elilo/gzip.h

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/*
* Copyright (C) 2001-2003 Hewlett-Packard Co.
* Contributed by Stephane Eranian <eranian@hpl.hp.com>
*
* This file is part of the ELILO, the EFI Linux boot loader.
*
* ELILO 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.
*
* ELILO 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 ELILO; see the file COPYING. If not, write to the Free
* Software Foundation, 59 Temple Place - Suite 330, Boston, MA
* 02111-1307, USA.
*
* Please check out the elilo.txt for complete documentation on how
* to use this program.
*/
#ifndef __GZIP_H__
#define __GZIP_H__
int gunzip_image(memdesc_t *);
int gunzip_kernel(fops_fd_t, kdesc_t *);
/* gzip flag byte */
#define ASCII_FLAG 0x01 /* bit 0 set: file probably ASCII text */
#define CONTINUATION 0x02 /* bit 1 set: continuation of multi-part gzip file */
#define EXTRA_FIELD 0x04 /* bit 2 set: extra field present */
#define ORIG_NAME 0x08 /* bit 3 set: original file name present */
#define COMMENT 0x10 /* bit 4 set: file comment present */
#define ENCRYPTED 0x20 /* bit 5 set: file is encrypted */
#define RESERVED 0xC0 /* bit 6,7: reserved */
/*
* check for valid gzip signature
* return:
* 0 : valid gzip archive
* -1: invalid gzip archive
*/
static inline int
gzip_probe(unsigned char *buf, unsigned long size)
{
if (size < 4) return -1;
if (buf[0] != 037 ||
((buf[1] != 0213) && (buf[1] != 0236))) return -1;
/* We only support method #8, DEFLATED */
if (buf[2] != 8) return -1;
if ((buf[3] & ENCRYPTED) != 0) return -1;
if ((buf[3] & CONTINUATION) != 0) return -1;
if ((buf[3] & RESERVED) != 0) return -1;
return 0;
}
#endif /* __GZIP_H__ */