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- /* 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>
-
- /* 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;
-
- _LHASH *lh_new(lhash_hash_func hash, lhash_cmp_func comp) {
- _LHASH *ret;
-
- ret = OPENSSL_malloc(sizeof(_LHASH));
- if (ret == NULL) {
- return NULL;
- }
- 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;
- }
- memset(ret->buckets, 0, sizeof(LHASH_ITEM *) * ret->num_buckets);
-
- ret->comp = comp;
- if (ret->comp == NULL) {
- ret->comp = (lhash_cmp_func) strcmp;
- }
- ret->hash = hash;
- if (ret->hash == NULL) {
- ret->hash = (lhash_hash_func) lh_strhash;
- }
-
- return ret;
- }
-
- void lh_free(_LHASH *lh) {
- size_t i;
- LHASH_ITEM *n, *next;
-
- if (lh == NULL) {
- return;
- }
-
- for (i = 0; i < lh->num_buckets; i++) {
- for (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;
- }
- 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) {
- size_t i;
- LHASH_ITEM *cur, *next;
-
- if (lh == NULL) {
- return;
- }
-
- if (lh->callback_depth < UINT_MAX) {
- /* |callback_depth| is a saturating counter. */
- lh->callback_depth++;
- }
-
- for (i = 0; i < lh->num_buckets; i++) {
- for (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) {
- /* The following hash seems to work very well on normal text strings
- * no collisions on /usr/dict/words and it distributes on %2^n quite
- * well, not as good as MD5, but still good. */
- unsigned long ret = 0;
- long n;
- unsigned long v;
- int r;
-
- if ((c == NULL) || (*c == '\0')) {
- return (ret);
- }
-
- n = 0x100;
- while (*c) {
- v = n | (*c);
- n += 0x100;
- r = (int)((v >> 2) ^ v) & 0x0f;
- ret = (ret << r) | (ret >> (32 - r));
- ret &= 0xFFFFFFFFL;
- ret ^= v * v;
- c++;
- }
-
- return ((ret >> 16) ^ ret);
- }
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