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/***************************************************************************
* lib/mng/disk_allocator.cpp
*
* Part of the STXXL. See http://stxxl.sourceforge.net
*
* Copyright (C) 2002 Roman Dementiev <dementiev@mpi-sb.mpg.de>
* Copyright (C) 2008, 2010 Andreas Beckmann <beckmann@cs.uni-frankfurt.de>
*
* Distributed under the Boost Software License, Version 1.0.
* (See accompanying file LICENSE_1_0.txt or copy at
* http://www.boost.org/LICENSE_1_0.txt)
**************************************************************************/
#include <stxxl/bits/common/error_handling.h>
#include <stxxl/bits/common/exceptions.h>
#include <stxxl/bits/common/types.h>
#include <stxxl/bits/mng/disk_allocator.h>
#include <stxxl/bits/namespace.h>
#include <stxxl/bits/verbose.h>
#include <cassert>
#include <map>
#include <ostream>
#include <utility>
STXXL_BEGIN_NAMESPACE
void disk_allocator::dump() const
{
int64 total = 0;
sortseq::const_iterator cur = free_space.begin();
STXXL_ERRMSG("Free regions dump:");
for ( ; cur != free_space.end(); ++cur)
{
STXXL_ERRMSG("Free chunk: begin: " << (cur->first) << " size: " << (cur->second));
total += cur->second;
}
STXXL_ERRMSG("Total bytes: " << total);
}
void disk_allocator::deallocation_error(
stxxl::int64 block_pos, stxxl::int64 block_size,
const sortseq::iterator& pred, const sortseq::iterator& succ) const
{
STXXL_ERRMSG("Error deallocating block at " << block_pos << " size " << block_size);
STXXL_ERRMSG(((pred == succ) ? "pred==succ" : "pred!=succ"));
if (pred == free_space.end()) {
STXXL_ERRMSG("pred==free_space.end()");
} else {
if (pred == free_space.begin())
STXXL_ERRMSG("pred==free_space.begin()");
STXXL_ERRMSG("pred: begin=" << pred->first << " size=" << pred->second);
}
if (succ == free_space.end()) {
STXXL_ERRMSG("succ==free_space.end()");
} else {
if (succ == free_space.begin())
STXXL_ERRMSG("succ==free_space.begin()");
STXXL_ERRMSG("succ: begin=" << succ->first << " size=" << succ->second);
}
dump();
}
void disk_allocator::add_free_region(stxxl::int64 block_pos, stxxl::int64 block_size)
{
//assert(block_size);
//dump();
STXXL_VERBOSE2("Deallocating a block with size: " << block_size << " position: " << block_pos);
stxxl::int64 region_pos = block_pos;
stxxl::int64 region_size = block_size;
if (!free_space.empty())
{
sortseq::iterator succ = free_space.upper_bound(region_pos);
sortseq::iterator pred = succ;
if (pred != free_space.begin())
pred--;
if (pred != free_space.end())
{
if (pred->first <= region_pos && pred->first + pred->second > region_pos)
{
STXXL_THROW2(bad_ext_alloc, "disk_allocator::check_corruption", "Error: double deallocation of external memory, trying to deallocate region " << region_pos << " + " << region_size << " in empty space [" << pred->first << " + " << pred->second << "]");
}
}
if (succ != free_space.end())
{
if (region_pos <= succ->first && region_pos + region_size > succ->first)
{
STXXL_THROW2(bad_ext_alloc, "disk_allocator::check_corruption", "Error: double deallocation of external memory, trying to deallocate region " << region_pos << " + " << region_size << " which overlaps empty space [" << succ->first << " + " << succ->second << "]");
}
}
if (succ == free_space.end())
{
if (pred == free_space.end())
{
deallocation_error(block_pos, block_size, pred, succ);
assert(pred != free_space.end());
}
if ((*pred).first + (*pred).second == region_pos)
{
// coalesce with predecessor
region_size += (*pred).second;
region_pos = (*pred).first;
free_space.erase(pred);
}
}
else
{
if (free_space.size() > 1)
{
#if 0
if (pred == succ)
{
deallocation_error(block_pos, block_size, pred, succ);
assert(pred != succ);
}
#endif
bool succ_is_not_the_first = (succ != free_space.begin());
if ((*succ).first == region_pos + region_size)
{
// coalesce with successor
region_size += (*succ).second;
free_space.erase(succ);
//-tb: set succ to pred afterwards due to iterator invalidation
succ = pred;
}
if (succ_is_not_the_first)
{
if (pred == free_space.end())
{
deallocation_error(block_pos, block_size, pred, succ);
assert(pred != free_space.end());
}
if ((*pred).first + (*pred).second == region_pos)
{
// coalesce with predecessor
region_size += (*pred).second;
region_pos = (*pred).first;
free_space.erase(pred);
}
}
}
else
{
if ((*succ).first == region_pos + region_size)
{
// coalesce with successor
region_size += (*succ).second;
free_space.erase(succ);
}
}
}
}
free_space[region_pos] = region_size;
free_bytes += block_size;
//dump();
}
STXXL_END_NAMESPACE
// vim: et:ts=4:sw=4
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