1 files changed, 163 insertions, 0 deletions
diff --git a/lib/isc/pool.c b/lib/isc/pool.c
new file mode 100644
index 0000000..5a5fb12
--- /dev/null
+++ b/lib/isc/pool.c
@@ -0,0 +1,163 @@
+/*
+ * 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));
+}