1 gzip Compression and File Creation
The file/gzip library provides
utilities to create archive files in gzip format, or simply to
compress data using the pkzip “deflate” method.
Compresses data to the same format as the gzip utility, writing
the compressed data directly to a file. The in-file argument
is the name of the file to compress. If the file named by
out-file exists, it will be overwritten.
Reads the port in for data and compresses it to out,
outputting the same format as the gzip utility. The
orig-filename string is embedded in this output;
orig-filename can be #f to omit the filename from
the compressed stream. The timestamp number is also embedded
in the output stream, as the modification date of the original file
(in Unix seconds, as file-or-directory-modify-seconds would
report under Unix).
Writes pkzip-format “deflated” data to the port out,
compressing data from the port in. The data in a file
created by gzip uses this format (preceded with header
The result is three values: the number of bytes read from in,
the number of bytes written to out, and a cyclic redundancy
check (CRC) value for the input.