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/*
* Copyright (c) 2020 Cisco and/or its affiliates.
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at:
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
/**
* \file pool.c
* \brief Implementation of fixed-size pool allocator
*/
#include <stdlib.h> // calloc
#include "common.h"
#include "pool.h"
/**
* \brief Initialize the pool data structure
* \param [in,out] pool - Pointer to the pool structure storage
* \param [in] elt_size - Size of elements in vector
* \param [in] max_elts - Maximum size
*
* Note that an empty pool might be equal to NULL
*/
void
_pool_init(void ** pool_ptr, size_t elt_size, size_t max_elts)
{
pool_hdr_t * ph = calloc(POOL_HDRLEN + elt_size * max_elts, 1);
if (!ph)
abort();
/* Free indices */
off_t * free_indices;
vector_init(free_indices, max_elts);
uint_fast32_t * fb = ph->free_bitmap;
bitmap_init(fb, max_elts);
bitmap_set_to(fb, max_elts);
for(unsigned i = 0; i < max_elts; i++)
free_indices[i] = (max_elts - 1) - i;
ph->free_indices = free_indices;
*pool_ptr = (uint8_t*)ph + POOL_HDRLEN;
}
void
_pool_free(void ** pool_ptr)
{
free(pool_hdr(*pool_ptr));
*pool_ptr = NULL;
}
void
_pool_resize(void ** pool_ptr, size_t elt_size)
{
pool_hdr_t * ph = pool_hdr(*pool_ptr);
size_t old_elts = ph->max_elts;
size_t new_elts = old_elts * 2;
/* Double pool storage */
ph = realloc(ph, POOL_HDRLEN + new_elts * elt_size);
if (!ph)
abort();
ph->max_elts = new_elts;
/*
* After resize, the pool will have old_elts free indices, ranging from
* old_elts to (new_elts - 1)
*/
off_t * free_indices = ph->free_indices;
vector_ensure_pos(free_indices, old_elts);
for (unsigned i = 0; i < old_elts; i++)
free_indices[i] = new_elts - 1 - i;
/* Reassign pool pointer */
*pool_ptr = (uint8_t*)ph + POOL_HDRLEN;
}
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