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Annotation of sys/ntfs/ntfs_compr.c, Revision 1.1

1.1     ! nbrk        1: /*     $OpenBSD: ntfs_compr.c,v 1.2 2003/05/20 03:23:11 mickey Exp $   */
        !             2: /*     $NetBSD: ntfs_compr.c,v 1.1 2002/12/23 17:38:31 jdolecek Exp $  */
        !             3:
        !             4: /*-
        !             5:  * Copyright (c) 1998, 1999 Semen Ustimenko
        !             6:  * All rights reserved.
        !             7:  *
        !             8:  * Redistribution and use in source and binary forms, with or without
        !             9:  * modification, are permitted provided that the following conditions
        !            10:  * are met:
        !            11:  * 1. Redistributions of source code must retain the above copyright
        !            12:  *    notice, this list of conditions and the following disclaimer.
        !            13:  * 2. Redistributions in binary form must reproduce the above copyright
        !            14:  *    notice, this list of conditions and the following disclaimer in the
        !            15:  *    documentation and/or other materials provided with the distribution.
        !            16:  *
        !            17:  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
        !            18:  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
        !            19:  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
        !            20:  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
        !            21:  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
        !            22:  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
        !            23:  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
        !            24:  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
        !            25:  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
        !            26:  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
        !            27:  * SUCH DAMAGE.
        !            28:  *
        !            29:  *     Id: ntfs_compr.c,v 1.4 1999/05/12 09:42:54 semenu Exp
        !            30:  */
        !            31:
        !            32: #include <sys/cdefs.h>
        !            33: #ifdef __KERNEL_RCSID
        !            34: __KERNEL_RCSID(0, "$NetBSD: ntfs_compr.c,v 1.1 2002/12/23 17:38:31 jdolecek Exp $");
        !            35: #endif
        !            36:
        !            37: #include <sys/param.h>
        !            38: #include <sys/systm.h>
        !            39: #include <sys/namei.h>
        !            40: #include <sys/proc.h>
        !            41: #include <sys/kernel.h>
        !            42: #include <sys/vnode.h>
        !            43: #include <sys/mount.h>
        !            44: #include <sys/buf.h>
        !            45: #include <sys/file.h>
        !            46: #include <sys/malloc.h>
        !            47: #ifdef __FreeBSD__
        !            48: #include <machine/clock.h>
        !            49: #endif
        !            50:
        !            51: #include <miscfs/specfs/specdev.h>
        !            52:
        !            53: #if defined(__FreeBSD__) || defined(__NetBSD__)
        !            54: #include <fs/ntfs/ntfs.h>
        !            55: #include <fs/ntfs/ntfs_compr.h>
        !            56: #else
        !            57: #include <ntfs/ntfs.h>
        !            58: #include <ntfs/ntfs_compr.h>
        !            59: #endif
        !            60:
        !            61: #define GET_UINT16(addr)       (*((u_int16_t *)(addr)))
        !            62:
        !            63: int
        !            64: ntfs_uncompblock(
        !            65:        u_int8_t * buf,
        !            66:        u_int8_t * cbuf)
        !            67: {
        !            68:        u_int32_t       ctag;
        !            69:        int             len, dshift, lmask;
        !            70:        int             blen, boff;
        !            71:        int             i, j;
        !            72:        int             pos, cpos;
        !            73:
        !            74:        len = GET_UINT16(cbuf) & 0xFFF;
        !            75:        dprintf(("ntfs_uncompblock: block length: %d + 3, 0x%x,0x%04x\n",
        !            76:            len, len, GET_UINT16(cbuf)));
        !            77:
        !            78:        if (!(GET_UINT16(cbuf) & 0x8000)) {
        !            79:                if ((len + 1) != NTFS_COMPBLOCK_SIZE) {
        !            80:                        dprintf(("ntfs_uncompblock: len: %x instead of %d\n",
        !            81:                            len, 0xfff));
        !            82:                }
        !            83:                memcpy(buf, cbuf + 2, len + 1);
        !            84:                bzero(buf + len + 1, NTFS_COMPBLOCK_SIZE - 1 - len);
        !            85:                return len + 3;
        !            86:        }
        !            87:        cpos = 2;
        !            88:        pos = 0;
        !            89:        while ((cpos < len + 3) && (pos < NTFS_COMPBLOCK_SIZE)) {
        !            90:                ctag = cbuf[cpos++];
        !            91:                for (i = 0; (i < 8) && (pos < NTFS_COMPBLOCK_SIZE); i++) {
        !            92:                        if (ctag & 1) {
        !            93:                                for (j = pos - 1, lmask = 0xFFF, dshift = 12;
        !            94:                                     j >= 0x10; j >>= 1) {
        !            95:                                        dshift--;
        !            96:                                        lmask >>= 1;
        !            97:                                }
        !            98:                                boff = -1 - (GET_UINT16(cbuf + cpos) >> dshift);
        !            99:                                blen = 3 + (GET_UINT16(cbuf + cpos) & lmask);
        !           100:                                for (j = 0; (j < blen) && (pos < NTFS_COMPBLOCK_SIZE); j++) {
        !           101:                                        buf[pos] = buf[pos + boff];
        !           102:                                        pos++;
        !           103:                                }
        !           104:                                cpos += 2;
        !           105:                        } else {
        !           106:                                buf[pos++] = cbuf[cpos++];
        !           107:                        }
        !           108:                        ctag >>= 1;
        !           109:                }
        !           110:        }
        !           111:        return len + 3;
        !           112: }
        !           113:
        !           114: int
        !           115: ntfs_uncompunit(
        !           116:        struct ntfsmount * ntmp,
        !           117:        u_int8_t * uup,
        !           118:        u_int8_t * cup)
        !           119: {
        !           120:        int             i;
        !           121:        int             off = 0;
        !           122:        int             new;
        !           123:
        !           124:        for (i = 0; i * NTFS_COMPBLOCK_SIZE < ntfs_cntob(NTFS_COMPUNIT_CL); i++) {
        !           125:                new = ntfs_uncompblock(uup + i * NTFS_COMPBLOCK_SIZE, cup + off);
        !           126:                if (new == 0)
        !           127:                        return (EINVAL);
        !           128:                off += new;
        !           129:        }
        !           130:        return (0);
        !           131: }