src/include/utils/datetime.h

   1 /*-------------------------------------------------------------------------
   2  *
   3  * datetime.h
   4  *        Definitions for date/time support code.
   5  *        The support code is shared with other date data types,
   6  *         including date, and time.
   7  *
   8  *
   9  * Portions Copyright (c) 1996-2023, PostgreSQL Global Development Group
  10  * Portions Copyright (c) 1994, Regents of the University of California
  11  *
  12  * src/include/utils/datetime.h
  13  *
  14  *-------------------------------------------------------------------------
  15  */
  16 #ifndef DATETIME_H
  17 #define DATETIME_H
  18
  19 #include "utils/timestamp.h"
  20
  21 /* this struct is declared in utils/tzparser.h: */
  22 struct tzEntry;
  23
  24
  25 /* ----------------------------------------------------------------
  26  *                              time types + support macros
  27  *
  28  * String definitions for standard time quantities.
  29  *
  30  * These strings are the defaults used to form output time strings.
  31  * Other alternative forms are hardcoded into token tables in datetime.c.
  32  * ----------------------------------------------------------------
  33  */
  34
  35 #define DAGO                    "ago"
  36 #define DCURRENT                "current"
  37 #define EPOCH                   "epoch"
  38 #define INVALID                 "invalid"
  39 #define EARLY                   "-infinity"
  40 #define LATE                    "infinity"
  41 #define NOW                             "now"
  42 #define TODAY                   "today"
  43 #define TOMORROW                "tomorrow"
  44 #define YESTERDAY               "yesterday"
  45 #define ZULU                    "zulu"
  46
  47 #define DMICROSEC               "usecond"
  48 #define DMILLISEC               "msecond"
  49 #define DSECOND                 "second"
  50 #define DMINUTE                 "minute"
  51 #define DHOUR                   "hour"
  52 #define DDAY                    "day"
  53 #define DWEEK                   "week"
  54 #define DMONTH                  "month"
  55 #define DQUARTER                "quarter"
  56 #define DYEAR                   "year"
  57 #define DDECADE                 "decade"
  58 #define DCENTURY                "century"
  59 #define DMILLENNIUM             "millennium"
  60 #define DA_D                    "ad"
  61 #define DB_C                    "bc"
  62 #define DTIMEZONE               "timezone"
  63
  64 /*
  65  * Fundamental time field definitions for parsing.
  66  *
  67  *      Meridian:  am, pm, or 24-hour style.
  68  *      Millennium: ad, bc
  69  */
  70
  71 #define AM              0
  72 #define PM              1
  73 #define HR24    2
  74
  75 #define AD              0
  76 #define BC              1
  77
  78 /*
  79  * Field types for time decoding.
  80  *
  81  * Can't have more of these than there are bits in an unsigned int
  82  * since these are turned into bit masks during parsing and decoding.
  83  *
  84  * Furthermore, the values for YEAR, MONTH, DAY, HOUR, MINUTE, SECOND
  85  * must be in the range 0..14 so that the associated bitmasks can fit
  86  * into the left half of an INTERVAL's typmod value.  Since those bits
  87  * are stored in typmods, you can't change them without initdb!
  88  */
  89
  90 #define RESERV  0
  91 #define MONTH   1
  92 #define YEAR    2
  93 #define DAY             3
  94 #define JULIAN  4
  95 #define TZ              5                               /* fixed-offset timezone abbreviation */
  96 #define DTZ             6                               /* fixed-offset timezone abbrev, DST */
  97 #define DYNTZ   7                               /* dynamic timezone abbreviation */
  98 #define IGNORE_DTF      8
  99 #define AMPM    9
 100 #define HOUR    10
 101 #define MINUTE  11
 102 #define SECOND  12
 103 #define MILLISECOND 13
 104 #define MICROSECOND 14
 105 #define DOY             15
 106 #define DOW             16
 107 #define UNITS   17
 108 #define ADBC    18
 109 /* these are only for relative dates */
 110 #define AGO             19
 111 #define ABS_BEFORE              20
 112 #define ABS_AFTER               21
 113 /* generic fields to help with parsing */
 114 #define ISODATE 22
 115 #define ISOTIME 23
 116 /* these are only for parsing intervals */
 117 #define WEEK            24
 118 #define DECADE          25
 119 #define CENTURY         26
 120 #define MILLENNIUM      27
 121 /* hack for parsing two-word timezone specs "MET DST" etc */
 122 #define DTZMOD  28                              /* "DST" as a separate word */
 123 /* reserved for unrecognized string values */
 124 #define UNKNOWN_FIELD   31
 125
 126 /*
 127  * Token field definitions for time parsing and decoding.
 128  *
 129  * Some field type codes (see above) use these as the "value" in datetktbl[].
 130  * These are also used for bit masks in DecodeDateTime and friends
 131  *      so actually restrict them to within [0,31] for now.
 132  * - thomas 97/06/19
 133  * Not all of these fields are used for masks in DecodeDateTime
 134  *      so allow some larger than 31. - thomas 1997-11-17
 135  *
 136  * Caution: there are undocumented assumptions in the code that most of these
 137  * values are not equal to IGNORE_DTF nor RESERV.  Be very careful when
 138  * renumbering values in either of these apparently-independent lists :-(
 139  */
 140
 141 #define DTK_NUMBER              0
 142 #define DTK_STRING              1
 143
 144 #define DTK_DATE                2
 145 #define DTK_TIME                3
 146 #define DTK_TZ                  4
 147 #define DTK_AGO                 5
 148
 149 #define DTK_SPECIAL             6
 150 #define DTK_EARLY               9
 151 #define DTK_LATE                10
 152 #define DTK_EPOCH               11
 153 #define DTK_NOW                 12
 154 #define DTK_YESTERDAY   13
 155 #define DTK_TODAY               14
 156 #define DTK_TOMORROW    15
 157 #define DTK_ZULU                16
 158
 159 #define DTK_DELTA               17
 160 #define DTK_SECOND              18
 161 #define DTK_MINUTE              19
 162 #define DTK_HOUR                20
 163 #define DTK_DAY                 21
 164 #define DTK_WEEK                22
 165 #define DTK_MONTH               23
 166 #define DTK_QUARTER             24
 167 #define DTK_YEAR                25
 168 #define DTK_DECADE              26
 169 #define DTK_CENTURY             27
 170 #define DTK_MILLENNIUM  28
 171 #define DTK_MILLISEC    29
 172 #define DTK_MICROSEC    30
 173 #define DTK_JULIAN              31
 174
 175 #define DTK_DOW                 32
 176 #define DTK_DOY                 33
 177 #define DTK_TZ_HOUR             34
 178 #define DTK_TZ_MINUTE   35
 179 #define DTK_ISOYEAR             36
 180 #define DTK_ISODOW              37
 181
 182
 183 /*
 184  * Bit mask definitions for time parsing.
 185  */
 186
 187 #define DTK_M(t)                (0x01 << (t))
 188
 189 /* Convenience: a second, plus any fractional component */
 190 #define DTK_ALL_SECS_M  (DTK_M(SECOND) | DTK_M(MILLISECOND) | DTK_M(MICROSECOND))
 191 #define DTK_DATE_M              (DTK_M(YEAR) | DTK_M(MONTH) | DTK_M(DAY))
 192 #define DTK_TIME_M              (DTK_M(HOUR) | DTK_M(MINUTE) | DTK_ALL_SECS_M)
 193
 194 /*
 195  * Working buffer size for input and output of interval, timestamp, etc.
 196  * Inputs that need more working space will be rejected early.  Longer outputs
 197  * will overrun buffers, so this must suffice for all possible output.  As of
 198  * this writing, interval_out() needs the most space at ~90 bytes.
 199  */
 200 #define MAXDATELEN              128
 201 /* maximum possible number of fields in a date string */
 202 #define MAXDATEFIELDS   25
 203 /* only this many chars are stored in datetktbl */
 204 #define TOKMAXLEN               10
 205
 206 /* keep this struct small; it gets used a lot */
 207 typedef struct
 208 {
 209         char            token[TOKMAXLEN + 1];   /* always NUL-terminated */
 210         char            type;                   /* see field type codes above */
 211         int32           value;                  /* meaning depends on type */
 212 } datetkn;
 213
 214 /* one of its uses is in tables of time zone abbreviations */
 215 typedef struct TimeZoneAbbrevTable
 216 {
 217         Size            tblsize;                /* size in bytes of TimeZoneAbbrevTable */
 218         int                     numabbrevs;             /* number of entries in abbrevs[] array */
 219         datetkn         abbrevs[FLEXIBLE_ARRAY_MEMBER];
 220         /* DynamicZoneAbbrev(s) may follow the abbrevs[] array */
 221 } TimeZoneAbbrevTable;
 222
 223 /* auxiliary data for a dynamic time zone abbreviation (non-fixed-offset) */
 224 typedef struct DynamicZoneAbbrev
 225 {
 226         pg_tz      *tz;                         /* NULL if not yet looked up */
 227         char            zone[FLEXIBLE_ARRAY_MEMBER];    /* NUL-terminated zone name */
 228 } DynamicZoneAbbrev;
 229
 230
 231 /* FMODULO()
 232  * Macro to replace modf(), which is broken on some platforms.
 233  * t = input and remainder
 234  * q = integer part
 235  * u = divisor
 236  */
 237 #define FMODULO(t,q,u) \
 238 do { \
 239         (q) = (((t) < 0) ? ceil((t) / (u)) : floor((t) / (u))); \
 240         if ((q) != 0) (t) -= rint((q) * (u)); \
 241 } while(0)
 242
 243 /* TMODULO()
 244  * Like FMODULO(), but work on the timestamp datatype (now always int64).
 245  * We assume that int64 follows the C99 semantics for division (negative
 246  * quotients truncate towards zero).
 247  */
 248 #define TMODULO(t,q,u) \
 249 do { \
 250         (q) = ((t) / (u)); \
 251         if ((q) != 0) (t) -= ((q) * (u)); \
 252 } while(0)
 253
 254 /*
 255  * Date/time validation
 256  * Include check for leap year.
 257  */
 258
 259 extern PGDLLIMPORT const char *const months[];  /* months (3-char
 260                                                                                                  * abbreviations) */
 261 extern PGDLLIMPORT const char *const days[];    /* days (full names) */
 262 extern PGDLLIMPORT const int day_tab[2][13];
 263
 264 /*
 265  * These are the rules for the Gregorian calendar, which was adopted in 1582.
 266  * However, we use this calculation for all prior years as well because the
 267  * SQL standard specifies use of the Gregorian calendar.  This prevents the
 268  * date 1500-02-29 from being stored, even though it is valid in the Julian
 269  * calendar.
 270  */
 271 #define isleap(y) (((y) % 4) == 0 && (((y) % 100) != 0 || ((y) % 400) == 0))
 272
 273
 274 /*
 275  * Datetime input parsing routines (ParseDateTime, DecodeDateTime, etc)
 276  * return zero or a positive value on success.  On failure, they return
 277  * one of these negative code values.  DateTimeParseError may be used to
 278  * produce a suitable error report.  For some of these codes,
 279  * DateTimeParseError requires additional information, which is carried
 280  * in struct DateTimeErrorExtra.
 281  */
 282 #define DTERR_BAD_FORMAT                (-1)
 283 #define DTERR_FIELD_OVERFLOW    (-2)
 284 #define DTERR_MD_FIELD_OVERFLOW (-3)    /* triggers hint about DateStyle */
 285 #define DTERR_INTERVAL_OVERFLOW (-4)
 286 #define DTERR_TZDISP_OVERFLOW   (-5)
 287 #define DTERR_BAD_TIMEZONE              (-6)
 288 #define DTERR_BAD_ZONE_ABBREV   (-7)
 289
 290 typedef struct DateTimeErrorExtra
 291 {
 292         /* Needed for DTERR_BAD_TIMEZONE and DTERR_BAD_ZONE_ABBREV: */
 293         const char *dtee_timezone;      /* incorrect time zone name */
 294         /* Needed for DTERR_BAD_ZONE_ABBREV: */
 295         const char *dtee_abbrev;        /* relevant time zone abbreviation */
 296 } DateTimeErrorExtra;
 297
 298 /* Result codes for DecodeTimezoneName() */
 299 #define TZNAME_FIXED_OFFSET     0
 300 #define TZNAME_DYNTZ            1
 301 #define TZNAME_ZONE                     2
 302
 303
 304 extern void GetCurrentDateTime(struct pg_tm *tm);
 305 extern void GetCurrentTimeUsec(struct pg_tm *tm, fsec_t *fsec, int *tzp);
 306 extern void j2date(int jd, int *year, int *month, int *day);
 307 extern int      date2j(int year, int month, int day);
 308
 309 extern int      ParseDateTime(const char *timestr, char *workbuf, size_t buflen,
 310                                                   char **field, int *ftype,
 311                                                   int maxfields, int *numfields);
 312 extern int      DecodeDateTime(char **field, int *ftype, int nf,
 313                                                    int *dtype, struct pg_tm *tm, fsec_t *fsec, int *tzp,
 314                                                    DateTimeErrorExtra *extra);
 315 extern int      DecodeTimezone(const char *str, int *tzp);
 316 extern int      DecodeTimeOnly(char **field, int *ftype, int nf,
 317                                                    int *dtype, struct pg_tm *tm, fsec_t *fsec, int *tzp,
 318                                                    DateTimeErrorExtra *extra);
 319 extern int      DecodeInterval(char **field, int *ftype, int nf, int range,
 320                                                    int *dtype, struct pg_itm_in *itm_in);
 321 extern int      DecodeISO8601Interval(char *str,
 322                                                                   int *dtype, struct pg_itm_in *itm_in);
 323
 324 extern void DateTimeParseError(int dterr, DateTimeErrorExtra *extra,
 325                                                            const char *str, const char *datatype,
 326                                                            struct Node *escontext);
 327
 328 extern int      DetermineTimeZoneOffset(struct pg_tm *tm, pg_tz *tzp);
 329 extern int      DetermineTimeZoneAbbrevOffset(struct pg_tm *tm, const char *abbr, pg_tz *tzp);
 330 extern int      DetermineTimeZoneAbbrevOffsetTS(TimestampTz ts, const char *abbr,
 331                                                                                         pg_tz *tzp, int *isdst);
 332
 333 extern void EncodeDateOnly(struct pg_tm *tm, int style, char *str);
 334 extern void EncodeTimeOnly(struct pg_tm *tm, fsec_t fsec, bool print_tz, int tz, int style, char *str);
 335 extern void EncodeDateTime(struct pg_tm *tm, fsec_t fsec, bool print_tz, int tz, const char *tzn, int style, char *str);
 336 extern void EncodeInterval(struct pg_itm *itm, int style, char *str);
 337 extern void EncodeSpecialTimestamp(Timestamp dt, char *str);
 338
 339 extern int      ValidateDate(int fmask, bool isjulian, bool is2digits, bool bc,
 340                                                  struct pg_tm *tm);
 341
 342 extern int      DecodeTimezoneAbbrev(int field, const char *lowtoken,
 343                                                                  int *ftype, int *offset, pg_tz **tz,
 344                                                                  DateTimeErrorExtra *extra);
 345 extern int      DecodeSpecial(int field, const char *lowtoken, int *val);
 346 extern int      DecodeUnits(int field, const char *lowtoken, int *val);
 347
 348 extern int      DecodeTimezoneName(const char *tzname, int *offset, pg_tz **tz);
 349 extern pg_tz *DecodeTimezoneNameToTz(const char *tzname);
 350
 351 extern int      j2day(int date);
 352
 353 extern struct Node *TemporalSimplify(int32 max_precis, struct Node *node);
 354
 355 extern bool CheckDateTokenTables(void);
 356
 357 extern TimeZoneAbbrevTable *ConvertTimeZoneAbbrevs(struct tzEntry *abbrevs,
 358                                                                                                    int n);
 359 extern void InstallTimeZoneAbbrevs(TimeZoneAbbrevTable *tbl);
 360
 361 extern bool AdjustTimestampForTypmod(Timestamp *time, int32 typmod,
 362                                                                          struct Node *escontext);
 363
 364 #endif                                                  /* DATETIME_H */