libepoch/include/epoch.h

/*                 _,.---._    .-._        .--.-. ,--.--------.
 *   _,..---._   ,-.' , -  `. /==/ \  .-._/==/  //==/,  -   , -\
 * /==/,   -  \ /==/_,  ,  - \|==|, \/ /, |==\ -\\==\.-.  - ,-./
 * |==|   _   _\==|   .=.     |==|-  \|  | \==\- \`--`\==\- \
 * |==|  .=.   |==|_ : ;=:  - |==| ,  | -|  `--`-'     \==\_ \
 * |==|,|   | -|==| , '='     |==| -   _ |             |==|- |
 * |==|  '='   /\==\ -    ,_ /|==|  /\ , |             |==|, |
 * |==|-,   _`/  '.='. -   .' /==/, | |- |             /==/ -/
 * `-.`.____.'     `--`--''   `--`./  `--`             `--`--`
 *                    _ __    ,---.      .-._         .=-.-.  _,.----.
 *                 .-`.' ,`..--.'  \    /==/ \  .-._ /==/_ /.' .' -   \
 *                /==/, -   \==\-/\ \   |==|, \/ /, /==|, |/==/  ,  ,-'
 *               |==| _ .=. /==/-|_\ |  |==|-  \|  ||==|  ||==|-   |  .
 *               |==| , '=',\==\,   - \ |==| ,  | -||==|- ||==|_   `-' \
 *               |==|-  '..'/==/ -   ,| |==| -   _ ||==| ,||==|   _  , |
 *               |==|,  |  /==/-  /\ - \|==|  /\ , ||==|- |\==\.       /
 *               /==/ - |  \==\ _.\=\.-'/==/, | |- |/==/. / `-.`.___.-'
 *               `--`---'   `--`        `--`./  `--``--`-`
 *
 *	@(#)Copyright (c) 2024, Nathan D. Fisher.
 *
 *      This is free software.  It comes with NO WARRANTY.
 *      Permission to use, modify and distribute this source code
 *      is granted subject to the following conditions.
 *      1/ that the above copyright notice and this notice
 *      are preserved in all copies and that due credit be given
 *      to the author.
 *      2/ that any changes to this code are clearly commented
 *      as such so that the author does not get blamed for bugs
 *      other than his own.
 */

#ifndef LIBEPOCH_H
#define LIBEPOCH_H 1

#include <stdint.h>
#include <time.h>

#define SECONDS_PER_MINUTE 60
#define SECONDS_PER_HOUR   3600
#define SECONDS_PER_DAY    86400

typedef enum {
    normalYear,
    leapYear,
} yearTag;

typedef struct {
    yearTag  tag;
    uint32_t year;
} Year;

typedef enum {
    January   = 1,
    February  = 2,
    March     = 3,
    April     = 4,
    May       = 5,
    June      = 6,
    July      = 7,
    August    = 8,
    September = 9,
    October   = 10,
    November  = 11,
    December  = 12,
} Month;

typedef enum {
    Thursday  = 0,
    Friday    = 1,
    Saturday  = 2,
    Sunday    = 3,
    Monday    = 4,
    Tuesday   = 5,
    Wednesday = 6,
} Weekday;

typedef enum {
    Offset,
    UTC,
} timeZoneTag;

typedef enum {
    Positive,
    Negative,
} offsetSign;

typedef struct {
    offsetSign sign;
    uint8_t    hours;
    uint8_t    minutes;
} TzOffset;

typedef struct {
    timeZoneTag tag;
    TzOffset   *offset;
} TimeZone;

typedef struct {
    Year     year;
    Month    month;
    uint8_t  day;
    uint8_t  hour;
    uint8_t  minute;
    uint8_t  second;
    int64_t  nanoseconds;
    TimeZone zone;
} DateTime;

typedef enum {
    YearPrecision,
    MonthPrecision,
    DayPrecision,
    HourPrecision,
    MinutePrecision,
    SecondPrecision,
    NanoSecondPrecision,
} datetimePrecision;

void        yearNew                     (Year *self, int32_t inner);
uint16_t    yearGetDays                 (Year *self);
int64_t     yearGetSeconds              (Year *self);
int32_t     yearGetInner                (Year *self);
void        yearIncrement               (Year *self);
void        yearDecrement               (Year *self);

uint8_t     monthGetDays                (Month  self, Year *year);
uint32_t    monthGetSeconds             (Month  self, Year *year);
int         monthIncrement              (Month *self);
int         monthDecrement              (Month *self);
const char* monthName                   (Month  self);
const char* monthAbbr                   (Month  self);
int         parseMonth                  (const char *s);

const char* weekdayName                 (Weekday self);
const char* weekdayAbbr                 (Weekday self);
int         parseWeekday                (const char *s);

int         offsetNew                   (TzOffset *self, offsetSign sign,
                                         uint8_t hours, uint8_t minutes);
void        printTz                     (TimeZone *self);
int64_t     timezoneAsSeconds           (TimeZone *self);

int32_t     dateTimeGetYear             (DateTime *self);
int64_t     dateTimeGetTimestampNaive   (DateTime *self);
int64_t     dateTimeGetTimestamp        (DateTime *self);
void        dateTimeGetTimespec         (DateTime *self, struct timespec *ts);
Weekday     dateTimeGetWeekday          (DateTime *self);
void        dateTimeFromTimestampParts  (DateTime *self, int64_t seconds,
                                         int64_t nanoseconds);
void        dateTimeFromTimespec        (DateTime *self, struct timespec *ts);

#endif // !LIBEPOCH_H