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