int kvs_helper_cursor_nextr(KVS_cursor *const cursor, KVS_range const *const range, KVS_val *const key, KVS_val *const data, int const dir) {
assert(kvs_cursor_cmp(cursor, range->min, range->max) < 0);
KVS_val tmp;
KVS_val *k = key ? key : &tmp;
int rc = kvs_cursor_next(cursor, k, data, dir);
if(rc < 0) return rc;
int const min = kvs_cursor_cmp(cursor, k, range->min);
int const max = kvs_cursor_cmp(cursor, k, range->max);
if(min > 0 && max < 0) return 0;
kvs_cursor_clear(cursor);
return KVS_NOTFOUND;
}
/*
* kvs_cursor_search_near --
* WT_CURSOR::search_near method.
*/
static int
kvs_cursor_search_near(WT_CURSOR *wt_cursor, int *exact)
{
int ret;
/*
* XXX
* I'm not confident this is sufficient: if there are multiple threads
* of control, it's possible for the search for an exact match to fail,
* another thread of control to insert (and commit) an exact match, and
* then it's possible we'll return the wrong value. This needs to be
* revisited once the transactional code is in place.
*/
/* Search for an exact match. */
if ((ret = kvs_cursor_search(wt_cursor)) == 0) {
*exact = 0;
return (0);
}
if (ret != WT_NOTFOUND)
return (ret);
/* Search for a key that's larger. */
if ((ret = kvs_cursor_next(wt_cursor)) == 0) {
*exact = 1;
return (0);
}
if (ret != WT_NOTFOUND)
return (ret);
/* Search for a key that's smaller. */
if ((ret = kvs_cursor_prev(wt_cursor)) == 0) {
*exact = -1;
return (0);
}
return (ret);
}
int kvs_helper_cursor_firstr(KVS_cursor *const cursor, KVS_range const *const range, KVS_val *const key, KVS_val *const data, int const dir) {
assert(kvs_cursor_cmp(cursor, range->min, range->max) < 0);
if(0 == dir) return KVS_EINVAL;
KVS_val const *const first = dir > 0 ? range->min : range->max;
KVS_val k = *first;
int rc = kvs_cursor_seek(cursor, &k, data, dir);
if(rc < 0) return rc;
int x = kvs_cursor_cmp(cursor, &k, first);
assert(x * dir >= 0);
if(0 == x) {
rc = kvs_cursor_next(cursor, &k, data, dir);
if(rc < 0) return rc;
}
KVS_val const *const last = dir < 0 ? range->min : range->max;
x = kvs_cursor_cmp(cursor, &k, last);
if(x * dir < 0) {
if(key) *key = k;
return 0;
} else {
kvs_cursor_clear(cursor);
return KVS_NOTFOUND;
}
}
