| .\" 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> |
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| .Dd June 18, 2021 |
| .Dt ZIP_SET_FILE_COMPRESSION 3 |
| .Os |
| .Sh NAME |
| .Nm zip_set_file_compression |
| .Nd set compression method for file in zip |
| .Sh LIBRARY |
| libzip (-lzip) |
| .Sh SYNOPSIS |
| .In zip.h |
| .Ft int |
| .Fn zip_set_file_compression "zip_t *archive" "zip_uint64_t index" "zip_int32_t comp" "zip_uint32_t comp_flags" |
| .Sh DESCRIPTION |
| The |
| .Fn zip_set_file_compression |
| function sets the compression method for the file at position |
| .Ar index |
| in the zip archive to |
| .Ar comp |
| with the compression method specific |
| .Ar comp_flags . |
| The |
| .Ar comp |
| is the same as returned by |
| .Xr zip_stat 3 . |
| For the |
| .Ar comp |
| argument, currently only the following values are supported: |
| .Bl -tag -width ZIP_CM_DEFLATE_XX |
| .It Dv ZIP_CM_DEFAULT |
| default compression; currently the same as |
| .Dv ZIP_CM_DEFLATE , |
| but |
| .Ar flags |
| are ignored. |
| .It Dv ZIP_CM_STORE |
| Store the file uncompressed. |
| .It Dv ZIP_CM_BZIP2 |
| Compress the file using the |
| .Xr bzip2 1 |
| algorithm. |
| .It Dv ZIP_CM_DEFLATE |
| Deflate the file with the |
| .Xr zlib 3 |
| algorithm and default options. |
| .It Dv ZIP_CM_XZ |
| Use the |
| .Xr xz 1 |
| algorithm for compression |
| .It Dv ZIP_CM_ZSTD |
| Use the |
| .Xr zstd 1 |
| algorithm for compression |
| .El |
| .Pp |
| .Em NOTE : |
| Only the deflate and store methods can be assumed to be universally |
| supported. |
| .Pp |
| The |
| .Ar 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 |
| .Dv ZIP_CM_BZIP , |
| .Dv ZIP_CM_DEFLATE , |
| and |
| .Dv ZIP_CM_XZ |
| 1 is the fastest compression and 9 the best, 0 chooses the default. |
| For |
| .Dv ZIP_CM_ZSTD |
| possible values are |
| .Xr ZSTD_minCLevel 3 |
| to |
| .Xr 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 |
| .Xr zip_stat 3 . |
| .Sh RETURN VALUES |
| Upon successful completion 0 is returned. |
| Otherwise, \-1 is returned and the error information in |
| .Ar archive |
| is set to indicate the error. |
| .Sh ERRORS |
| .Fn zip_set_file_compression |
| fails if: |
| .Bl -tag -width Er |
| .It Bq Er ZIP_ER_COMPNOTSUPP |
| Unsupported compression method requested. |
| .It Bq Er ZIP_ER_INVAL |
| .Ar index |
| is not a valid file index in |
| .Ar archive , |
| or the argument combination is invalid. |
| .It Bq Er ZIP_ER_RDONLY |
| Read-only zip file, no changes allowed. |
| .El |
| .Sh SEE ALSO |
| .Xr libzip 3 , |
| .Xr zip_compression_method_supported 3 , |
| .Xr zip_stat 3 |
| .Sh HISTORY |
| .Fn zip_set_file_compression |
| was added in libzip 0.11. |
| .Sh AUTHORS |
| .An -nosplit |
| .An Dieter Baron Aq Mt dillo@nih.at |
| and |
| .An Thomas Klausner Aq Mt tk@giga.or.at |