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-rw-r--r--lib/isc/pool.c163
1 files changed, 163 insertions, 0 deletions
diff --git a/lib/isc/pool.c b/lib/isc/pool.c
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+/*
+ * Copyright (C) Internet Systems Consortium, Inc. ("ISC")
+ *
+ * SPDX-License-Identifier: MPL-2.0
+ *
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, you can obtain one at https://mozilla.org/MPL/2.0/.
+ *
+ * See the COPYRIGHT file distributed with this work for additional
+ * information regarding copyright ownership.
+ */
+
+/*! \file */
+
+#include <string.h>
+
+#include <isc/mem.h>
+#include <isc/pool.h>
+#include <isc/random.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));
+ 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 *));
+ 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) {
+ return (pool->pool[isc_random_uniform(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;
+ *sourcep = NULL;
+ 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;
+
+ /* Populate the new entries */
+ for (i = pool->count; i < count; i++) {
+ result = newpool->init(&newpool->pool[i],
+ newpool->initarg);
+ if (result != ISC_R_SUCCESS) {
+ isc_pool_destroy(&newpool);
+ return (result);
+ }
+ }
+
+ /* 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;
+ }
+
+ isc_pool_destroy(&pool);
+ pool = newpool;
+ }
+
+ *targetp = pool;
+ return (ISC_R_SUCCESS);
+}
+
+void
+isc_pool_destroy(isc_pool_t **poolp) {
+ unsigned int i;
+ isc_pool_t *pool = *poolp;
+ *poolp = NULL;
+ 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));
+}