Module Zip

module Zip: sig .. end
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 identical to 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 identical to the JAR file format used by Java.



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*)
   extra :string; (*extra information attached to 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.

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
Open the ZIP file with the given filename. 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 -> Pervasives.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.

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
Create (or truncate to zero length) the ZIP file with the given filename. Return a handle opened for writing to this file. The optional argument comment is a comment string that is attached to the ZIP file as a whole (as opposed to the comments that can be attached to individual ZIP entries).
val add_entry : string ->
out_file ->
?extra:string ->
?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. Several optional arguments can be provided to control the format and attached information of the entry:
extra : extra data attached to the entry (a string). Default: empty.
comment : attached to the entry (a string). Default: empty.
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).
mtime : last modification time (in seconds since the epoch). Default: the current time.
val copy_channel_to_entry : Pervasives.in_channel ->
out_file ->
?extra:string ->
?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 ->
?extra:string ->
?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 ->
?extra:string ->
?comment:string ->
?level:int ->
?mtime:float -> string -> (string -> 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 string 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.

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.