beats.h File Reference

Pure swatch .beats math, operates on ms since Biel Mean Time (UTC+1) midnight. Also holds the token a date format uses to ask for a .beats reading. More...

#include <stdbool.h>
#include <stdint.h>

Go to the source code of this file.

Macros
#define	MS_PER_BEAT   86400
	Milliseconds in one .beat which is one thousandth of a day.
#define	MS_PER_DAY   86400000
	Milliseconds in a full day.
#define	MS_PER_SEC   1000
	Milliseconds in one second.
#define	SECS_PER_DAY   86400
	Seconds in a full day.
#define	SECS_PER_HOUR   3600
	Seconds in one hour.
#define	SECS_PER_MIN   60
	Seconds in one minute.
#define	BMT_UTC_OFFSET_S   3600
	Biel Mean Time is UTC plus 1 hour, in seconds.
#define	BEATS_TOKEN   "{B}"
	The marker a date format carries where a .beats reading should go.
#define	BEATS_TOKEN_LEN   3
	Length of BEATS_TOKEN, which matches a three digit reading.

Functions
int	beats_from_ms (int32_t ms_into_bmt_day)
	Calculates swatch internet time in .beats (0..999) for a given ms.
uint32_t	ms_until_next_beat (int32_t ms_into_bmt_day)
	Calculates milliseconds until the next .beats boundary.
int32_t	beats_ms_from_hms (int hour, int minute, int second, uint16_t ms)
	Milliseconds into the Biel Mean Time day, from a UTC wall clock.
bool	beats_has_token (const char *format)
	Whether a date format asks for a .beats reading.
void	beats_expand_token (char *text, int beats)
	Overwrite every BEATS_TOKEN in a string with a three digit .beats reading.

Detailed Description

Pure swatch .beats math, operates on ms since Biel Mean Time (UTC+1) midnight. Also holds the token a date format uses to ask for a .beats reading.

Macro Definition Documentation

BEATS_TOKEN

#define BEATS_TOKEN   "{B}"

The marker a date format carries where a .beats reading should go.

Braces rather than a percent, because the date format is handed to strftime first and every percent belongs to it (B is already the month name). strftime copies anything else through untouched, so the token survives the pass and can be filled in afterwards.

Three characters wide on purpose. A reading is always three digits, so swapping one for the other is a same-length overwrite that cannot grow the string past the buffer it arrived in.