NAME

       zip_set_file_compression — set compression method for file in zip

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

       The zip_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.

AUTHORS

       Dieter Baron <dillo@nih.at> and Thomas Klausner <wiz@gatalith.at>

Debian                                          February 2, 2023                     ZIP_SET_FILE_COMPRESSION(3)