bool Compatible::isdup(const Row& row) {
if (disjoint != "")
return false;
// test if row is in source2
if (nil(hdr1)) {
hdr1 = source->header();
hdr2 = source2->header();
}
Record key = row_to_key(hdr1, row, ki);
source2->select(ki, key);
Row row2 = source2->get(NEXT);
if (row2 == Eof)
return false;
return equal(row, row2);
}
Row Project::get(Dir dir)
{
static Record emptyrec;
if (first)
{
first = false;
src_hdr = source->header();
proj_hdr = src_hdr.project(flds);
if (strategy == LOOKUP)
{
if (idx)
idx->free();
idx = new VVtree(td = new TempDest);
indexed = false;
}
}
if (strategy == COPY)
{
return source->get(dir);
}
else if (strategy == SEQUENTIAL)
{
if (dir == NEXT)
{
// output the first of each group
// i.e. skip over rows the same as previous output
Row row;
do
if (Eof == (row = source->get(NEXT)))
return Eof;
while (! rewound && equal(proj_hdr, row, currow));
rewound = false;
prevrow = currow;
currow = row;
// output the first row of a new group
return Row(lisp(emptyrec, row_to_key(src_hdr, row, flds)));
}
else // dir == PREV
{
// output the last of each group
// i.e. output when *next* record is different
// (to get the same records as NEXT)
if (rewound)
prevrow = source->get(PREV);
rewound = false;
Row row;
do
{
if (Eof == (row = prevrow))
return Eof;
prevrow = source->get(PREV);
}
while (equal(proj_hdr, row, prevrow));
// output the last row of a group
currow = row;
return Row(lisp(emptyrec, row_to_key(src_hdr, row, flds)));
}
}
else
{
verify(strategy == LOOKUP);
if (rewound)
{
rewound = false;
if (dir == PREV && ! indexed)
{
// pre-build the index
Row row;
while (Eof != (row = source->get(NEXT)))
{
Record key = row_to_key(src_hdr, row, flds);
Vdata data(row.data);
for (Lisp<Record> rs = row.data; ! nil(rs); ++rs)
td->addref(rs->ptr());
// insert will only succeed on first of dups
idx->insert(VVslot(key, &data));
}
source->rewind();
indexed = true;
}
}
Row row;
while (Eof != (row = source->get(dir)))
{
Record key = row_to_key(src_hdr, row, flds);
VVtree::iterator iter = idx->find(key);
if (iter == idx->end())
{
for (Lisp<Record> rs = row.data; ! nil(rs); ++rs)
td->addref(rs->ptr());
Vdata data(row.data);
verify(idx->insert(VVslot(key, &data)));
return Row(lisp(emptyrec, key));
}
else
{
Vdata* d = iter->data;
Records rs;
for (int i = d->n - 1; i >= 0; --i)
rs.push(Record::from_int(d->r[i], theDB()->mmf));
Row irow(rs);
if (row == irow)
return Row(lisp(emptyrec, key));
}
}
if (dir == NEXT)
indexed = true;
return Eof;
}
}
