(* Basic string functions.
 * Copyright (C) 2004 Merjis Ltd.
 * Written By Richard W.M. Jones (rich@merjis.com)
 * $Id: cocanwiki_strings.ml,v 1.1 2004/09/07 14:58:34 rich Exp $
 *)

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