sys/vfs/ntfs/ntfs_compr.c

   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: src/sys/ntfs/ntfs_compr.c,v 1.7 1999/12/03 20:37:38 semenu Exp $
  29  */
  30
  31 #include <sys/param.h>
  32 #include <sys/systm.h>
  33 #include <sys/proc.h>
  34 #include <sys/namei.h>
  35 #include <sys/kernel.h>
  36 #include <sys/vnode.h>
  37 #include <sys/mount.h>
  38 #include <sys/buf.h>
  39 #include <sys/file.h>
  40 #include <sys/malloc.h>
  41
  42 #include "ntfs.h"
  43 #include "ntfs_compr.h"
  44
  45 #define GET_UINT16(addr)        (*((u_int16_t *)(addr)))
  46
  47 int
  48 ntfs_uncompblock(u_int8_t * buf, u_int8_t * cbuf)
  49 {
  50         u_int32_t       ctag;
  51         int             len, dshift, lmask;
  52         int             blen, boff;
  53         int             i, j;
  54         int             pos, cpos;
  55
  56         len = GET_UINT16(cbuf) & 0xFFF;
  57         dprintf(("ntfs_uncompblock: block length: %d + 3, 0x%x,0x%04x\n",
  58             len, len, GET_UINT16(cbuf)));
  59
  60         if (!(GET_UINT16(cbuf) & 0x8000)) {
  61                 if ((len + 1) != NTFS_COMPBLOCK_SIZE) {
  62                         dprintf(("ntfs_uncompblock: len: %x instead of %d\n",
  63                             len, 0xfff));
  64                 }
  65                 memcpy(buf, cbuf + 2, len + 1);
  66                 bzero(buf + len + 1, NTFS_COMPBLOCK_SIZE - 1 - len);
  67                 return len + 3;
  68         }
  69         cpos = 2;
  70         pos = 0;
  71         while ((cpos < len + 3) && (pos < NTFS_COMPBLOCK_SIZE)) {
  72                 ctag = cbuf[cpos++];
  73                 for (i = 0; (i < 8) && (pos < NTFS_COMPBLOCK_SIZE); i++) {
  74                         if (ctag & 1) {
  75                                 for (j = pos - 1, lmask = 0xFFF, dshift = 12;
  76                                      j >= 0x10; j >>= 1) {
  77                                         dshift--;
  78                                         lmask >>= 1;
  79                                 }
  80                                 boff = -1 - (GET_UINT16(cbuf + cpos) >> dshift);
  81                                 blen = 3 + (GET_UINT16(cbuf + cpos) & lmask);
  82                                 for (j = 0; (j < blen) && (pos < NTFS_COMPBLOCK_SIZE); j++) {
  83                                         buf[pos] = buf[pos + boff];
  84                                         pos++;
  85                                 }
  86                                 cpos += 2;
  87                         } else {
  88                                 buf[pos++] = cbuf[cpos++];
  89                         }
  90                         ctag >>= 1;
  91                 }
  92         }
  93         return len + 3;
  94 }
  95
  96 int
  97 ntfs_uncompunit(
  98         struct ntfsmount * ntmp,
  99         u_int8_t * uup,
 100         u_int8_t * cup)
 101 {
 102         int             i;
 103         int             off = 0;
 104         int             new;
 105
 106         for (i = 0; i * NTFS_COMPBLOCK_SIZE < ntfs_cntob(NTFS_COMPUNIT_CL); i++) {
 107                 new = ntfs_uncompblock(uup + i * NTFS_COMPBLOCK_SIZE, cup + off);
 108                 if (new == 0)
 109                         return (EINVAL);
 110                 off += new;
 111         }
 112         return (0);
 113 }