/*
 *  call-seq:
 *     index_reader.term_vectors(doc_id) -> hash of TermVector
 *
 *  Return the TermVectors for the document at +doc_id+ in the index. The
 *  value returned is a hash of the TermVectors for each field in the document
 *  and they are referenced by field names (as symbols).
 */
static VALUE
frt_ir_term_vectors(VALUE self, VALUE rdoc_id)
{
    IndexReader *ir = (IndexReader *)DATA_PTR(self);
    HashTable *tvs = ir->term_vectors(ir, FIX2INT(rdoc_id));
    VALUE rtvs = rb_hash_new();
    h_each(tvs, &frt_add_each_tv, (void *)rtvs);
    h_destroy(tvs);

    return rtvs;
}