module Make:
Functor building an implementation of the weak hash table structure.
type
data
The type of the elements stored in the table.
type
t
The type of tables that contain elements of type
data
.
Note that weak hash tables cannot be marshaled using
output_value
or the functions of the
Marshal
module.
val create : int -> t
create n
creates a new empty weak hash table, of initial
size n
. The table will grow as needed.
val clear : t -> unit
Remove all elements from the table.
val merge : t -> data -> data
merge t x
returns an instance of x
found in t
if any,
or else adds x
to t
and return x
.
val add : t -> data -> unit
add t x
adds x
to t
. If there is already an instance
of x
in t
, it is unspecified which one will be
returned by subsequent calls to find
and merge
.
val remove : t -> data -> unit
remove t x
removes from t
one instance of x
. Does
nothing if there is no instance of x
in t
.
val find : t -> data -> data
find t x
returns an instance of x
found in t
.
Raise Not_found
if there is no such element.
val find_all : t -> data -> data list
find_all t x
returns a list of all the instances of x
found in t
.
val mem : t -> data -> bool
mem t x
returns true
if there is at least one instance
of x
in t
, false otherwise.
val iter : (data -> unit) -> t -> unit
iter f t
calls f
on each element of t
, in some unspecified
order. It is not specified what happens if f
tries to change
t
itself.
val fold : (data -> 'a -> 'a) -> t -> 'a -> 'a
fold f t init
computes (f d1 (... (f dN init)))
where
d1 ... dN
are the elements of t
in some unspecified order.
It is not specified what happens if f
tries to change t
itself.
val count : t -> int
Count the number of elements in the table. count t
gives the
same result as fold (fun _ n -> n+1) t 0
but does not delay the
deallocation of the dead elements.
val stats : t -> int * int * int * int * int * int
Return statistics on the table. The numbers are, in order:
table length, number of entries, sum of bucket lengths,
smallest bucket length, median bucket length, biggest bucket length.