1------------------------------------------------------------------------------ 2-- -- 3-- GNAT RUN-TIME COMPONENTS -- 4-- -- 5-- A D A . C A L E N D A R -- 6-- -- 7-- S p e c -- 8-- -- 9-- Copyright (C) 1992-2012, Free Software Foundation, Inc. -- 10-- -- 11-- This specification is derived from the Ada Reference Manual for use with -- 12-- GNAT. The copyright notice above, and the license provisions that follow -- 13-- apply solely to the contents of the part following the private keyword. -- 14-- -- 15-- GNAT is free software; you can redistribute it and/or modify it under -- 16-- terms of the GNU General Public License as published by the Free Soft- -- 17-- ware Foundation; either version 3, or (at your option) any later ver- -- 18-- sion. GNAT is distributed in the hope that it will be useful, but WITH- -- 19-- OUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY -- 20-- or FITNESS FOR A PARTICULAR PURPOSE. -- 21-- -- 22-- As a special exception under Section 7 of GPL version 3, you are granted -- 23-- additional permissions described in the GCC Runtime Library Exception, -- 24-- version 3.1, as published by the Free Software Foundation. -- 25-- -- 26-- You should have received a copy of the GNU General Public License and -- 27-- a copy of the GCC Runtime Library Exception along with this program; -- 28-- see the files COPYING3 and COPYING.RUNTIME respectively. If not, see -- 29-- <http://www.gnu.org/licenses/>. -- 30-- -- 31-- GNAT was originally developed by the GNAT team at New York University. -- 32-- Extensive contributions were provided by Ada Core Technologies Inc. -- 33-- -- 34------------------------------------------------------------------------------ 35 36package Ada.Calendar is 37 38 type Time is private; 39 40 -- Declarations representing limits of allowed local time values. Note that 41 -- these do NOT constrain the possible stored values of time which may well 42 -- permit a larger range of times (this is explicitly allowed in Ada 95). 43 44 subtype Year_Number is Integer range 1901 .. 2399; 45 subtype Month_Number is Integer range 1 .. 12; 46 subtype Day_Number is Integer range 1 .. 31; 47 48 -- A Day_Duration value of 86_400.0 designates a new day 49 50 subtype Day_Duration is Duration range 0.0 .. 86_400.0; 51 52 function Clock return Time; 53 -- The returned time value is the number of nanoseconds since the start 54 -- of Ada time (1901-01-01 00:00:00.0 UTC). If leap seconds are enabled, 55 -- the result will contain all elapsed leap seconds since the start of 56 -- Ada time until now. 57 58 function Year (Date : Time) return Year_Number; 59 function Month (Date : Time) return Month_Number; 60 function Day (Date : Time) return Day_Number; 61 function Seconds (Date : Time) return Day_Duration; 62 63 procedure Split 64 (Date : Time; 65 Year : out Year_Number; 66 Month : out Month_Number; 67 Day : out Day_Number; 68 Seconds : out Day_Duration); 69 -- Break down a time value into its date components set in the current 70 -- time zone. If Split is called on a time value created using Ada 2005 71 -- Time_Of in some arbitrary time zone, the input value will always be 72 -- interpreted as relative to the local time zone. 73 74 function Time_Of 75 (Year : Year_Number; 76 Month : Month_Number; 77 Day : Day_Number; 78 Seconds : Day_Duration := 0.0) return Time; 79 -- GNAT Note: Normally when procedure Split is called on a Time value 80 -- result of a call to function Time_Of, the out parameters of procedure 81 -- Split are identical to the in parameters of function Time_Of. However, 82 -- when a non-existent time of day is specified, the values for Seconds 83 -- may or may not be different. This may happen when Daylight Saving Time 84 -- (DST) is in effect, on the day when switching to DST, if Seconds 85 -- specifies a time of day in the hour that does not exist. For example, 86 -- in New York: 87 -- 88 -- Time_Of (Year => 1998, Month => 4, Day => 5, Seconds => 10740.0) 89 -- 90 -- will return a Time value T. If Split is called on T, the resulting 91 -- Seconds may be 14340.0 (3:59:00) instead of 10740.0 (2:59:00 being 92 -- a time that not exist). 93 94 function "+" (Left : Time; Right : Duration) return Time; 95 function "+" (Left : Duration; Right : Time) return Time; 96 function "-" (Left : Time; Right : Duration) return Time; 97 function "-" (Left : Time; Right : Time) return Duration; 98 -- The first three functions will raise Time_Error if the resulting time 99 -- value is less than the start of Ada time in UTC or greater than the 100 -- end of Ada time in UTC. The last function will raise Time_Error if the 101 -- resulting difference cannot fit into a duration value. 102 103 function "<" (Left, Right : Time) return Boolean; 104 function "<=" (Left, Right : Time) return Boolean; 105 function ">" (Left, Right : Time) return Boolean; 106 function ">=" (Left, Right : Time) return Boolean; 107 108 Time_Error : exception; 109 110private 111 pragma Inline (Clock); 112 113 pragma Inline (Year); 114 pragma Inline (Month); 115 pragma Inline (Day); 116 117 pragma Inline ("+"); 118 pragma Inline ("-"); 119 120 pragma Inline ("<"); 121 pragma Inline ("<="); 122 pragma Inline (">"); 123 pragma Inline (">="); 124 125 -- The units used in this version of Ada.Calendar are nanoseconds. The 126 -- following constants provide values used in conversions of seconds or 127 -- days to the underlying units. 128 129 Nano : constant := 1_000_000_000; 130 Nano_F : constant := 1_000_000_000.0; 131 Nanos_In_Day : constant := 86_400_000_000_000; 132 Secs_In_Day : constant := 86_400; 133 134 ---------------------------- 135 -- Implementation of Time -- 136 ---------------------------- 137 138 -- Time is represented as a signed 64 bit integer count of nanoseconds 139 -- since the start of Ada time (1901-01-01 00:00:00.0 UTC). Time values 140 -- produced by Time_Of are internally normalized to UTC regardless of their 141 -- local time zone. This representation ensures correct handling of leap 142 -- seconds as well as performing arithmetic. In Ada 95, Split and Time_Of 143 -- will treat a time value as being in the local time zone, in Ada 2005, 144 -- Split and Time_Of will treat a time value as being in the designated 145 -- time zone by the formal parameter or in UTC by default. The size of the 146 -- type is large enough to cover the Ada 2005 range of time (1901-01-01 147 -- 00:00:00.0 UTC - 2399-12-31-23:59:59.999999999 UTC). 148 149 ------------------ 150 -- Leap Seconds -- 151 ------------------ 152 153 -- Due to Earth's slowdown, the astronomical time is not as precise as the 154 -- International Atomic Time. To compensate for this inaccuracy, a single 155 -- leap second is added after the last day of June or December. The count 156 -- of seconds during those occurrences becomes: 157 158 -- ... 58, 59, leap second 60, 0, 1, 2 ... 159 160 -- Unlike leap days, leap seconds occur simultaneously around the world. 161 -- In other words, if a leap second occurs at 23:59:60 UTC, it also occurs 162 -- on 18:59:60 -5 the same day or 2:59:60 +2 on the next day. 163 164 -- Leap seconds do not follow a formula. The International Earth Rotation 165 -- and Reference System Service decides when to add one. Leap seconds are 166 -- included in the representation of time in Ada 95 mode. As a result, 167 -- the following two time values will differ by two seconds: 168 169 -- 1972-06-30 23:59:59.0 170 -- 1972-07-01 00:00:00.0 171 172 -- When a new leap second is introduced, the following steps must be 173 -- carried out: 174 175 -- 1) Increment Leap_Seconds_Count in a-calend.adb by one 176 -- 2) Increment LS_Count in xleaps.adb by one 177 -- 3) Add the new date to the aggregate of array LS_Dates in 178 -- xleaps.adb 179 -- 4) Compile and execute xleaps 180 -- 5) Replace the values of Leap_Second_Times in a-calend.adb with the 181 -- aggregate generated by xleaps 182 183 -- The algorithms that build the actual leap second values and discover 184 -- how many leap seconds have occurred between two dates do not need any 185 -- modification. 186 187 ------------------------------ 188 -- Non-leap Centennial Years -- 189 ------------------------------ 190 191 -- Over the range of Ada time, centennial years 2100, 2200 and 2300 are 192 -- non-leap. As a consequence, seven non-leap years occur over the period 193 -- of year - 4 to year + 4. Internally, routines Split and Time_Of add or 194 -- subtract a "fake" February 29 to facilitate the arithmetic involved. 195 196 ------------------------ 197 -- Local Declarations -- 198 ------------------------ 199 200 type Time_Rep is range -2 ** 63 .. +2 ** 63 - 1; 201 type Time is new Time_Rep; 202 -- The underlying type of Time has been chosen to be a 64 bit signed 203 -- integer number since it allows for easier processing of sub seconds 204 -- and arithmetic. 205 206 Days_In_Month : constant array (Month_Number) of Day_Number := 207 (31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31); 208 -- Days in month for non-leap year, leap year case is adjusted in code 209 210 Invalid_Time_Zone_Offset : Long_Integer; 211 pragma Import (C, Invalid_Time_Zone_Offset, "__gnat_invalid_tzoff"); 212 213 function Is_Leap (Year : Year_Number) return Boolean; 214 -- Determine whether a given year is leap 215 216 ---------------------------------------------------------- 217 -- Target-Independent Interface to Children of Calendar -- 218 ---------------------------------------------------------- 219 220 -- The following packages provide a target-independent interface to the 221 -- children of Calendar - Arithmetic, Conversions, Delays, Formatting and 222 -- Time_Zones. 223 224 --------------------------- 225 -- Arithmetic_Operations -- 226 --------------------------- 227 228 package Arithmetic_Operations is 229 230 function Add (Date : Time; Days : Long_Integer) return Time; 231 -- Add a certain number of days to a time value 232 233 procedure Difference 234 (Left : Time; 235 Right : Time; 236 Days : out Long_Integer; 237 Seconds : out Duration; 238 Leap_Seconds : out Integer); 239 -- Calculate the difference between two time values in terms of days, 240 -- seconds and leap seconds elapsed. The leap seconds are not included 241 -- in the seconds returned. If Left is greater than Right, the returned 242 -- values are positive, negative otherwise. 243 244 function Subtract (Date : Time; Days : Long_Integer) return Time; 245 -- Subtract a certain number of days from a time value 246 247 end Arithmetic_Operations; 248 249 --------------------------- 250 -- Conversion_Operations -- 251 --------------------------- 252 253 package Conversion_Operations is 254 255 function To_Ada_Time (Unix_Time : Long_Integer) return Time; 256 -- Unix to Ada Epoch conversion 257 258 function To_Ada_Time 259 (tm_year : Integer; 260 tm_mon : Integer; 261 tm_day : Integer; 262 tm_hour : Integer; 263 tm_min : Integer; 264 tm_sec : Integer; 265 tm_isdst : Integer) return Time; 266 -- Struct tm to Ada Epoch conversion 267 268 function To_Duration 269 (tv_sec : Long_Integer; 270 tv_nsec : Long_Integer) return Duration; 271 -- Struct timespec to Duration conversion 272 273 procedure To_Struct_Timespec 274 (D : Duration; 275 tv_sec : out Long_Integer; 276 tv_nsec : out Long_Integer); 277 -- Duration to struct timespec conversion 278 279 procedure To_Struct_Tm 280 (T : Time; 281 tm_year : out Integer; 282 tm_mon : out Integer; 283 tm_day : out Integer; 284 tm_hour : out Integer; 285 tm_min : out Integer; 286 tm_sec : out Integer); 287 -- Time to struct tm conversion 288 289 function To_Unix_Time (Ada_Time : Time) return Long_Integer; 290 -- Ada to Unix Epoch conversion 291 292 end Conversion_Operations; 293 294 ---------------------- 295 -- Delay_Operations -- 296 ---------------------- 297 298 package Delay_Operations is 299 300 function To_Duration (Date : Time) return Duration; 301 -- Given a time value in nanoseconds since 1901, convert it into a 302 -- duration value giving the number of nanoseconds since the Unix Epoch. 303 304 end Delay_Operations; 305 306 --------------------------- 307 -- Formatting_Operations -- 308 --------------------------- 309 310 package Formatting_Operations is 311 312 function Day_Of_Week (Date : Time) return Integer; 313 -- Determine which day of week Date falls on. The returned values are 314 -- within the range of 0 .. 6 (Monday .. Sunday). 315 316 procedure Split 317 (Date : Time; 318 Year : out Year_Number; 319 Month : out Month_Number; 320 Day : out Day_Number; 321 Day_Secs : out Day_Duration; 322 Hour : out Integer; 323 Minute : out Integer; 324 Second : out Integer; 325 Sub_Sec : out Duration; 326 Leap_Sec : out Boolean; 327 Use_TZ : Boolean; 328 Is_Historic : Boolean; 329 Time_Zone : Long_Integer); 330 pragma Export (Ada, Split, "__gnat_split"); 331 -- Split a time value into its components. If flag Is_Historic is set, 332 -- this routine would try to use to the best of the OS's abilities the 333 -- time zone offset that was or will be in effect on Date. Set Use_TZ 334 -- to use the local time zone (the value in Time_Zone is ignored) when 335 -- splitting a time value. 336 337 function Time_Of 338 (Year : Year_Number; 339 Month : Month_Number; 340 Day : Day_Number; 341 Day_Secs : Day_Duration; 342 Hour : Integer; 343 Minute : Integer; 344 Second : Integer; 345 Sub_Sec : Duration; 346 Leap_Sec : Boolean; 347 Use_Day_Secs : Boolean; 348 Use_TZ : Boolean; 349 Is_Historic : Boolean; 350 Time_Zone : Long_Integer) return Time; 351 pragma Export (Ada, Time_Of, "__gnat_time_of"); 352 -- Given all the components of a date, return the corresponding time 353 -- value. Set Use_Day_Secs to use the value in Day_Secs, otherwise the 354 -- day duration will be calculated from Hour, Minute, Second and Sub_ 355 -- Sec. If flag Is_Historic is set, this routine would try to use to the 356 -- best of the OS's abilities the time zone offset that was or will be 357 -- in effect on the input date. Set Use_TZ to use the local time zone 358 -- (the value in formal Time_Zone is ignored) when building a time value 359 -- and to verify the validity of a requested leap second. 360 361 end Formatting_Operations; 362 363 --------------------------- 364 -- Time_Zones_Operations -- 365 --------------------------- 366 367 package Time_Zones_Operations is 368 369 function UTC_Time_Offset (Date : Time) return Long_Integer; 370 -- Return (in seconds) the difference between the local time zone and 371 -- UTC time at a specific historic date. 372 373 end Time_Zones_Operations; 374 375end Ada.Calendar; 376