gunzip.c

来自「uboot详细解读可用启动引导LINUX2.6内核」· C语言 代码 · 共 114 行

/*
 * (C) Copyright 2000-2006
 * Wolfgang Denk, DENX Software Engineering, [e-mail].
 *
 * See file CREDITS for list of people who contributed to this
 * project.
 *
 * 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 of
 * the License, 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, Inc., 59 Temple Place, Suite 330, Boston,
 * MA 02111-1307 USA
 */

#include <common.h>
#include <watchdog.h>
#include <command.h>
#include <image.h>
#include <malloc.h>
#include <zlib.h>

#define	ZALLOC_ALIGNMENT	16
#define HEAD_CRC		2
#define EXTRA_FIELD		4
#define ORIG_NAME		8
#define COMMENT			0x10
#define RESERVED		0xe0
#define DEFLATED		8

int gunzip(void *, int, unsigned char *, unsigned long *);
void *zalloc(void *, unsigned, unsigned);
void zfree(void *, void *, unsigned);

void *zalloc(void *x, unsigned items, unsigned size)
{
	void *p;

	size *= items;
	size = (size + ZALLOC_ALIGNMENT - 1) & ~(ZALLOC_ALIGNMENT - 1);

	p = malloc (size);

	return (p);
}

void zfree(void *x, void *addr, unsigned nb)
{
	free (addr);
}

int gunzip(void *dst, int dstlen, unsigned char *src, unsigned long *lenp)
{
	z_stream s;
	int r, i, flags;

	/* skip header */
	i = 10;
	flags = src[3];
	if (src[2] != DEFLATED || (flags & RESERVED) != 0) {
		puts ("Error: Bad gzipped data\n");
		return (-1);
	}
	if ((flags & EXTRA_FIELD) != 0)
		i = 12 + src[10] + (src[11] << 8);
	if ((flags & ORIG_NAME) != 0)
		while (src[i++] != 0)
			;
	if ((flags & COMMENT) != 0)
		while (src[i++] != 0)
			;
	if ((flags & HEAD_CRC) != 0)
		i += 2;
	if (i >= *lenp) {
		puts ("Error: gunzip out of data in header\n");
		return (-1);
	}

	s.zalloc = zalloc;
	s.zfree = zfree;
#if defined(CONFIG_HW_WATCHDOG) || defined(CONFIG_WATCHDOG)
	s.outcb = (cb_func)WATCHDOG_RESET;
#else
	s.outcb = Z_NULL;
#endif	/* CONFIG_HW_WATCHDOG */

	r = inflateInit2(&s, -MAX_WBITS);
	if (r != Z_OK) {
		printf ("Error: inflateInit2() returned %d\n", r);
		return (-1);
	}
	s.next_in = src + i;
	s.avail_in = *lenp - i;
	s.next_out = dst;
	s.avail_out = dstlen;
	r = inflate(&s, Z_FINISH);
	if (r != Z_OK && r != Z_STREAM_END) {
		printf ("Error: inflate() returned %d\n", r);
		return (-1);
	}
	*lenp = s.next_out - (unsigned char *) dst;
	inflateEnd(&s);

	return (0);
}