zip_set_file_compression(3)

1ZIP_SET_FILE_COMPRESS... BSD Library Functions Manual ZIP_SET_FILE_COMPRESS...
2

NAME

4     zip_set_file_compression — set compression method for file in zip
5

LIBRARY

7     libzip (-lzip)
8

SYNOPSIS

10     #include <zip.h>
11
12     int
13     zip_set_file_compression(zip_t *archive, zip_uint64_t index,
14         zip_int32_t comp, zip_uint32_t comp_flags);
15

DESCRIPTION

17     The zip_set_file_compression() function sets the compression method for
18     the file at position index in the zip archive to comp with the compres‐
19     sion method specific comp_flags.  The comp is the same as returned by
20     zip_stat(3).  For the comp argument, currently only the following values
21     are supported:
22
23     ZIP_CM_DEFAULT     default compression; currently the same as
24                        ZIP_CM_DEFLATE, but flags are ignored.
25
26     ZIP_CM_STORE       Store the file uncompressed.
27
28     ZIP_CM_BZIP2       Compress the file using the bzip2(1) algorithm.
29
30     ZIP_CM_DEFLATE     Deflate the file with the zlib(3) algorithm and de‐
31                        fault options.
32
33     ZIP_CM_XZ          Use the xz(1) algorithm for compression
34
35     ZIP_CM_ZSTD        Use the zstd(1) algorithm for compression
36
37     NOTE: Only the deflate and store methods can be assumed to be universally
38     supported.
39
40     The comp_flags argument defines the compression level.  This value is de‐
41     pendent on the compression algorithm.  In general, lower numbers mean
42     faster de/compression and higher numbers mean slower de/compression.  For
43     ZIP_CM_BZIP, ZIP_CM_DEFLATE, and ZIP_CM_XZ 1 is the fastest compression
44     and 9 the best, 0 chooses the default.  For ZIP_CM_ZSTD possible values
45     are ZSTD_minCLevel(3) to ZSTD_maxCLevel(3); negative values must be cast
46     to zip_uint32_t.
47
48     Further compression method specific flags might be added over time.
49
50     The current compression method for a file in a zip archive can be deter‐
51     mined using zip_stat(3).
52

RETURN VALUES

54     Upon successful completion 0 is returned.  Otherwise, -1 is returned and
55     the error information in archive is set to indicate the error.
56

ERRORS

58     zip_set_file_compression() fails if:
59
60     [ZIP_ER_COMPNOTSUPP]
61                        Unsupported compression method requested.
62
63     [ZIP_ER_INVAL]     index is not a valid file index in archive, or the ar‐
64                        gument combination is invalid.
65
66     [ZIP_ER_RDONLY]    Read-only zip file, no changes allowed.
67

HISTORY

72     zip_set_file_compression() was added in libzip 0.11.
73

AUTHORS

75     Dieter Baron <dillo@nih.at> and Thomas Klausner <tk@giga.or.at>
76
77BSD                            February 2, 2023                            BSD