--- /dev/null
+/* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com)
+ * All rights reserved.
+ *
+ * This package is an SSL implementation written
+ * by Eric Young (eay@cryptsoft.com).
+ * The implementation was written so as to conform with Netscapes SSL.
+ *
+ * This library is free for commercial and non-commercial use as long as
+ * the following conditions are aheared to. The following conditions
+ * apply to all code found in this distribution, be it the RC4, RSA,
+ * lhash, DES, etc., code; not just the SSL code. The SSL documentation
+ * included with this distribution is covered by the same copyright terms
+ * except that the holder is Tim Hudson (tjh@cryptsoft.com).
+ *
+ * Copyright remains Eric Young's, and as such any Copyright notices in
+ * the code are not to be removed.
+ * If this package is used in a product, Eric Young should be given attribution
+ * as the author of the parts of the library used.
+ * This can be in the form of a textual message at program startup or
+ * in documentation (online or textual) provided with the package.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the copyright
+ * notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ * notice, this list of conditions and the following disclaimer in the
+ * documentation and/or other materials provided with the distribution.
+ * 3. All advertising materials mentioning features or use of this software
+ * must display the following acknowledgement:
+ * "This product includes cryptographic software written by
+ * Eric Young (eay@cryptsoft.com)"
+ * The word 'cryptographic' can be left out if the rouines from the library
+ * being used are not cryptographic related :-).
+ * 4. If you include any Windows specific code (or a derivative thereof) from
+ * the apps directory (application code) you must include an acknowledgement:
+ * "This product includes software written by Tim Hudson (tjh@cryptsoft.com)"
+ *
+ * THIS SOFTWARE IS PROVIDED BY ERIC YOUNG ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ *
+ * The licence and distribution terms for any publically available version or
+ * derivative of this code cannot be changed. i.e. this code cannot simply be
+ * copied and put under another distribution licence
+ * [including the GNU Public Licence.] */
+
+#include <openssl/lhash.h>
+
+#include <assert.h>
+#include <limits.h>
+#include <string.h>
+
+#include <openssl/mem.h>
+
+#include "../internal.h"
+
+
+// kMinNumBuckets is the minimum size of the buckets array in an |_LHASH|.
+static const size_t kMinNumBuckets = 16;
+
+// kMaxAverageChainLength contains the maximum, average chain length. When the
+// average chain length exceeds this value, the hash table will be resized.
+static const size_t kMaxAverageChainLength = 2;
+static const size_t kMinAverageChainLength = 1;
+
+struct lhash_st {
+ // num_items contains the total number of items in the hash table.
+ size_t num_items;
+ // buckets is an array of |num_buckets| pointers. Each points to the head of
+ // a chain of LHASH_ITEM objects that have the same hash value, mod
+ // |num_buckets|.
+ LHASH_ITEM **buckets;
+ // num_buckets contains the length of |buckets|. This value is always >=
+ // kMinNumBuckets.
+ size_t num_buckets;
+ // callback_depth contains the current depth of |lh_doall| or |lh_doall_arg|
+ // calls. If non-zero then this suppresses resizing of the |buckets| array,
+ // which would otherwise disrupt the iteration.
+ unsigned callback_depth;
+
+ lhash_cmp_func comp;
+ lhash_hash_func hash;
+};
+
+_LHASH *lh_new(lhash_hash_func hash, lhash_cmp_func comp) {
+ _LHASH *ret = OPENSSL_malloc(sizeof(_LHASH));
+ if (ret == NULL) {
+ return NULL;
+ }
+ OPENSSL_memset(ret, 0, sizeof(_LHASH));
+
+ ret->num_buckets = kMinNumBuckets;
+ ret->buckets = OPENSSL_malloc(sizeof(LHASH_ITEM *) * ret->num_buckets);
+ if (ret->buckets == NULL) {
+ OPENSSL_free(ret);
+ return NULL;
+ }
+ OPENSSL_memset(ret->buckets, 0, sizeof(LHASH_ITEM *) * ret->num_buckets);
+
+ ret->comp = comp;
+ ret->hash = hash;
+ return ret;
+}
+
+void lh_free(_LHASH *lh) {
+ if (lh == NULL) {
+ return;
+ }
+
+ for (size_t i = 0; i < lh->num_buckets; i++) {
+ LHASH_ITEM *next;
+ for (LHASH_ITEM *n = lh->buckets[i]; n != NULL; n = next) {
+ next = n->next;
+ OPENSSL_free(n);
+ }
+ }
+
+ OPENSSL_free(lh->buckets);
+ OPENSSL_free(lh);
+}
+
+size_t lh_num_items(const _LHASH *lh) { return lh->num_items; }
+
+// get_next_ptr_and_hash returns a pointer to the pointer that points to the
+// item equal to |data|. In other words, it searches for an item equal to |data|
+// and, if it's at the start of a chain, then it returns a pointer to an
+// element of |lh->buckets|, otherwise it returns a pointer to the |next|
+// element of the previous item in the chain. If an element equal to |data| is
+// not found, it returns a pointer that points to a NULL pointer. If |out_hash|
+// is not NULL, then it also puts the hash value of |data| in |*out_hash|.
+static LHASH_ITEM **get_next_ptr_and_hash(const _LHASH *lh, uint32_t *out_hash,
+ const void *data) {
+ const uint32_t hash = lh->hash(data);
+ LHASH_ITEM *cur, **ret;
+
+ if (out_hash != NULL) {
+ *out_hash = hash;
+ }
+
+ ret = &lh->buckets[hash % lh->num_buckets];
+ for (cur = *ret; cur != NULL; cur = *ret) {
+ if (lh->comp(cur->data, data) == 0) {
+ break;
+ }
+ ret = &cur->next;
+ }
+
+ return ret;
+}
+
+void *lh_retrieve(const _LHASH *lh, const void *data) {
+ LHASH_ITEM **next_ptr;
+
+ next_ptr = get_next_ptr_and_hash(lh, NULL, data);
+
+ if (*next_ptr == NULL) {
+ return NULL;
+ }
+
+ return (*next_ptr)->data;
+}
+
+// lh_rebucket allocates a new array of |new_num_buckets| pointers and
+// redistributes the existing items into it before making it |lh->buckets| and
+// freeing the old array.
+static void lh_rebucket(_LHASH *lh, const size_t new_num_buckets) {
+ LHASH_ITEM **new_buckets, *cur, *next;
+ size_t i, alloc_size;
+
+ alloc_size = sizeof(LHASH_ITEM *) * new_num_buckets;
+ if (alloc_size / sizeof(LHASH_ITEM*) != new_num_buckets) {
+ return;
+ }
+
+ new_buckets = OPENSSL_malloc(alloc_size);
+ if (new_buckets == NULL) {
+ return;
+ }
+ OPENSSL_memset(new_buckets, 0, alloc_size);
+
+ for (i = 0; i < lh->num_buckets; i++) {
+ for (cur = lh->buckets[i]; cur != NULL; cur = next) {
+ const size_t new_bucket = cur->hash % new_num_buckets;
+ next = cur->next;
+ cur->next = new_buckets[new_bucket];
+ new_buckets[new_bucket] = cur;
+ }
+ }
+
+ OPENSSL_free(lh->buckets);
+
+ lh->num_buckets = new_num_buckets;
+ lh->buckets = new_buckets;
+}
+
+// lh_maybe_resize resizes the |buckets| array if needed.
+static void lh_maybe_resize(_LHASH *lh) {
+ size_t avg_chain_length;
+
+ if (lh->callback_depth > 0) {
+ // Don't resize the hash if we are currently iterating over it.
+ return;
+ }
+
+ assert(lh->num_buckets >= kMinNumBuckets);
+ avg_chain_length = lh->num_items / lh->num_buckets;
+
+ if (avg_chain_length > kMaxAverageChainLength) {
+ const size_t new_num_buckets = lh->num_buckets * 2;
+
+ if (new_num_buckets > lh->num_buckets) {
+ lh_rebucket(lh, new_num_buckets);
+ }
+ } else if (avg_chain_length < kMinAverageChainLength &&
+ lh->num_buckets > kMinNumBuckets) {
+ size_t new_num_buckets = lh->num_buckets / 2;
+
+ if (new_num_buckets < kMinNumBuckets) {
+ new_num_buckets = kMinNumBuckets;
+ }
+
+ lh_rebucket(lh, new_num_buckets);
+ }
+}
+
+int lh_insert(_LHASH *lh, void **old_data, void *data) {
+ uint32_t hash;
+ LHASH_ITEM **next_ptr, *item;
+
+ *old_data = NULL;
+ next_ptr = get_next_ptr_and_hash(lh, &hash, data);
+
+
+ if (*next_ptr != NULL) {
+ // An element equal to |data| already exists in the hash table. It will be
+ // replaced.
+ *old_data = (*next_ptr)->data;
+ (*next_ptr)->data = data;
+ return 1;
+ }
+
+ // An element equal to |data| doesn't exist in the hash table yet.
+ item = OPENSSL_malloc(sizeof(LHASH_ITEM));
+ if (item == NULL) {
+ return 0;
+ }
+
+ item->data = data;
+ item->hash = hash;
+ item->next = NULL;
+ *next_ptr = item;
+ lh->num_items++;
+ lh_maybe_resize(lh);
+
+ return 1;
+}
+
+void *lh_delete(_LHASH *lh, const void *data) {
+ LHASH_ITEM **next_ptr, *item, *ret;
+
+ next_ptr = get_next_ptr_and_hash(lh, NULL, data);
+
+ if (*next_ptr == NULL) {
+ // No such element.
+ return NULL;
+ }
+
+ item = *next_ptr;
+ *next_ptr = item->next;
+ ret = item->data;
+ OPENSSL_free(item);
+
+ lh->num_items--;
+ lh_maybe_resize(lh);
+
+ return ret;
+}
+
+static void lh_doall_internal(_LHASH *lh, void (*no_arg_func)(void *),
+ void (*arg_func)(void *, void *), void *arg) {
+ if (lh == NULL) {
+ return;
+ }
+
+ if (lh->callback_depth < UINT_MAX) {
+ // |callback_depth| is a saturating counter.
+ lh->callback_depth++;
+ }
+
+ for (size_t i = 0; i < lh->num_buckets; i++) {
+ LHASH_ITEM *next;
+ for (LHASH_ITEM *cur = lh->buckets[i]; cur != NULL; cur = next) {
+ next = cur->next;
+ if (arg_func) {
+ arg_func(cur->data, arg);
+ } else {
+ no_arg_func(cur->data);
+ }
+ }
+ }
+
+ if (lh->callback_depth < UINT_MAX) {
+ lh->callback_depth--;
+ }
+
+ // The callback may have added or removed elements and the non-zero value of
+ // |callback_depth| will have suppressed any resizing. Thus any needed
+ // resizing is done here.
+ lh_maybe_resize(lh);
+}
+
+void lh_doall(_LHASH *lh, void (*func)(void *)) {
+ lh_doall_internal(lh, func, NULL, NULL);
+}
+
+void lh_doall_arg(_LHASH *lh, void (*func)(void *, void *), void *arg) {
+ lh_doall_internal(lh, NULL, func, arg);
+}
+
+uint32_t lh_strhash(const char *c) {
+ if (c == NULL) {
+ return 0;
+ }
+
+ return OPENSSL_hash32(c, strlen(c));
+}
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