A queue of flat tuples, represented in a [root:Flat_array].
The elements of a queue are numbered 0, 1, ...,
length t - 1, where element
at the front of the queue. One can access the
j'th component of the
get t i Slot.tj.
A flat tuple is like an ordinary OCaml tuple, except it is second class and mutable.
The flat tuples in a flat queue are layed out sequentially, with each flat tuple's
components immediately following the components of the prior flat tuple. A flat tuple
is not first class -- one can only refer to a flat tuple via its index in the queue
holding it. Flat tuples are mutable via
The type of a flat queue.
'slots will look like
('a1, ..., 'an) Slots.tn, and the
queue holds flat tuples of type
'a1 * ... * 'an.
capacity t returns the length of the array backing
t. Enqueueing values will not
cause the array to grow as long as
length t <= capacity t. A queue at capacity
will automatically increase capacity when enqueueing. The capacity never decreases
automatically; one can only decrease capacity via
set_capacity t capacity sets the length of the array backing
t to as small as
value as possible that is not less than
max capacity (length t). To shrink as much
as possible, do
set_capacity t 0.
drop_front ?n t drops the the first
n elements of
t. It raises if
n < 0 || n >
Flat_queue does not have
dequeue_exn because the expected usage is to
get t 0 Slot.tj to access the front of the queue, and then to use
to remove it. This usage avoids ever allocating an ordinary OCaml tuple.
The functions below deal with Flat-array tuples as ordinary OCaml tuples. These are intended for convenience but not for performance-critical code, due to the tuple allocation.
get_all_slots t i allocates a new ordinary OCaml tuple whose components are equal to
the slots of the flat tuple at index
t. This is esentially an allocation
plus a blit from
t to the newly allocated tuple.
set_all_slots t i tuple sets all slots of the flat tuple at index
their corresponding components of
tuple. This is essentially a blit from
It is required that
0 <= i < length t.