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type t = { mutable contents : bytes; mutable length : int }
let v ?(capacity = 1024) () = { contents = Bytes.create capacity; length = 0 }
let length t = t.length
let capacity t = Bytes.length t.contents
let extend t amount = t.contents <- Bytes.extend t.contents 0 amount
let rec nearest_power_of_2 acc target =
if acc >= target then acc else nearest_power_of_2 (acc * 2) target
let ensure_size t ~ =
let current_capacity = capacity t in
let needed_capacity = t.length + extra in
if needed_capacity >= current_capacity then
extend t
(nearest_power_of_2 current_capacity needed_capacity - current_capacity)
let copy_from_bigstringaf ~src_off ~src ~dst ~length =
ensure_size dst ~extra:length;
Bigstringaf.blit_to_bytes ~src_off src ~dst_off:dst.length dst.contents
~len:length;
dst.length <- dst.length + length
let sub ~start ~length t =
let contents = Bytes.sub t.contents start length in
{ contents; length }
let to_bytes t = Bytes.sub t.contents 0 t.length
let to_string t = to_bytes t |> Bytes.to_string
let shift_left ~by t =
Bytes.blit t.contents by t.contents 0 (t.length - by);
t.length <- t.length - by
let get_u8 ~pos t = Bytes.get_uint8 t.contents pos
let get_u32_be ~pos t =
let high = Bytes.get_uint16_be t.contents pos in
let low = Bytes.get_uint16_be t.contents (pos + 2) in
(high lsl 16) lor low