hoey@ai.etl.army.mil (Dan Hoey) (05/13/88)
Index: usr.bin/calendar/calendar.c 4.3BSD +FIX
Description:
On some Fridays calendar(1) says ``egrep: regular expression too
long.'' This is because /usr/lib/calendar makes a regular expression
that is too long. It only happens on Fridays because the pattern has
to match four days on Fridays.
I have only observed this problem near the end of the month, and it
isn't happening today (13 May). I don't know why it only happens on
some Fridays. It definitely happens when the date is Friday 29 April.
I sent in a fix for this for 4.2 but the bug was still there in 4.3.
I sent in a fix for 4.3, but I haven't seen it here, so this is my
latest attempt to find out what price I have to pay to get out of
going through all these things twice.
Repeat-By:
On Friday 29 April type "calendar".
Fix:
The pattern can be made smaller by grouping some common parts with
parentheses. This fix also allows dates of the form "*/5" to match
the fifth of any month just like "* 5" does. Note that it is unwise
to mention "*/5" inside a C comment.
Of course, this can be fixed by fixing egrep's idea of what a regular
expression's maximum size is, but I don't see why we shouldn't fix
calendar, too. Someone else can show how to fix egrep.
Context diff:
*** /tmp/,RCSt1028981 Fri Apr 29 09:34:42 1988
--- calendar.c Fri Apr 29 09:34:24 1988
***************
*** 1,4
! static char *sccsid = "@(#)calendar.c 4.5 (Berkeley) 84/05/07";
/* /usr/lib/calendar produces an egrep -f file
that will select today's and tomorrow's
calendar entries, with special weekend provisions
--- 1,4 -----
! static char *sccsid = "@(#)calendar.c 4.>5 (Hoey) 88/04/29";
/* /usr/lib/calendar produces an egrep -f file
that will select today's and tomorrow's
calendar entries, with special weekend provisions
***************
*** 4,9
calendar entries, with special weekend provisions
used by calendar command
*/
#include <sys/time.h>
--- 4,12 -----
calendar entries, with special weekend provisions
used by calendar command
+
+ Modified to minimize pattern size so egrep won't barf. Also allow
+ wild-card dates in slash format.
*/
#include <sys/time.h>
***************
*** 25,30
};
struct tm *localtime();
tprint(t)
long t;
{
--- 28,36 -----
};
struct tm *localtime();
+ int disjunct = 0; /* True if we are working on second or later disjunct of
+ the pattern. */
+
tprint(t)
long t;
{
***************
*** 30,36
{
struct tm *tm;
tm = localtime(&t);
! printf("(^|[ (,;])((%s[^ \t]*[ \t]*|(0%d|%d)/)0*%d)([^0123456789]|$)\n",
month[tm->tm_mon],
tm->tm_mon + 1, tm->tm_mon + 1, tm->tm_mday);
printf("(^|[ (,;])((\\*[ \t]*)0*%d)([^0123456789]|$)\n",
--- 36,51 -----
{
struct tm *tm;
tm = localtime(&t);
! if (!disjunct) {
! /* Pattern for start of date and open parenthesis */
! printf("(^|[ \t(,;])(");
! disjunct = 1;
! } else {
! /* Next date */
! printf ("\n");
! }
! /* [Jj]an 5 or \* 5 or 1/5 */
! printf("((%s[^ \t]*|\\*)[ \t]*|(0*%d|\\*)/)0*%d",
month[tm->tm_mon],
tm->tm_mon + 1, tm->tm_mday);
}
***************
*** 32,40
tm = localtime(&t);
printf("(^|[ (,;])((%s[^ \t]*[ \t]*|(0%d|%d)/)0*%d)([^0123456789]|$)\n",
month[tm->tm_mon],
! tm->tm_mon + 1, tm->tm_mon + 1, tm->tm_mday);
! printf("(^|[ (,;])((\\*[ \t]*)0*%d)([^0123456789]|$)\n",
! tm->tm_mday);
}
main()
--- 47,53 -----
/* [Jj]an 5 or \* 5 or 1/5 */
printf("((%s[^ \t]*|\\*)[ \t]*|(0*%d|\\*)/)0*%d",
month[tm->tm_mon],
! tm->tm_mon + 1, tm->tm_mday);
}
main()
***************
*** 53,56
t += DAY;
tprint(t);
}
}
--- 66,71 -----
t += DAY;
tprint(t);
}
+ /* End of date. Make sure date ends cleanly. */
+ printf(")([^0-9]|$)\n");
}