- significantly larger than the allowed range of Ada times. Note that + -- these checks are wider than required to make absolutely sure that + -- there are no end effects from time zone differences. + + if D < LowD or else D > HighD then + raise Time_Error; + end if; + + -- The unix localtime_r function is more or less exactly what we need + -- here. The less comes from the fact that it does not support the + -- required range of years (the guaranteed range available is only + -- EPOCH through EPOCH + N seconds). N is in practice 2 ** 31 - 1. + + -- If we have a value outside this range, then we first adjust it to be + -- in the required range by adding multiples of 56 years. For the range + -- we are interested in, the number of days in any consecutive 56 year + -- period is constant. Then we do the split on the adjusted value, and + -- readjust the years value accordingly. + + Year_Val := 0; + + while D < 0.0 loop + D := D + Seconds_In_56_YearsD; + Year_Val := Year_Val - 56; + end loop; + + while D >= Seconds_In_56_YearsD loop + D := D - Seconds_In_56_YearsD; + Year_Val := Year_Val + 56; + end loop; + + -- Now we need to take the value D, which is now non-negative, and + -- break it down into seconds (to pass to the localtime_r function) and + -- fractions of seconds (for the adjustment below). + + -- Surprisingly there is no easy way to do this in Ada, and certainly + -- no easy way to do it and generate efficient code. Therefore we do it + -- at a low level, knowing that it is really represented as an integer + -- with units of Small + + declare + type D_Int is range 0 .. 2 ** (Duration'Size - 1) - 1; + for D_Int'Size use Duration'Size; + + Small_Div : constant D_Int := D_Int (1.0 / Duration'Small); + D_As_Int : D_Int; + + function To_D_As_Int is new Unchecked_Conversion (Duration, D_Int); + function To_Duration is new Unchecked_Conversion (D_Int, Duration); + + begin + D_As_Int := To_D_As_Int (D); + Adjusted_Seconds := time_t (D_As_Int / Small_Div); + Frac_Sec := To_Duration (D_As_Int rem Small_Div); + end; + + localtime_r (Adjusted_Seconds'Unchecked_Access, Tm_Val'Unchecked_Access); + + Year_Val := Tm_Val.tm_year + 1900 + Year_Val; + Month := Tm_Val.tm_mon + 1; + Day := Tm_Val.tm_mday; + + -- The Seconds value is a little complex. The localtime function + -- returns the integral number of seconds, which is what we want, but + -- we want to retain the fractional part from the original Time value, + -- since this is typically stored more accurately. + + Seconds := Duration (Tm_Val.tm_hour * 3600 + + Tm_Val.tm_min * 60 + + Tm_Val.tm_sec) + + Frac_Sec; + + -- Note: the above expression is pretty horrible, one of these days we + -- should stop using time_of and do everything ourselves to avoid these + -- unnecessary divides and multiplies???. + + -- The Year may still be out of range, since our entry test was + -- deliberately crude. Trying to make this entry test accurate is + -- tricky due to time zone adjustment issues affecting the exact + -- boundary. It is interesting to note that whether or not a given + -- Calendar.Time value gets Time_Error when split depends on the + -- current time zone setting. + + if Year_Val not in Ada_Year_Min .. Ada_Year_Max then + raise Time_Error; + else + Year := Year_Val; + end if; + end Split; + + ------------- + -- Time_Of -- + ------------- + + function Time_Of + (Year : Year_Number; + Month : Month_Number; + Day : Day_Number; + Seconds : Day_Duration := 0.0) + return Time + is + Result_Secs : aliased time_t; + TM_Val : aliased tm; + Int_Secs : constant Integer := Integer (Seconds); + + Year_Val : Integer := Year; + Duration_Adjust : Duration := 0.0; + + begin + -- The following checks are redundant with respect to the constraint + -- error checks that should normally be made on parameters, but we + -- decide to raise Constraint_Error in any case if bad values come in + -- (as a result of checks being off in the caller, or for other + -- erroneous or bounded error cases). + + if not Year 'Valid + or else not Month 'Valid + or else not Day 'Valid + or else not Seconds'Valid + then + raise Constraint_Error; + end if; + + -- Check for Day value too large (one might expect mktime to do this + -- check, as well as the basic checks we did with 'Valid, but it seems + -- that at least on some systems, this built-in check is too weak). + + if Day > Days_In_Month (Month) + and then (Day /= 29 or Month /= 2 or Year mod 4 /= 0) + then + raise Time_Error; + end if; + + TM_Val.tm_sec := Int_Secs mod 60; + TM_Val.tm_min := (Int_Secs / 60) mod 60; + TM_Val.tm_hour := (Int_Secs / 60) / 60; + TM_Val.tm_mday := Day; + TM_Val.tm_mon := Month - 1; + + -- For the year, we have to adjust it to a year that Unix can handle. + -- We do this in 56 year steps, since the number of days in 56 years is + -- constant, so the timezone effect on the conversion from local time + -- to GMT is unaffected; also the DST change dates are usually not + -- modified. + + while Year_Val < Unix_Year_Min loop + Year_Val := Year_Val + 56; + Duration_Adjust := Duration_Adjust - Seconds_In_56_YearsD; + end loop; + + while Year_Val >= Unix_Year_Max loop + Year_Val := Year_Val - 56; + Duration_Adjust := Duration_Adjust + Seconds_In_56_YearsD; + end loop; + + TM_Val.tm_year := Year_Val - 1900; + + -- Since we do not have information on daylight savings, rely on the + -- default information. + + TM_Val.tm_isdst := -1; + Result_Secs := mktime (TM_Val'Unchecked_Access); + + -- That gives us the basic value in seconds. Two adjustments are + -- needed. First we must undo the year adjustment carried out above. + -- Second we put back the fraction seconds value since in general the + -- Day_Duration value we received has additional precision which we do + -- not want to lose in the constructed result. + + return + Time (Duration (Result_Secs) + + Duration_Adjust + + (Seconds - Duration (Int_Secs))); + end Time_Of; + + ---------- + -- Year -- + ---------- + + function Year (Date : Time) return Year_Number is + DY : Year_Number; + DM : Month_Number; + DD : Day_Number; + DS : Day_Duration; + begin + Split (Date, DY, DM, DD, DS); + return DY; + end Year; + +begin + System.OS_Primitives.Initialize; +end Ada.Calendar; |