30aa951db8
instead of `string-append`-ing the extension, because that doesn't work for all path strings
54 lines
2.2 KiB
Racket
54 lines
2.2 KiB
Racket
#lang scribble/doc
|
|
@(require "common.rkt" (for-label file/gzip))
|
|
|
|
@title[#:tag "gzip"]{@exec{gzip} Compression and File Creation}
|
|
|
|
@defmodule[file/gzip]{The @racketmodname[file/gzip] library provides
|
|
utilities to create archive files in @exec{gzip} format, or simply to
|
|
compress data using the @exec{pkzip} ``deflate'' method.}
|
|
|
|
@defproc[(gzip [in-file path-string?]
|
|
[out-file path-string? (path-add-extension in-file ".gz" #".")])
|
|
void?]{
|
|
|
|
Compresses data to the same format as the @exec{gzip} utility, writing
|
|
the compressed data directly to a file. The @racket[in-file] argument
|
|
is the name of the file to compress. If the file named by
|
|
@racket[out-file] exists, it will be overwritten.
|
|
|
|
@history[#:changed "6.8.0.2"
|
|
@elem{Changed default expression of @racket[out-file] to use
|
|
@racket[path-add-extension] instead of @racket[string-append].}]}
|
|
|
|
|
|
@defproc[(gzip-through-ports [in input-port?]
|
|
[out output-port?]
|
|
[orig-filename (or/c string? false/c)]
|
|
[timestamp exact-integer?])
|
|
void?]{
|
|
|
|
Reads the port @racket[in] for data and compresses it to @racket[out],
|
|
outputting the same format as the @exec{gzip} utility. The
|
|
@racket[orig-filename] string is embedded in this output;
|
|
@racket[orig-filename] can be @racket[#f] to omit the filename from
|
|
the compressed stream. The @racket[timestamp] number is also embedded
|
|
in the output stream, as the modification date of the original file
|
|
(in Unix seconds, as @racket[file-or-directory-modify-seconds] would
|
|
report on Unix).}
|
|
|
|
|
|
@defproc[(deflate [in input-port?]
|
|
[out output-port?])
|
|
(values exact-nonnegative-integer?
|
|
exact-nonnegative-integer?
|
|
exact-nonnegative-integer?)]{
|
|
|
|
Writes @exec{pkzip}-format ``deflated'' data to the port @racket[out],
|
|
compressing data from the port @racket[in]. The data in a file
|
|
created by @exec{gzip} uses this format (preceded with header
|
|
information).
|
|
|
|
The result is three values: the number of bytes read from @racket[in],
|
|
the number of bytes written to @racket[out], and a cyclic redundancy
|
|
check (CRC) value for the input.}
|