pool.c

Go to the documentation of this file.

/*
 * Copyright (C) 2013, 2015  Internet Systems Consortium, Inc. ("ISC")
 *
 * Permission to use, copy, modify, and/or distribute this software for any
 * purpose with or without fee is hereby granted, provided that the above
 * copyright notice and this permission notice appear in all copies.
 *
 * THE SOFTWARE IS PROVIDED "AS IS" AND ISC DISCLAIMS ALL WARRANTIES WITH
 * REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY
 * AND FITNESS.  IN NO EVENT SHALL ISC BE LIABLE FOR ANY SPECIAL, DIRECT,
 * INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM
 * LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE
 * OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR
 * PERFORMANCE OF THIS SOFTWARE.
 */

/* $Id$ */

/*! \file */

#include <config.h>

#include <string.h>

#include <isc/mem.h>
#include <isc/random.h>
#include <isc/pool.h>
#include <isc/util.h>

/***
 *** Types.
 ***/

struct isc_pool {
        isc_mem_t *                     mctx;
        unsigned int                    count;
        isc_pooldeallocator_t           free;
        isc_poolinitializer_t           init;
        void *                          initarg;
        void **                         pool;
};

/***
 *** Functions.
 ***/

static isc_result_t
alloc_pool(isc_mem_t *mctx, unsigned int count, isc_pool_t **poolp) {
        isc_pool_t *pool;

        pool = isc_mem_get(mctx, sizeof(*pool));
        if (pool == NULL)
                return (ISC_R_NOMEMORY);
        pool->count = count;
        pool->free = NULL;
        pool->init = NULL;
        pool->initarg = NULL;
        pool->mctx = NULL;
        isc_mem_attach(mctx, &pool->mctx);
        pool->pool = isc_mem_get(mctx, count * sizeof(void *));
        if (pool->pool == NULL) {
                isc_mem_put(mctx, pool, sizeof(*pool));
                return (ISC_R_NOMEMORY);
        }
        memset(pool->pool, 0, count * sizeof(void *));

        *poolp = pool;
        return (ISC_R_SUCCESS);
}

isc_result_t
isc_pool_create(isc_mem_t *mctx, unsigned int count,
                   isc_pooldeallocator_t release,
                   isc_poolinitializer_t init, void *initarg,
                   isc_pool_t **poolp)
{
        isc_pool_t *pool = NULL;
        isc_result_t result;
        unsigned int i;

        INSIST(count > 0);

        /* Allocate the pool structure */
        result = alloc_pool(mctx, count, &pool);
        if (result != ISC_R_SUCCESS)
                return (result);

        pool->free = release;
        pool->init = init;
        pool->initarg = initarg;

        /* Populate the pool */
        for (i = 0; i < count; i++) {
                result = init(&pool->pool[i], initarg);
                if (result != ISC_R_SUCCESS) {
                        isc_pool_destroy(&pool);
                        return (result);
                }
        }

        *poolp = pool;
        return (ISC_R_SUCCESS);
}

void *
isc_pool_get(isc_pool_t *pool) {
        isc_uint32_t i;
        isc_random_get(&i);
        return (pool->pool[i % pool->count]);
}

int
isc_pool_count(isc_pool_t *pool) {
        REQUIRE(pool != NULL);
        return (pool->count);
}

isc_result_t
isc_pool_expand(isc_pool_t **sourcep, unsigned int count,
                   isc_pool_t **targetp)
{
        isc_result_t result;
        isc_pool_t *pool;

        REQUIRE(sourcep != NULL && *sourcep != NULL);
        REQUIRE(targetp != NULL && *targetp == NULL);

        pool = *sourcep;
        if (count > pool->count) {
                isc_pool_t *newpool = NULL;
                unsigned int i;

                /* Allocate a new pool structure */
                result = alloc_pool(pool->mctx, count, &newpool);
                if (result != ISC_R_SUCCESS)
                        return (result);

                newpool->free = pool->free;
                newpool->init = pool->init;
                newpool->initarg = pool->initarg;

                /* Copy over the objects from the old pool */
                for (i = 0; i < pool->count; i++) {
                        newpool->pool[i] = pool->pool[i];
                        pool->pool[i] = NULL;
                }

                /* Populate the new entries */
                for (i = pool->count; i < count; i++) {
                        result = pool->init(&newpool->pool[i], pool->initarg);
                        if (result != ISC_R_SUCCESS) {
                                isc_pool_destroy(&pool);
                                return (result);
                        }
                }

                isc_pool_destroy(&pool);
                pool = newpool;
        }

        *sourcep = NULL;
        *targetp = pool;
        return (ISC_R_SUCCESS);
}

void
isc_pool_destroy(isc_pool_t **poolp) {
        unsigned int i;
        isc_pool_t *pool = *poolp;
        for (i = 0; i < pool->count; i++) {
                if (pool->free != NULL && pool->pool[i] != NULL)
                        pool->free(&pool->pool[i]);
        }
        isc_mem_put(pool->mctx, pool->pool, pool->count * sizeof(void *));
        isc_mem_putanddetach(&pool->mctx, pool, sizeof(*pool));
        *poolp = NULL;
}

---