helpers.ml
(*****************************************************************************)
(* *)
(* Open Source License *)
(* Copyright (c) 2018 Dynamic Ledger Solutions, Inc. <contact@tezos.com> *)
(* *)
(* Permission is hereby granted, free of charge, to any person obtaining a *)
(* copy of this software and associated documentation files (the "Software"),*)
(* to deal in the Software without restriction, including without limitation *)
(* the rights to use, copy, modify, merge, publish, distribute, sublicense, *)
(* and/or sell copies of the Software, and to permit persons to whom the *)
(* Software is furnished to do so, subject to the following conditions: *)
(* *)
(* The above copyright notice and this permission notice shall be included *)
(* in all copies or substantial portions of the Software. *)
(* *)
(* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR*)
(* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, *)
(* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL *)
(* THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER*)
(* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING *)
(* FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER *)
(* DEALINGS IN THE SOFTWARE. *)
(* *)
(*****************************************************************************)
let cut ?(copy = false) sz bytes =
let length = Bytes.length bytes in
if length <= sz then [bytes] (* if the result fits in the given sz *)
else
let may_copy = if copy then Bytes.copy else fun t -> t in
let nb_full = length / sz in
(* nb of blocks of size sz *)
let sz_full = nb_full * sz in
(* size of the full part *)
let acc =
(* eventually init acc with a non-full block *)
if sz_full = length then []
else [may_copy (Bytes.sub bytes sz_full (length - sz_full))]
in
let rec split_full_blocks curr_upper_limit acc =
let start = curr_upper_limit - sz in
assert (start >= 0) ;
(* copy the block [ start, curr_upper_limit [ of size sz *)
let acc = may_copy (Bytes.sub bytes start sz) :: acc in
if start = 0 then acc else split_full_blocks start acc
in
split_full_blocks sz_full acc