SEO

Hi,

I just committed the diff. Thanks to everybody for testing.

There remains one issue: in some cases, the current diff is slow,
because it scans the list of previous telldir positions to avoid
allocating a new entry and to implement the requirement that
seekdir(loc); telldir() should return loc.

The diff below (against current) should solve that. It makes use of
the fact that telldirs alwas return a pos >= the current pos. So we
can remember the pos last set by seekdir() or returned by telldir() and
largely avoid having to scan the list all the time.

-Otto

Index: opendir.c
================================================== =================
RCS file: /cvs/src/lib/libc/gen/opendir.c,v
retrieving revision 1.16
diff -u -p -r1.16 opendir.c
--- opendir.c 1 Apr 2006 18:06:59 -0000 1.16
+++ opendir.c 1 Apr 2006 18:22:00 -0000
@@ -78,7 +78,7 @@ __opendir2(const char *name, int flags)
dirp->dd_td->td_locs = NULL;
dirp->dd_td->td_sz = 0;
dirp->dd_td->td_loccnt = 0;
-
+ dirp->dd_td->td_last = 0;

/*
* If the machine's page size is an exact multiple of DIRBLKSIZ,
Index: telldir.c
================================================== =================
RCS file: /cvs/src/lib/libc/gen/telldir.c,v
retrieving revision 1.8
diff -u -p -r1.8 telldir.c
--- telldir.c 1 Apr 2006 18:06:59 -0000 1.8
+++ telldir.c 1 Apr 2006 18:22:00 -0000
@@ -42,14 +42,18 @@
long
telldir(DIR *dirp)
{
- long i = 0;
- struct ddloc *lp = dirp->dd_td->td_locs;
+ long i = dirp->dd_td->td_last;
+ struct ddloc *lp;
+
+ lp = &dirp->dd_td->td_locs[i];

/* return previous telldir, if there */
for (; i < dirp->dd_td->td_loccnt; i++, lp++) {
if (lp->loc_seek == dirp->dd_seek &&
- lp->loc_loc == dirp->dd_loc)
+ lp->loc_loc == dirp->dd_loc) {
+ dirp->dd_td->td_last = i;
return (i);
+ }
}

if (dirp->dd_td->td_loccnt == dirp->dd_td->td_sz) {
@@ -65,6 +69,7 @@ telldir(DIR *dirp)
dirp->dd_td->td_loccnt++;
lp->loc_seek = dirp->dd_seek;
lp->loc_loc = dirp->dd_loc;
+ dirp->dd_td->td_last = i;
return (i);
}

@@ -81,6 +86,7 @@ __seekdir(DIR *dirp, long loc)
if (loc < 0 || loc >= dirp->dd_td->td_loccnt)
return;
lp = &dirp->dd_td->td_locs[loc];
+ dirp->dd_td->td_last = loc;
if (lp->loc_loc == dirp->dd_loc && lp->loc_seek == dirp->dd_seek)
return;
(void) lseek(dirp->dd_fd, (off_t)lp->loc_seek, SEEK_SET);
Index: telldir.h
================================================== =================
RCS file: /cvs/src/lib/libc/gen/telldir.h,v
retrieving revision 1.1
diff -u -p -r1.1 telldir.h
--- telldir.h 1 Apr 2006 18:06:59 -0000 1.1
+++ telldir.h 1 Apr 2006 18:22:00 -0000
@@ -55,6 +55,7 @@ struct _telldir {
struct ddloc *td_locs; /* locations */
size_t td_sz; /* size of locations */
long td_loccnt; /* index of entry for sequential readdir's */
+ long td_last; /* last tell/seekdir */
};

void __seekdir(DIR *, long);