1/*
2 * Copyright (C) 2013  Internet Systems Consortium, Inc. ("ISC")
3 *
4 * Permission to use, copy, modify, and/or distribute this software for any
5 * purpose with or without fee is hereby granted, provided that the above
6 * copyright notice and this permission notice appear in all copies.
7 *
8 * THE SOFTWARE IS PROVIDED "AS IS" AND ISC DISCLAIMS ALL WARRANTIES WITH
9 * REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY
10 * AND FITNESS.  IN NO EVENT SHALL ISC BE LIABLE FOR ANY SPECIAL, DIRECT,
11 * INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM
12 * LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE
13 * OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR
14 * PERFORMANCE OF THIS SOFTWARE.
15 */
16
17/* $Id$ */
18
19/*! \file */
20
21#include <config.h>
22
23#include <string.h>
24
25#include <isc/mem.h>
26#include <isc/random.h>
27#include <isc/pool.h>
28#include <isc/util.h>
29
30/***
31 *** Types.
32 ***/
33
34struct isc_pool {
35	isc_mem_t *			mctx;
36	unsigned int			count;
37	isc_pooldeallocator_t		free;
38	isc_poolinitializer_t		init;
39	void *				initarg;
40	void **				pool;
41};
42
43/***
44 *** Functions.
45 ***/
46
47static isc_result_t
48alloc_pool(isc_mem_t *mctx, unsigned int count, isc_pool_t **poolp) {
49	isc_pool_t *pool;
50
51	pool = isc_mem_get(mctx, sizeof(*pool));
52	if (pool == NULL)
53		return (ISC_R_NOMEMORY);
54	pool->count = count;
55	pool->free = NULL;
56	pool->init = NULL;
57	pool->initarg = NULL;
58	pool->mctx = NULL;
59	isc_mem_attach(mctx, &pool->mctx);
60	pool->pool = isc_mem_get(mctx, count * sizeof(void *));
61	if (pool->pool == NULL) {
62		isc_mem_put(mctx, pool, sizeof(*pool));
63		return (ISC_R_NOMEMORY);
64	}
65	memset(pool->pool, 0, count * sizeof(void *));
66
67	*poolp = pool;
68	return (ISC_R_SUCCESS);
69}
70
71isc_result_t
72isc_pool_create(isc_mem_t *mctx, unsigned int count,
73		   isc_pooldeallocator_t free,
74		   isc_poolinitializer_t init, void *initarg,
75		   isc_pool_t **poolp)
76{
77	isc_pool_t *pool = NULL;
78	isc_result_t result;
79	unsigned int i;
80
81	INSIST(count > 0);
82
83	/* Allocate the pool structure */
84	result = alloc_pool(mctx, count, &pool);
85	if (result != ISC_R_SUCCESS)
86		return (result);
87
88	pool->free = free;
89	pool->init = init;
90	pool->initarg = initarg;
91
92	/* Populate the pool */
93	for (i = 0; i < count; i++) {
94		result = init(&pool->pool[i], initarg);
95		if (result != ISC_R_SUCCESS) {
96			isc_pool_destroy(&pool);
97			return (result);
98		}
99	}
100
101	*poolp = pool;
102	return (ISC_R_SUCCESS);
103}
104
105void *
106isc_pool_get(isc_pool_t *pool) {
107	isc_uint32_t i;
108	isc_random_get(&i);
109	return (pool->pool[i % pool->count]);
110}
111
112int
113isc_pool_count(isc_pool_t *pool) {
114	REQUIRE(pool != NULL);
115	return (pool->count);
116}
117
118isc_result_t
119isc_pool_expand(isc_pool_t **sourcep, unsigned int count,
120		   isc_pool_t **targetp)
121{
122	isc_result_t result;
123	isc_pool_t *pool;
124
125	REQUIRE(sourcep != NULL && *sourcep != NULL);
126	REQUIRE(targetp != NULL && *targetp == NULL);
127
128	pool = *sourcep;
129	if (count > pool->count) {
130		isc_pool_t *newpool = NULL;
131		unsigned int i;
132
133		/* Allocate a new pool structure */
134		result = alloc_pool(pool->mctx, count, &newpool);
135		if (result != ISC_R_SUCCESS)
136			return (result);
137
138		newpool->free = pool->free;
139		newpool->init = pool->init;
140		newpool->initarg = pool->initarg;
141
142		/* Copy over the objects from the old pool */
143		for (i = 0; i < pool->count; i++) {
144			newpool->pool[i] = pool->pool[i];
145			pool->pool[i] = NULL;
146		}
147
148		/* Populate the new entries */
149		for (i = pool->count; i < count; i++) {
150			result = pool->init(&newpool->pool[i], pool->initarg);
151			if (result != ISC_R_SUCCESS) {
152				isc_pool_destroy(&pool);
153				return (result);
154			}
155		}
156
157		isc_pool_destroy(&pool);
158		pool = newpool;
159	}
160
161	*sourcep = NULL;
162	*targetp = pool;
163	return (ISC_R_SUCCESS);
164}
165
166void
167isc_pool_destroy(isc_pool_t **poolp) {
168	unsigned int i;
169	isc_pool_t *pool = *poolp;
170	for (i = 0; i < pool->count; i++) {
171		if (pool->free != NULL && pool->pool[i] != NULL)
172			pool->free(&pool->pool[i]);
173	}
174	isc_mem_put(pool->mctx, pool->pool, pool->count * sizeof(void *));
175	isc_mem_putanddetach(&pool->mctx, pool, sizeof(*pool));
176	*poolp = NULL;
177}
178