5 Relation *Relation_create(TupleSchema *schema) {
6 Relation *r = (Relation *) malloc( sizeof( Relation ) );
8 .content = (HashVector) {
10 .variant = Nibble_index_levels,
14 .fill = 0, .holes = 0, .type = (ItemKeyFun*) schema
16 .constraints = (Vector) {
17 .variant = single_index_level,
25 #define COPYA(T,P,N) (T*) memcpy( malloc( N * sizeof(T) ), P, N * sizeof( T ) )
26 #define COPY(T,P) COPYA(T,P,1)
28 // Add an indexing HashVector to the Relation using the given column
29 // flags with 1 indicating key column and 0 indicating value column.
30 int Relation_add_constraint(Relation *r,...) {
32 TupleSchema *ts = (TupleSchema *) r->content.type;
33 Tuple *columns = Tuple_clone( ts->columns );
36 for ( ; i < columns->size; i++ ) {
37 if ( va_arg( ap, int ) == 0 ) {
38 columns->elements[i] = 0;
42 ts = TupleSchema_create( columns );
43 i = (int) r->constraints.size;
46 HashVector_create( Nibble_index_levels, (ItemKeyFun*) ts ) );
50 //============== Adding an item =============
51 // Iteration context for adding or Querying a Relation
58 // Determine matches to ((Knockout*)data)->key in
59 // (HashVector*)item, optionally using ((Knockout*)data)->columns
60 // for ignoring full matches to the key tuple.
61 static int knockout_check(VectorIndex index,void *item,void *data) {
62 Knockout *kod = (Knockout*) data;
63 void *key = kod->item;
64 HashVector *hv = (HashVector*) item;
65 TupleSchema *type = (TupleSchema *)hv->type;
67 for ( ; i < hv->table.size; i++ ) {
68 void *old = HashVector_next( hv, &i );
70 if ( key && type->base.haskey( type, old, key ) == 0 ) {
73 HashVector_add( &kod->knockouts, old );
79 // delete the (tuple*)item from the (HashVector*)data
80 static int knockout_delete(VectorIndex index,void *item,void *data) {
81 HashVector_delete( (HashVector*) item, data );
85 // add the (tuple*)data to the (HashVector*)item
86 static int knockout_add(VectorIndex index,void *item,void *data) {
87 HashVector_add( (HashVector*)item, data );
91 // Find and remove all collisions for a Query, unless "add" is
92 // non-zero in which case the function aborts if there is any match in
94 static int knockout_clear(Knockout *this,Relation *r,Tuple *item,int add) {
95 (*this) = (Knockout) {
99 .variant = Nibble_index_levels, .size = 16, .entries = 0
101 .fill = 0, .holes = 0, .type = r->content.type,
105 knockout_check( 0, &r->content, this );
107 if ( this->knockouts.fill > 0 ) {
110 // Find all constraint knockouts for addition
111 Vector_iterate( &r->constraints, 0, knockout_check, this );
113 if ( this->knockouts.fill > 0 ) {
114 // Delete them from all tables
116 for ( i = 0; i < this->knockouts.table.size; i++ ) {
117 void *t = HashVector_next( &this->knockouts, &i );
119 HashVector_delete( &r->content, t );
120 Vector_iterate( &r->constraints, 0, knockout_delete, t );
127 // add a tuple to a Relation and return a Vector of knocked out
128 // tuples, if any, or 0 otherwise.
129 Vector *Relation_add(Relation *r,Tuple *item) {
131 if ( knockout_clear( &data, r, item, 1 ) ) {
133 HashVector_add( &r->content, item );
134 Vector_iterate( &r->constraints, 0, knockout_add, item );
135 return HashVector_contents( &data.knockouts, single_index_level, 0 );
140 Vector *Relation_delete(Relation *r,Tuple *item) {
142 (void) knockout_clear( &data, r, item, 0 );
143 return HashVector_contents( &data.knockouts, single_index_level, 0 );
146 void *Relation_next(Relation *r,VectorIndex *index,Tuple *query) {
147 HashVector *hv = &r->content;
149 TupleSchema *type = (TupleSchema *) hv->type;
150 for ( ; (*index) < hv->table.size; (*index)++ ) {
151 void *old = HashVector_next( hv, index );
153 if ( key && type->base.haskey( type, old, key ) == 0 ) {
159 (*index) = hv->table.size;