(*
* UTF-8 - UTF-8 encoded Unicode string
* Copyright 2002, 2003 (C) Yamagata Yoriyuki.
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version,
* with the special exception on linking described in file LICENSE.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*)
(** UTF-8 encoded Unicode strings.
The Module for UTF-8 encoded Unicode strings.
*)
open UChar
(** UTF-8 encoded Unicode strings. the type is normal string. *)
type t = string
exception Malformed_code
(** [validate s]
Succeeds if s is valid UTF-8, otherwise raises Malformed_code.
Other functions assume strings are valid UTF-8, so it is prudent
to test their validity for strings from untrusted origins. *)
val validate : t -> unit
(* All functions below assume string are valid UTF-8. If not,
* the result is unspecified. *)
(** [get s n] returns [n]-th Unicode character of [s].
The call requires O(n)-time. *)
val get : t -> int -> uchar
(** [init len f]
returns a new string which contains [len] Unicode characters.
The i-th Unicode character is initialized by [f i] *)
val init : int -> (int -> uchar) -> t
(** [length s] returns the number of Unicode characters contained in s *)
val length : t -> int
(** Positions in the string represented by the number of bytes from the head.
The location of the first character is [0] *)
type index = int
(** [nth s n] returns the position of the [n]-th Unicode character.
The call requires O(n)-time *)
val nth : t -> int -> index
(** The position of the head of the last Unicode character. *)
val last : t -> index
(** [look s i]
returns the Unicode character of the location [i] in the string [s]. *)
val look : t -> index -> uchar
(** [substring s i len] returns the substring made of the Unicode locations [i] to [i + len - 1] inclusive.
The string is always copied *)
val substring : t -> int -> int -> t
(** [out_of_range s i]
tests whether [i] is a position inside of [s]. *)
val out_of_range : t -> index -> bool
(** [compare_index s i1 i2] returns
a value < 0 if [i1] is the position located before [i2],
0 if [i1] and [i2] points the same location,
a value > 0 if [i1] is the position located after [i2]. *)
val compare_index : t -> index -> index -> int
(** [next s i]
returns the position of the head of the Unicode character
located immediately after [i].
If [i] is inside of [s], the function always successes.
If [i] is inside of [s] and there is no Unicode character after [i],
the position outside [s] is returned.
If [i] is not inside of [s], the behaviour is unspecified. *)
val next : t -> index -> index
(** [prev s i]
returns the position of the head of the Unicode character
located immediately before [i].
If [i] is inside of [s], the function always successes.
If [i] is inside of [s] and there is no Unicode character before [i],
the position outside [s] is returned.
If [i] is not inside of [s], the behaviour is unspecified. *)
val prev : t -> index -> index
(** [move s i n]
returns [n]-th Unicode character after [i] if n >= 0,
[n]-th Unicode character before [i] if n < 0.
If there is no such character, the result is unspecified. *)
val move : t -> index -> int -> index
(** [iter f s]
applies [f] to all Unicode characters in [s].
The order of application is same to the order
of the Unicode characters in [s]. *)
val iter : (uchar -> unit) -> t -> unit
(** Code point comparison by the lexicographic order.
[compare s1 s2] returns
a positive integer if [s1] > [s2],
0 if [s1] = [s2],
a negative integer if [s1] < [s2]. *)
val compare : t -> t -> int
(** Buffer module for UTF-8 strings *)
module Buf : sig
(** Buffers for UTF-8 strings. *)
type buf
(** [create n] creates a buffer with the initial size [n]-bytes. *)
val create : int -> buf
(* The rest of functions is similar to the ones of Buffer in stdlib. *)
(** [contents buf] returns the contents of the buffer. *)
val contents : buf -> t
(** Empty the buffer,
but retains the internal storage which was holding the contents *)
val clear : buf -> unit
(** Empty the buffer and de-allocate the internal storage. *)
val reset : buf -> unit
(** Add one Unicode character to the buffer. *)
val add_char : buf -> uchar -> unit
(** Add the UTF-8 string to the buffer. *)
val add_string : buf -> t -> unit
(** [add_buffer b1 b2] adds the contents of [b2] to [b1].
The contents of [b2] is not changed. *)
val add_buffer : buf -> buf -> unit
end