(* COCANWIKI - a wiki written in Objective CAML.
 * Written by Richard W.M. Jones <rich@merjis.com>.
 * Copyright (C) 2004 Merjis Ltd.
 * $Id: cocanwiki_strings.ml,v 1.2 2004/09/09 12:21:22 rich Exp $
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program 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 General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; see the file COPYING.  If not, write to
 * the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
 * Boston, MA 02111-1307, USA.
 *)

open ExtString

let string_contains substr str =
  try String.find str substr; true
  with String.Invalid_string -> false

let string_of_char = String.make 1

let truncate n str =
  if String.length str < n then str else String.sub str 0 (n-1)

(* These versions only work in the C locale for 7-bit characters. *)
let isspace c =
  c = ' '
  (* || c = '\f' *) || c = '\n' || c = '\r' || c = '\t' (* || c = '\v' *)

let isalpha c =
  c >= 'a' && c <= 'z' || c >= 'A' && c <= 'Z'

let isdigit c =
  c >= '0' && c <= '9'

let isalnum c =
  c >= '0' && c <= '9' || c >= 'a' && c <= 'z' || c >= 'A' && c <= 'Z'

let islower c =
  c >= 'a' && c <= 'z'

let isupper c =
  c >= 'A' && c <= 'Z'

let isxdigit c =
  c >= '0' && c <= '9' || c >= 'a' && c <= 'f' || c >= 'A' && c <= 'F'

let triml ?(test = isspace) str =
  let i = ref 0 in
  let n = ref (String.length str) in
  while !n > 0 && test str.[!i]; do
    decr n;
    incr i
  done;
  if !i = 0 then str
  else String.sub str !i !n

let trimr ?(test = isspace) str =
  let n = ref (String.length str) in
  while !n > 0 && test str.[!n-1]; do
    decr n
  done;
  if !n = String.length str then str
  else String.sub str 0 !n

let trim ?(test = isspace) str =
  trimr (triml str)

let string_for_all f str =
  let len = String.length str in
  let rec loop i =
    if i = len then true
    else (
      let c = str.[i] in
      if not (f c) then false
      else loop (i+1)
    )
  in
  loop 0

let string_exists f str =
  let len = String.length str in
  let rec loop i =
    if i = len then false
    else (
      let c = str.[i] in
      if f c then true
      else loop (i+1)
    )
  in
  loop 0

let string_is_whitespace = string_for_all isspace