zip_set_file_compression
NAME
zip_set_file_compression —
LIBRARY
libzip (-lzip)SYNOPSIS
#include <zip.h>
int
zip_set_file_compression(zip_t
*archive, zip_uint64_t
index, zip_int32_t
comp, zip_uint32_t
comp_flags);
DESCRIPTION
Thezip_set_file_compression() function sets the
compression method for the file at position index in the
zip archive to comp with the compression method specific
comp_flags. The comp is the same
as returned by zip_stat(3). For the
comp argument, currently only the following values are
supported:
ZIP_CM_DEFAULT- default compression; currently the same as
ZIP_CM_DEFLATE, but flags are ignored. ZIP_CM_STORE- Store the file uncompressed.
ZIP_CM_BZIP2- Compress the file using the bzip2(1) algorithm.
ZIP_CM_DEFLATE- Deflate the file with the zlib(3) algorithm and default options.
ZIP_CM_XZ- Use the xz(1) algorithm for compression
ZIP_CM_ZSTD- Use the zstd(1) algorithm for compression
NOTE: Only the deflate and store methods can be assumed to be universally supported.
The comp_flags 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 ZIP_CM_BZIP,
ZIP_CM_DEFLATE, and
ZIP_CM_XZ 1 is the fastest compression and 9 the
best, 0 chooses the default. For ZIP_CM_ZSTD
possible values are
ZSTD_minCLevel(3) to
ZSTD_maxCLevel(3); negative
values must be cast to zip_uint32_t.
Further compression method specific flags might be added over time.
The current compression method for a file in a zip archive can be determined using zip_stat(3).
RETURN VALUES
Upon successful completion 0 is returned. Otherwise, -1 is returned and the error information in archive is set to indicate the error.ERRORS
zip_set_file_compression() fails if:
- [
ZIP_ER_COMPNOTSUPP] - Unsupported compression method requested.
- [
ZIP_ER_INVAL] - index is not a valid file index in archive, or the argument combination is invalid.
- [
ZIP_ER_RDONLY] - Read-only zip file, no changes allowed.
SEE ALSO
libzip(3), zip_compression_method_supported(3), zip_stat(3)HISTORY
zip_set_file_compression() was added in libzip 0.11.