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/*
* libhfs - library for reading and writing Macintosh HFS volumes
*
* The iterator shown here iterates over the blocks of a fork.
*
* Copyright (C) 2000 Klaus Halfmann <khalfmann@libra.de>
* Original work by 1996-1998 Robert Leslie <rob@mars.org>
* other work 2000 from Brad Boyer (flar@pants.nu)
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street - Fifth Floor, Boston,
* MA 02110-1301, USA.
*
* $Id: blockiter.c,v 1.2 2000/10/17 05:58:46 hasi Exp $
*/
#include "config.h"
#include "libhfsp.h"
#include "blockiter.h"
#include "volume.h"
#include "record.h"
#include "btree.h"
#include "os.h"
#include "swab.h"
#include "hfstime.h"
/* Initialize iterator for a given fork */
void
blockiter_init(blockiter* b, volume* vol, hfsp_fork_raw* f,
UInt8 forktype, UInt32 fileId)
{
b->vol = vol;
b->curr_block = 0;
b->block = 0;
b->max_block = f->total_blocks;
b->fileId = fileId;
b->index = 0;
b->file = f->extents;
b->e = f->extents;
b->forktype = forktype;
b->in_extent = 0;
}
/* get next extent record when needed */
static int
blockiter_next_extent(blockiter *b)
{
btree* extents_tree = volume_get_extents_tree(b->vol);
int err;
b->index = 0;
if (b->in_extent) // already using extents record ?
{
err = record_next_extent(&b->er);
// Hope there is no need to check this ...
// if (b->er.key.start_block != b->curr_block)
// HFSP_ERROR(ENOENT,
// "Extents record inconistent");
}
else
{
err = record_init_file(&b->er, extents_tree, b->forktype,
b->fileId, b->curr_block);
b->in_extent = -1; // true
}
b->e = b->er.extent;
return err;
}
/* find next block of the fork iterating over */
int
blockiter_next(blockiter *b)
{
b->curr_block ++;
b->block ++;
if (b->curr_block >= b->max_block)
return -1; // end of Blocks, but no error
// in current part of extent ?
if (b->block >= b->e->block_count)
{
b->index++;
b->block = 0; // reset relative position
b->e++;
if (b -> index >= 8) // need to fetch another extent
{
if (blockiter_next_extent(b))
HFSP_ERROR(ENOENT, "Extends record not found.");
}
}
return 0;
fail:
return -1;
}
/* skip the indicated number of blocks */
int
blockiter_skip(blockiter *b, UInt32 skip)
{
while (skip > 0)
{
// Skip to skip or end of current extent
UInt32 diff = b->e->block_count - b->block;
if (skip < diff)
{
diff = skip;
skip = 0;
}
else
skip -= diff;
b->curr_block += diff;
b->block += diff;
if (b->curr_block >= b->max_block)
return -1; // end of Blocks, but no error
if (b->block >= b->e->block_count)
{
b->index++;
b->block = 0; // reset relative position
b->e++;
if (b -> index >= 8) // need to fetch another extent
{
if (blockiter_next_extent(b))
HFSP_ERROR(ENOENT, "Extends record not found.");
}
}
} // we are here when skip was null, thats ok
return 0;
fail:
return -1;
}
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