Module CCBV
Imperative Bitvectors
BREAKING CHANGES since 1.2: size is now stored along with the bitvector. Some functions have a new signature.
The size of the bitvector used to be rounded up to the multiple of 30 or 62. In other words some functions such as iter
would iterate on more bits than what was originally asked for. This is not the case anymore.
val empty : unit -> t
Empty bitvector.
val create : size:int -> bool -> t
Create a bitvector of given size, with given default value.
val cardinal : t -> int
Number of bits set to one, seen as a set of bits.
val length : t -> int
Size of underlying bitvector. This is not related to the underlying implementation. Changed at 1.2
val capacity : t -> int
The number of bits this bitvector can store without resizing.
- since
- 1.2
val resize : t -> int -> unit
Resize the BV so that it has the specified length. This can grow or shrink the underlying bitvector.
- raises Invalid_arg
on negative sizes.
val is_empty : t -> bool
Are there any true bits?
val set : t -> int -> unit
Set i-th bit, extending the bitvector if needed.
val get : t -> int -> bool
Is the i-th bit true? Return false if the index is too high.
val reset : t -> int -> unit
Set i-th bit to 0, extending the bitvector if needed.
val flip : t -> int -> unit
Flip i-th bit, extending the bitvector if needed.
val clear : t -> unit
Set every bit to 0.
val iter : t -> (int -> bool -> unit) -> unit
Iterate on all bits.
val iter_true : t -> (int -> unit) -> unit
Iterate on bits set to 1.
val to_list : t -> int list
List of indexes that are true.
val to_sorted_list : t -> int list
Same as
to_list
, but also guarantees the list is sorted in increasing order.
val of_list : int list -> t
From a list of true bits.
The bits are interpreted as indices into the returned bitvector, so the final bitvector will have
length t
equal to 1 more than max of list indices.
val first : t -> int option
First set bit, or return
None
. Changed type at 1.2
val first_exn : t -> int
First set bit, or
- raises Not_found
if all bits are 0.
- since
- 1.2
val filter : t -> (int -> bool) -> unit
filter bv p
only keeps the true bits ofbv
whoseindex
satisfiesp index
.
val negate_self : t -> unit
negate_self t
flips all of the bits int
.- since
- 1.2
val union_into : into:t -> t -> unit
union_into ~into bv
setsinto
to the union of itself andbv
. Also updates the length ofinto
to be at leastlength bv
.
val inter_into : into:t -> t -> unit
inter_into ~into bv
setsinto
to the intersection of itself andbv
. Also updates the length ofinto
to be at mostlength bv
.
val diff_into : into:t -> t -> unit
diff_into ~into t
modifiesinto
with only the bits set but not int
.- since
- 1.2
val select : t -> 'a array -> 'a list
select arr bv
selects the elements ofarr
whose index corresponds to a true bit inbv
. Ifbv
is too short, elements ofarr
with too high an index cannot be selected and are therefore not selected.