man/zip_set_file_compression.man

.\" Automatically generated from an mdoc input file.  Do not edit.
.\" zip_set_file_compression.mdoc -- set compression method and its flags
.\" Copyright (C) 2012-2021 Dieter Baron and Thomas Klausner
.\"
.\" This file is part of libzip, a library to manipulate ZIP files.
.\" The authors can be contacted at <libzip@nih.at>
.\"
.\" Redistribution and use in source and binary forms, with or without
.\" modification, are permitted provided that the following conditions
.\" are met:
.\" 1. Redistributions of source code must retain the above copyright
.\"    notice, this list of conditions and the following disclaimer.
.\" 2. Redistributions in binary form must reproduce the above copyright
.\"    notice, this list of conditions and the following disclaimer in
.\"    the documentation and/or other materials provided with the
.\"    distribution.
.\" 3. The names of the authors may not be used to endorse or promote
.\"    products derived from this software without specific prior
.\"    written permission.
.\"
.\" THIS SOFTWARE IS PROVIDED BY THE AUTHORS ``AS IS'' AND ANY EXPRESS
.\" OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
.\" WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
.\" ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHORS BE LIABLE FOR ANY
.\" DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE
.\" GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
.\" INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER
.\" IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
.\" OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN
.\" IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
.\"
.TH "ZIP_SET_FILE_COMPRESSION" "3" "June 18, 2021" "NiH" "Library Functions Manual"
.nh
.if n .ad l
.SH "NAME"
\fBzip_set_file_compression\fR
\- set compression method for file in zip
.SH "LIBRARY"
libzip (-lzip)
.SH "SYNOPSIS"
\fB#include <zip.h>\fR
.sp
\fIint\fR
.br
.PD 0
.HP 4n
\fBzip_set_file_compression\fR(\fIzip_t\ *archive\fR, \fIzip_uint64_t\ index\fR, \fIzip_int32_t\ comp\fR, \fIzip_uint32_t\ comp_flags\fR);
.PD
.SH "DESCRIPTION"
The
\fBzip_set_file_compression\fR()
function sets the compression method for the file at position
\fIindex\fR
in the zip archive to
\fIcomp\fR
with the compression method specific
\fIcomp_flags\fR.
The
\fIcomp\fR
is the same as returned by
zip_stat(3).
For the
\fIcomp\fR
argument, currently only the following values are supported:
.TP 19n
\fRZIP_CM_DEFAULT\fR
default compression; currently the same as
\fRZIP_CM_DEFLATE\fR,
but
\fIflags\fR
are ignored.
.TP 19n
\fRZIP_CM_STORE\fR
Store the file uncompressed.
.TP 19n
\fRZIP_CM_BZIP2\fR
Compress the file using the
bzip2(1)
algorithm.
.TP 19n
\fRZIP_CM_DEFLATE\fR
Deflate the file with the
zlib(3)
algorithm and default options.
.TP 19n
\fRZIP_CM_XZ\fR
Use the
xz(1)
algorithm for compression
.TP 19n
\fRZIP_CM_ZSTD\fR
Use the
zstd(1)
algorithm for compression
.PP
\fINOTE\fR:
Only the deflate and store methods can be assumed to be universally
supported.
.PP
The
\fIcomp_flags\fR
argument defines the compression level.
This value is dependent on the compression algorithm.
In general, lower numbers mean faster de/compression and higher
numbers mean slower de/compression.
For
\fRZIP_CM_BZIP\fR,
\fRZIP_CM_DEFLATE\fR,
and
\fRZIP_CM_XZ\fR
1 is the fastest compression and 9 the best, 0 chooses the default.
For
\fRZIP_CM_ZSTD\fR
possible values are
ZSTD_minCLevel(3)
to
ZSTD_maxCLevel(3).
.PP
Further compression method specific flags might be added over time.
.PP
The current compression method for a file in a zip archive can be
determined using
zip_stat(3).
.SH "RETURN VALUES"
Upon successful completion 0 is returned.
Otherwise, \-1 is returned and the error information in
\fIarchive\fR
is set to indicate the error.
.SH "ERRORS"
\fBzip_set_file_compression\fR()
fails if:
.TP 19n
[\fRZIP_ER_COMPNOTSUPP\fR]
Unsupported compression method requested.
.TP 19n
[\fRZIP_ER_INVAL\fR]
\fIindex\fR
is not a valid file index in
\fIarchive\fR,
or the argument combination is invalid.
.TP 19n
[\fRZIP_ER_RDONLY\fR]
Read-only zip file, no changes allowed.
.SH "SEE ALSO"
libzip(3),
zip_compression_method_supported(3),
zip_stat(3)
.SH "HISTORY"
\fBzip_set_file_compression\fR()
was added in libzip 0.11.
.SH "AUTHORS"
Dieter Baron <\fIdillo@nih.at\fR>
and
Thomas Klausner <\fItk@giga.or.at\fR>