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) 1992-2014, 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 new Long_Long_Integer; 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. We use Long_Long_Integer to allow this unit to compile 205 -- when using custom target configuration files where the max integer is 206 -- 32 bits. This is useful for static analysis tools such as SPARK or 207 -- CodePeer. 208 -- 209 -- Note: the reason we have two separate types here is to avoid problems 210 -- with overloading ambiguities in the body if we tried to use Time as an 211 -- internal computational type. 212 213 Days_In_Month : constant array (Month_Number) of Day_Number := 214 (31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31); 215 -- Days in month for non-leap year, leap year case is adjusted in code 216 217 Invalid_Time_Zone_Offset : Long_Integer; 218 pragma Import (C, Invalid_Time_Zone_Offset, "__gnat_invalid_tzoff"); 219 220 function Is_Leap (Year : Year_Number) return Boolean; 221 -- Determine whether a given year is leap 222 223 ---------------------------------------------------------- 224 -- Target-Independent Interface to Children of Calendar -- 225 ---------------------------------------------------------- 226 227 -- The following packages provide a target-independent interface to the 228 -- children of Calendar - Arithmetic, Conversions, Delays, Formatting and 229 -- Time_Zones. 230 231 --------------------------- 232 -- Arithmetic_Operations -- 233 --------------------------- 234 235 package Arithmetic_Operations is 236 237 function Add (Date : Time; Days : Long_Integer) return Time; 238 -- Add a certain number of days to a time value 239 240 procedure Difference 241 (Left : Time; 242 Right : Time; 243 Days : out Long_Integer; 244 Seconds : out Duration; 245 Leap_Seconds : out Integer); 246 -- Calculate the difference between two time values in terms of days, 247 -- seconds and leap seconds elapsed. The leap seconds are not included 248 -- in the seconds returned. If Left is greater than Right, the returned 249 -- values are positive, negative otherwise. 250 251 function Subtract (Date : Time; Days : Long_Integer) return Time; 252 -- Subtract a certain number of days from a time value 253 254 end Arithmetic_Operations; 255 256 --------------------------- 257 -- Conversion_Operations -- 258 --------------------------- 259 260 package Conversion_Operations is 261 262 function To_Ada_Time (Unix_Time : Long_Integer) return Time; 263 -- Unix to Ada Epoch conversion 264 265 function To_Ada_Time 266 (tm_year : Integer; 267 tm_mon : Integer; 268 tm_day : Integer; 269 tm_hour : Integer; 270 tm_min : Integer; 271 tm_sec : Integer; 272 tm_isdst : Integer) return Time; 273 -- Struct tm to Ada Epoch conversion 274 275 function To_Duration 276 (tv_sec : Long_Integer; 277 tv_nsec : Long_Integer) return Duration; 278 -- Struct timespec to Duration conversion 279 280 procedure To_Struct_Timespec 281 (D : Duration; 282 tv_sec : out Long_Integer; 283 tv_nsec : out Long_Integer); 284 -- Duration to struct timespec conversion 285 286 procedure To_Struct_Tm 287 (T : Time; 288 tm_year : out Integer; 289 tm_mon : out Integer; 290 tm_day : out Integer; 291 tm_hour : out Integer; 292 tm_min : out Integer; 293 tm_sec : out Integer); 294 -- Time to struct tm conversion 295 296 function To_Unix_Time (Ada_Time : Time) return Long_Integer; 297 -- Ada to Unix Epoch conversion 298 299 end Conversion_Operations; 300 301 ---------------------- 302 -- Delay_Operations -- 303 ---------------------- 304 305 package Delay_Operations is 306 307 function To_Duration (Date : Time) return Duration; 308 -- Given a time value in nanoseconds since 1901, convert it into a 309 -- duration value giving the number of nanoseconds since the Unix Epoch. 310 311 end Delay_Operations; 312 313 --------------------------- 314 -- Formatting_Operations -- 315 --------------------------- 316 317 package Formatting_Operations is 318 319 function Day_Of_Week (Date : Time) return Integer; 320 -- Determine which day of week Date falls on. The returned values are 321 -- within the range of 0 .. 6 (Monday .. Sunday). 322 323 procedure Split 324 (Date : Time; 325 Year : out Year_Number; 326 Month : out Month_Number; 327 Day : out Day_Number; 328 Day_Secs : out Day_Duration; 329 Hour : out Integer; 330 Minute : out Integer; 331 Second : out Integer; 332 Sub_Sec : out Duration; 333 Leap_Sec : out Boolean; 334 Use_TZ : Boolean; 335 Is_Historic : Boolean; 336 Time_Zone : Long_Integer); 337 pragma Export (Ada, Split, "__gnat_split"); 338 -- Split a time value into its components. If flag Is_Historic is set, 339 -- this routine would try to use to the best of the OS's abilities the 340 -- time zone offset that was or will be in effect on Date. Set Use_TZ 341 -- to use the local time zone (the value in Time_Zone is ignored) when 342 -- splitting a time value. 343 344 function Time_Of 345 (Year : Year_Number; 346 Month : Month_Number; 347 Day : Day_Number; 348 Day_Secs : Day_Duration; 349 Hour : Integer; 350 Minute : Integer; 351 Second : Integer; 352 Sub_Sec : Duration; 353 Leap_Sec : Boolean; 354 Use_Day_Secs : Boolean; 355 Use_TZ : Boolean; 356 Is_Historic : Boolean; 357 Time_Zone : Long_Integer) return Time; 358 pragma Export (Ada, Time_Of, "__gnat_time_of"); 359 -- Given all the components of a date, return the corresponding time 360 -- value. Set Use_Day_Secs to use the value in Day_Secs, otherwise the 361 -- day duration will be calculated from Hour, Minute, Second and Sub_ 362 -- Sec. If flag Is_Historic is set, this routine would try to use to the 363 -- best of the OS's abilities the time zone offset that was or will be 364 -- in effect on the input date. Set Use_TZ to use the local time zone 365 -- (the value in formal Time_Zone is ignored) when building a time value 366 -- and to verify the validity of a requested leap second. 367 368 end Formatting_Operations; 369 370 --------------------------- 371 -- Time_Zones_Operations -- 372 --------------------------- 373 374 package Time_Zones_Operations is 375 376 function UTC_Time_Offset (Date : Time) return Long_Integer; 377 -- Return (in seconds) the difference between the local time zone and 378 -- UTC time at a specific historic date. 379 380 end Time_Zones_Operations; 381 382end Ada.Calendar; 383