wp_revisions_to_keep( WP_Post $post )

function wp_revisions_to_keep( $post ) {
	$num = WP_POST_REVISIONS;

	if ( true === $num )
		$num = -1;
	else
		$num = intval( $num );

	if ( ! post_type_supports( $post->post_type, 'revisions' ) )
		$num = 0;

	/**
	 * Filters the number of revisions to save for the given post.
	 *
	 * Overrides the value of WP_POST_REVISIONS.
	 *
	 * @since WP-3.6.0
	 *
	 * @param int     $num  Number of revisions to store.
	 * @param WP_Post $post Post object.
	 */
	return (int) apply_filters( 'wp_revisions_to_keep', $num, $post );
}