spot/spot/misc/mspool.hh
Alexandre Duret-Lutz 0ab8dc06c4 install back the safety check of includes.test
Compilation of each header file alone, as a safety check, was removed
when introducing "#pragma once" because we did not have to check for
possible double inclusion.  However we still need to compile each
header to make sure they are self-contained.

* tests/sanity/includes.test: Compile each header.
* tests/run.in: Export various compiler and directory flags.
* spot/twaalgos/emptiness_stats.hh, spot/misc/mspool.hh,
spot/misc/fixpool.hh: Include <spot/misc/common.hh>.
* spot/misc/common.hh: Include <cassert>.
* NEWS: Mention the fixed headers.
2016-12-02 15:03:43 +01:00

126 lines
3.4 KiB
C++

// -*- coding: utf-8 -*-
// Copyright (C) 2011, 2013, 2015, 2016 Laboratoire de Recherche et
// Developpement de l'Epita (LRDE)
//
// This file is part of Spot, a model checking library.
//
// Spot 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 3 of the License, or
// (at your option) any later version.
//
// Spot 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, see <http://www.gnu.org/licenses/>.
#pragma once
#include <spot/misc/common.hh>
#include <spot/misc/hash.hh>
#include <new>
#include <cstddef>
#include <cstdlib>
namespace spot
{
/// A multiple-size memory pool implementation.
class multiple_size_pool
{
static const size_t alignment_ = 2 * sizeof(size_t) - 1;
public:
/// Create a pool.
multiple_size_pool()
: free_start_(nullptr), free_end_(nullptr), chunklist_(nullptr)
{
}
/// Free any memory allocated by this pool.
~multiple_size_pool()
{
while (chunklist_)
{
chunk_* prev = chunklist_->prev;
free(chunklist_);
chunklist_ = prev;
}
}
size_t fixsize(size_t size) const
{
if (size < sizeof(block_))
size = sizeof(block_);
return (size + alignment_ - 1) & ~(alignment_ - 1);
}
/// Allocate \a size bytes of memory.
void*
allocate(size_t size)
{
size = fixsize(size);
block_*& f = freelist_[size];
// If we have free blocks available, return the first one.
if (f)
{
block_* first = f;
f = f->next;
return first;
}
// Else, create a block out of the last chunk of allocated
// memory.
// If all the last chunk has been used, allocate one more.
if (free_start_ + size > free_end_)
{
const size_t requested = (size > 128 ? size : 128) * 8192 - 64;
chunk_* c = reinterpret_cast<chunk_*>(malloc(requested));
if (!c)
throw std::bad_alloc();
c->prev = chunklist_;
chunklist_ = c;
free_start_ = c->data_ + size;
free_end_ = c->data_ + requested;
}
void* res = free_start_;
free_start_ += size;
return res;
}
/// \brief Recycle \a size bytes of memory.
///
/// Despite the name, the memory is not really deallocated in the
/// "delete" sense: it is still owned by the pool and will be
/// reused by allocate as soon as possible. The memory is only
/// freed when the pool is destroyed.
///
/// The size argument should be the same as the one passed to
/// allocate().
void
deallocate (const void* ptr, size_t size)
{
SPOT_ASSERT(ptr);
size = fixsize(size);
block_* b = reinterpret_cast<block_*>(const_cast<void*>(ptr));
block_*& f = freelist_[size];
b->next = f;
f = b;
}
private:
struct block_ { block_* next; };
std::unordered_map<size_t, block_*> freelist_;
char* free_start_;
char* free_end_;
// chunk = several agglomerated blocks
union chunk_ { chunk_* prev; char data_[1]; }* chunklist_;
};
}