ocaml/stdlib/string.ml

128 lines
3.9 KiB
OCaml

(***********************************************************************)
(* *)
(* OCaml *)
(* *)
(* Damien Doligez, projet Gallium, INRIA Rocquencourt *)
(* *)
(* Copyright 2014 Institut National de Recherche en Informatique et *)
(* en Automatique. All rights reserved. This file is distributed *)
(* under the terms of the GNU Library General Public License, with *)
(* the special exception on linking described in file ../LICENSE. *)
(* *)
(***********************************************************************)
(* String operations, based on byte sequence operations *)
external length : string -> int = "%string_length"
external get : string -> int -> char = "%string_safe_get"
external set : bytes -> int -> char -> unit = "%string_safe_set"
external create : int -> bytes = "caml_create_string"
external unsafe_get : string -> int -> char = "%string_unsafe_get"
external unsafe_set : bytes -> int -> char -> unit = "%string_unsafe_set"
external unsafe_blit : string -> int -> bytes -> int -> int -> unit
= "caml_blit_string" "noalloc"
external unsafe_fill : bytes -> int -> int -> char -> unit
= "caml_fill_string" "noalloc"
module B = Bytes
let bts = B.unsafe_to_string
let bos = B.unsafe_of_string
let make n c =
B.make n c |> bts
let init n f =
B.init n f |> bts
let copy s =
B.copy (bos s) |> bts
let sub s ofs len =
B.sub (bos s) ofs len |> bts
let fill =
B.fill
let blit =
B.blit_string
let concat sep l =
match l with
| [] -> ""
| hd :: tl ->
let num = ref 0 and len = ref 0 in
List.iter (fun s -> incr num; len := !len + length s) l;
let r = B.create (!len + length sep * (!num - 1)) in
unsafe_blit hd 0 r 0 (length hd);
let pos = ref(length hd) in
List.iter
(fun s ->
unsafe_blit sep 0 r !pos (length sep);
pos := !pos + length sep;
unsafe_blit s 0 r !pos (length s);
pos := !pos + length s)
tl;
Bytes.unsafe_to_string r
let iter f s =
B.iter f (bos s)
let iteri f s =
B.iteri f (bos s)
let map f s =
B.map f (bos s) |> bts
let mapi f s =
B.mapi f (bos s) |> bts
(* Beware: we cannot use B.trim or B.escape because they always make a
copy, but String.mli spells out some cases where we are not allowed
to make a copy. *)
external is_printable: char -> bool = "caml_is_printable"
let is_space = function
| ' ' | '\012' | '\n' | '\r' | '\t' -> true
| _ -> false
let trim s =
if s = "" then s
else if is_space (unsafe_get s 0) || is_space (unsafe_get s (length s - 1))
then bts (B.trim (bos s))
else s
let escaped s =
let rec needs_escape i =
if i >= length s then false else
match unsafe_get s i with
| '"' | '\\' | '\n' | '\t' | '\r' | '\b' -> true
| c when is_printable c -> needs_escape (i+1)
| _ -> true
in
if needs_escape 0 then
bts (B.escaped (bos s))
else
s
let index s c =
B.index (bos s) c
let rindex s c =
B.rindex (bos s) c
let index_from s i c=
B.index_from (bos s) i c
let rindex_from s i c =
B.rindex_from (bos s) i c
let contains s c =
B.contains (bos s) c
let contains_from s i c =
B.contains_from (bos s) i c
let rcontains_from s i c =
B.rcontains_from (bos s) i c
let uppercase s =
B.uppercase (bos s) |> bts
let lowercase s =
B.lowercase (bos s) |> bts
let capitalize s =
B.capitalize (bos s) |> bts
let uncapitalize s =
B.uncapitalize (bos s) |> bts
type t = string
let compare (x: t) (y: t) = Pervasives.compare x y
external equal : string -> string -> bool = "caml_string_equal"