#define COLUMN def->columns
-unsigned long tupleitem_hashcode(itemkeyfun *this,void *key) {
+/**
+ * This callback function returns the hashcode of a key.
+ *
+ * \param this is a pointer to the itemkeyfun record from where this
+ * callback got invoked
+ *
+ * \param key is the key to produce a hascode for
+ *
+ * \returns the hashcode which is a vector_index (i.e. unsigned long)
+ *
+ * The hashcode is used for indexing into the backing vector for
+ * finding the an item via its key. The same key must map consistently
+ * to the same hashcode while the hashtable contains an item with that
+ * key. Different keys map map to the same hashcode, in which case the
+ * vector placement is made at the first empty or hole slot following
+ * the hashcode index.
+ */
+static unsigned long tupleitem_hashcode(itemkeyfun *this,void *key) {
tupleschema *def = (tupleschema *) this;
tuple *kp = (tuple*) key;
int i = 0;
* This callback function determines whether an item has a
* given key or not.
*/
-int tupleitem_haskey(itemkeyfun *this,void *item,void *key) {
+static int tupleitem_haskey(itemkeyfun *this,void *item,void *key) {
tupleschema *def = (tupleschema *) this;
tuple *kp = (tuple*) key;
tuple *tp = (tuple*) item;
int i = 0;
- int haskey = 1;
for ( ; i < def->arity; i++ ) {
- if ( COLUMN[i] ) {
- haskey &= COLUMN[i]->haskey( COLUMN[i], (*tp)[i], (*kp)[i] );
+ if ( COLUMN[i] == 0 ) {
+ if ( (*kp)[i] && (*tp)[i] != (*kp)[i] ) {
+ return 0;
+ }
+ continue;
+ }
+ if ( (*kp)[i] &&
+ COLUMN[i]->haskey( COLUMN[i], (*tp)[i], (*kp)[i] ) == 0 ) {
+ return 0;
}
}
- return haskey;
+ return 1;
}
* This callback function returns the key of an item by considering
* the arity and mask.
*/
-void *tupleitem_itemkey(itemkeyfun *this,void *item) {
+static void *tupleitem_itemkey(itemkeyfun *this,void *item) {
tupleschema *def = (tupleschema *) this;
tuple *tp = (tuple*) item;
int i, j;
* This callback function handles a key obtained from the itemkey
* callback function to reclaim temporary allocation.
*/
-void tupleitem_releasekey(itemkeyfun *this,void *key) {
+static void tupleitem_releasekey(itemkeyfun *this,void *key) {
tupleschema *def = (tupleschema *) this;
tuple *kp = (tuple*) key;
int i,j;
va_list ap;
int i;
tuple *t = (tuple *)malloc( arity * sizeof( void* ) );
+ va_start( ap, arity );
for ( i = 0; i < arity; i++ ) {
(*t)[i] = va_arg( ap, void* );
}
+ va_end( ap );
return t;
}
tupleschema *tupleschema_create(int arity,tuple *columns) {
tupleschema *ts = (tupleschema*) malloc( sizeof( tupleschema ) );
(*ts) = (tupleschema) {
- .functions = {
+ .base = {
.hashcode = tupleitem_hashcode,
.haskey = tupleitem_haskey,
.itemkey = tupleitem_itemkey,
masked->columns = COPYA( itemkeyfun*, schema->columns, schema->arity );
va_list ap;
int i;
+ va_start( ap, schema );
for ( ;; ) {
i = va_arg( ap, int );
if ( i < 0 || i >= schema->arity ) {
}
masked->columns[i] = 0;
};
+ va_end( ap );
return masked;
}
+
+unsigned long tuple_mask(int arity,tuple *t) {
+ unsigned long mask = 0;
+ while ( arity-- > 0 ) {
+ mask <<= 1;
+ if ( (*t)[ arity ] ) {
+ mask++;
+ }
+ }
+ return mask;
+}
+