How to compare an Oracle database with a Postgresql database?

We are currently migrating an Oracle database 10gR2 to a Postgresql database 9.3. Thanks to Hibernate, all tables can be recreated seamlessly.

However, the Oracle database is huge. We are going to write a small tool that will bring the data from one db to the other.

We want to check the quality of the migration with some kind of third-party database comparator.

Do you know a tool that can compare an Oracle database and a Postgresql database (schema + data) ?