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dpavlin |
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/* |
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* libhfs - library for reading and writing Macintosh HFS volumes |
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* |
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* The iterator shown here iterates over the blocks of a fork. |
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* |
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* Copyright (C) 2000 Klaus Halfmann <klaus.halfmann@feri.de> |
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* Original work by 1996-1998 Robert Leslie <rob@mars.org> |
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* other work 2000 from Brad Boyer (flar@pants.nu) |
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* |
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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 2 of the License, or |
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* (at your option) any later version. |
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* |
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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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* |
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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, write to the Free Software |
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* Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. |
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* |
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*/ |
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# ifdef HAVE_CONFIG_H |
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# include "config.h" |
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# endif |
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# include <stdlib.h> |
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# include <stdio.h> |
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# include <string.h> |
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# include <time.h> |
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# include <errno.h> |
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# include "libhfsp.h" |
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# include "blockiter.h" |
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# include "volume.h" |
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# include "record.h" |
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# include "btree.h" |
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# include "os.h" |
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# include "hfstime.h" |
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/* Initialize iterator for a given fork */ |
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void blockiter_init(blockiter* b, volume* vol, hfsp_fork_raw* f, |
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UInt8 forktype, UInt32 fileId) |
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{ |
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b->vol = vol; |
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b->curr_block = 0; |
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b->block = 0; |
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b->max_block = f->total_blocks; |
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b->fileId = fileId; |
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b->index = 0; |
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b->file = f->extents; |
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b->e = f->extents; |
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b->forktype = forktype; |
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b->in_extent = 0; |
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} |
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/* get next extent record when needed */ |
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static int blockiter_next_extent(blockiter *b) |
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{ |
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btree* extents_tree = volume_get_extents_tree(b->vol); |
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int err; |
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b->index = 0; |
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if (b->in_extent) // already using extents record ? |
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{ |
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err = record_next_extent(&b->er); |
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// Hope there is no need to check this ... |
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// if (b->er.key.start_block != b->curr_block) |
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// HFSP_ERROR(ENOENT, |
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// "Extents record inconistent"); |
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} |
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else |
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{ |
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err = record_init_file(&b->er, extents_tree, b->forktype, |
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b->fileId, b->curr_block); |
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b->in_extent = -1; // true |
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} |
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b->e = b->er.extent; |
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return err; |
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} |
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/* find next block of the fork iterating over */ |
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int blockiter_next(blockiter *b) |
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{ |
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b->curr_block ++; |
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b->block ++; |
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if (b->curr_block >= b->max_block) |
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return -1; // end of Blocks, but no error |
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// in current part of extent ? |
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if (b->block >= b->e->block_count) |
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{ |
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b->index++; |
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b->block = 0; // reset relative position |
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b->e++; |
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if (b -> index >= 8) // need to fetch another extent |
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{ |
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if (blockiter_next_extent(b)) |
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HFSP_ERROR(ENOENT, "Extends record not found."); |
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} |
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} |
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return 0; |
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fail: |
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return -1; |
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} |
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/* skip the indicated number of blocks */ |
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int blockiter_skip(blockiter *b, UInt32 skip) |
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{ |
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while (skip > 0) |
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{ |
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// Skip to skip or end of current extent |
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UInt32 diff = b->e->block_count - b->block; |
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if (skip < diff) |
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{ |
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diff = skip; |
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skip = 0; |
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} |
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else |
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skip -= diff; |
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b->curr_block += diff; |
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b->block += diff; |
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if (b->curr_block >= b->max_block) |
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return -1; // end of Blocks, but no error |
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if (b->block >= b->e->block_count) |
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{ |
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b->index++; |
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b->block = 0; // reset relative position |
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b->e++; |
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if (b -> index >= 8) // need to fetch another extent |
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{ |
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if (blockiter_next_extent(b)) |
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HFSP_ERROR(ENOENT, "Extends record not found."); |
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} |
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} |
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} // we are here when skip was null, thats ok |
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return 0; |
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fail: |
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return -1; |
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} |
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