106 lines
3.1 KiB
C++
106 lines
3.1 KiB
C++
/*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License
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* as published by the Free Software Foundation; either version 2
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* of the License, or (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software Foundation,
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* Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
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*/
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#ifndef __BLI_ALLOCATOR_HH__
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#define __BLI_ALLOCATOR_HH__
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/** \file
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* \ingroup bli
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*
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* This file offers a couple of memory allocators that can be used with containers such as Vector
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* and Map. Note that these allocators are not designed to work with standard containers like
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* std::vector.
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*
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* Also see http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2007/n2271.html for why the standard
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* allocators are not a good fit applications like Blender. The current implementations in this
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* file are fairly simple still, more complexity can be added when necessary. For now they do their
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* job good enough.
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*/
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#include <algorithm>
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#include <stdlib.h>
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#include "MEM_guardedalloc.h"
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#include "BLI_math_base.h"
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#include "BLI_utildefines.h"
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namespace BLI {
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/**
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* Use Blenders guarded allocator (aka MEM_malloc). This should always be used except there is a
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* good reason not to use it.
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*/
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class GuardedAllocator {
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public:
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void *allocate(uint size, const char *name)
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{
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return MEM_mallocN(size, name);
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}
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void *allocate_aligned(uint size, uint alignment, const char *name)
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{
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return MEM_mallocN_aligned(size, alignment, name);
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}
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void deallocate(void *ptr)
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{
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MEM_freeN(ptr);
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}
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};
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/**
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* This is a simple wrapper around malloc/free. Only use this when the GuardedAllocator cannot be
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* used. This can be the case when the allocated element might live longer than Blenders Allocator.
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*/
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class RawAllocator {
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private:
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struct MemHead {
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int offset;
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};
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public:
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void *allocate(uint size, const char *UNUSED(name))
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{
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void *ptr = malloc(size + sizeof(MemHead));
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((MemHead *)ptr)->offset = sizeof(MemHead);
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return POINTER_OFFSET(ptr, sizeof(MemHead));
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}
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void *allocate_aligned(uint size, uint alignment, const char *UNUSED(name))
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{
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BLI_assert(is_power_of_2_i((int)alignment));
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void *ptr = malloc(size + alignment + sizeof(MemHead));
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void *used_ptr = (void *)((uintptr_t)POINTER_OFFSET(ptr, alignment + sizeof(MemHead)) &
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~((uintptr_t)alignment - 1));
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uint offset = (uint)((uintptr_t)used_ptr - (uintptr_t)ptr);
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BLI_assert(offset >= sizeof(MemHead));
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((MemHead *)used_ptr - 1)->offset = (int)offset;
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return used_ptr;
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}
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void deallocate(void *ptr)
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{
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MemHead *head = (MemHead *)ptr - 1;
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int offset = -head->offset;
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void *actual_pointer = POINTER_OFFSET(ptr, offset);
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free(actual_pointer);
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}
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};
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} // namespace BLI
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#endif /* __BLI_ALLOCATOR_HH__ */
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