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) 1992-2018, 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 with 37 SPARK_Mode, 38 Abstract_State => (Clock_Time with Synchronous, 39 External => (Async_Readers, 40 Async_Writers)), 41 Initializes => Clock_Time 42is 43 44 type Time is private; 45 46 -- Declarations representing limits of allowed local time values. Note that 47 -- these do NOT constrain the possible stored values of time which may well 48 -- permit a larger range of times (this is explicitly allowed in Ada 95). 49 50 subtype Year_Number is Integer range 1901 .. 2399; 51 subtype Month_Number is Integer range 1 .. 12; 52 subtype Day_Number is Integer range 1 .. 31; 53 54 -- A Day_Duration value of 86_400.0 designates a new day 55 56 subtype Day_Duration is Duration range 0.0 .. 86_400.0; 57 58 function Clock return Time with 59 Volatile_Function, 60 Global => Clock_Time; 61 -- The returned time value is the number of nanoseconds since the start 62 -- of Ada time (1901-01-01 00:00:00.0 UTC). If leap seconds are enabled, 63 -- the result will contain all elapsed leap seconds since the start of 64 -- Ada time until now. 65 66 function Year (Date : Time) return Year_Number; 67 function Month (Date : Time) return Month_Number; 68 function Day (Date : Time) return Day_Number; 69 function Seconds (Date : Time) return Day_Duration; 70 71 procedure Split 72 (Date : Time; 73 Year : out Year_Number; 74 Month : out Month_Number; 75 Day : out Day_Number; 76 Seconds : out Day_Duration); 77 -- Break down a time value into its date components set in the current 78 -- time zone. If Split is called on a time value created using Ada 2005 79 -- Time_Of in some arbitrary time zone, the input value will always be 80 -- interpreted as relative to the local time zone. 81 82 function Time_Of 83 (Year : Year_Number; 84 Month : Month_Number; 85 Day : Day_Number; 86 Seconds : Day_Duration := 0.0) return Time; 87 -- GNAT Note: Normally when procedure Split is called on a Time value 88 -- result of a call to function Time_Of, the out parameters of procedure 89 -- Split are identical to the in parameters of function Time_Of. However, 90 -- when a non-existent time of day is specified, the values for Seconds 91 -- may or may not be different. This may happen when Daylight Saving Time 92 -- (DST) is in effect, on the day when switching to DST, if Seconds 93 -- specifies a time of day in the hour that does not exist. For example, 94 -- in New York: 95 -- 96 -- Time_Of (Year => 1998, Month => 4, Day => 5, Seconds => 10740.0) 97 -- 98 -- will return a Time value T. If Split is called on T, the resulting 99 -- Seconds may be 14340.0 (3:59:00) instead of 10740.0 (2:59:00 being 100 -- a time that not exist). 101 102 function "+" (Left : Time; Right : Duration) return Time; 103 function "+" (Left : Duration; Right : Time) return Time; 104 function "-" (Left : Time; Right : Duration) return Time; 105 function "-" (Left : Time; Right : Time) return Duration; 106 -- The first three functions will raise Time_Error if the resulting time 107 -- value is less than the start of Ada time in UTC or greater than the 108 -- end of Ada time in UTC. The last function will raise Time_Error if the 109 -- resulting difference cannot fit into a duration value. 110 111 function "<" (Left, Right : Time) return Boolean; 112 function "<=" (Left, Right : Time) return Boolean; 113 function ">" (Left, Right : Time) return Boolean; 114 function ">=" (Left, Right : Time) return Boolean; 115 116 Time_Error : exception; 117 118private 119 -- Mark the private part as SPARK_Mode Off to avoid accounting for variable 120 -- Invalid_Time_Zone_Offset in abstract state. 121 122 pragma SPARK_Mode (Off); 123 124 pragma Inline (Clock); 125 126 pragma Inline (Year); 127 pragma Inline (Month); 128 pragma Inline (Day); 129 130 pragma Inline ("+"); 131 pragma Inline ("-"); 132 133 pragma Inline ("<"); 134 pragma Inline ("<="); 135 pragma Inline (">"); 136 pragma Inline (">="); 137 138 -- The units used in this version of Ada.Calendar are nanoseconds. The 139 -- following constants provide values used in conversions of seconds or 140 -- days to the underlying units. 141 142 Nano : constant := 1_000_000_000; 143 Nano_F : constant := 1_000_000_000.0; 144 Nanos_In_Day : constant := 86_400_000_000_000; 145 Secs_In_Day : constant := 86_400; 146 147 ---------------------------- 148 -- Implementation of Time -- 149 ---------------------------- 150 151 -- Time is represented as a signed 64 bit integer count of nanoseconds 152 -- since the start of Ada time (1901-01-01 00:00:00.0 UTC). Time values 153 -- produced by Time_Of are internally normalized to UTC regardless of their 154 -- local time zone. This representation ensures correct handling of leap 155 -- seconds as well as performing arithmetic. In Ada 95, Split and Time_Of 156 -- will treat a time value as being in the local time zone, in Ada 2005, 157 -- Split and Time_Of will treat a time value as being in the designated 158 -- time zone by the formal parameter or in UTC by default. The size of the 159 -- type is large enough to cover the Ada 2005 range of time (1901-01-01 160 -- 00:00:00.0 UTC - 2399-12-31-23:59:59.999999999 UTC). 161 162 ------------------ 163 -- Leap Seconds -- 164 ------------------ 165 166 -- Due to Earth's slowdown, the astronomical time is not as precise as the 167 -- International Atomic Time. To compensate for this inaccuracy, a single 168 -- leap second is added after the last day of June or December. The count 169 -- of seconds during those occurrences becomes: 170 171 -- ... 58, 59, leap second 60, 0, 1, 2 ... 172 173 -- Unlike leap days, leap seconds occur simultaneously around the world. 174 -- In other words, if a leap second occurs at 23:59:60 UTC, it also occurs 175 -- on 18:59:60 -5 the same day or 2:59:60 +2 on the next day. 176 177 -- Leap seconds do not follow a formula. The International Earth Rotation 178 -- and Reference System Service decides when to add one. Leap seconds are 179 -- included in the representation of time in Ada 95 mode. As a result, 180 -- the following two time values will differ by two seconds: 181 182 -- 1972-06-30 23:59:59.0 183 -- 1972-07-01 00:00:00.0 184 185 -- When a new leap second is introduced, the following steps must be 186 -- carried out: 187 188 -- 1) Increment Leap_Seconds_Count in a-calend.adb by one 189 -- 2) Increment LS_Count in xleaps.adb by one 190 -- 3) Add the new date to the aggregate of array LS_Dates in 191 -- xleaps.adb 192 -- 4) Compile and execute xleaps 193 -- 5) Replace the values of Leap_Second_Times in a-calend.adb with the 194 -- aggregate generated by xleaps 195 196 -- The algorithms that build the actual leap second values and discover 197 -- how many leap seconds have occurred between two dates do not need any 198 -- modification. 199 200 ------------------------------ 201 -- Non-leap Centennial Years -- 202 ------------------------------ 203 204 -- Over the range of Ada time, centennial years 2100, 2200 and 2300 are 205 -- non-leap. As a consequence, seven non-leap years occur over the period 206 -- of year - 4 to year + 4. Internally, routines Split and Time_Of add or 207 -- subtract a "fake" February 29 to facilitate the arithmetic involved. 208 209 ------------------------ 210 -- Local Declarations -- 211 ------------------------ 212 213 type Time_Rep is new Long_Long_Integer; 214 type Time is new Time_Rep; 215 -- The underlying type of Time has been chosen to be a 64 bit signed 216 -- integer number since it allows for easier processing of sub-seconds 217 -- and arithmetic. We use Long_Long_Integer to allow this unit to compile 218 -- when using custom target configuration files where the max integer is 219 -- 32 bits. This is useful for static analysis tools such as SPARK or 220 -- CodePeer. 221 -- 222 -- Note: the reason we have two separate types here is to avoid problems 223 -- with overloading ambiguities in the body if we tried to use Time as an 224 -- internal computational type. 225 226 Days_In_Month : constant array (Month_Number) of Day_Number := 227 (31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31); 228 -- Days in month for non-leap year, leap year case is adjusted in code 229 230 Invalid_Time_Zone_Offset : Long_Integer; 231 pragma Import (C, Invalid_Time_Zone_Offset, "__gnat_invalid_tzoff"); 232 233 function Is_Leap (Year : Year_Number) return Boolean; 234 -- Determine whether a given year is leap 235 236 ---------------------------------------------------------- 237 -- Target-Independent Interface to Children of Calendar -- 238 ---------------------------------------------------------- 239 240 -- The following packages provide a target-independent interface to the 241 -- children of Calendar - Arithmetic, Conversions, Delays, Formatting and 242 -- Time_Zones. 243 244 --------------------------- 245 -- Arithmetic_Operations -- 246 --------------------------- 247 248 package Arithmetic_Operations is 249 250 function Add (Date : Time; Days : Long_Integer) return Time; 251 -- Add a certain number of days to a time value 252 253 procedure Difference 254 (Left : Time; 255 Right : Time; 256 Days : out Long_Integer; 257 Seconds : out Duration; 258 Leap_Seconds : out Integer); 259 -- Calculate the difference between two time values in terms of days, 260 -- seconds and leap seconds elapsed. The leap seconds are not included 261 -- in the seconds returned. If Left is greater than Right, the returned 262 -- values are positive, negative otherwise. 263 264 function Subtract (Date : Time; Days : Long_Integer) return Time; 265 -- Subtract a certain number of days from a time value 266 267 end Arithmetic_Operations; 268 269 --------------------------- 270 -- Conversion_Operations -- 271 --------------------------- 272 273 package Conversion_Operations is 274 275 function To_Ada_Time (Unix_Time : Long_Integer) return Time; 276 -- Unix to Ada Epoch conversion 277 278 function To_Ada_Time 279 (tm_year : Integer; 280 tm_mon : Integer; 281 tm_day : Integer; 282 tm_hour : Integer; 283 tm_min : Integer; 284 tm_sec : Integer; 285 tm_isdst : Integer) return Time; 286 -- Struct tm to Ada Epoch conversion 287 288 function To_Duration 289 (tv_sec : Long_Integer; 290 tv_nsec : Long_Integer) return Duration; 291 -- Struct timespec to Duration conversion 292 293 procedure To_Struct_Timespec 294 (D : Duration; 295 tv_sec : out Long_Integer; 296 tv_nsec : out Long_Integer); 297 -- Duration to struct timespec conversion 298 299 procedure To_Struct_Tm 300 (T : Time; 301 tm_year : out Integer; 302 tm_mon : out Integer; 303 tm_day : out Integer; 304 tm_hour : out Integer; 305 tm_min : out Integer; 306 tm_sec : out Integer); 307 -- Time to struct tm conversion 308 309 function To_Unix_Time (Ada_Time : Time) return Long_Integer; 310 -- Ada to Unix Epoch conversion 311 312 end Conversion_Operations; 313 314 ---------------------- 315 -- Delay_Operations -- 316 ---------------------- 317 318 package Delay_Operations is 319 320 function To_Duration (Date : Time) return Duration; 321 -- Given a time value in nanoseconds since 1901, convert it into a 322 -- duration value giving the number of nanoseconds since the Unix Epoch. 323 324 end Delay_Operations; 325 326 --------------------------- 327 -- Formatting_Operations -- 328 --------------------------- 329 330 package Formatting_Operations is 331 332 function Day_Of_Week (Date : Time) return Integer; 333 -- Determine which day of week Date falls on. The returned values are 334 -- within the range of 0 .. 6 (Monday .. Sunday). 335 336 procedure Split 337 (Date : Time; 338 Year : out Year_Number; 339 Month : out Month_Number; 340 Day : out Day_Number; 341 Day_Secs : out Day_Duration; 342 Hour : out Integer; 343 Minute : out Integer; 344 Second : out Integer; 345 Sub_Sec : out Duration; 346 Leap_Sec : out Boolean; 347 Use_TZ : Boolean; 348 Is_Historic : Boolean; 349 Time_Zone : Long_Integer); 350 pragma Export (Ada, Split, "__gnat_split"); 351 -- Split a time value into its components. If flag Is_Historic is set, 352 -- this routine would try to use to the best of the OS's abilities the 353 -- time zone offset that was or will be in effect on Date. Set Use_TZ 354 -- to use the local time zone (the value in Time_Zone is ignored) when 355 -- splitting a time value. 356 357 function Time_Of 358 (Year : Year_Number; 359 Month : Month_Number; 360 Day : Day_Number; 361 Day_Secs : Day_Duration; 362 Hour : Integer; 363 Minute : Integer; 364 Second : Integer; 365 Sub_Sec : Duration; 366 Leap_Sec : Boolean; 367 Use_Day_Secs : Boolean; 368 Use_TZ : Boolean; 369 Is_Historic : Boolean; 370 Time_Zone : Long_Integer) return Time; 371 pragma Export (Ada, Time_Of, "__gnat_time_of"); 372 -- Given all the components of a date, return the corresponding time 373 -- value. Set Use_Day_Secs to use the value in Day_Secs, otherwise the 374 -- day duration will be calculated from Hour, Minute, Second and Sub_ 375 -- Sec. If flag Is_Historic is set, this routine would try to use to the 376 -- best of the OS's abilities the time zone offset that was or will be 377 -- in effect on the input date. Set Use_TZ to use the local time zone 378 -- (the value in formal Time_Zone is ignored) when building a time value 379 -- and to verify the validity of a requested leap second. 380 381 end Formatting_Operations; 382 383 --------------------------- 384 -- Time_Zones_Operations -- 385 --------------------------- 386 387 package Time_Zones_Operations is 388 389 function UTC_Time_Offset (Date : Time) return Long_Integer; 390 -- Return (in seconds) the difference between the local time zone and 391 -- UTC time at a specific historic date. 392 393 end Time_Zones_Operations; 394 395end Ada.Calendar; 396