/*
** Take all the entries on p->pEntry and on the trees in p->pForest and
** sort them all together into one big ordered list on p->pEntry.
**
** This routine should only be called once in the life of a RowSet.
*/
static void rowSetToList(RowSet *p){
/* This routine is called only once */
assert( p!=0 && (p->rsFlags & ROWSET_NEXT)==0 );
if( (p->rsFlags & ROWSET_SORTED)==0 ){
p->pEntry = rowSetEntrySort(p->pEntry);
}
/* While this module could theoretically support it, sqlite3RowSetNext()
** is never called after sqlite3RowSetText() for the same RowSet. So
** there is never a forest to deal with. Should this change, simply
** remove the assert() and the #if 0. */
assert( p->pForest==0 );
#if 0
while( p->pForest ){
struct RowSetEntry *pTree = p->pForest->pLeft;
if( pTree ){
struct RowSetEntry *pHead, *pTail;
rowSetTreeToList(pTree, &pHead, &pTail);
p->pEntry = rowSetEntryMerge(p->pEntry, pHead);
}
p->pForest = p->pForest->pRight;
}
#endif
p->rsFlags |= ROWSET_NEXT; /* Verify this routine is never called again */
}
/*
** Extract the smallest element from the RowSet.
** Write the element into *pRowid. Return 1 on success. Return
** 0 if the RowSet is already empty.
**
** After this routine has been called, the sqlite3RowSetInsert()
** routine may not be called again.
**
** This routine may not be called after sqlite3RowSetTest() has
** been used. Older versions of RowSet allowed that, but as the
** capability was not used by the code generator, it was removed
** for code economy.
*/
int sqlite3RowSetNext(RowSet *p, i64 *pRowid){
assert( p!=0 );
assert( p->pForest==0 ); /* Cannot be used with sqlite3RowSetText() */
/* Merge the forest into a single sorted list on first call */
if( (p->rsFlags & ROWSET_NEXT)==0 ){ /*OPTIMIZATION-IF-FALSE*/
if( (p->rsFlags & ROWSET_SORTED)==0 ){ /*OPTIMIZATION-IF-FALSE*/
p->pEntry = rowSetEntrySort(p->pEntry);
}
p->rsFlags |= ROWSET_SORTED|ROWSET_NEXT;
}
/* Return the next entry on the list */
if( p->pEntry ){
*pRowid = p->pEntry->v;
p->pEntry = p->pEntry->pRight;
if( p->pEntry==0 ){ /*OPTIMIZATION-IF-TRUE*/
/* Free memory immediately, rather than waiting on sqlite3_finalize() */
sqlite3RowSetClear(p);
}
return 1;
}else{
return 0;
}
}
/*
** Check to see if element iRowid was inserted into the rowset as
** part of any insert batch prior to iBatch. Return 1 or 0.
**
** If this is the first test of a new batch and if there exist entires
** on pRowSet->pEntry, then sort those entires into the forest at
** pRowSet->pForest so that they can be tested.
*/
int sqlite3RowSetTest(RowSet *pRowSet, u8 iBatch, sqlite3_int64 iRowid){
struct RowSetEntry *p, *pTree;
/* This routine is never called after sqlite3RowSetNext() */
assert( pRowSet!=0 && (pRowSet->rsFlags & ROWSET_NEXT)==0 );
/* Sort entries into the forest on the first test of a new batch
*/
if( iBatch!=pRowSet->iBatch ){
p = pRowSet->pEntry;
if( p ){
struct RowSetEntry **ppPrevTree = &pRowSet->pForest;
if( (pRowSet->rsFlags & ROWSET_SORTED)==0 ){
p = rowSetEntrySort(p);
}
for(pTree = pRowSet->pForest; pTree; pTree=pTree->pRight){
ppPrevTree = &pTree->pRight;
if( pTree->pLeft==0 ){
pTree->pLeft = rowSetListToTree(p);
break;
}else{
struct RowSetEntry *pAux, *pTail;
rowSetTreeToList(pTree->pLeft, &pAux, &pTail);
pTree->pLeft = 0;
p = rowSetEntryMerge(pAux, p);
}
}
if( pTree==0 ){
*ppPrevTree = pTree = rowSetEntryAlloc(pRowSet);
if( pTree ){
pTree->v = 0;
pTree->pRight = 0;
pTree->pLeft = rowSetListToTree(p);
}
}
pRowSet->pEntry = 0;
pRowSet->pLast = 0;
pRowSet->rsFlags |= ROWSET_SORTED;
}
pRowSet->iBatch = iBatch;
}
/* Test to see if the iRowid value appears anywhere in the forest.
** Return 1 if it does and 0 if not.
*/
for(pTree = pRowSet->pForest; pTree; pTree=pTree->pRight){
p = pTree->pLeft;
while( p ){
if( p->v<iRowid ){
p = p->pRight;
}else if( p->v>iRowid ){
p = p->pLeft;
}else{
return 1;
}
}
}
return 0;
}
