zzip_fopen(3) zziplib Function List zzip_fopen(3)
NAME
zzip_fopen, zzip_freopen - start usage.
SYNOPSIS
#include <zzip/lib.h>
ZZIP_FILE*
zzip_fopen(zzip_char_t* filename, zzip_char_t* mode)
ZZIP_FILE*
zzip_freopen(zzip_char_t* filename, zzip_char_t* mode, ZZIP_FILE* stream)
DESCRIPTION
The zzip_fopen function will fopen(3) 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).
unlike the posix-wrapper zzip_open the mode-argument is a string which
allows for more freedom to support the extra zzip modes called
ZZIP_CASEINSENSITIVE and ZZIP_IGNOREPATH. Currently, this zzip_fopen
call will convert the following characters in the mode-string into
their corrsponding mode-bits:
"r" : O_RDONLY : read-only
"b" : O_BINARY : binary (win32 specific)
"f" : O_NOCTTY : no char device (unix)
"i" : ZZIP_CASELESS : inside zip file
"*" : ZZIP_NOPATHS : inside zip file only
all other modes will be ignored for zip-contained entries but they are
transferred for compatibility and portability, including these extra
sugar bits:
"x" : O_EXCL : fail if file did exist
"s" : O_SYNC : synchronized access
"n" : O_NONBLOCK : nonblocking access
"z#" : compression level : for zlib
"g#" : group access : unix access bits
"u#" : owner access : unix access bits
"o#" : world access : unix access bits
... the access bits are in traditional unix bit format with 7 =
read/write/execute, 6 = read/write, 4 = read-only.
The default access mode is 0664, and the compression level is ignored
since the lib can not yet write zip files, otherwise it would be the
initialisation value for the zlib deflateInit where 0 = no-compression,
1 = best-speed, 9 = best-compression.
The zzip_fopen function returns a new zzip-handle (use zzip_close to
return it). On error the zzip_fopen function will return null setting
errno(3).
The zzip_freopen function receives an additional argument pointing to
a ZZIP_FILE* being already in use. If this extra argument is null then
the zzip_freopen function is identical with calling zzip_fopen
Per default, the old file stream is closed and only the internal
structures associated with it are kept. These internal structures may
be reused for the return value, and this is a lot quicker when the
filename matches a zipped file that is incidentally in the very same
zip arch as the old filename wrapped in the stream struct.
That's simply because the zip arch's central directory does not need
to be read again. As an extension for the zzip_freopen function, if the
mode-string contains a "q" then the old stream is not closed but left
untouched, instead it is only given as a hint that a new file handle
may share/copy the zip arch structures of the old file handle if that
is possible, i.e when they are in the same zip arch.
The zzip_freopen function returns a new zzip-handle (use zzip_close to
return it). On error the zzip_freopen 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)
SEE ALSO
fopen(2)
zziplib 0.13.74 zzip_fopen(3)
libzzip 0.13.74 - Generated Sat Mar 23 07:02:44 CDT 2024