(**************************************************************************)
(*                                                                        *)
(*    Copyright (c) 2014 - 2017.                                          *)
(*    Dynamic Ledger Solutions, Inc. <contact@tezos.com>                  *)
(*                                                                        *)
(*    All rights reserved. No warranty, explicit or implicit, provided.   *)
(*                                                                        *)
(**************************************************************************)

module Map = Map.Make (String)

let split delim ?(dup = true) ?(limit = max_int) path =
  let l = String.length path in
  let rec do_slashes acc limit i =
    if i >= l then
      List.rev acc
    else if String.get path i = delim then
      if dup then
        do_slashes acc limit (i + 1)
      else
        do_split acc limit (i + 1)
    else
      do_split acc limit i
  and do_split acc limit i =
    if limit <= 0 then
      if i = l then
        List.rev acc
      else
        List.rev (String.sub path i (l - i) :: acc)
    else
      do_component acc (pred limit) i i
  and do_component acc limit i j =
    if j >= l then
      if i = j then
        List.rev acc
      else
        List.rev (String.sub path i (j - i) :: acc)
    else if String.get path j = delim then
      do_slashes (String.sub path i (j - i) :: acc) limit j
    else
      do_component acc limit i (j + 1) in
  if limit > 0 then
    do_slashes [] limit 0
  else
    [ path ]

let split_path path = split '/' path

let has_prefix ~prefix s =
  let x = String.length prefix in
  let n = String.length s in
  n >= x && String.sub s 0 x = prefix

let remove_prefix ~prefix s =
  let x = String.length prefix in
  let n = String.length s in
  if n >= x && String.sub s 0 x = prefix then
    Some (String.sub s x (n - x))
  else
    None

let common_prefix s1 s2 =
  let last = min (String.length s1) (String.length s2) in
  let rec loop i =
    if last <= i then last
    else if s1.[i] = s2.[i] then
      loop (i+1)
    else
      i in
  loop 0

let mem_char s c =
  match String.index s c with
  | exception Not_found -> false
  | _ -> true

let fold_left f init s =
  let acc = ref init in
  String.iter (fun c -> acc := f !acc c) s ;
  !acc