(* Guestfs Browser.
 * Copyright (C) 2010 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.
 *)

(** General-purpose utility code used everywhere. *)

val (+^) : int64 -> int64 -> int64
val (-^) : int64 -> int64 -> int64
val ( *^ ) : int64 -> int64 -> int64
val (/^) : int64 -> int64 -> int64
  (** Int64 arithmetic operators. *)

type ('a, 'b) either = Left of 'a | Right of 'b
  (** A value which is either an ['a] or a ['b], just like Haskell's
      "Either" type. *)

val verbose : unit -> bool
val set_verbose_flag : unit -> unit
  (** If this contains [true] then {!debug} will send debugging
      messages to stderr, else debugging messages are dropped.

      This is set through the --verbose command line option. *)

val write_flag : unit -> bool
val set_write_flag : unit -> unit
  (** Writes are prevented unless the user sets this to [true]
      through the command line option --write. *)

val debug : ('a, unit, string, unit) format4 -> 'a
  (** A printf-like function for writing debugging messages. *)

val failwith : ('a, unit, string, 'b) format4 -> 'a
  (** Replacement for standard OCaml [failwith] function.  This can
      take a printf-like argument list, and also logs errors on stderr
      when verbose is enabled. *)

val utf8_rarrow : string (** UTF-8 RIGHTWARDS ARROW *)

val human_size_1k : int64 -> string
  (** Convert a number (of 1K blocks) into a human readable string. *)