(* virt-sysprep
 * Copyright (C) 2010-2012 Red Hat Inc.
 *
 * 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; if not, write to the Free Software Foundation, Inc.,
 * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
 *)

open Printf

module G = Guestfs

let (//) = Filename.concat

let () = Random.self_init ()

let string_prefix str prefix =
  let n = String.length prefix in
  String.length str >= n && String.sub str 0 n = prefix

let rec string_find s sub =
  let len = String.length s in
  let sublen = String.length sub in
  let rec loop i =
    if i <= len-sublen then (
      let rec loop2 j =
        if j < sublen then (
          if s.[i+j] = sub.[j] then loop2 (j+1)
          else -1
        ) else
          i (* found *)
      in
      let r = loop2 0 in
      if r = -1 then loop (i+1) else r
    ) else
      -1 (* not found *)
  in
  loop 0

let rec string_split sep str =
  let len = String.length str in
  let seplen = String.length sep in
  let i = string_find str sep in
  if i = -1 then [str]
  else (
    let s' = String.sub str 0 i in
    let s'' = String.sub str (i+seplen) (len-i-seplen) in
    s' :: string_split sep s''
  )

let string_random8 =
  let chars = "abcdefghijklmnopqrstuvwxyz0123456789" in
  fun () ->
    String.concat "" (
      List.map (
        fun _ ->
          let c = Random.int 36 in
          let c = chars.[c] in
          String.make 1 c
      ) [1;2;3;4;5;6;7;8]
    )

(* Skip any leading '-' characters when comparing command line args. *)
let skip_dashes str =
  let n = String.length str in
  let rec loop i =
    if i >= n then invalid_arg "skip_dashes"
    else if String.unsafe_get str i = '-' then loop (i+1)
    else i
  in
  let i = loop 0 in
  if i = 0 then str
  else String.sub str i (n-i)

let compare_command_line_args a b =
  compare (String.lowercase (skip_dashes a)) (String.lowercase (skip_dashes b))
