On Sun, Apr 06, 2008 at 09:39:20AM -0400, Todd C. Miller wrote:
> In message <20080406082118.GA19070@roppongi.boxsoft.com>
> so spake patrick keshishian (sidster):
>
> > Also, hashp->cndx is decremented (adjusted) during deletion of
> > the key/data pair if hashp->cndx is pointing to the entry being
> > deleted. The side-effect of not doing this is entries are
> > skipped due to the way __delpair "shuffles" keys.
>
> Looks reasonable, though I wonder if it would not be better to do
> the cndx fixup inside __delpair() for the shuffle case.

Does this look OK?


(Again hash.c diff is based on first patch in my original email)

--- /usr/src/lib/libc/db/hash/hash.c Tue Aug 1 03:11:31 2006
+++ hash/hash.c Sun Apr 6 18:18:38 2008
@@ -705,7 +708,7 @@ hash_seq(const DB *dbp, DBT *key, DBT *data, u_int32_t
hashp->cndx = 1;
hashp->cpage = NULL;
}
-
+ next_bucket:
for (bp = NULL; !bp || !bp[0]; ) {
if (!(bufp = hashp->cpage)) {
for (bucket = hashp->cbucket;
@@ -724,8 +727,18 @@ hash_seq(const DB *dbp, DBT *key, DBT *data, u_int32_t
hashp->cbucket = -1;
return (ABNORMAL);
}
- } else
+ } else {
bp = (u_int16_t *)hashp->cpage->page;
+ if (flag == R_NEXT) {
+ hashp->cndx += 2;
+ if (hashp->cndx > bp[0]) {
+ hashp->cpage = NULL;
+ hashp->cbucket++;
+ hashp->cndx = 1;
+ goto next_bucket;
+ }
+ }
+ }

#ifdef DEBUG
assert(bp);
@@ -755,13 +768,6 @@ hash_seq(const DB *dbp, DBT *key, DBT *data, u_int32_t
key->size = (ndx > 1 ? bp[ndx - 1] : hashp->BSIZE) - bp[ndx];
data->data = (u_char *)hashp->cpage->page + bp[ndx + 1];
data->size = bp[ndx] - bp[ndx + 1];
- ndx += 2;
- if (ndx > bp[0]) {
- hashp->cpage = NULL;
- hashp->cbucket++;
- hashp->cndx = 1;
- } else
- hashp->cndx = ndx;
}
return (SUCCESS);
}

--- /usr/src/lib/libc/db/hash/hash_page.c Fri Aug 5 06:03:00 2005
+++ hash/hash_page.c Sun Apr 6 18:18:05 2008
@@ -149,6 +149,14 @@ __delpair(HTAB *hashp, BUFHEAD *bufp, int ndx)
bp[i - 1] = bp[i + 1] + pairlen;
}
}
+ if (ndx == hashp->cndx) {
+ /*
+ * We just removed pair we were "pointing" to.
+ * By moving back the cndx we ensure subsequent
+ * hash_seq() calls won't skip over any entries.
+ */
+ hashp->cndx -= 2;
+ }
}
/* Finally adjust the page data */
bp[n] = OFFSET(bp) + pairlen;