Re: gist access methods parameter types

Please can you answer the question of whether entry->key in compress should
be of delta3d sql type (composite type) and if not of what it should be
since the type I index is different from the type stored in tree?
Taking into consideration the types I described before this is my code for
compress.

Datum delta3d_compress(PG_FUNCTION_ARGS) {
GISTENTRY *entry = (GISTENTRY *) PG_GETARG_POINTER(0);
GISTENTRY *retval;

HeapTupleHeader in;
HeapTupleHeader i;
HeapTupleHeader e;
bool isnull;

if (entry->leafkey) {
in = DatumGetHeapTupleHeader(entry->key);

if (in != NULL) {
i = DatumGetHeapTupleHeader(GetAttributeByName(in, "i",
&isnull));
e = DatumGetHeapTupleHeader(GetAttributeByName(in, "e",
&isnull));

delta3d *compressed_data = (delta3d *) palloc(sizeof (delta3d));
compressed_data->xi = DatumGetFloat8(GetAttributeByName(i, "x",
&isnull));
compressed_data->yi = DatumGetFloat8(GetAttributeByName(i, "y",
&isnull));
compressed_data->ti = DatumGetTimestamp(GetAttributeByName(i,
"t", &isnull));
compressed_data->xe = DatumGetFloat8(GetAttributeByName(e, "x",
&isnull));
compressed_data->ye = DatumGetFloat8(GetAttributeByName(e, "y",
&isnull));
compressed_data->te = DatumGetTimestamp(GetAttributeByName(e,
"t", &isnull));
compressed_data->trajectory =
DatumGetInt32(GetAttributeByName(in, "trajectory", &isnull));

retval = palloc(sizeof (GISTENTRY));
gistentryinit(*retval, PointerGetDatum(compressed_data),
entry->rel, entry->page, entry->offset, FALSE);
} else {
retval = palloc(sizeof (GISTENTRY));
gistentryinit(*retval, (Datum) 0, entry->rel, entry->page,
entry->offset, FALSE);
}
} else {
retval = entry; *//does this have to change? I thing it is going to
be of C type delta3d_mbb, am I right?*
}

PG_RETURN_POINTER(retval);
}