thodg/libgit2/src/util/date.c

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• Hash : c3b7ace9
  Author :
  Date : 2021-11-14T16:43:53
  

  refactor: make util an object library Instead of simply including the utility files directly, make them a cmake object library for easy reusability between other projects within libgit2. Now the top-level `src` is responsible for platform selection, while the next-level `libgit2` and `util` configurations are responsible for identifying what objects they include.

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• src/util/date.c

• /*
   * Copyright (C) the libgit2 contributors. All rights reserved.
   *
   * This file is part of libgit2, distributed under the GNU GPL v2 with
   * a Linking Exception. For full terms see the included COPYING file.
   */
  
  #include "git2_util.h"
  
  #ifndef GIT_WIN32
  #include <sys/time.h>
  #endif
  
  #include "util.h"
  #include "posix.h"
  #include "date.h"
  
  #include <ctype.h>
  #include <time.h>
  
  typedef enum {
  	DATE_NORMAL = 0,
  	DATE_RELATIVE,
  	DATE_SHORT,
  	DATE_LOCAL,
  	DATE_ISO8601,
  	DATE_RFC2822,
  	DATE_RAW
  } date_mode;
  
  /*
   * This is like mktime, but without normalization of tm_wday and tm_yday.
   */
  static git_time_t tm_to_time_t(const struct tm *tm)
  {
  	static const int mdays[] = {
  	    0, 31, 59, 90, 120, 151, 181, 212, 243, 273, 304, 334
  	};
  	int year = tm->tm_year - 70;
  	int month = tm->tm_mon;
  	int day = tm->tm_mday;
  
  	if (year < 0 || year > 129) /* algo only works for 1970-2099 */
  		return -1;
  	if (month < 0 || month > 11) /* array bounds */
  		return -1;
  	if (month < 2 || (year + 2) % 4)
  		day--;
  	if (tm->tm_hour < 0 || tm->tm_min < 0 || tm->tm_sec < 0)
  		return -1;
  	return (year * 365 + (year + 1) / 4 + mdays[month] + day) * 24*60*60UL +
  		tm->tm_hour * 60*60 + tm->tm_min * 60 + tm->tm_sec;
  }
  
  static const char *month_names[] = {
  	"January", "February", "March", "April", "May", "June",
  	"July", "August", "September", "October", "November", "December"
  };
  
  static const char *weekday_names[] = {
  	"Sundays", "Mondays", "Tuesdays", "Wednesdays", "Thursdays", "Fridays", "Saturdays"
  };
  
  
  
  /*
   * Check these. And note how it doesn't do the summer-time conversion.
   *
   * In my world, it's always summer, and things are probably a bit off
   * in other ways too.
   */
  static const struct {
  	const char *name;
  	int offset;
  	int dst;
  } timezone_names[] = {
  	{ "IDLW", -12, 0, },	/* International Date Line West */
  	{ "NT",   -11, 0, },	/* Nome */
  	{ "CAT",  -10, 0, },	/* Central Alaska */
  	{ "HST",  -10, 0, },	/* Hawaii Standard */
  	{ "HDT",  -10, 1, },	/* Hawaii Daylight */
  	{ "YST",   -9, 0, },	/* Yukon Standard */
  	{ "YDT",   -9, 1, },	/* Yukon Daylight */
  	{ "PST",   -8, 0, },	/* Pacific Standard */
  	{ "PDT",   -8, 1, },	/* Pacific Daylight */
  	{ "MST",   -7, 0, },	/* Mountain Standard */
  	{ "MDT",   -7, 1, },	/* Mountain Daylight */
  	{ "CST",   -6, 0, },	/* Central Standard */
  	{ "CDT",   -6, 1, },	/* Central Daylight */
  	{ "EST",   -5, 0, },	/* Eastern Standard */
  	{ "EDT",   -5, 1, },	/* Eastern Daylight */
  	{ "AST",   -3, 0, },	/* Atlantic Standard */
  	{ "ADT",   -3, 1, },	/* Atlantic Daylight */
  	{ "WAT",   -1, 0, },	/* West Africa */
  
  	{ "GMT",    0, 0, },	/* Greenwich Mean */
  	{ "UTC",    0, 0, },	/* Universal (Coordinated) */
  	{ "Z",      0, 0, },    /* Zulu, alias for UTC */
  
  	{ "WET",    0, 0, },	/* Western European */
  	{ "BST",    0, 1, },	/* British Summer */
  	{ "CET",   +1, 0, },	/* Central European */
  	{ "MET",   +1, 0, },	/* Middle European */
  	{ "MEWT",  +1, 0, },	/* Middle European Winter */
  	{ "MEST",  +1, 1, },	/* Middle European Summer */
  	{ "CEST",  +1, 1, },	/* Central European Summer */
  	{ "MESZ",  +1, 1, },	/* Middle European Summer */
  	{ "FWT",   +1, 0, },	/* French Winter */
  	{ "FST",   +1, 1, },	/* French Summer */
  	{ "EET",   +2, 0, },	/* Eastern Europe */
  	{ "EEST",  +2, 1, },	/* Eastern European Daylight */
  	{ "WAST",  +7, 0, },	/* West Australian Standard */
  	{ "WADT",  +7, 1, },	/* West Australian Daylight */
  	{ "CCT",   +8, 0, },	/* China Coast */
  	{ "JST",   +9, 0, },	/* Japan Standard */
  	{ "EAST", +10, 0, },	/* Eastern Australian Standard */
  	{ "EADT", +10, 1, },	/* Eastern Australian Daylight */
  	{ "GST",  +10, 0, },	/* Guam Standard */
  	{ "NZT",  +12, 0, },	/* New Zealand */
  	{ "NZST", +12, 0, },	/* New Zealand Standard */
  	{ "NZDT", +12, 1, },	/* New Zealand Daylight */
  	{ "IDLE", +12, 0, },	/* International Date Line East */
  };
  
  static size_t match_string(const char *date, const char *str)
  {
  	size_t i = 0;
  
  	for (i = 0; *date; date++, str++, i++) {
  		if (*date == *str)
  			continue;
  		if (toupper(*date) == toupper(*str))
  			continue;
  		if (!isalnum(*date))
  			break;
  		return 0;
  	}
  	return i;
  }
  
  static int skip_alpha(const char *date)
  {
  	int i = 0;
  	do {
  		i++;
  	} while (isalpha(date[i]));
  	return i;
  }
  
  /*
  * Parse month, weekday, or timezone name
  */
  static size_t match_alpha(const char *date, struct tm *tm, int *offset)
  {
  	unsigned int i;
  
  	for (i = 0; i < 12; i++) {
  		size_t match = match_string(date, month_names[i]);
  		if (match >= 3) {
  			tm->tm_mon = i;
  			return match;
  		}
  	}
  
  	for (i = 0; i < 7; i++) {
  		size_t match = match_string(date, weekday_names[i]);
  		if (match >= 3) {
  			tm->tm_wday = i;
  			return match;
  		}
  	}
  
  	for (i = 0; i < ARRAY_SIZE(timezone_names); i++) {
  		size_t match = match_string(date, timezone_names[i].name);
  		if (match >= 3 || match == strlen(timezone_names[i].name)) {
  			int off = timezone_names[i].offset;
  
  			/* This is bogus, but we like summer */
  			off += timezone_names[i].dst;
  
  			/* Only use the tz name offset if we don't have anything better */
  			if (*offset == -1)
  				*offset = 60*off;
  
  			return match;
  		}
  	}
  
  	if (match_string(date, "PM") == 2) {
  		tm->tm_hour = (tm->tm_hour % 12) + 12;
  		return 2;
  	}
  
  	if (match_string(date, "AM") == 2) {
  		tm->tm_hour = (tm->tm_hour % 12) + 0;
  		return 2;
  	}
  
  	/* BAD */
  	return skip_alpha(date);
  }
  
  static int is_date(int year, int month, int day, struct tm *now_tm, time_t now, struct tm *tm)
  {
  	if (month > 0 && month < 13 && day > 0 && day < 32) {
  		struct tm check = *tm;
  		struct tm *r = (now_tm ? &check : tm);
  		git_time_t specified;
  
  		r->tm_mon = month - 1;
  		r->tm_mday = day;
  		if (year == -1) {
  			if (!now_tm)
  				return 1;
  			r->tm_year = now_tm->tm_year;
  		}
  		else if (year >= 1970 && year < 2100)
  			r->tm_year = year - 1900;
  		else if (year > 70 && year < 100)
  			r->tm_year = year;
  		else if (year < 38)
  			r->tm_year = year + 100;
  		else
  			return 0;
  		if (!now_tm)
  			return 1;
  
  		specified = tm_to_time_t(r);
  
  		/* Be it commit time or author time, it does not make
  		 * sense to specify timestamp way into the future.  Make
  		 * sure it is not later than ten days from now...
  		 */
  		if (now + 10*24*3600 < specified)
  			return 0;
  		tm->tm_mon = r->tm_mon;
  		tm->tm_mday = r->tm_mday;
  		if (year != -1)
  			tm->tm_year = r->tm_year;
  		return 1;
  	}
  	return 0;
  }
  
  static size_t match_multi_number(unsigned long num, char c, const char *date, char *end, struct tm *tm)
  {
  	time_t now;
  	struct tm now_tm;
  	struct tm *refuse_future;
  	long num2, num3;
  
  	num2 = strtol(end+1, &end, 10);
  	num3 = -1;
  	if (*end == c && isdigit(end[1]))
  		num3 = strtol(end+1, &end, 10);
  
  	/* Time? Date? */
  	switch (c) {
  	case ':':
  		if (num3 < 0)
  			num3 = 0;
  		if (num < 25 && num2 >= 0 && num2 < 60 && num3 >= 0 && num3 <= 60) {
  			tm->tm_hour = num;
  			tm->tm_min = num2;
  			tm->tm_sec = num3;
  			break;
  		}
  		return 0;
  
  	case '-':
  	case '/':
  	case '.':
  		now = time(NULL);
  		refuse_future = NULL;
  		if (p_gmtime_r(&now, &now_tm))
  			refuse_future = &now_tm;
  
  		if (num > 70) {
  			/* yyyy-mm-dd? */
  			if (is_date(num, num2, num3, refuse_future, now, tm))
  				break;
  			/* yyyy-dd-mm? */
  			if (is_date(num, num3, num2, refuse_future, now, tm))
  				break;
  		}
  		/* Our eastern European friends say dd.mm.yy[yy]
  		 * is the norm there, so giving precedence to
  		 * mm/dd/yy[yy] form only when separator is not '.'
  		 */
  		if (c != '.' &&
  		    is_date(num3, num, num2, refuse_future, now, tm))
  			break;
  		/* European dd.mm.yy[yy] or funny US dd/mm/yy[yy] */
  		if (is_date(num3, num2, num, refuse_future, now, tm))
  			break;
  		/* Funny European mm.dd.yy */
  		if (c == '.' &&
  		    is_date(num3, num, num2, refuse_future, now, tm))
  			break;
  		return 0;
  	}
  	return end - date;
  }
  
  /*
   * Have we filled in any part of the time/date yet?
   * We just do a binary 'and' to see if the sign bit
   * is set in all the values.
   */
  static int nodate(struct tm *tm)
  {
  	return (tm->tm_year &
  		tm->tm_mon &
  		tm->tm_mday &
  		tm->tm_hour &
  		tm->tm_min &
  		tm->tm_sec) < 0;
  }
  
  /*
   * We've seen a digit. Time? Year? Date?
   */
  static size_t match_digit(const char *date, struct tm *tm, int *offset, int *tm_gmt)
  {
  	size_t n;
  	char *end;
  	unsigned long num;
  
  	num = strtoul(date, &end, 10);
  
  	/*
  	 * Seconds since 1970? We trigger on that for any numbers with
  	 * more than 8 digits. This is because we don't want to rule out
  	 * numbers like 20070606 as a YYYYMMDD date.
  	 */
  	if (num >= 100000000 && nodate(tm)) {
  		time_t time = num;
  		if (p_gmtime_r(&time, tm)) {
  			*tm_gmt = 1;
  			return end - date;
  		}
  	}
  
  	/*
  	 * Check for special formats: num[-.:/]num[same]num
  	 */
  	switch (*end) {
  	case ':':
  	case '.':
  	case '/':
  	case '-':
  		if (isdigit(end[1])) {
  			size_t match = match_multi_number(num, *end, date, end, tm);
  			if (match)
  				return match;
  		}
  	}
  
  	/*
  	 * None of the special formats? Try to guess what
  	 * the number meant. We use the number of digits
  	 * to make a more educated guess..
  	 */
  	n = 0;
  	do {
  		n++;
  	} while (isdigit(date[n]));
  
  	/* Four-digit year or a timezone? */
  	if (n == 4) {
  		if (num <= 1400 && *offset == -1) {
  			unsigned int minutes = num % 100;
  			unsigned int hours = num / 100;
  			*offset = hours*60 + minutes;
  		} else if (num > 1900 && num < 2100)
  			tm->tm_year = num - 1900;
  		return n;
  	}
  
  	/*
  	 * Ignore lots of numerals. We took care of 4-digit years above.
  	 * Days or months must be one or two digits.
  	 */
  	if (n > 2)
  		return n;
  
  	/*
  	 * NOTE! We will give precedence to day-of-month over month or
  	 * year numbers in the 1-12 range. So 05 is always "mday 5",
  	 * unless we already have a mday..
  	 *
  	 * IOW, 01 Apr 05 parses as "April 1st, 2005".
  	 */
  	if (num > 0 && num < 32 && tm->tm_mday < 0) {
  		tm->tm_mday = num;
  		return n;
  	}
  
  	/* Two-digit year? */
  	if (n == 2 && tm->tm_year < 0) {
  		if (num < 10 && tm->tm_mday >= 0) {
  			tm->tm_year = num + 100;
  			return n;
  		}
  		if (num >= 70) {
  			tm->tm_year = num;
  			return n;
  		}
  	}
  
  	if (num > 0 && num < 13 && tm->tm_mon < 0)
  		tm->tm_mon = num-1;
  
  	return n;
  }
  
  static size_t match_tz(const char *date, int *offp)
  {
  	char *end;
  	int hour = strtoul(date + 1, &end, 10);
  	size_t n = end - (date + 1);
  	int min = 0;
  
  	if (n == 4) {
  		/* hhmm */
  		min = hour % 100;
  		hour = hour / 100;
  	} else if (n != 2) {
  		min = 99; /* random stuff */
  	} else if (*end == ':') {
  		/* hh:mm? */
  		min = strtoul(end + 1, &end, 10);
  		if (end - (date + 1) != 5)
  			min = 99; /* random stuff */
  	} /* otherwise we parsed "hh" */
  
  	/*
  	 * Don't accept any random stuff. Even though some places have
  	 * offset larger than 12 hours (e.g. Pacific/Kiritimati is at
  	 * UTC+14), there is something wrong if hour part is much
  	 * larger than that. We might also want to check that the
  	 * minutes are divisible by 15 or something too. (Offset of
  	 * Kathmandu, Nepal is UTC+5:45)
  	 */
  	if (min < 60 && hour < 24) {
  		int offset = hour * 60 + min;
  		if (*date == '-')
  			offset = -offset;
  		*offp = offset;
  	}
  	return end - date;
  }
  
  /*
   * Parse a string like "0 +0000" as ancient timestamp near epoch, but
   * only when it appears not as part of any other string.
   */
  static int match_object_header_date(const char *date, git_time_t *timestamp, int *offset)
  {
  	char *end;
  	unsigned long stamp;
  	int ofs;
  
  	if (*date < '0' || '9' <= *date)
  		return -1;
  	stamp = strtoul(date, &end, 10);
  	if (*end != ' ' || stamp == ULONG_MAX || (end[1] != '+' && end[1] != '-'))
  		return -1;
  	date = end + 2;
  	ofs = strtol(date, &end, 10);
  	if ((*end != '\0' && (*end != '\n')) || end != date + 4)
  		return -1;
  	ofs = (ofs / 100) * 60 + (ofs % 100);
  	if (date[-1] == '-')
  		ofs = -ofs;
  	*timestamp = stamp;
  	*offset = ofs;
  	return 0;
  }
  
  /* Gr. strptime is crap for this; it doesn't have a way to require RFC2822
     (i.e. English) day/month names, and it doesn't work correctly with %z. */
  static int parse_date_basic(const char *date, git_time_t *timestamp, int *offset)
  {
  	struct tm tm;
  	int tm_gmt;
  	git_time_t dummy_timestamp;
  	int dummy_offset;
  
  	if (!timestamp)
  		timestamp = &dummy_timestamp;
  	if (!offset)
  		offset = &dummy_offset;
  
  	memset(&tm, 0, sizeof(tm));
  	tm.tm_year = -1;
  	tm.tm_mon = -1;
  	tm.tm_mday = -1;
  	tm.tm_isdst = -1;
  	tm.tm_hour = -1;
  	tm.tm_min = -1;
  	tm.tm_sec = -1;
  	*offset = -1;
  	tm_gmt = 0;
  
  	if (*date == '@' &&
  	    !match_object_header_date(date + 1, timestamp, offset))
  		return 0; /* success */
  	for (;;) {
  		size_t match = 0;
  		unsigned char c = *date;
  
  		/* Stop at end of string or newline */
  		if (!c || c == '\n')
  			break;
  
  		if (isalpha(c))
  			match = match_alpha(date, &tm, offset);
  		else if (isdigit(c))
  			match = match_digit(date, &tm, offset, &tm_gmt);
  		else if ((c == '-' || c == '+') && isdigit(date[1]))
  			match = match_tz(date, offset);
  
  		if (!match) {
  			/* BAD */
  			match = 1;
  		}
  
  		date += match;
  	}
  
  	/* mktime uses local timezone */
  	*timestamp = tm_to_time_t(&tm);
  	if (*offset == -1)
  		*offset = (int)((time_t)*timestamp - mktime(&tm)) / 60;
  
  	if (*timestamp == (git_time_t)-1)
  		return -1;
  
  	if (!tm_gmt)
  		*timestamp -= *offset * 60;
  	return 0; /* success */
  }
  
  
  /*
   * Relative time update (eg "2 days ago").  If we haven't set the time
   * yet, we need to set it from current time.
   */
  static git_time_t update_tm(struct tm *tm, struct tm *now, unsigned long sec)
  {
  	time_t n;
  
  	if (tm->tm_mday < 0)
  		tm->tm_mday = now->tm_mday;
  	if (tm->tm_mon < 0)
  		tm->tm_mon = now->tm_mon;
  	if (tm->tm_year < 0) {
  		tm->tm_year = now->tm_year;
  		if (tm->tm_mon > now->tm_mon)
  			tm->tm_year--;
  	}
  
  	n = mktime(tm) - sec;
  	p_localtime_r(&n, tm);
  	return n;
  }
  
  static void date_now(struct tm *tm, struct tm *now, int *num)
  {
     GIT_UNUSED(num);
  	update_tm(tm, now, 0);
  }
  
  static void date_yesterday(struct tm *tm, struct tm *now, int *num)
  {
     GIT_UNUSED(num);
  	update_tm(tm, now, 24*60*60);
  }
  
  static void date_time(struct tm *tm, struct tm *now, int hour)
  {
  	if (tm->tm_hour < hour)
  		date_yesterday(tm, now, NULL);
  	tm->tm_hour = hour;
  	tm->tm_min = 0;
  	tm->tm_sec = 0;
  }
  
  static void date_midnight(struct tm *tm, struct tm *now, int *num)
  {
     GIT_UNUSED(num);
  	date_time(tm, now, 0);
  }
  
  static void date_noon(struct tm *tm, struct tm *now, int *num)
  {
     GIT_UNUSED(num);
  	date_time(tm, now, 12);
  }
  
  static void date_tea(struct tm *tm, struct tm *now, int *num)
  {
     GIT_UNUSED(num);
  	date_time(tm, now, 17);
  }
  
  static void date_pm(struct tm *tm, struct tm *now, int *num)
  {
  	int hour, n = *num;
  	*num = 0;
     GIT_UNUSED(now);
  
  	hour = tm->tm_hour;
  	if (n) {
  		hour = n;
  		tm->tm_min = 0;
  		tm->tm_sec = 0;
  	}
  	tm->tm_hour = (hour % 12) + 12;
  }
  
  static void date_am(struct tm *tm, struct tm *now, int *num)
  {
  	int hour, n = *num;
  	*num = 0;
     GIT_UNUSED(now);
  
  	hour = tm->tm_hour;
  	if (n) {
  		hour = n;
  		tm->tm_min = 0;
  		tm->tm_sec = 0;
  	}
  	tm->tm_hour = (hour % 12);
  }
  
  static void date_never(struct tm *tm, struct tm *now, int *num)
  {
  	time_t n = 0;
     GIT_UNUSED(now);
     GIT_UNUSED(num);
  	p_localtime_r(&n, tm);
  }
  
  static const struct special {
  	const char *name;
  	void (*fn)(struct tm *, struct tm *, int *);
  } special[] = {
  	{ "yesterday", date_yesterday },
  	{ "noon", date_noon },
  	{ "midnight", date_midnight },
  	{ "tea", date_tea },
  	{ "PM", date_pm },
  	{ "AM", date_am },
  	{ "never", date_never },
  	{ "now", date_now },
  	{ NULL }
  };
  
  static const char *number_name[] = {
  	"zero", "one", "two", "three", "four",
  	"five", "six", "seven", "eight", "nine", "ten",
  };
  
  static const struct typelen {
  	const char *type;
  	int length;
  } typelen[] = {
  	{ "seconds", 1 },
  	{ "minutes", 60 },
  	{ "hours", 60*60 },
  	{ "days", 24*60*60 },
  	{ "weeks", 7*24*60*60 },
  	{ NULL }
  };
  
  static const char *approxidate_alpha(const char *date, struct tm *tm, struct tm *now, int *num, int *touched)
  {
  	const struct typelen *tl;
  	const struct special *s;
  	const char *end = date;
  	int i;
  
  	while (isalpha(*++end))
  		/* scan to non-alpha */;
  
  	for (i = 0; i < 12; i++) {
  		size_t match = match_string(date, month_names[i]);
  		if (match >= 3) {
  			tm->tm_mon = i;
  			*touched = 1;
  			return end;
  		}
  	}
  
  	for (s = special; s->name; s++) {
  		size_t len = strlen(s->name);
  		if (match_string(date, s->name) == len) {
  			s->fn(tm, now, num);
  			*touched = 1;
  			return end;
  		}
  	}
  
  	if (!*num) {
  		for (i = 1; i < 11; i++) {
  			size_t len = strlen(number_name[i]);
  			if (match_string(date, number_name[i]) == len) {
  				*num = i;
  				*touched = 1;
  				return end;
  			}
  		}
  		if (match_string(date, "last") == 4) {
  			*num = 1;
  			*touched = 1;
  		}
  		return end;
  	}
  
  	tl = typelen;
  	while (tl->type) {
  		size_t len = strlen(tl->type);
  		if (match_string(date, tl->type) >= len-1) {
  			update_tm(tm, now, tl->length * (unsigned long)*num);
  			*num = 0;
  			*touched = 1;
  			return end;
  		}
  		tl++;
  	}
  
  	for (i = 0; i < 7; i++) {
  		size_t match = match_string(date, weekday_names[i]);
  		if (match >= 3) {
  			int diff, n = *num -1;
  			*num = 0;
  
  			diff = tm->tm_wday - i;
  			if (diff <= 0)
  				n++;
  			diff += 7*n;
  
  			update_tm(tm, now, diff * 24 * 60 * 60);
  			*touched = 1;
  			return end;
  		}
  	}
  
  	if (match_string(date, "months") >= 5) {
  		int n;
  		update_tm(tm, now, 0); /* fill in date fields if needed */
  		n = tm->tm_mon - *num;
  		*num = 0;
  		while (n < 0) {
  			n += 12;
  			tm->tm_year--;
  		}
  		tm->tm_mon = n;
  		*touched = 1;
  		return end;
  	}
  
  	if (match_string(date, "years") >= 4) {
  		update_tm(tm, now, 0); /* fill in date fields if needed */
  		tm->tm_year -= *num;
  		*num = 0;
  		*touched = 1;
  		return end;
  	}
  
  	return end;
  }
  
  static const char *approxidate_digit(const char *date, struct tm *tm, int *num)
  {
  	char *end;
  	unsigned long number = strtoul(date, &end, 10);
  
  	switch (*end) {
  	case ':':
  	case '.':
  	case '/':
  	case '-':
  		if (isdigit(end[1])) {
  			size_t match = match_multi_number(number, *end, date, end, tm);
  			if (match)
  				return date + match;
  		}
  	}
  
  	/* Accept zero-padding only for small numbers ("Dec 02", never "Dec 0002") */
  	if (date[0] != '0' || end - date <= 2)
  		*num = number;
  	return end;
  }
  
  /*
   * Do we have a pending number at the end, or when
   * we see a new one? Let's assume it's a month day,
   * as in "Dec 6, 1992"
   */
  static void pending_number(struct tm *tm, int *num)
  {
  	int number = *num;
  
  	if (number) {
  		*num = 0;
  		if (tm->tm_mday < 0 && number < 32)
  			tm->tm_mday = number;
  		else if (tm->tm_mon < 0 && number < 13)
  			tm->tm_mon = number-1;
  		else if (tm->tm_year < 0) {
  			if (number > 1969 && number < 2100)
  				tm->tm_year = number - 1900;
  			else if (number > 69 && number < 100)
  				tm->tm_year = number;
  			else if (number < 38)
  				tm->tm_year = 100 + number;
  			/* We mess up for number = 00 ? */
  		}
  	}
  }
  
  static git_time_t approxidate_str(const char *date,
  	time_t time_sec,
  	int *error_ret)
  {
  	int number = 0;
  	int touched = 0;
  	struct tm tm = {0}, now;
  
  	p_localtime_r(&time_sec, &tm);
  	now = tm;
  
  	tm.tm_year = -1;
  	tm.tm_mon = -1;
  	tm.tm_mday = -1;
  
  	for (;;) {
  		unsigned char c = *date;
  		if (!c)
  			break;
  		date++;
  		if (isdigit(c)) {
  			pending_number(&tm, &number);
  			date = approxidate_digit(date-1, &tm, &number);
  			touched = 1;
  			continue;
  		}
  		if (isalpha(c))
  			date = approxidate_alpha(date-1, &tm, &now, &number, &touched);
  	}
  	pending_number(&tm, &number);
  	if (!touched)
  		*error_ret = -1;
  	return update_tm(&tm, &now, 0);
  }
  
  int git_date_parse(git_time_t *out, const char *date)
  {
  	time_t time_sec;
  	git_time_t timestamp;
  	int offset, error_ret=0;
  
  	if (!parse_date_basic(date, &timestamp, &offset)) {
  		*out = timestamp;
  		return 0;
  	}
  
  	if (time(&time_sec) == -1)
  		return -1;
  
  	*out = approxidate_str(date, time_sec, &error_ret);
  	return error_ret;
  }
  
  int git_date_rfc2822_fmt(git_str *out, git_time_t time, int offset)
  {
  	time_t t;
  	struct tm gmt;
  
  	GIT_ASSERT_ARG(out);
  
  	t = (time_t) (time + offset * 60);
  
  	if (p_gmtime_r(&t, &gmt) == NULL)
  		return -1;
  
  	return git_str_printf(out, "%.3s, %u %.3s %.4u %02u:%02u:%02u %+03d%02d",
  		weekday_names[gmt.tm_wday],
  		gmt.tm_mday,
  		month_names[gmt.tm_mon],
  		gmt.tm_year + 1900,
  		gmt.tm_hour, gmt.tm_min, gmt.tm_sec,
  		offset / 60, offset % 60);
  }
  
  

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