(***********************************************************************)
(*                                                                     *)
(*                         The CamlZip library                         *)
(*                                                                     *)
(*            Xavier Leroy, projet Cristal, INRIA Rocquencourt         *)
(*                                                                     *)
(*  Copyright 2001 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, with     *)
(*  the special exception on linking described in file LICENSE.        *)
(*                                                                     *)
(***********************************************************************)

(* $Id$ *)

(** Reading and writing ZIP archives

    This module provides functions for reading and writing ZIP archive
    files.  ZIP archives package one or more compressed files into
    a single ZIP file, along with information about the files,
    including file name, date and time of last modification, user-provided
    comments, and a checksum to verify the integrity of each entry.
    The entries of a ZIP file are not necessarily actual files, and can
    actually consist of arbitrary data.

    The ZIP file format used in this module is compatible with that
    implemented by the popular [pkzip] archiver under Windows,
    and by the Info-ZIP [zip] and [unzip] commands under Unix and Windows.
    This format is also compatible with the JAR file format used by Java. *)

(** {1 Information on ZIP entries} *)

type compression_method =
  | Stored                     (** data is stored without compression *)
  | Deflated                   (** data is compressed with the ``deflate'' algorithm *)
        (** Indicate whether the data in the entry is compressed or not. *)

type entry =
  { filename: string;          (** file name for entry *)
    comment: string;           (** comment attached to entry *)
    methd: compression_method; (** compression method *)
    mtime: float;              (** last modification time (seconds since epoch) *)
    crc: int32;                (** cyclic redundancy check for data *)
    uncompressed_size: int;    (** size of original data in bytes *)
    compressed_size: int;      (** size of compressed data *)
    is_directory: bool;        (** whether this entry represents a directory *)
    file_offset: int64         (** for internal use *)
  }
          (** Description of an entry in a ZIP file. *)

(** {1 Reading from ZIP files} *)

type in_file
          (** Abstract type representing a handle opened for reading from
              a ZIP file. *)
val open_in: string -> in_file
          (** [Zip.open_in zipfilename] opens the ZIP file with the given
              filename.  The file must already exist.
              Return a handle opened for reading from this file. *)
val entries: in_file -> entry list
          (** Return a list of all entries in the given ZIP file. *)
val comment: in_file -> string
          (** Return the comment attached to the given ZIP file, or the
              empty string if none. *)
val find_entry: in_file -> string -> entry
          (** [Zip.find_entry zf filename] returns the description of the
              entry having name [filename] in the ZIP file [zf].
              Raises [Not_found] if no such entry exists.
              The file name must match exactly; in particular, case is
              significant.  File names must use [/] (slash) as the directory
              separator.  The name of a directory must end with a trailing 
              [/] (slash). *)
val read_entry: in_file -> entry -> string
          (** [Zip.read_entry zf e] reads and uncompresses the data
              (file contents) associated with entry [e] of ZIP file [zf].
              The data is returned as a character string. *)
val copy_entry_to_channel: in_file -> entry -> out_channel -> unit
          (** [Zip.copy_entry_to_channel zf e oc] reads and uncompresses
              the data associated with entry [e] of ZIP file [zf].
              It then writes this data to the output channel [oc]. *)
val copy_entry_to_file: in_file -> entry -> string -> unit
          (** [Zip.copy_entry_to_file zf e destfile] reads and uncompresses
              the data associated with entry [e] of ZIP file [zf].
              It then writes this data to the file named [destfile].
              The file [destfile] is created if it does not exist,
              and overwritten otherwise.  The last modification date of
              the file is set to that indicated in the ZIP entry [e],
              if possible. *)
val close_in: in_file -> unit
          (** Close the given ZIP file handle.  If the ZIP file handle was
              created by [open_in_channel], the underlying input channel
              is closed. *)

(** {1 Writing to ZIP files} *)

type out_file
          (** Abstract type representing a handle opened for writing to
              a ZIP file. *)
val open_out: ?comment: string -> string -> out_file
          (** [Zip.open_out zipfilename] creates (or truncates to zero length)
              the ZIP file with the given filename.
              Return a handle opened for writing to this file.
              @param comment  comment string attached to the ZIP file as
                as whole.  Default: empty. *)
val open_update: ?comment: string -> string -> out_file
          (** [Zip.open_update zipfilename] opens the ZIP file with the
              given filename, preserving its contents.  The file must already
              exist.  Return a handle opened for writing to this file.
              Entries added via this handle will be added to the existing
              entries.  If an entry is added with the same file name as
              an existing entry, the old entry becomes inaccessible, only
              the new entry remains.
              @param comment  comment string attached to the ZIP file as
                as whole.  Default: keep the comment that was attached
                to the original ZIP file. *)
val add_entry:
  string -> out_file -> 
    ?comment: string -> ?level: int -> ?mtime: float ->
    string -> unit
          (** [Zip.add_entry data zf name] adds a new entry to the 
              ZIP file [zf].  The data (file contents) associated with
              the entry is taken from the string [data].  It is compressed
              and written to the ZIP file [zf].  [name] is the file name
              stored along with this entry. 

              Under Windows, backslash characters in the [name] parameter
              are stored in the ZIP file as forward slashes [/], for
              compatibility with other operating systems.

              Several optional arguments can be provided to control
              the format and attached information of the entry:
              @param comment  attached to the entry (a string).
                Default: empty.
              @param level  compression level for the entry.  This is an
                integer between 0 and 9, with 0 meaning no compression (store
                as is), 1 lowest compression, 9 highest compression.  Higher
                levels result in smaller compressed data, but longer
                compression times.
                Default: 6 (moderate compression).
              @param mtime  last modification time (in seconds since the
                epoch).
                Default: the current time. *)

val copy_channel_to_entry:
  in_channel -> out_file -> 
    ?comment: string -> ?level: int -> ?mtime: float ->
    string -> unit
          (** Same as [Zip.add_entry], but the data associated with the
              entry is read from the input channel given as first argument.
              The channel is read up to end of file. *)
val copy_file_to_entry:
  string -> out_file -> 
    ?comment: string -> ?level: int -> ?mtime: float ->
    string -> unit
          (** Same as [Zip.add_entry], but the data associated with the
              entry is read from the file whose name is given as first
              argument.  Also, the default value for the [mtime]
              optional parameter is the time of last modification of the
              file. *)
val add_entry_generator:
  out_file ->
    ?comment: string -> ?level: int -> ?mtime: float -> 
    string -> (bytes -> int -> int -> unit) * (unit -> unit)
          (** [Zip.add_entry_generator zf name] returns a pair of functions
              [(add, finish)].  It adds a new entry to the 
              ZIP file [zf].  The file name stored along with this entry
              is [name].  Initially, no data is stored in this entry.
              To store data in this entry, the program must repeatedly call
              the [add] function returned by [Zip.add_entry_generator].
              An invocation [add s ofs len] stores [len] characters of
              byte sequence [s] starting at offset [ofs] in the ZIP entry.
              When all the data forming the entry has been sent, the
              program must call the [finish] function returned by
              [Zip.add_entry_generator].  [finish] must be called exactly once.
              The optional arguments to [Zip.add_entry_generator]
              are as described in {!Zip.add_entry}. *)
val close_out: out_file -> unit
          (** Finish writing the ZIP archive by adding the table of
              contents, and close it. *)

(** {1 Error reporting} *)

exception Error of string * string * string
          (** Exception raised when an ill-formed ZIP archive is encountered,
              or illegal parameters are given to the functions in this
              module.  The exception is of the form
              [Error(ZIP_name, entry_name, message)] where [ZIP_name]
              is the name of the ZIP file, [entry_name] the name of
              the offending entry, and [message] an explanation of the
              error. *)
