/*
* __BT_CMP -- Compare a key to a given record.
*
* Parameters:
* t: tree
* k1: DBT pointer of first arg to comparison
* e: pointer to EPG for comparison
*
* Returns:
* < 0 if k1 is < record
* = 0 if k1 is = record
* > 0 if k1 is > record
*/
int
__bt_cmp(BTREE *t, const DBT *k1, EPG *e)
{
BINTERNAL *bi;
BLEAF *bl;
DBT k2;
PAGE *h;
void *bigkey;
/*
* The left-most key on internal pages, at any level of the tree, is
* guaranteed by the following code to be less than any user key.
* This saves us from having to update the leftmost key on an internal
* page when the user inserts a new key in the tree smaller than
* anything we've yet seen.
*/
h = e->page;
if (e->index == 0 && h->prevpg == P_INVALID && !(h->flags & P_BLEAF))
return (1);
bigkey = NULL;
if (h->flags & P_BLEAF) {
bl = GETBLEAF(h, e->index);
if (bl->flags & P_BIGKEY)
bigkey = bl->bytes;
else {
k2.data = bl->bytes;
k2.size = bl->ksize;
}
} else {
bi = GETBINTERNAL(h, e->index);
if (bi->flags & P_BIGKEY)
bigkey = bi->bytes;
else {
k2.data = bi->bytes;
k2.size = bi->ksize;
}
}
if (bigkey) {
if (__ovfl_get(t, bigkey,
&k2.size, &t->bt_rdata.data, &t->bt_rdata.size))
return (RET_ERROR);
k2.data = t->bt_rdata.data;
}
return ((*t->bt_cmp)(k1, &k2));
}
/*
* __bt_ret --
* Build return key/data pair.
*
* Parameters:
* t: tree
* e: key/data pair to be returned
* key: user's key structure (NULL if not to be filled in)
* rkey: memory area to hold key
* data: user's data structure (NULL if not to be filled in)
* rdata: memory area to hold data
* copy: always copy the key/data item
*
* Returns:
* RET_SUCCESS, RET_ERROR.
*/
int
__bt_ret(BTREE *t, EPG *e, DBT *key, DBT *rkey, DBT *data, DBT *rdata, int copy)
{
BLEAF *bl;
void *p;
bl = GETBLEAF(e->page, e->index);
/*
* We must copy big keys/data to make them contiguous. Otherwise,
* leave the page pinned and don't copy unless the user specified
* concurrent access.
*/
if (key == NULL)
goto dataonly;
if (bl->flags & P_BIGKEY) {
if (__ovfl_get(t, bl->bytes,
&key->size, &rkey->data, &rkey->size))
return (RET_ERROR);
key->data = rkey->data;
} else if (copy || F_ISSET(t, B_DB_LOCK)) {
if (bl->ksize > rkey->size) {
p = (void *)(rkey->data == NULL ?
malloc(bl->ksize) : realloc(rkey->data, bl->ksize));
if (p == NULL)
return (RET_ERROR);
rkey->data = p;
rkey->size = bl->ksize;
}
memmove(rkey->data, bl->bytes, bl->ksize);
key->size = bl->ksize;
key->data = rkey->data;
} else {
key->size = bl->ksize;
key->data = bl->bytes;
}
dataonly:
if (data == NULL)
return (RET_SUCCESS);
if (bl->flags & P_BIGDATA) {
if (__ovfl_get(t, bl->bytes + bl->ksize,
&data->size, &rdata->data, &rdata->size))
return (RET_ERROR);
data->data = rdata->data;
} else if (copy || F_ISSET(t, B_DB_LOCK)) {
/* Use +1 in case the first record retrieved is 0 length. */
if (bl->dsize + 1 > rdata->size) {
p = (void *)(rdata->data == NULL ?
malloc(bl->dsize + 1) :
realloc(rdata->data, bl->dsize + 1));
if (p == NULL)
return (RET_ERROR);
rdata->data = p;
rdata->size = bl->dsize + 1;
}
memmove(rdata->data, bl->bytes + bl->ksize, bl->dsize);
data->size = bl->dsize;
data->data = rdata->data;
} else {
data->size = bl->dsize;
data->data = bl->bytes + bl->ksize;
}
return (RET_SUCCESS);
}
