uchar.res

/* ************************************************************************ */
/*  */
/* OCaml */
/*  */
/* Daniel C. Buenzli */
/*  */
/* Copyright 2014 Institut National de Recherche en Informatique et */
/* en Automatique. */
/*  */
/* All rights reserved.  This file is distributed under the terms of */
/* the GNU Lesser General Public License version 2.1, with the */
/* special exception on linking described in the file LICENSE. */
/*  */
/* ************************************************************************ */

external format_int: (string, int) => string = "?format_int"

let err_no_pred = "U+0000 has no predecessor"
let err_no_succ = "U+10FFFF has no successor"
let err_not_sv = i => format_int("%X", i) ++ " is not an Unicode scalar value"
let err_not_latin1 = u => "U+" ++ (format_int("%04X", u) ++ " is not a latin1 character")

type t = int

let min = 0x0000
let max = 0x10FFFF
let lo_bound = 0xD7FF
let hi_bound = 0xE000

let bom = 0xFEFF
let rep = 0xFFFD

let succ = u =>
  if u == lo_bound {
    hi_bound
  } else if u == max {
    invalid_arg(err_no_succ)
  } else {
    u + 1
  }

let pred = u =>
  if u == hi_bound {
    lo_bound
  } else if u == min {
    invalid_arg(err_no_pred)
  } else {
    u - 1
  }

let is_valid = i => (min <= i && i <= lo_bound) || (hi_bound <= i && i <= max)
let of_int = i =>
  if is_valid(i) {
    i
  } else {
    invalid_arg(err_not_sv(i))
  }
external unsafe_of_int: int => t = "%identity"
external to_int: t => int = "%identity"

let is_char = u => u < 256
let of_char = c => Char.code(c)
let to_char = u =>
  if u > 255 {
    invalid_arg(err_not_latin1(u))
  } else {
    Char.unsafe_chr(u)
  }

let unsafe_to_char = Char.unsafe_chr

let equal: (int, int) => bool = \"="
let compare: (int, int) => int = Pervasives.compare
let hash = to_int