forked from bartvdbraak/blender
be2186ad62
Policy here is a bit more complicated, if tree becomes too deep we're forced to create a leaf node and size of that leaf wouldn't be so well predicted, which means it's quite tricky to use single stack array for that. Made it more official feature that StackAllocator will fall-back to heap when running out of stack memory. It's still much better than always using heap allocator.
160 lines
3.0 KiB
C++
160 lines
3.0 KiB
C++
/*
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* Copyright 2011-2016 Blender Foundation
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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#ifndef __UTIL_STACK_ALLOCATOR_H__
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#define __UTIL_STACK_ALLOCATOR_H__
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#include <cstddef>
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#include <memory>
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#include "util_debug.h"
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#include "util_types.h"
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CCL_NAMESPACE_BEGIN
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/* Stack allocator for the use with STL. */
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template <int SIZE, typename T>
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class ccl_try_align(16) StackAllocator {
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public:
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typedef size_t size_type;
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typedef ptrdiff_t difference_type;
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typedef T *pointer;
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typedef const T *const_pointer;
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typedef T& reference;
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typedef const T& const_reference;
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typedef T value_type;
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/* Allocator construction/destruction. */
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StackAllocator()
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: pointer_(0) {}
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StackAllocator(const StackAllocator&)
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: pointer_(0) {}
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template <class U>
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StackAllocator(const StackAllocator<SIZE, U>&)
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: pointer_(0) {}
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/* Memory allocation/deallocation. */
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T *allocate(size_t n, const void *hint = 0)
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{
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(void)hint;
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if(n == 0) {
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return NULL;
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}
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if(pointer_ + n >= SIZE) {
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size_t size = n * sizeof(T);
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util_guarded_mem_alloc(size);
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#ifdef WITH_BLENDER_GUARDEDALLOC
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return (T*)MEM_mallocN_aligned(size, 16, "Cycles Alloc");
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#else
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return (T*)malloc(size);
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#endif
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}
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T *mem = &data_[pointer_];
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pointer_ += n;
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return mem;
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}
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void deallocate(T *p, size_t n)
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{
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if(p == NULL) {
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return;
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}
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if(p < data_ || p >= data_ + SIZE) {
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util_guarded_mem_free(n * sizeof(T));
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#ifdef WITH_BLENDER_GUARDEDALLOC
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MEM_freeN(p);
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#else
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free(p);
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#endif
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return;
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}
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/* We don't support memory free for the stack allocator. */
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}
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/* Address of an reference. */
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T *address(T& x) const
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{
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return &x;
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}
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const T *address(const T& x) const
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{
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return &x;
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}
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/* Object construction/destruction. */
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void construct(T *p, const T& val)
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{
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new ((T *)p) T(val);
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}
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void destroy(T *p)
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{
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p->~T();
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}
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/* Maximum allocation size. */
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size_t max_size() const
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{
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return size_t(-1);
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}
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/* Rebind to other ype of allocator. */
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template <class U>
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struct rebind {
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typedef StackAllocator<SIZE, U> other;
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};
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/* Operators */
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template <class U>
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inline StackAllocator& operator=(const StackAllocator<SIZE, U>&)
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{
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return *this;
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}
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StackAllocator<SIZE, T>& operator=(const StackAllocator&)
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{
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return *this;
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}
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inline bool operator==(StackAllocator const& /*other*/) const
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{
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return true;
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}
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inline bool operator!=(StackAllocator const& other) const
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{
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return !operator==(other);
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}
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private:
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int pointer_;
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T data_[SIZE];
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};
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CCL_NAMESPACE_END
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#endif /* __UTIL_GUARDED_ALLOCATOR_H__ */
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