[apple/icu.git] / icuSources / tools / tzcode / asctime.c

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

/*
** Avoid the temptation to punt entirely to strftime;
** the output of strftime is supposed to be locale specific
** whereas the output of asctime is supposed to be constant.
*/

#ifndef lint
#ifndef NOID
static char	elsieid[] = "@(#)asctime.c	8.2";
#endif /* !defined NOID */
#endif /* !defined lint */

/*LINTLIBRARY*/

#include "private.h"
#include "tzfile.h"

/*
** Some systems only handle "%.2d"; others only handle "%02d";
** "%02.2d" makes (most) everybody happy.
** At least some versions of gcc warn about the %02.2d;
** we conditionalize below to avoid the warning.
*/
/*
** All years associated with 32-bit time_t values are exactly four digits long;
** some years associated with 64-bit time_t values are not.
** Vintage programs are coded for years that are always four digits long
** and may assume that the newline always lands in the same place.
** For years that are less than four digits, we pad the output with
** leading zeroes to get the newline in the traditional place.
** The -4 ensures that we get four characters of output even if
** we call a strftime variant that produces fewer characters for some years.
** The ISO C 1999 and POSIX 1003.1-2004 standards prohibit padding the year,
** but many implementations pad anyway; most likely the standards are buggy.
*/
#ifdef __GNUC__
#define ASCTIME_FMT	"%.3s %.3s%3d %2.2d:%2.2d:%2.2d %-4s\n"
#else /* !defined __GNUC__ */
#define ASCTIME_FMT	"%.3s %.3s%3d %02.2d:%02.2d:%02.2d %-4s\n"
#endif /* !defined __GNUC__ */
/*
** For years that are more than four digits we put extra spaces before the year
** so that code trying to overwrite the newline won't end up overwriting
** a digit within a year and truncating the year (operating on the assumption
** that no output is better than wrong output).
*/
#ifdef __GNUC__
#define ASCTIME_FMT_B	"%.3s %.3s%3d %2.2d:%2.2d:%2.2d     %s\n"
#else /* !defined __GNUC__ */
#define ASCTIME_FMT_B	"%.3s %.3s%3d %02.2d:%02.2d:%02.2d     %s\n"
#endif /* !defined __GNUC__ */

#define STD_ASCTIME_BUF_SIZE	26
/*
** Big enough for something such as
** ??? ???-2147483648 -2147483648:-2147483648:-2147483648     -2147483648\n
** (two three-character abbreviations, five strings denoting integers,
** seven explicit spaces, two explicit colons, a newline,
** and a trailing ASCII nul).
** The values above are for systems where an int is 32 bits and are provided
** as an example; the define below calculates the maximum for the system at
** hand.
*/
#define MAX_ASCTIME_BUF_SIZE	(2*3+5*INT_STRLEN_MAXIMUM(int)+7+2+1+1)

static char	buf_asctime[MAX_ASCTIME_BUF_SIZE];

/*
** A la ISO/IEC 9945-1, ANSI/IEEE Std 1003.1, 2004 Edition.
*/

char *
asctime_r(timeptr, buf)
register const struct tm *	timeptr;
char *				buf;
{
	static const char	wday_name[][3] = {
		"Sun", "Mon", "Tue", "Wed", "Thu", "Fri", "Sat"
	};
	static const char	mon_name[][3] = {
		"Jan", "Feb", "Mar", "Apr", "May", "Jun",
		"Jul", "Aug", "Sep", "Oct", "Nov", "Dec"
	};
	register const char *	wn;
	register const char *	mn;
	char			year[INT_STRLEN_MAXIMUM(int) + 2];
	char			result[MAX_ASCTIME_BUF_SIZE];

	if (timeptr->tm_wday < 0 || timeptr->tm_wday >= DAYSPERWEEK)
		wn = "???";
	else	wn = wday_name[timeptr->tm_wday];
	if (timeptr->tm_mon < 0 || timeptr->tm_mon >= MONSPERYEAR)
		mn = "???";
	else	mn = mon_name[timeptr->tm_mon];
	/*
	** Use strftime's %Y to generate the year, to avoid overflow problems
	** when computing timeptr->tm_year + TM_YEAR_BASE.
	** Assume that strftime is unaffected by other out-of-range members
	** (e.g., timeptr->tm_mday) when processing "%Y".
	*/
	(void) strftime(year, sizeof year, "%Y", timeptr);
	/*
	** We avoid using snprintf since it's not available on all systems.
	*/
	(void) sprintf(result,
		((strlen(year) <= 4) ? ASCTIME_FMT : ASCTIME_FMT_B),
		wn, mn,
		timeptr->tm_mday, timeptr->tm_hour,
		timeptr->tm_min, timeptr->tm_sec,
		year);
	if (strlen(result) < STD_ASCTIME_BUF_SIZE || buf == buf_asctime) {
		(void) strcpy(buf, result);
		return buf;
	} else {
#ifdef EOVERFLOW
		errno = EOVERFLOW;
#else /* !defined EOVERFLOW */
		errno = EINVAL;
#endif /* !defined EOVERFLOW */
		return NULL;
	}
}

/*
** A la ISO/IEC 9945-1, ANSI/IEEE Std 1003.1, 2004 Edition.
*/

char *
asctime(timeptr)
register const struct tm *	timeptr;
{
	return asctime_r(timeptr, buf_asctime);
}
Commit	Line	Data
73c04bcf A	1	/*
	2	** This file is in the public domain, so clarified as of
	3	** 1996-06-05 by Arthur David Olson.
	4	*/
	5
	6	/*
	7	** Avoid the temptation to punt entirely to strftime;
	8	** the output of strftime is supposed to be locale specific
	9	** whereas the output of asctime is supposed to be constant.
	10	*/
	11
	12	#ifndef lint
	13	#ifndef NOID
	14	static char elsieid[] = "@(#)asctime.c 8.2";
	15	#endif /* !defined NOID */
	16	#endif /* !defined lint */
	17
	18	/LINTLIBRARY/
	19
	20	#include "private.h"
	21	#include "tzfile.h"
	22
	23	/*
	24	** Some systems only handle "%.2d"; others only handle "%02d";
	25	** "%02.2d" makes (most) everybody happy.
	26	** At least some versions of gcc warn about the %02.2d;
	27	** we conditionalize below to avoid the warning.
	28	*/
	29	/*
	30	** All years associated with 32-bit time_t values are exactly four digits long;
	31	** some years associated with 64-bit time_t values are not.
	32	** Vintage programs are coded for years that are always four digits long
	33	** and may assume that the newline always lands in the same place.
	34	** For years that are less than four digits, we pad the output with
	35	** leading zeroes to get the newline in the traditional place.
	36	** The -4 ensures that we get four characters of output even if
	37	** we call a strftime variant that produces fewer characters for some years.
	38	** The ISO C 1999 and POSIX 1003.1-2004 standards prohibit padding the year,
	39	** but many implementations pad anyway; most likely the standards are buggy.
	40	*/
	41	#ifdef __GNUC__
	42	#define ASCTIME_FMT "%.3s %.3s%3d %2.2d:%2.2d:%2.2d %-4s\n"
	43	#else /* !defined __GNUC__ */
	44	#define ASCTIME_FMT "%.3s %.3s%3d %02.2d:%02.2d:%02.2d %-4s\n"
	45	#endif /* !defined __GNUC__ */
	46	/*
	47	** For years that are more than four digits we put extra spaces before the year
	48	** so that code trying to overwrite the newline won't end up overwriting
	49	** a digit within a year and truncating the year (operating on the assumption
	50	** that no output is better than wrong output).
	51	*/
	52	#ifdef __GNUC__
	53	#define ASCTIME_FMT_B "%.3s %.3s%3d %2.2d:%2.2d:%2.2d %s\n"
	54	#else /* !defined __GNUC__ */
	55	#define ASCTIME_FMT_B "%.3s %.3s%3d %02.2d:%02.2d:%02.2d %s\n"
	56	#endif /* !defined __GNUC__ */
	57
	58	#define STD_ASCTIME_BUF_SIZE 26
	59	/*
	60	** Big enough for something such as
	61	** ??? ???-2147483648 -2147483648:-2147483648:-2147483648 -2147483648\n
	62	** (two three-character abbreviations, five strings denoting integers,
	63	** seven explicit spaces, two explicit colons, a newline,
	64	** and a trailing ASCII nul).
65	** The values above are for systems where an int is 32 bits and are provided
66	** as an example; the define below calculates the maximum for the system at
67	** hand.
68	*/
69	#define MAX_ASCTIME_BUF_SIZE (23+5INT_STRLEN_MAXIMUM(int)+7+2+1+1)
70
71	static char buf_asctime[MAX_ASCTIME_BUF_SIZE];
72
73	/*
74	** A la ISO/IEC 9945-1, ANSI/IEEE Std 1003.1, 2004 Edition.
75	*/
76
77	char *
78	asctime_r(timeptr, buf)
79	register const struct tm * timeptr;
80	char * buf;
81	{
82	static const char wday_name[][3] = {
83	"Sun", "Mon", "Tue", "Wed", "Thu", "Fri", "Sat"
84	};
85	static const char mon_name[][3] = {
86	"Jan", "Feb", "Mar", "Apr", "May", "Jun",
87	"Jul", "Aug", "Sep", "Oct", "Nov", "Dec"
88	};
89	register const char * wn;
90	register const char * mn;
91	char year[INT_STRLEN_MAXIMUM(int) + 2];
92	char result[MAX_ASCTIME_BUF_SIZE];
93
94	if (timeptr->tm_wday < 0 \|\| timeptr->tm_wday >= DAYSPERWEEK)
95	wn = "???";
96	else wn = wday_name[timeptr->tm_wday];
97	if (timeptr->tm_mon < 0 \|\| timeptr->tm_mon >= MONSPERYEAR)
98	mn = "???";
99	else mn = mon_name[timeptr->tm_mon];
100	/*
101	** Use strftime's %Y to generate the year, to avoid overflow problems
102	** when computing timeptr->tm_year + TM_YEAR_BASE.
103	** Assume that strftime is unaffected by other out-of-range members
104	** (e.g., timeptr->tm_mday) when processing "%Y".
105	*/
106	(void) strftime(year, sizeof year, "%Y", timeptr);
107	/*
108	** We avoid using snprintf since it's not available on all systems.
109	*/
110	(void) sprintf(result,
111	((strlen(year) <= 4) ? ASCTIME_FMT : ASCTIME_FMT_B),
112	wn, mn,
113	timeptr->tm_mday, timeptr->tm_hour,
114	timeptr->tm_min, timeptr->tm_sec,
115	year);
116	if (strlen(result) < STD_ASCTIME_BUF_SIZE \|\| buf == buf_asctime) {
117	(void) strcpy(buf, result);
118	return buf;
119	} else {
120	#ifdef EOVERFLOW
121	errno = EOVERFLOW;
122	#else /* !defined EOVERFLOW */
123	errno = EINVAL;
124	#endif /* !defined EOVERFLOW */
125	return NULL;
126	}
127	}
128
129	/*
130	** A la ISO/IEC 9945-1, ANSI/IEEE Std 1003.1, 2004 Edition.
131	*/
132
133	char *
134	asctime(timeptr)
135	register const struct tm * timeptr;
136	{
137	return asctime_r(timeptr, buf_asctime);
138	}