zip_source_file, zip_source_file_create — create data source from a file

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

Debian                                            June 30, 2023                               ZIP_SOURCE_FILE(3)

       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().

zip_source_file() and zip_source_file_create() fail if:

       [ZIP_ER_INVAL]     fname, start, or len are invalid.

       [ZIP_ER_MEMORY]    Required memory could not be allocated.

       [ZIP_ER_OPEN]      Opening fname failed.

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.

       libzip (-lzip)

       zip_source_file, zip_source_file_create — create data source from a file

       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.

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

#include<zip.h>zip_source_t*zip_source_file(zip_t*archive, constchar*fname, zip_uint64_tstart, zip_int64_tlen);

       zip_source_t*zip_source_file_create(constchar*fname, zip_uint64_tstart, zip_int64_tlen, zip_error_t*error);