1 /* 2 * Copyright 2009 Nicolai Hhnle <nhaehnle (at) 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 */ 81
