libvieter/include/vieter_cron.h

#ifndef VIETER_CRON
#define VIETER_CRON

#include <stdbool.h>
#include <stdint.h>
#include <stdlib.h>
#include <string.h>
#include <time.h>

typedef enum cron_parse_error {
  cron_parse_ok = 0,
  cron_parse_invalid_expression = 1,
  cron_parse_invalid_number = 2,
  cron_parse_out_of_range = 3,
  cron_parse_too_many_parts = 4,
  cron_parse_not_enough_parts = 5
} cron_parse_error;

typedef struct cron_expression {
  uint8_t *minutes;
  uint8_t *hours;
  uint8_t *days;
  uint8_t *months;
  uint8_t minute_count;
  uint8_t hour_count;
  uint8_t day_count;
  uint8_t month_count;
} cron_expression;

typedef struct cron_simple_time {
  int year;
  int month;
  int day;
  int hour;
  int minute;
} cron_simple_time;

cron_expression *ce_init();

void cron_ce_free(cron_expression *ce);

void cron_ce_next(cron_simple_time *out, cron_expression *ce,
                  cron_simple_time *ref);

void cron_ce_next_from_now(cron_simple_time *out, cron_expression *ce);

enum cron_parse_error cron_ce_parse_expression(cron_expression *out,
                                               const char *expression);

#endif