NAME

       zzip_disk_findfile, zzip_disk_findfirst, zzip_disk_findnext, zzip_disk_findmatch -  search
       for files in the (mmapped) zip central directory

SYNOPSIS

       #include <zzip/mmapped.h>

       struct zzip_disk_entry *
       zzip_disk_findfile(ZZIP_DISK * disk, char *filename,
                          struct zzip_disk_entry *after, zzip_strcmp_fn_t compare)

       struct zzip_disk_entry *
       zzip_disk_findfirst(ZZIP_DISK * disk)

       struct zzip_disk_entry *
       zzip_disk_findnext(ZZIP_DISK * disk, struct zzip_disk_entry *entry)

       struct zzip_disk_entry *
       zzip_disk_findmatch(ZZIP_DISK * disk, char *filespec,
                           struct zzip_disk_entry *after,
                           zzip_fnmatch_fn_t compare, int flags)

DESCRIPTION

        The zzip_disk_findfile function is given a filename as an additional argument, to find
       the disk_entry matching a given filename. The compare-function is usually strcmp or
       strcasecmp or perhaps strcoll, if null then strcmp is used. - use null as argument for
       "after"-entry when searching the first matching entry, otherwise the last returned value
       if you look for other entries with a special "compare" function (if null then a doubled
       search is rather useless with this variant of _findfile).

        The zzip_disk_findfile functionreturns the entry pointer. The zzip_disk_findfile function
       may return null on error. (errno = ENOMEM|EBADMSG|ENOENT)

        The zzip_disk_findfirst function is the first call of all the zip access functions here.
       It contains the code to find the first entry of the zip central directory. Here we require
       the mmapped block to represent a real zip file where the disk_trailer is _last_ in the
       file area, so that its position would be at a fixed offset from the end of the file area
       if not for the comment field allowed to be of variable length (which needs us to do a
       little search for the disk_tailer). However, in this simple implementation we disregard
       any disk_trailer info telling about multidisk archives, so we just return a pointer to the
       zip central directory.

        For an actual means, we are going to search backwards from the end of the mmaped block
       looking for the PK-magic signature of a disk_trailer. If we see one then we check the
       rootseek value to find the first disk_entry of the root central directory. If we find the
       correct PK-magic signature of a disk_entry over there then we assume we are done and we
       are going to return a pointer to that label.

        The return value is a pointer to the first zzip_disk_entry being checked to be within the
       bounds of the file area specified by the arguments. If no disk_trailer was found then null
       is returned, and likewise we only accept a disk_trailer with a seekvalue that points to a
       disk_entry and both parts have valid PK-magic parts. Beyond some sanity check we try to
       catch a common brokeness with zip archives that still allows us to find the start of the
       zip central directory.So the zzip_disk_findfirst function may return null and sets errno.

        The zzip_disk_findnext function takes an existing disk_entry in the central root
       directory (e.g. from zzip_disk_findfirst) and returns the next entry within in the given
       bounds of the mmapped file area.

        The zzip_disk_findnext function returns null if no next entry can be found. The
       zzip_disk_findnext function may return null on errors. (errno = ENOENT|EINVAL|EBADMSG)

        The zzip_disk_findmatch function uses a compare-function with an additional argument and
       it is called just like fnmatch(3) from POSIX.2 AD:1993), i.e. the argument filespec first
       and the ziplocal filename second with the integer-flags put in as third to the indirect
       call. If the platform has fnmatch available then null-compare will use that one and
       otherwise we fall back to mere strcmp, so if you need fnmatch searching then please
       provide an implementation somewhere else. - use null as argument for "after"-entry when
       searching the first matching entry, or the last disk_entry return-value to find the next
       entry matching the given filespec.

        The zzip_disk_findmatch function will return the matching entry pointer. The
       zzip_disk_findmatch function may return null on error. (errno = ENOMEM|EBADMSG|ENOENT)

AUTHOR

        Guido Draheim <guidod@gmx.de>

COPYRIGHT

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