zip_source_file

zip_source_file, zip_source_file_create —
create data source from a file

libzip (-lzip)

#include <zip.h>

zip_source_t *
zip_source_file(zip_t *archive, const char *fname, zip_uint64_t start, zip_int64_t len);

zip_source_t *
zip_source_file_create(const char *fname, zip_uint64_t start, zip_int64_t len, zip_error_t *error);

The functions zip_source_file() and zip_source_file_create() create a zip source from a file. They open fname and read len bytes from offset start from it.

When passing ZIP_LENGTH_TO_END (or -1, which is deprecated) as len, zip_source_file determines the file size when it is called and uses that as the expected file size. If the file size grows between creating and reading from the source, the additional data is ignored. If the file shrinks, libzip treats it as an error (ZIP_ER_DATA_LENGTH).

When passing ZIP_LENGTH_UNCHECKED as len, zip_source_file assumes the file's size is unknown. Reading from the source returns as much data as is there at that time (usually when calling zip_close(3)).

libzip can do various optimizations if the size of a source is known when it's created, so ZIP_LENGTH_TO_END is preferable. If you deal with files that are likely to change while you are processing them, you can use the less efficient ZIP_LENGTH_UNCHECKED.

If the file supports seek, the source can be used to open a zip archive from.

The file is opened and read when the data from the source is used, usually by zip_close() or zip_open_from_source().

Upon successful completion, the created source is returned. Otherwise, NULL is returned and the error code in archive or error is set to indicate the error.

zip_source_file() and zip_source_file_create() fail if:
[]
fname, start, or len are invalid.
[]
Required memory could not be allocated.
[]
Opening fname failed.

libzip(3), zip_file_add(3), zip_file_replace(3), zip_source(3)

zip_source_file() and zip_source_file_create() were added in libzip 1.0.

ZIP_LENGTH_TO_END and ZIP_LENGTH_UNCHECKED were added in libzip 1.10.1.

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