NAME

       zzip_open, zzip_open_ext_io, zzip_open_shared_io -  start usage.

SYNOPSIS

       #include <zzip/lib.h>

       ZZIP_FILE *
       zzip_open(zzip_char_t * filename, int o_flags)

       ZZIP_FILE *
       zzip_open_ext_io(zzip_char_t * filename, int o_flags, int o_modes,
                        zzip_strings_t * ext, zzip_plugin_io_t io)

       ZZIP_FILE *
       zzip_open_shared_io(ZZIP_FILE * stream,
                           zzip_char_t * filename, int o_flags, int o_modes,
                           zzip_strings_t * ext, zzip_plugin_io_t io)

DESCRIPTION

        The zzip_open function will open(2) a real/zipped file

        It has some magic functionality builtin - it will first try to open the given
       <emphasis>filename</emphasis> as a normal file. If it does not exist, the given path to
       the filename (if any) is split into its directory-part and the file-part. A ".zip"
       extension is then added to the directory-part to create the name of a zip-archive. That
       zip-archive (if it exists) is being searched for the file-part, and if found a zzip-handle
       is returned.

        Note that if the file is found in the normal fs-directory the returned structure is
       mostly empty and the zzip_read call will use the libc read(2) to obtain data. Otherwise a
       zzip_file_open is performed and any error mapped to errno(3).

        There was a possibility to transfer zziplib-specific openmodes through o_flags but you
       should please not use them anymore and look into zzip_open_ext_io to submit them down. The
       zzip_open function is shallow in that it just extracts the zzipflags and calls

        zzip_open_ext_io(filename, o_flags, zzipflags|0664, 0, 0)

        you must stop using this extra functionality (not well known anyway) since zzip_open
       might be later usable to open files for writing in which case the _EXTRAFLAGS will get in
       conflict.

        compare with open(2) and zzip_fopen

        The zzip_open_ext_io function uses explicit ext and io instead of the internal defaults,
       setting them to zero is equivalent to zzip_open

        note that the two flag types have been split into an o_flags (for fcntl-like openflags)
       and o_modes where the latter shall carry the zzip_flags and possibly accessmodes for unix
       filesystems. Since this version of zziplib can not write zipfiles, it is not yet used for
       anything else than zzip-specific modeflags.

        The zzip_open_ext_io function returns a new zzip-handle (use zzip_close to return it). On
       error the zzip_open_ext_io function will return null setting errno(3).

        If any ext_io handlers were used then the referenced structure should be static as the
       allocated ZZIP_FILE does not copy them.

        The zzip_open_shared_io function takes an extra stream argument - if a handle has been
       then ext/io can be left null and the new stream handle will pick up the ext/io. This
       should be used only in specific environment however since zzip_file_real does not store
       any ext-sequence.

        The benefit for the zzip_open_shared_io function comes in when the old file handle was
       openened from a file within a zip archive. When the new file is in the same zip archive
       then the internal zzip_dir structures will be shared. It is even quicker, as no check
       needs to be done anymore trying to guess the zip archive place in the filesystem, here we
       just check whether the zip archive's filepath is a prefix part of the filename to be
       opened.

        Note that the zzip_open_shared_io function is also used by zzip_freopen that will unshare
       the old handle, thereby possibly closing the handle.

        The zzip_open_shared_io function returns a new zzip-handle (use zzip_close to return it).
       On error the zzip_open_shared_io function will return null setting errno(3).

AUTHOR

        Guido Draheim <guidod@gmx.de> Tomi Ollila <Tomi.Ollila@iki.fi>

COPYRIGHT

        Copyright (c) Guido Draheim, use under copyleft (LGPL,MPL)