FreeBSD/Linux Kernel Cross Reference
sys/ufs/lfs/lfs_cksum.c

     /*      $NetBSD: lfs_cksum.c,v 1.24 2004/03/09 07:43:49 yamt Exp $      */
     
     /*-
      * Copyright (c) 1999, 2000, 2001, 2002 The NetBSD Foundation, Inc.
      * All rights reserved.
      *
      * This code is derived from software contributed to The NetBSD Foundation
      * by Konrad E. Schroder <perseant@hhhh.org>.
      *
     * 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.
     * 3. All advertising materials mentioning features or use of this software
     *    must display the following acknowledgement:
     *      This product includes software developed by the NetBSD
     *      Foundation, Inc. and its contributors.
     * 4. Neither the name of The NetBSD Foundation nor the names of its
     *    contributors may be used to endorse or promote products derived
     *    from this software without specific prior written permission.
     *
     * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
     * ``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 FOUNDATION OR CONTRIBUTORS
     * 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.
     */
    /*-
     * Copyright (c) 1991, 1993
     *      The Regents of the University of California.  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.
     * 3. Neither the name of the University nor the names of its contributors
     *    may be used to endorse or promote products derived from this software
     *    without specific prior written permission.
     *
     * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``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 REGENTS OR CONTRIBUTORS 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.
     *
     *      @(#)lfs_cksum.c 8.2 (Berkeley) 10/9/94
     */
    
    #include <sys/cdefs.h>
    __KERNEL_RCSID(0, "$NetBSD: lfs_cksum.c,v 1.24 2004/03/09 07:43:49 yamt Exp $");
    
    #include <sys/param.h>
    #ifdef _KERNEL
    # include <sys/systm.h>
    # include <sys/lock.h>
    #else
    # include <stddef.h>
    #endif
    #include <sys/mount.h>
    #include <ufs/ufs/inode.h>
    #include <ufs/lfs/lfs.h>
    #include <ufs/lfs/lfs_extern.h>
    
    /*
     * Simple, general purpose, fast checksum.  Data must be short-aligned.
     * Returns a u_long in case we ever want to do something more rigorous.
     *
     * XXX
     * Use the TCP/IP checksum instead.
     */
    u_int32_t
    lfs_cksum_part(void *str, size_t len, u_int32_t sum)
    {
            
            len &= ~(sizeof(u_int16_t) - 1);
            for (; len; len -= sizeof(u_int16_t)) {
                    sum ^= *(u_int16_t *)str;
                    str = (void *)((u_int16_t *)str + 1);
            }
           return (sum);
   }
   
   u_int32_t
   cksum(void *str, size_t len)
   {
   
           return lfs_cksum_fold(lfs_cksum_part(str, len, 0));
   }
   
   u_int32_t
   lfs_sb_cksum(struct dlfs *fs)
   {
           size_t size;  
           
           size = (size_t)offsetof(struct dlfs, dlfs_cksum);
           return cksum(fs, size);
   }

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