/*
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* Copyright 2007 Nouveau Project
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*
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* Permission is hereby granted, free of charge, to any person obtaining a
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* copy of this software and associated documentation files (the "Software"),
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* to deal in the Software without restriction, including without limitation
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* the rights to use, copy, modify, merge, publish, distribute, sublicense,
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* and/or sell copies of the Software, and to permit persons to whom the
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* Software is furnished to do so, subject to the following conditions:
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*
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* The above copyright notice and this permission notice shall be included in
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* all copies or substantial portions of the Software.
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*
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* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
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* THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR
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* OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
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* ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
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* OTHER DEALINGS IN THE SOFTWARE.
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*/
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#ifndef __NOUVEAU_HEAP_H__
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#define __NOUVEAU_HEAP_H__
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/* This datastructure represents a memory allocation heap. Fundamentally, this
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* is a doubly-linked list with a few properties, and a usage convention.
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*
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* On initial allocation, there is a single node with the full size that's
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* marked as not in-use. As allocations are made, blocks are taken off the end
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* of that first node, and inserted right after it. If the first node doesn't
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* have enough free space, we look for free space down in the rest of the
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* list. This can happen if an allocation is made and then freed.
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*
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* The first node will remain with in_use == 0 even if the whole heap is
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* exhausted. Another invariant is that there will never be two sequential
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* in_use == 0 nodes. If a node is freed and it has one (or both) adjacent
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* free nodes, they are merged into one, and the relevant heap entries are
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* freed.
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*
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* The pattern to free the whole heap is to start with the first node and then
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* just free the "next" node, until there is no next node. This should assure
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* that at the end the first (and only) node is not in use and contains the
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* full size of the heap.
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*/
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struct nouveau_heap {
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struct nouveau_heap *prev;
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struct nouveau_heap *next;
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void *priv;
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unsigned start;
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unsigned size;
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int in_use;
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};
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int
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nouveau_heap_init(struct nouveau_heap **heap, unsigned start,
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unsigned size);
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void
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nouveau_heap_destroy(struct nouveau_heap **heap);
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int
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nouveau_heap_alloc(struct nouveau_heap *heap, unsigned size, void *priv,
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struct nouveau_heap **);
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void
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nouveau_heap_free(struct nouveau_heap **);
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#endif
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