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_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.
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_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.
AUTHOR
ยท Guido Draheim <guidod@gmx.de>
COPYRIGHT
Copyright (c) 2003,2004,2006 Guido Draheim All rights reserved, use
under the restrictions of the Lesser GNU General Public License or
alternatively the restrictions of the Mozilla Public License 1.1