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/* ntfscomp.c - compression support for the NTFS filesystem */
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* Copyright (C) 2007 Free Software Foundation, Inc.
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* This program is free software: you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation, either version 3 of the License, or
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* (at your option) any later version.
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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* You should have received a copy of the GNU General Public License
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* along with this program. If not, see <http://www.gnu.org/licenses/>.
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#include <grub/file.h>
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#include <grub/misc.h>
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#include <grub/disk.h>
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#include <grub/fshelp.h>
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#include <grub/ntfs.h>
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decomp_nextvcn (struct grub_ntfs_comp *cc)
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if (cc->comp_head >= cc->comp_tail)
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return grub_error (GRUB_ERR_BAD_FS, "compression block overflown");
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(cc->comp_table[cc->comp_head][1] -
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(cc->comp_table[cc->comp_head][0] - cc->cbuf_vcn)) * cc->spc, 0,
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cc->spc << BLK_SHR, cc->cbuf))
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if ((cc->cbuf_vcn >= cc->comp_table[cc->comp_head][0]))
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decomp_getch (struct grub_ntfs_comp *cc, unsigned char *res)
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if (cc->cbuf_ofs >= (cc->spc << BLK_SHR))
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if (decomp_nextvcn (cc))
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*res = (unsigned char) cc->cbuf[cc->cbuf_ofs++];
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decomp_get16 (struct grub_ntfs_comp *cc, grub_uint16_t * res)
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unsigned char c1 = 0, c2 = 0;
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if ((decomp_getch (cc, &c1)) || (decomp_getch (cc, &c2)))
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*res = ((grub_uint16_t) c2) * 256 + ((grub_uint16_t) c1);
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/* Decompress a block (4096 bytes) */
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decomp_block (struct grub_ntfs_comp *cc, char *dest)
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grub_uint16_t flg, cnt;
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if (decomp_get16 (cc, &flg))
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cnt = (flg & 0xFFF) + 1;
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grub_uint32_t bits, copied;
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bits = copied = tag = 0;
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return grub_error (GRUB_ERR_BAD_FS,
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"compression block too large");
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if (decomp_getch (cc, &tag))
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grub_uint32_t i, len, delta, code, lmask, dshift;
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if (decomp_get16 (cc, &word))
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grub_error (GRUB_ERR_BAD_FS, "nontext window empty");
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for (i = copied - 1, lmask = 0xFFF, dshift = 12; i >= 0x10;
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delta = code >> dshift;
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len = (code & lmask) + 3;
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for (i = 0; i < len; i++)
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dest[copied] = dest[copied - delta - 1];
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unsigned char ch = 0;
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if (decomp_getch (cc, &ch))
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return grub_error (GRUB_ERR_BAD_FS,
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"invalid compression block size");
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n = (cc->spc << BLK_SHR) - cc->cbuf_ofs;
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grub_memcpy (dest, &cc->cbuf[cc->cbuf_ofs], n);
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if ((cnt) && (decomp_nextvcn (cc)))
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read_block (struct grub_ntfs_rlst *ctx, char *buf, int num)
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int cpb = COM_SEC / ctx->comp.spc;
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if ((ctx->target_vcn & 0xF) == 0)
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if (ctx->comp.comp_head != ctx->comp.comp_tail)
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return grub_error (GRUB_ERR_BAD_FS, "invalid compression block");
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ctx->comp.comp_head = ctx->comp.comp_tail = 0;
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ctx->comp.cbuf_vcn = ctx->target_vcn;
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ctx->comp.cbuf_ofs = (ctx->comp.spc << BLK_SHR);
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if (ctx->target_vcn >= ctx->next_vcn)
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if (grub_ntfs_read_run_list (ctx))
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while (ctx->target_vcn + 16 > ctx->next_vcn)
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if (ctx->flags & RF_BLNK)
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ctx->comp.comp_table[ctx->comp.comp_tail][0] = ctx->next_vcn;
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ctx->comp.comp_table[ctx->comp.comp_tail][1] =
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ctx->curr_lcn + ctx->next_vcn - ctx->curr_vcn;
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ctx->comp.comp_tail++;
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if (grub_ntfs_read_run_list (ctx))
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nn = (16 - (unsigned) (ctx->target_vcn & 0xF)) / cpb;
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if (ctx->flags & RF_BLNK)
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ctx->target_vcn += nn * cpb;
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if (ctx->comp.comp_tail == 0)
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grub_memset (buf, 0, nn * COM_LEN);
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if (decomp_block (&ctx->comp, buf))
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while ((ctx->comp.comp_head < ctx->comp.comp_tail) && (nn))
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ctx->comp.comp_table[ctx->comp.comp_head][0] -
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ctx->target_vcn += tt;
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(ctx->comp.comp_table[ctx->comp.comp_head][1] -
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(ctx->comp.comp_table[ctx->comp.comp_head][0] -
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ctx->target_vcn)) * ctx->comp.spc, 0,
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tt * (ctx->comp.spc << BLK_SHR), buf))
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buf += tt * (ctx->comp.spc << BLK_SHR);
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if (ctx->target_vcn >=
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ctx->comp.comp_table[ctx->comp.comp_head][0])
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ctx->comp.comp_head++;
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(ctx->target_vcn - ctx->curr_vcn +
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ctx->curr_lcn) * ctx->comp.spc, 0,
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nn * (ctx->comp.spc << BLK_SHR), buf))
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buf += nn * (ctx->comp.spc << BLK_SHR);
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ctx->target_vcn += nn;
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ntfscomp (struct grub_ntfs_attr *at, char *dest, grub_uint32_t ofs,
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grub_uint32_t len, struct grub_ntfs_rlst *ctx, grub_uint32_t vcn)
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ctx->comp.comp_head = ctx->comp.comp_tail = 0;
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ctx->comp.cbuf = grub_malloc ((ctx->comp.spc) << BLK_SHR);
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//ctx->comp.disk->read_hook = read_hook;
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if ((vcn > ctx->target_vcn) &&
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(ctx, NULL, ((vcn - ctx->target_vcn) * ctx->comp.spc) / COM_SEC)))
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grub_uint32_t t, n, o;
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t = ctx->target_vcn * (ctx->comp.spc << BLK_SHR);
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if (read_block (ctx, at->sbuf, 1))
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grub_memcpy (dest, &at->sbuf[o], n);
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if (read_block (ctx, dest, len / COM_LEN))
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dest += (len / COM_LEN) * COM_LEN;
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t = ctx->target_vcn * (ctx->comp.spc << BLK_SHR);
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if (read_block (ctx, at->sbuf, 1))
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grub_memcpy (dest, at->sbuf, len);
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//ctx->comp.disk->read_hook = 0;
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grub_free (ctx->comp.cbuf);
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GRUB_MOD_INIT (ntfscomp)
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grub_ntfscomp_func = ntfscomp;
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GRUB_MOD_FINI (ntfscomp)
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grub_ntfscomp_func = NULL;