zip_source_seek_compute_offset — validate arguments and compute offset

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

Debian                                          December 18, 2017              ZIP_SOURCE_SEEK_COMPUTE_OFFSET(3)

       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.

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.

zip_source_seek_compute_offset() was added in libzip 1.0.

       libzip (-lzip)

       zip_source_seek_compute_offset — validate arguments and compute offset

       On success, it returns the new offset, on error it returns -1 and sets error.

zip_source_function(3)

#include<zip.h>zip_int64_tzip_source_seek_compute_offset(zip_uint64_toffset,     zip_uint64_tlength,     void*data,
           zip_uint64_tdata_length, zip_error_t*error);