Commit 94751666 authored by Paul Eggert's avatar Paul Eggert

(tm_diff): Renamed from difftm. Yield int, not long.

This now uses the same code as the GNU C Library.  All callers changed.
(TM_YEAR_BASE): Renamed from TM_YEAR_ORIGIN.
parent 36fe2f9a
......@@ -42,7 +42,7 @@ Boston, MA 02111-1307, USA. */
extern char **environ;
extern Lisp_Object make_time ();
extern void insert_from_buffer ();
static long difftm ();
static int tm_diff ();
static void update_buffer_properties ();
void set_time_zone_rule ();
......@@ -703,7 +703,7 @@ ZONE is an integer indicating the number of seconds east of Greenwich.\n\
if (decoded_time == 0)
list_args[8] = Qnil;
else
XSETINT (list_args[8], difftm (&save_tm, decoded_time));
XSETINT (list_args[8], tm_diff (&save_tm, decoded_time));
return Flist (9, list_args);
}
......@@ -821,31 +821,29 @@ and from `file-attributes'.")
return build_string (buf);
}
#define TM_YEAR_ORIGIN 1900
#define TM_YEAR_BASE 1900
/* Yield A - B, measured in seconds. */
static long
difftm (a, b)
/* Yield A - B, measured in seconds.
This function is copied from the GNU C Library. */
static int
tm_diff (a, b)
struct tm *a, *b;
{
int ay = a->tm_year + (TM_YEAR_ORIGIN - 1);
int by = b->tm_year + (TM_YEAR_ORIGIN - 1);
/* Divide years by 100, rounding towards minus infinity. */
int ac = ay / 100 - (ay % 100 < 0);
int bc = by / 100 - (by % 100 < 0);
/* Some compilers can't handle this as a single return statement. */
long days = (
/* difference in day of year */
a->tm_yday - b->tm_yday
/* + intervening leap days */
+ ((ay >> 2) - (by >> 2))
- (ac - bc)
+ ((ac >> 2) - (bc >> 2))
/* + difference in years * 365 */
+ (long)(ay-by) * 365
);
return (60*(60*(24*days + (a->tm_hour - b->tm_hour))
+ (a->tm_min - b->tm_min))
/* Compute intervening leap days correctly even if year is negative.
Take care to avoid int overflow in leap day calculations,
but it's OK to assume that A and B are close to each other. */
int a4 = (a->tm_year >> 2) + (TM_YEAR_BASE >> 2) - ! (a->tm_year & 3);
int b4 = (b->tm_year >> 2) + (TM_YEAR_BASE >> 2) - ! (b->tm_year & 3);
int a100 = a4 / 25 - (a4 % 25 < 0);
int b100 = b4 / 25 - (b4 % 25 < 0);
int a400 = a100 >> 2;
int b400 = b100 >> 2;
int intervening_leap_days = (a4 - b4) - (a100 - b100) + (a400 - b400);
int years = a->tm_year - b->tm_year;
int days = (365 * years + intervening_leap_days
+ (a->tm_yday - b->tm_yday));
return (60 * (60 * (24 * days + (a->tm_hour - b->tm_hour))
+ (a->tm_min - b->tm_min))
+ (a->tm_sec - b->tm_sec));
}
......@@ -876,12 +874,12 @@ the data it can't find.")
&& (t = gmtime (&value)) != 0)
{
struct tm gmt;
long offset;
int offset;
char *s, buf[6];
gmt = *t; /* Make a copy, in case localtime modifies *t. */
t = localtime (&value);
offset = difftm (t, &gmt);
offset = tm_diff (t, &gmt);
s = 0;
#ifdef HAVE_TM_ZONE
if (t->tm_zone)
......
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