private.h

#ifndef PRIVATE_H
#define PRIVATE_H

/*
 * This file is in the public domain, so clarified as of
 * 1996-06-05 by Arthur David Olson.
 *
 * IDENTIFICATION
 *	  src/timezone/private.h
 */

/*
 * This header is for use ONLY with the time conversion code.
 * There is no guarantee that it will remain unchanged,
 * or that it will remain at all.
 * Do NOT copy it to any system include directory.
 * Thank you!
 */

#include <limits.h>				/* for CHAR_BIT et al. */
#include <sys/wait.h>			/* for WIFEXITED and WEXITSTATUS */
#include <unistd.h>				/* for F_OK and R_OK */

#include "pgtime.h"

/* This string was in the Factory zone through version 2016f.  */
#define GRANDPARENTED	"Local time zone must be set--see zic manual page"

/*
 * IANA has a bunch of HAVE_FOO #defines here, but in PG we want pretty
 * much all of that to be done by PG's configure script.
 */

#ifndef ENOTSUP
#define ENOTSUP EINVAL
#endif
#ifndef EOVERFLOW
#define EOVERFLOW EINVAL
#endif

/* Unlike <ctype.h>'s isdigit, this also works if c < 0 | c > UCHAR_MAX. */
#define is_digit(c) ((unsigned)(c) - '0' <= 9)


/*
 * Finally, some convenience items.
 */

#define TYPE_BIT(type)	(sizeof (type) * CHAR_BIT)
#define TYPE_SIGNED(type) (((type) -1) < 0)
#define TWOS_COMPLEMENT(t) ((t) ~ (t) 0 < 0)

/*
 * Max and min values of the integer type T, of which only the bottom
 * B bits are used, and where the highest-order used bit is considered
 * to be a sign bit if T is signed.
 */
#define MAXVAL(t, b)						\
  ((t) (((t) 1 << ((b) - 1 - TYPE_SIGNED(t)))			\
	- 1 + ((t) 1 << ((b) - 1 - TYPE_SIGNED(t)))))
#define MINVAL(t, b)						\
  ((t) (TYPE_SIGNED(t) ? - TWOS_COMPLEMENT(t) - MAXVAL(t, b) : 0))

/* The extreme time values, assuming no padding.  */
#define TIME_T_MIN MINVAL(pg_time_t, TYPE_BIT(pg_time_t))
#define TIME_T_MAX MAXVAL(pg_time_t, TYPE_BIT(pg_time_t))

/*
 * 302 / 1000 is log10(2.0) rounded up.
 * Subtract one for the sign bit if the type is signed;
 * add one for integer division truncation;
 * add one more for a minus sign if the type is signed.
 */
#define INT_STRLEN_MAXIMUM(type) \
	((TYPE_BIT(type) - TYPE_SIGNED(type)) * 302 / 1000 + \
	1 + TYPE_SIGNED(type))

/*
 * INITIALIZE(x)
 */
#define INITIALIZE(x)	((x) = 0)

#undef _
#define _(msgid) (msgid)

/* Handy macros that are independent of tzfile implementation.  */

#define YEARSPERREPEAT		400 /* years before a Gregorian repeat */

#define SECSPERMIN	60
#define MINSPERHOUR 60
#define HOURSPERDAY 24
#define DAYSPERWEEK 7
#define DAYSPERNYEAR	365
#define DAYSPERLYEAR	366
#define SECSPERHOUR (SECSPERMIN * MINSPERHOUR)
#define SECSPERDAY	((int32) SECSPERHOUR * HOURSPERDAY)
#define MONSPERYEAR 12

#define TM_SUNDAY	0
#define TM_MONDAY	1
#define TM_TUESDAY	2
#define TM_WEDNESDAY	3
#define TM_THURSDAY 4
#define TM_FRIDAY	5
#define TM_SATURDAY 6

#define TM_JANUARY	0
#define TM_FEBRUARY 1
#define TM_MARCH	2
#define TM_APRIL	3
#define TM_MAY		4
#define TM_JUNE		5
#define TM_JULY		6
#define TM_AUGUST	7
#define TM_SEPTEMBER	8
#define TM_OCTOBER	9
#define TM_NOVEMBER 10
#define TM_DECEMBER 11

#define TM_YEAR_BASE	1900

#define EPOCH_YEAR	1970
#define EPOCH_WDAY	TM_THURSDAY

#define isleap(y) (((y) % 4) == 0 && (((y) % 100) != 0 || ((y) % 400) == 0))

/*
 * Since everything in isleap is modulo 400 (or a factor of 400), we know that
 *	isleap(y) == isleap(y % 400)
 * and so
 *	isleap(a + b) == isleap((a + b) % 400)
 * or
 *	isleap(a + b) == isleap(a % 400 + b % 400)
 * This is true even if % means modulo rather than Fortran remainder
 * (which is allowed by C89 but not by C99 or later).
 * We use this to avoid addition overflow problems.
 */

#define isleap_sum(a, b)	isleap((a) % 400 + (b) % 400)


/*
 * The Gregorian year averages 365.2425 days, which is 31556952 seconds.
 */

#define AVGSECSPERYEAR		31556952L
#define SECSPERREPEAT \
  ((int64) YEARSPERREPEAT * (int64) AVGSECSPERYEAR)
#define SECSPERREPEAT_BITS	34	/* ceil(log2(SECSPERREPEAT)) */

#endif							/* !defined PRIVATE_H */