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/*
* Copyright 2009 Nicolai Hähnle <nhaehnle@gmail.com>
*
* 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
* on the rights to use, copy, modify, merge, publish, distribute, sub
* license, 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 (including the next
* paragraph) 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 NON-INFRINGEMENT. IN NO EVENT SHALL
* THE AUTHOR(S) AND/OR THEIR SUPPLIERS 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 MEMORY_POOL_H
#define MEMORY_POOL_H
struct memory_block;
/**
* Provides a pool of memory that can quickly be allocated from, at the
* cost of being unable to explicitly free one of the allocated blocks.
* Instead, the entire pool can be freed at once.
*
* The idea is to allow one to quickly allocate a flexible amount of
* memory during operations like shader compilation while avoiding
* reference counting headaches.
*/
struct memory_pool {
unsigned char * head;
unsigned char * end;
unsigned int total_allocated;
struct memory_block * blocks;
};
void memory_pool_init(struct memory_pool * pool);
void memory_pool_destroy(struct memory_pool * pool);
void * memory_pool_malloc(struct memory_pool * pool, unsigned int bytes);
/**
* Generic helper for growing an array that has separate size/count
* and reserved counters to accomodate up to num new element.
*
* type * Array;
* unsigned int Size;
* unsigned int Reserved;
*
* memory_pool_array_reserve(pool, type, Array, Size, Reserved, k);
* assert(Size + k < Reserved);
*
* \note Size is not changed by this macro.
*
* \warning Array, Size, Reserved have to be lvalues and may be evaluated
* several times.
*/
#define memory_pool_array_reserve(pool, type, array, size, reserved, num) do { \
unsigned int _num = (num); \
if ((size) + _num > (reserved)) { \
unsigned int newreserve = (reserved) * 2; \
type * newarray; \
if (newreserve < _num) \
newreserve = 4 * _num; /* arbitrary heuristic */ \
newarray = memory_pool_malloc((pool), newreserve * sizeof(type)); \
memcpy(newarray, (array), (size) * sizeof(type)); \
(array) = newarray; \
(reserved) = newreserve; \
} \
} while(0)
#endif /* MEMORY_POOL_H */
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