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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. */
#include "memory_pool.h"
#include <assert.h>
#include <stdlib.h>
#include <string.h>
#define POOL_LARGE_ALLOC 4096
#define POOL_ALIGN 8
struct memory_block {
struct memory_block * next;
};
void memory_pool_init(struct memory_pool * pool)
{
memset(pool, 0, sizeof(struct memory_pool));
}
void memory_pool_destroy(struct memory_pool * pool)
{
while(pool->blocks) {
struct memory_block * block = pool->blocks;
pool->blocks = block->next;
free(block);
}
}
static void refill_pool(struct memory_pool * pool)
{
unsigned int blocksize = pool->total_allocated;
struct memory_block * newblock;
if (!blocksize)
blocksize = 2*POOL_LARGE_ALLOC;
newblock = malloc(blocksize);
newblock->next = pool->blocks;
pool->blocks = newblock;
pool->head = (unsigned char*)(newblock + 1);
pool->end = ((unsigned char*)newblock) + blocksize;
pool->total_allocated += blocksize;
}
void * memory_pool_malloc(struct memory_pool * pool, unsigned int bytes)
{
if (bytes < POOL_LARGE_ALLOC) {
void * ptr;
if (pool->head + bytes > pool->end)
refill_pool(pool);
assert(pool->head + bytes <= pool->end);
ptr = pool->head;
pool->head += bytes;
pool->head = (unsigned char*)(((unsigned long)pool->head + POOL_ALIGN - 1) & ~(POOL_ALIGN - 1));
return ptr;
} else {
struct memory_block * block = malloc(bytes + sizeof(struct memory_block));
block->next = pool->blocks;
pool->blocks = block;
return (block + 1);
}
}
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