sys/fs/ntfs/ntfs_compr.c

   1 /*      $NetBSD: ntfs_compr.c,v 1.4 2008/01/29 18:21:10 pooka 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  *      Id: ntfs_compr.c,v 1.4 1999/05/12 09:42:54 semenu Exp
  29  */
  30
  31 #include <sys/cdefs.h>
  32 __KERNEL_RCSID(0, "$NetBSD: ntfs_compr.c,v 1.4 2008/01/29 18:21:10 pooka Exp $");
  33
  34 #include <sys/param.h>
  35 #include <sys/systm.h>
  36 #include <sys/namei.h>
  37 #include <sys/proc.h>
  38 #include <sys/kernel.h>
  39 #include <sys/vnode.h>
  40 #include <sys/mount.h>
  41 #include <sys/buf.h>
  42 #include <sys/file.h>
  43 #include <sys/malloc.h>
  44
  45 #include <miscfs/specfs/specdev.h>
  46
  47 #include <fs/ntfs/ntfs.h>
  48 #include <fs/ntfs/ntfs_compr.h>
  49
  50 #define GET_UINT16(addr)        (*((u_int16_t *)(addr)))
  51
  52 int
  53 ntfs_uncompblock(
  54         u_int8_t * dbuf,
  55         u_int8_t * cbuf)
  56 {
  57         u_int32_t       ctag;
  58         int             len, dshift, lmask;
  59         int             blen, boff;
  60         int             i, j;
  61         int             pos, cpos;
  62
  63         len = GET_UINT16(cbuf) & 0xFFF;
  64         dprintf(("ntfs_uncompblock: block length: %d + 3, 0x%x,0x%04x\n",
  65             len, len, GET_UINT16(cbuf)));
  66
  67         if (!(GET_UINT16(cbuf) & 0x8000)) {
  68                 if ((len + 1) != NTFS_COMPBLOCK_SIZE) {
  69                         dprintf(("ntfs_uncompblock: len: %x instead of %d\n",
  70                             len, 0xfff));
  71                 }
  72                 memcpy(dbuf, cbuf + 2, len + 1);
  73                 memset(dbuf + len + 1, 0, NTFS_COMPBLOCK_SIZE - 1 - len);
  74                 return len + 3;
  75         }
  76         cpos = 2;
  77         pos = 0;
  78         while ((cpos < len + 3) && (pos < NTFS_COMPBLOCK_SIZE)) {
  79                 ctag = cbuf[cpos++];
  80                 for (i = 0; (i < 8) && (pos < NTFS_COMPBLOCK_SIZE); i++) {
  81                         if (ctag & 1) {
  82                                 for (j = pos - 1, lmask = 0xFFF, dshift = 12;
  83                                      j >= 0x10; j >>= 1) {
  84                                         dshift--;
  85                                         lmask >>= 1;
  86                                 }
  87                                 boff = -1 - (GET_UINT16(cbuf + cpos) >> dshift);
  88                                 blen = 3 + (GET_UINT16(cbuf + cpos) & lmask);
  89                                 for (j = 0; (j < blen) && (pos < NTFS_COMPBLOCK_SIZE); j++) {
  90                                         dbuf[pos] = dbuf[pos + boff];
  91                                         pos++;
  92                                 }
  93                                 cpos += 2;
  94                         } else {
  95                                 dbuf[pos++] = cbuf[cpos++];
  96                         }
  97                         ctag >>= 1;
  98                 }
  99         }
 100         return len + 3;
 101 }
 102
 103 int
 104 ntfs_uncompunit(
 105         struct ntfsmount * ntmp,
 106         u_int8_t * uup,
 107         u_int8_t * cup)
 108 {
 109         int             i;
 110         int             off = 0;
 111         int             new;
 112
 113         for (i = 0; i * NTFS_COMPBLOCK_SIZE < ntfs_cntob(NTFS_COMPUNIT_CL); i++) {
 114                 new = ntfs_uncompblock(uup + i * NTFS_COMPBLOCK_SIZE, cup + off);
 115                 if (new == 0)
 116                         return (EINVAL);
 117                 off += new;
 118         }
 119         return (0);
 120 }