| /* 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 <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); |
| } |