Reading and writing to/from gzip compressed files
This module provides functions to read and write compressed data
to/from files in gzip format.
Abstract type representing a channel opened for reading from a compressed file.
Open a compressed file for reading. The argument is the file name.
Open a compressed file for reading. The argument is a regular file channel already opened on the compressed file.
Uncompress one character from the given channel, and return it.
Raise End_of_file if no more compressed data is available.
Same as Gzip.input_char, but return the 8-bit integer
representing the character.
Raise End_of_file if no more compressed data is available.
input ic buf pos len uncompresses up to len characters
from the given channel ic,
storing them in string buf, starting at character number pos.
It returns the actual number of characters read, between 0 and
len (inclusive).
A return value of 0 means that the end of file was reached.
A return value between 0 and len exclusive means that
not all requested len characters were read, either because
no more characters were available at that time, or because
the implementation found it convenient to do a partial read;
input must be called again to read the remaining characters,
if desired. (See also Gzip.really_input for reading
exactly len characters.)
Exception Invalid_argument "Gzip.input" is raised if
pos and len do not designate a valid substring of buf.
really_input ic buf pos len uncompresses len characters
from the given channel, storing them in
string buf, starting at character number pos.
Raise End_of_file if fewer than len characters can be read.
Raise Invalid_argument "Gzip.input" if
pos and len do not designate a valid substring of buf.
Close the given input channel. If the channel was created with
Gzip.open_in_chan, the underlying regular file channel
(of type Pervasives.in_channel) is also closed.
Do not apply any of the functions above to a closed channel.
Same as Gzip.close_in, but does not close the underlying
regular file channel (of type Pervasives.in_channel);
just dispose of the resources associated with the decompression
channel. This can be useful if e.g. the underlying file channel
is a network socket on which more (uncompressed) data
is expected.
Abstract type representing a channel opened for writing to a compressed file.
Open a compressed file for writing. The argument is the file
name. The file is created if it does not exist, or
truncated to zero length if it exists.
The optional level argument (an integer between 1 and 9)
indicates the compression level, with 1 being the weakest
(but fastest) compression and 9 being the strongest
(but slowest) compression. The default level is 6
(medium compression).
Open a compressed file for writing. The argument is a
regular file channel already opened on the compressed file.
The optional level argument sets the compression level
as documented for Gzip.open_out.
Same as Gzip.output_char, but the output character is given
by its code. The given integer is taken modulo 256.
output oc buf pos len compresses and writes len characters
from string buf, starting at offset pos, and writes the
compressed data to the channel oc.
Raise Invalid_argument "Gzip.output" if
pos and len do not designate a valid substring of buf.
Close the given output channel. If the channel was created with
Gzip.open_out_chan, the underlying regular file channel
(of type Pervasives.out_channel) is also closed.
Do not apply any of the functions above to a closed channel.
Same as Gzip.close_out, but do not close the underlying
regular file channel (of type Pervasives.out_channel);
just flush all pending compressed data and
dispose of the resources associated with the compression
channel. This can be useful if e.g. the underlying file channel
is a network socket on which more data is to be sent.
Exception raised by the functions above to signal errors during compression or decompression, or ill-formed input files.