freebsd-skq/lib/libarchive/archive_read_support_format_empty.c
Tim Kientzle 056e26b45e Thanks to Christoph Mallon for pointing out the dead variable here.
Also, rework this a little to make the logic excruciatingly clear.
2009-04-12 05:38:35 +00:00

96 lines
2.9 KiB
C

/*-
* Copyright (c) 2003-2007 Tim Kientzle
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR(S) ``AS IS'' AND ANY EXPRESS OR
* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
* IN NO EVENT SHALL THE AUTHOR(S) BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#include "archive_platform.h"
__FBSDID("$FreeBSD$");
#include "archive.h"
#include "archive_entry.h"
#include "archive_private.h"
#include "archive_read_private.h"
static int archive_read_format_empty_bid(struct archive_read *);
static int archive_read_format_empty_read_data(struct archive_read *,
const void **, size_t *, off_t *);
static int archive_read_format_empty_read_header(struct archive_read *,
struct archive_entry *);
int
archive_read_support_format_empty(struct archive *_a)
{
struct archive_read *a = (struct archive_read *)_a;
int r;
r = __archive_read_register_format(a,
NULL,
NULL,
archive_read_format_empty_bid,
NULL,
archive_read_format_empty_read_header,
archive_read_format_empty_read_data,
NULL,
NULL);
return (r);
}
static int
archive_read_format_empty_bid(struct archive_read *a)
{
ssize_t avail;
(void)__archive_read_ahead(a, 1, &avail);
/* Bid 1 if we successfully read exactly zero bytes. */
if (avail == 0)
return (1);
/* Otherwise, we don't bid on this. */
return (-1);
}
static int
archive_read_format_empty_read_header(struct archive_read *a,
struct archive_entry *entry)
{
(void)a; /* UNUSED */
(void)entry; /* UNUSED */
a->archive.archive_format = ARCHIVE_FORMAT_EMPTY;
a->archive.archive_format_name = "Empty file";
return (ARCHIVE_EOF);
}
static int
archive_read_format_empty_read_data(struct archive_read *a,
const void **buff, size_t *size, off_t *offset)
{
(void)a; /* UNUSED */
(void)buff; /* UNUSED */
(void)size; /* UNUSED */
(void)offset; /* UNUSED */
return (ARCHIVE_EOF);
}