zip_source_seek_compute_offset - validate arguments and compute offset
#include <zip.h> zip_int64_t zip_source_seek_compute_offset(zip_uint64_t offset, zip_uint64_t length, void *data, zip_uint64_t data_length, zip_error_t *error);
ZIP_SOURCE_SEEK_COMPU... BSD Library Functions Manual ZIP_SOURCE_SEEK_COMPU...
NAME
     zip_source_seek_compute_offset -- validate arguments and compute offset
LIBRARY
     libzip (-lzip)
SYNOPSIS
     #include <zip.h>
     zip_int64_t
     zip_source_seek_compute_offset(zip_uint64_t offset, zip_uint64_t length,
         void *data, zip_uint64_t data_length, zip_error_t *error);
DESCRIPTION
     Use this function to compute the offset for a ZIP_SOURCE_SEEK or
     ZIP_SOURCE_SEEK_WRITE command.  data and data_length are the arguments to
     the source callback, offset is the current offset and length is the
     length of the source data or, for ZIP_SOURCE_SEEK_WRITE, the amount of
     data written.
RETURN VALUES
     On success, it returns the new offset, on error it returns -1 and sets
     error.
ERRORS
     zip_source_seek_compute_offset() fails if:
     [ZIP_ER_INVAL]     One of the arguments is invalid or the seek would
                        place the offset outside the data.
ATTRIBUTES
     See attributes(7) for descriptions of the following attributes:
     +---------------+------------------+
     |ATTRIBUTE TYPE | ATTRIBUTE VALUE  |
     +---------------+------------------+
     |Availability   | compress/libzip  |
     +---------------+------------------+
     |Stability      | Volatile         |
     +---------------+------------------+
SEE ALSO
     zip_source_function(3)
HISTORY
     zip_source_seek_compute_offset() was added in libzip 1.0.
AUTHORS
     Dieter Baron <dillo@nih.at> and Thomas Klausner <tk@giga.or.at>
NOTES
     Source code for open source software components in Oracle Solaris can be
     found at https://www.oracle.com/downloads/opensource/solaris-source-code-
     downloads.html.
     This software was built from source available at https://github.com/ora-
     cle/solaris-userland.  The original community source was downloaded from
     https://libzip.org/download/libzip-1.7.3.tar.gz.
     Further information about this software can be found on the open source
     community website at https://libzip.org/.
BSD                            December 18, 2017                           BSD