ntfs_compr.c

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    1 /*      $NetBSD: ntfs_compr.c,v 1.3 1999/07/26 14:02:31 jdolecek Exp $  */
    2 
    3 /*-
    4  * Copyright (c) 1998, 1999 Semen Ustimenko
    5  * All rights reserved.
    6  *
    7  * Redistribution and use in source and binary forms, with or without
    8  * modification, are permitted provided that the following conditions
    9  * are met:
   10  * 1. Redistributions of source code must retain the above copyright
   11  *    notice, this list of conditions and the following disclaimer.
   12  * 2. Redistributions in binary form must reproduce the above copyright
   13  *    notice, this list of conditions and the following disclaimer in the
   14  *    documentation and/or other materials provided with the distribution.
   15  *
   16  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
   17  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
   18  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
   19  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
   20  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
   21  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
   22  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
   23  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
   24  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
   25  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
   26  * SUCH DAMAGE.
   27  *
   28  * $FreeBSD$
   29  */
   30 
   31 #include <sys/param.h>
   32 #include <sys/systm.h>
   33 #include <sys/namei.h>
   34 #include <sys/vnode.h>
   35 #include <sys/mount.h>
   36 #include <sys/file.h>
   37 
   38 #include <fs/ntfs/ntfs.h>
   39 #include <fs/ntfs/ntfs_compr.h>
   40 
   41 #define GET_UINT16(addr)        (*((u_int16_t *)(addr)))
   42 
   43 int
   44 ntfs_uncompblock(
   45         u_int8_t * buf,
   46         u_int8_t * cbuf)
   47 {
   48         u_int32_t       ctag;
   49         int             len, dshift, lmask;
   50         int             blen, boff;
   51         int             i, j;
   52         int             pos, cpos;
   53 
   54         len = GET_UINT16(cbuf) & 0xFFF;
   55         dprintf(("ntfs_uncompblock: block length: %d + 3, 0x%x,0x%04x\n",
   56             len, len, GET_UINT16(cbuf)));
   57 
   58         if (!(GET_UINT16(cbuf) & 0x8000)) {
   59                 if ((len + 1) != NTFS_COMPBLOCK_SIZE) {
   60                         dprintf(("ntfs_uncompblock: len: %x instead of %d\n",
   61                             len, 0xfff));
   62                 }
   63                 memcpy(buf, cbuf + 2, len + 1);
   64                 bzero(buf + len + 1, NTFS_COMPBLOCK_SIZE - 1 - len);
   65                 return len + 3;
   66         }
   67         cpos = 2;
   68         pos = 0;
   69         while ((cpos < len + 3) && (pos < NTFS_COMPBLOCK_SIZE)) {
   70                 ctag = cbuf[cpos++];
   71                 for (i = 0; (i < 8) && (pos < NTFS_COMPBLOCK_SIZE); i++) {
   72                         if (ctag & 1) {
   73                                 for (j = pos - 1, lmask = 0xFFF, dshift = 12;
   74                                      j >= 0x10; j >>= 1) {
   75                                         dshift--;
   76                                         lmask >>= 1;
   77                                 }
   78                                 boff = -1 - (GET_UINT16(cbuf + cpos) >> dshift);
   79                                 blen = 3 + (GET_UINT16(cbuf + cpos) & lmask);
   80                                 for (j = 0; (j < blen) && (pos < NTFS_COMPBLOCK_SIZE); j++) {
   81                                         buf[pos] = buf[pos + boff];
   82                                         pos++;
   83                                 }
   84                                 cpos += 2;
   85                         } else {
   86                                 buf[pos++] = cbuf[cpos++];
   87                         }
   88                         ctag >>= 1;
   89                 }
   90         }
   91         return len + 3;
   92 }
   93 
   94 int
   95 ntfs_uncompunit(
   96         struct ntfsmount * ntmp,
   97         u_int8_t * uup,
   98         u_int8_t * cup)
   99 {
  100         int             i;
  101         int             off = 0;
  102         int             new;
  103 
  104         for (i = 0; i * NTFS_COMPBLOCK_SIZE < ntfs_cntob(NTFS_COMPUNIT_CL); i++) {
  105                 new = ntfs_uncompblock(uup + i * NTFS_COMPBLOCK_SIZE, cup + off);
  106                 if (new == 0)
  107                         return (EINVAL);
  108                 off += new;
  109         }
  110         return (0);
  111 }

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FreeBSD/Linux Kernel Cross Reference sys/fs/ntfs/ntfs_compr.c

FreeBSD/Linux Kernel Cross Reference
sys/fs/ntfs/ntfs_compr.c