/* Tree data structure. */
struct bst_table
  {
    struct bst_node *bst_root;          /* Tree's root. */
    bst_comparison_func *bst_compare;   /* Comparison function. */
    void *bst_param;                    /* Extra argument to |bst_compare|. */
    struct libavl_allocator *bst_alloc; /* Memory allocator. */
    size_t bst_count;                   /* Number of items in tree. */
    unsigned long bst_generation;       /* Generation number. */
  };

