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/* Calculation of various derived store fields
Copyright (C) 1995, 1996 Free Software Foundation, Inc.
Written by Miles Bader <miles@gnu.ai.mit.edu>
This file is part of the GNU Hurd.
The GNU Hurd 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, or (at
your option) any later version.
The GNU Hurd 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., 675 Mass Ave, Cambridge, MA 02139, USA. */
#include "store.h"
/* Fills in the values of the various fields in STORE that are derivable from
the set of runs & the block size. */
void
_store_derive (struct store *store)
{
unsigned i;
off_t *runs = store->runs;
unsigned runs_len = store->runs_len;
size_t bsize = store->block_size;
/* BLOCK & SIZE */
store->blocks = 0;
for (i = 0; i < runs_len; i += 2)
{
store->wrap_src += runs[i + 1];
if (runs[i] >= 0)
store->blocks += runs[i + 1];
}
if (store->end == 0)
/* END not set; set it using the info from RUNS. */
store->end = store->wrap_src;
else if (store->wrap_src < store->end)
/* A wrapped disk! RUNS is repeated N times to reach END. Adjust BLOCKS
to include all iterations. */
{
size_t num_iters = store->end / store->wrap_src;
off_t last_part_base = num_iters * store->wrap_src;
store->blocks *= num_iters;
for (i = 0; i < runs_len; i += 2)
if (last_part_base + runs[i + 1] < store->end)
{
store->blocks += store->end - (last_part_base + runs[i + 1]);
break;
}
else if (runs[i] >= 0)
store->blocks += runs[i + 1];
/* WRAP_DST must be set by the caller. */
}
store->size = store->end * bsize;
/* LOG2_BLOCK_SIZE */
store->log2_block_size = 0;
while ((1 << store->log2_block_size) < bsize)
store->log2_block_size++;
if ((1 << store->log2_block_size) != bsize)
store->log2_block_size = 0;
/* LOG2_BLOCKS_PER_PAGE */
store->log2_blocks_per_page = 0;
while ((bsize << store->log2_blocks_per_page) < vm_page_size)
store->log2_blocks_per_page++;
if ((bsize << store->log2_blocks_per_page) != vm_page_size)
store->log2_blocks_per_page = 0;
}
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