src/gallium/drivers/r300/compiler/memory_pool.h

   1 /*
   2  * Copyright 2009 Nicolai Hähnle <nhaehnle@gmail.com>
   3  *
   4  * Permission is hereby granted, free of charge, to any person obtaining a
   5  * copy of this software and associated documentation files (the "Software"),
   6  * to deal in the Software without restriction, including without limitation
   7  * on the rights to use, copy, modify, merge, publish, distribute, sub
   8  * license, and/or sell copies of the Software, and to permit persons to whom
   9  * the Software is furnished to do so, subject to the following conditions:
  10  *
  11  * The above copyright notice and this permission notice (including the next
  12  * paragraph) shall be included in all copies or substantial portions of the
  13  * Software.
  14  *
  15  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  16  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  17  * FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT. IN NO EVENT SHALL
  18  * THE AUTHOR(S) AND/OR THEIR SUPPLIERS BE LIABLE FOR ANY CLAIM,
  19  * DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
  20  * OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE
  21  * USE OR OTHER DEALINGS IN THE SOFTWARE. */
  22
  23 #ifndef MEMORY_POOL_H
  24 #define MEMORY_POOL_H
  25
  26 struct memory_block;
  27
  28 /**
  29  * Provides a pool of memory that can quickly be allocated from, at the
  30  * cost of being unable to explicitly free one of the allocated blocks.
  31  * Instead, the entire pool can be freed at once.
  32  *
  33  * The idea is to allow one to quickly allocate a flexible amount of
  34  * memory during operations like shader compilation while avoiding
  35  * reference counting headaches.
  36  */
  37 struct memory_pool {
  38         unsigned char * head;
  39         unsigned char * end;
  40         unsigned int total_allocated;
  41         struct memory_block * blocks;
  42 };
  43
  44
  45 void memory_pool_init(struct memory_pool * pool);
  46 void memory_pool_destroy(struct memory_pool * pool);
  47 void * memory_pool_malloc(struct memory_pool * pool, unsigned int bytes);
  48
  49
  50 /**
  51  * Generic helper for growing an array that has separate size/count
  52  * and reserved counters to accommodate up to num new element.
  53  *
  54  *  type * Array;
  55  *  unsigned int Size;
  56  *  unsigned int Reserved;
  57  *
  58  * memory_pool_array_reserve(pool, type, Array, Size, Reserved, k);
  59  * assert(Size + k < Reserved);
  60  *
  61  * \note Size is not changed by this macro.
  62  *
  63  * \warning Array, Size, Reserved have to be lvalues and may be evaluated
  64  * several times.
  65  */
  66 #define memory_pool_array_reserve(pool, type, array, size, reserved, num) do { \
  67         unsigned int _num = (num); \
  68         if ((size) + _num > (reserved)) { \
  69                 unsigned int newreserve = (reserved) * 2; \
  70                 type * newarray; \
  71                 if (newreserve < _num) \
  72                         newreserve = 4 * _num; /* arbitrary heuristic */ \
  73                 newarray = memory_pool_malloc((pool), newreserve * sizeof(type)); \
  74                 memcpy(newarray, (array), (size) * sizeof(type)); \
  75                 (array) = newarray; \
  76                 (reserved) = newreserve; \
  77         } \
  78 } while(0)
  79
  80 #endif /* MEMORY_POOL_H */