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/*
* 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.
*/
#ifndef __BLI_ALLOCATOR_H__
#define __BLI_ALLOCATOR_H__
/** \file
* \ingroup bli
*
* This file offers a couple of memory allocators that can be used with containers such as Vector
* and Map. Note that these allocators are not designed to work with standard containers like
* std::vector.
*
* Also see http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2007/n2271.html for why the standard
* allocators are not a good fit applications like Blender. The current implementations in this
* file are fairly simple still, more complexity can be added when necessary. For now they do their
* job good enough.
*/
#include <stdlib.h>
#include <algorithm>
#include "MEM_guardedalloc.h"
#include "BLI_utildefines.h"
#include "BLI_math_base.h"
#include "BLI_temporary_allocator.h"
namespace BLI {
/**
* Use Blenders guarded allocator (aka MEM_malloc). This should always be used except there is a
* good reason not to use it.
*/
class GuardedAllocator {
public:
void *allocate(uint size, const char *name)
{
return MEM_mallocN(size, name);
}
void *allocate_aligned(uint size, uint alignment, const char *name)
{
alignment = std::max<uint>(alignment, 8);
return MEM_mallocN_aligned(size, alignment, name);
}
void deallocate(void *ptr)
{
MEM_freeN(ptr);
}
};
/**
* This is a simple wrapper around malloc/free. Only use this when the GuardedAllocator cannot be
* used. This can be the case when the allocated element might live longer than Blenders Allocator.
*/
class RawAllocator {
private:
struct MemHead {
int offset;
};
public:
void *allocate(uint size, const char *UNUSED(name))
{
void *ptr = malloc(size + sizeof(MemHead));
((MemHead *)ptr)->offset = sizeof(MemHead);
return POINTER_OFFSET(ptr, sizeof(MemHead));
}
void *allocate_aligned(uint size, uint alignment, const char *UNUSED(name))
{
BLI_assert(is_power_of_2_i((int)alignment));
void *ptr = malloc(size + alignment + sizeof(MemHead));
void *used_ptr = (void *)((uintptr_t)POINTER_OFFSET(ptr, alignment + sizeof(MemHead)) &
~((uintptr_t)alignment - 1));
uint offset = (uint)((uintptr_t)used_ptr - (uintptr_t)ptr);
BLI_assert(offset >= sizeof(MemHead));
((MemHead *)used_ptr - 1)->offset = (int)offset;
return used_ptr;
}
void deallocate(void *ptr)
{
MemHead *head = (MemHead *)ptr - 1;
int offset = -head->offset;
void *actual_pointer = POINTER_OFFSET(ptr, offset);
free(actual_pointer);
}
};
/**
* Use this only under specific circumstances as described in BLI_temporary_allocator.h.
*/
class TemporaryAllocator {
public:
void *allocate(uint size, const char *UNUSED(name))
{
return BLI_temporary_allocate(size);
}
void *allocate_aligned(uint size, uint alignment, const char *UNUSED(name))
{
BLI_assert(alignment <= 64);
UNUSED_VARS_NDEBUG(alignment);
return BLI_temporary_allocate(size);
}
void deallocate(void *ptr)
{
BLI_temporary_deallocate(ptr);
}
};
} // namespace BLI
#endif /* __BLI_ALLOCATOR_H__ */
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