linux-stable/fs/squashfs/decompressor.h
Phillip Lougher 846b730e99 Squashfs: Generalise paging handling in the decompressors
Further generalise the decompressors by adding a page handler
abstraction.  This adds helpers to allow the decompressors
to access and process the output buffers in an implementation
independant manner.

This allows different types of output buffer to be passed
to the decompressors, with the implementation specific
aspects handled at decompression time, but without the
knowledge being held in the decompressor wrapper code.

This will allow the decompressors to handle Squashfs
cache buffers, and page cache pages.

This patch adds the abstraction and an implementation for
the caches.

Signed-off-by: Phillip Lougher <phillip@squashfs.org.uk>
Reviewed-by: Minchan Kim <minchan@kernel.org>
2013-11-20 03:59:01 +00:00

57 lines
1.8 KiB
C

#ifndef DECOMPRESSOR_H
#define DECOMPRESSOR_H
/*
* Squashfs - a compressed read only filesystem for Linux
*
* Copyright (c) 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009
* Phillip Lougher <phillip@squashfs.org.uk>
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version 2,
* or (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
*
* decompressor.h
*/
struct squashfs_decompressor {
void *(*init)(struct squashfs_sb_info *, void *);
void *(*comp_opts)(struct squashfs_sb_info *, void *, int);
void (*free)(void *);
int (*decompress)(struct squashfs_sb_info *, void *,
struct buffer_head **, int, int, int,
struct squashfs_page_actor *);
int id;
char *name;
int supported;
};
static inline void *squashfs_comp_opts(struct squashfs_sb_info *msblk,
void *buff, int length)
{
return msblk->decompressor->comp_opts ?
msblk->decompressor->comp_opts(msblk, buff, length) : NULL;
}
#ifdef CONFIG_SQUASHFS_XZ
extern const struct squashfs_decompressor squashfs_xz_comp_ops;
#endif
#ifdef CONFIG_SQUASHFS_LZO
extern const struct squashfs_decompressor squashfs_lzo_comp_ops;
#endif
#ifdef CONFIG_SQUASHFS_ZLIB
extern const struct squashfs_decompressor squashfs_zlib_comp_ops;
#endif
#endif