diff options
author | russell <russell@f38db490-d61c-443f-a65b-d21fe96a405b> | 2008-01-19 00:19:29 +0000 |
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committer | russell <russell@f38db490-d61c-443f-a65b-d21fe96a405b> | 2008-01-19 00:19:29 +0000 |
commit | f8247040e6231c4b3b5099ea3a526348b7941566 (patch) | |
tree | 0cc92ad6ebf6ae49a62f6e7ef8ec819121d63630 /trunk/main/hashtab.c | |
parent | d88e56c61ce2042544c1a8a71c93b69ab2e6ffba (diff) |
Creating tag for the release of asterisk-1.6.0-beta1v1.6.0-beta1
git-svn-id: http://svn.digium.com/svn/asterisk/tags/1.6.0-beta1@99163 f38db490-d61c-443f-a65b-d21fe96a405b
Diffstat (limited to 'trunk/main/hashtab.c')
-rw-r--r-- | trunk/main/hashtab.c | 805 |
1 files changed, 805 insertions, 0 deletions
diff --git a/trunk/main/hashtab.c b/trunk/main/hashtab.c new file mode 100644 index 000000000..82a28ee10 --- /dev/null +++ b/trunk/main/hashtab.c @@ -0,0 +1,805 @@ +/* + * Asterisk -- An open source telephony toolkit. + * + * Copyright (C) 2007, Digium, Inc. + * + * Steve Murphy <murf@digium.com> + * + * See http://www.asterisk.org for more information about + * the Asterisk project. Please do not directly contact + * any of the maintainers of this project for assistance; + * the project provides a web site, mailing lists and IRC + * channels for your use. + * + * This program is free software, distributed under the terms of + * the GNU General Public License Version 2. See the LICENSE file + * at the top of the source tree. + */ +/*! \file + * + * \brief code to implement generic hash tables + * + * \author Steve Murphy <murf@digium.com> + */ + +#include "asterisk.h" + +ASTERISK_FILE_VERSION(__FILE__, "$Revision") + +#include <ctype.h> + +#include "asterisk/lock.h" +#include "asterisk/frame.h" +#include "asterisk/channel.h" +#include "asterisk/cli.h" +#include "asterisk/term.h" +#include "asterisk/utils.h" +#include "asterisk/threadstorage.h" +#include "asterisk/linkedlists.h" +#include "asterisk/hashtab.h" + +static void ast_hashtab_resize( struct ast_hashtab *tab); +static void *ast_hashtab_lookup_internal(struct ast_hashtab *tab, const void *obj, unsigned int h); + +/* some standard, default routines for general use */ + +int ast_hashtab_compare_strings(const void *a, const void *b) +{ + return strcmp((char*)a,(char*)b); +} + +int ast_hashtab_compare_strings_nocase(const void *a, const void *b) +{ + return strcasecmp((const char*)a,(const char*)b); +} + +int ast_hashtab_compare_ints(const void *a, const void *b) +{ + int ai = *((int *) a); + int bi = *((int *) b); + + if (ai < bi) + return -1; + + return !(ai == bi); +} + +int ast_hashtab_compare_shorts(const void *a, const void *b) +{ + short as = *((short *) a); + short bs = *((short *) b); + + if (as < bs) + return -1; + + return !(as == bs); +} + +int ast_hashtab_resize_java(struct ast_hashtab *tab) +{ + double loadfactor = (double) tab->hash_tab_elements / (double) tab->hash_tab_size; + + return (loadfactor > 0.75); +} + +int ast_hashtab_resize_tight(struct ast_hashtab *tab) +{ + return (tab->hash_tab_elements > tab->hash_tab_size); /* this is quicker than division */ +} + +int ast_hashtab_resize_none(struct ast_hashtab *tab) /* always return 0 -- no resizing */ +{ + return 0; +} + +int ast_is_prime(int num) +{ + int tnum, limit; + + if (!(num & 0x1)) /* even number -- not prime */ + return 0; + + /* Loop through ODD numbers starting with 3 */ + + tnum = 3; + limit = num; + while (tnum < limit) { + if (!(num % tnum)) + return 0; + + /* really, we only need to check sqrt(num) numbers */ + limit = num / tnum; + + /* we only check odd numbers */ + tnum = tnum + 2; + } + + /* if we made it through the loop, the number is a prime */ + + return 1; +} + +int ast_hashtab_newsize_java(struct ast_hashtab *tab) +{ + int i = (tab->hash_tab_size << 1); /* multiply by two */ + + while (!ast_is_prime(i)) + i++; + + return i; +} + +int ast_hashtab_newsize_tight(struct ast_hashtab *tab) +{ + int x = (tab->hash_tab_size << 1); + int i = (tab->hash_tab_size + x); + + while (!ast_is_prime(i)) + i++; + + return i; +} + +int ast_hashtab_newsize_none(struct ast_hashtab *tab) /* always return current size -- no resizing */ +{ + return tab->hash_tab_size; +} + +unsigned int ast_hashtab_hash_string(const void *obj) +{ + unsigned char *str = (unsigned char *) obj; + unsigned int total; + + for (total = 0; *str; str++) + { + unsigned int tmp = total; + total <<= 1; /* multiply by 2 */ + total += tmp; /* multiply by 3 */ + total <<= 2; /* multiply by 12 */ + total += tmp; /* multiply by 13 */ + + total += ((unsigned int)(*str)); + } + return total; +} + +unsigned int ast_hashtab_hash_string_sax(const void *obj) /* from Josh */ +{ + unsigned char *str = (unsigned char *) obj; + unsigned int total = 0, c = 0; + + while ((c = *str++)) + total ^= (total << 5) + (total >> 2) + (total << 10) + c; + + return total; +} + +unsigned int ast_hashtab_hash_string_nocase(const void *obj) +{ + unsigned char *str = (unsigned char*)obj; + unsigned int total; + + for (total = 0; *str; str++) { + unsigned int tmp = total; + unsigned int charval = toupper(*str); + + /* hopefully, the following is faster than multiplication by 7 */ + /* why do I go to this bother? A good compiler will do this + anyway, if I say total *= 13 */ + /* BTW, tried *= 7, and it doesn't do as well in spreading things around! */ + total <<= 1; /* multiply by 2 */ + total += tmp; /* multiply by 3 */ + total <<= 2; /* multiply by 12 */ + total += tmp; /* multiply by 13 */ + + total += (charval); + } + + return total; +} + +unsigned int ast_hashtab_hash_int(const int x) +{ + return x; +} + +unsigned int ast_hashtab_hash_short(const short x) +{ + /* hmmmm.... modulus is best < 65535 !! */ + return x; +} + +struct ast_hashtab *ast_hashtab_create(int initial_buckets, + int (*compare)(const void *a, const void *b), + int (*resize)(struct ast_hashtab *), + int (*newsize)(struct ast_hashtab *tab), + unsigned int (*hash)(const void *obj), + int do_locking) +{ + struct ast_hashtab *ht; + + if (!(ht = ast_calloc(1, sizeof(*ht)))) + return NULL; + + while (!ast_is_prime(initial_buckets)) /* make sure this is prime */ + initial_buckets++; + + if (!(ht->array = ast_calloc(initial_buckets, sizeof(*(ht->array))))) { + free(ht); + return NULL; + } + + ht->hash_tab_size = initial_buckets; + ht->compare = compare; + ht->resize = resize; + ht->newsize = newsize; + ht->hash = hash; + ht->do_locking = do_locking; + + if (do_locking) + ast_rwlock_init(&ht->lock); + + if (!ht->resize) + ht->resize = ast_hashtab_resize_java; + + if (!ht->newsize) + ht->newsize = ast_hashtab_newsize_java; + + return ht; +} + +struct ast_hashtab *ast_hashtab_dup(struct ast_hashtab *tab, void *(*obj_dup_func)(const void *obj)) +{ + struct ast_hashtab *ht; + unsigned int i; + + if (!(ht = ast_calloc(1, sizeof(*ht)))) + return NULL; + + if (!(ht->array = ast_calloc(tab->hash_tab_size, sizeof(*(ht->array))))) { + free(ht); + return NULL; + } + + ht->hash_tab_size = tab->hash_tab_size; + ht->compare = tab->compare; + ht->resize = tab->resize; + ht->newsize = tab->newsize; + ht->hash = tab->hash; + ht->do_locking = tab->do_locking; + + if (ht->do_locking) + ast_rwlock_init(&ht->lock); + + /* now, dup the objects in the buckets and get them into the table */ + /* the fast way is to use the existing array index, and not have to hash + the objects again */ + for (i = 0; i < ht->hash_tab_size; i++) { + struct ast_hashtab_bucket *b = tab->array[i]; + while (b) { + void *newobj = (*obj_dup_func)(b->object); + if (newobj) + ast_hashtab_insert_immediate_bucket(ht, newobj, i); + b = b->next; + } + } + + return ht; +} + +static void tlist_del_item(struct ast_hashtab_bucket **head, struct ast_hashtab_bucket *item) +{ + /* item had better be in the list! or suffer the weirdness that occurs, later! */ + if (*head == item) { /* first item in the list */ + *head = item->tnext; + if (item->tnext) + item->tnext->tprev = NULL; + } else { + /* short circuit stuff */ + item->tprev->tnext = item->tnext; + if (item->tnext) + item->tnext->tprev = item->tprev; + } +} + +static void tlist_add_head(struct ast_hashtab_bucket **head, struct ast_hashtab_bucket *item) +{ + if (*head) { + item->tnext = *head; + item->tprev = NULL; + (*head)->tprev = item; + *head = item; + } else { + /* the list is empty */ + *head = item; + item->tprev = NULL; + item->tnext = NULL; + } +} + +/* user-controlled hashtab locking. Create a hashtab without locking, then call the + following locking routines yourself to lock the table between threads. */ + +void ast_hashtab_wrlock(struct ast_hashtab *tab) +{ + ast_rwlock_wrlock(&tab->lock); +} + +void ast_hashtab_rdlock(struct ast_hashtab *tab) +{ + ast_rwlock_rdlock(&tab->lock); +} + +void ast_hashtab_initlock(struct ast_hashtab *tab) +{ + ast_rwlock_init(&tab->lock); +} + +void ast_hashtab_destroylock(struct ast_hashtab *tab) +{ + ast_rwlock_destroy(&tab->lock); +} + +void ast_hashtab_unlock(struct ast_hashtab *tab) +{ + ast_rwlock_unlock(&tab->lock); +} + +void ast_hashtab_destroy( struct ast_hashtab *tab, void (*objdestroyfunc)(void *obj)) +{ + /* this func will free the hash table and all its memory. It + doesn't touch the objects stored in it */ + if (tab) { + + if (tab->do_locking) + ast_rwlock_wrlock(&tab->lock); + + if (tab->array) { + /* go thru and destroy the buckets */ + struct ast_hashtab_bucket *t; + int i; + + while (tab->tlist) { + t = tab->tlist; + if (t->object && objdestroyfunc) + (*objdestroyfunc)((void *) t->object); /* I cast this because I'm not going to MOD it, I'm going to DESTROY it */ + + tlist_del_item(&(tab->tlist), tab->tlist); + free(t); + } + + for (i = 0; i < tab->hash_tab_size; i++) + tab->array[i] = NULL; /* not totally necc., but best to destroy old ptrs */ + + free(tab->array); + } + if (tab->do_locking) { + ast_rwlock_unlock(&tab->lock); + ast_rwlock_destroy(&tab->lock); + } + free(tab); + } +} + +int ast_hashtab_insert_immediate(struct ast_hashtab *tab, const void *obj) +{ + unsigned int h; + int res=0; + + if (!tab || !obj) + return res; + + if (tab->do_locking) + ast_rwlock_wrlock(&tab->lock); + + h = (*tab->hash)(obj) % tab->hash_tab_size; + + res = ast_hashtab_insert_immediate_bucket(tab,obj,h); + + if (tab->do_locking) + ast_rwlock_unlock(&tab->lock); + + return res; +} + +int ast_hashtab_insert_immediate_bucket(struct ast_hashtab *tab, const void *obj, unsigned int h) +{ + int c; + struct ast_hashtab_bucket *b; + + if (!tab || !obj) + return 0; + + for (c = 0, b = tab->array[h]; b; b= b->next) + c++; + + if (c + 1 > tab->largest_bucket_size) + tab->largest_bucket_size = c + 1; + + if (!(b = ast_calloc(1, sizeof(*b)))) + return 0; + + b->object = obj; + b->next = tab->array[h]; + tab->array[h] = b; + + if (b->next) + b->next->prev = b; + + tlist_add_head(&(tab->tlist), b); + tab->hash_tab_elements++; + + if ((*tab->resize)(tab)) + ast_hashtab_resize(tab); + + return 1; +} + +int ast_hashtab_insert_safe(struct ast_hashtab *tab, const void *obj) +{ + /* check to see if the element is already there; insert only if + it is not there. */ + /* will force a resize if the resize func returns 1 */ + /* returns 1 on success, 0 if there's a problem, or it's already there. */ + unsigned int bucket = 0; + + if (tab->do_locking) + ast_rwlock_wrlock(&tab->lock); + + if (!ast_hashtab_lookup_bucket(tab, obj, &bucket)) { + int ret2 = ast_hashtab_insert_immediate_bucket(tab, obj, bucket); + + if (tab->do_locking) + ast_rwlock_unlock(&tab->lock); + + return ret2; + } + + if (tab->do_locking) + ast_rwlock_unlock(&tab->lock); + + return 0; +} + +void *ast_hashtab_lookup(struct ast_hashtab *tab, const void *obj) +{ + /* lookup this object in the hash table. return a ptr if found, or NULL if not */ + unsigned int h; + void *ret; + + if (!tab || !obj) + return 0; + + if (tab->do_locking) + ast_rwlock_rdlock(&tab->lock); + + h = (*tab->hash)(obj) % tab->hash_tab_size; + + ret = ast_hashtab_lookup_internal(tab,obj,h); + + if (tab->do_locking) + ast_rwlock_unlock(&tab->lock); + + return ret; +} + + +void *ast_hashtab_lookup_with_hash(struct ast_hashtab *tab, const void *obj, unsigned int hashval) +{ + /* lookup this object in the hash table. return a ptr if found, or NULL if not */ + unsigned int h; + void *ret; + + if (!tab || !obj) + return 0; + + if (tab->do_locking) + ast_rwlock_rdlock(&tab->lock); + + h = hashval % tab->hash_tab_size; + + ret = ast_hashtab_lookup_internal(tab,obj,h); + + if (tab->do_locking) + ast_rwlock_unlock(&tab->lock); + + return ret; +} + +void *ast_hashtab_lookup_bucket(struct ast_hashtab *tab, const void *obj, unsigned int *bucket) +{ + /* lookup this object in the hash table. return a ptr if found, or NULL if not */ + unsigned int h; + void *ret; + + if (!tab || !obj) + return 0; + + h = (*tab->hash)(obj) % tab->hash_tab_size; + + ret = ast_hashtab_lookup_internal(tab,obj,h); + + *bucket = h; + + return ret; +} + +static void *ast_hashtab_lookup_internal(struct ast_hashtab *tab, const void *obj, unsigned int h) +{ + struct ast_hashtab_bucket *b; + + for (b = tab->array[h]; b; b = b->next) { + if (!(*tab->compare)(obj,b->object)) { + return (void*) b->object; /* I can't touch obj in this func, but the outside world is welcome to */ + } + } + + return NULL; +} + +void ast_hashtab_get_stats( struct ast_hashtab *tab, int *biggest_bucket_size, int *resize_count, int *num_objects, int *num_buckets) +{ + /* returns key stats for the table */ + if (tab->do_locking) + ast_rwlock_rdlock(&tab->lock); + *biggest_bucket_size = tab->largest_bucket_size; + *resize_count = tab->resize_count; + *num_objects = tab->hash_tab_elements; + *num_buckets = tab->hash_tab_size; + if (tab->do_locking) + ast_rwlock_unlock(&tab->lock); +} + + /* this function returns the number of elements stored in the hashtab */ +int ast_hashtab_size( struct ast_hashtab *tab) +{ + return tab->hash_tab_elements; +} + + /* this function returns the size of the bucket array in the hashtab */ +int ast_hashtab_capacity( struct ast_hashtab *tab) +{ + return tab->hash_tab_size; +} + + + +/* the insert operation calls this, and is wrlock'd when it does. */ +/* if you want to call it, you should set the wrlock yourself */ + + +static void ast_hashtab_resize( struct ast_hashtab *tab) +{ + /* this function is called either internally, when the resize func returns 1, or + externally by the user to force a resize of the hash table */ + int newsize = (*tab->newsize)(tab), i, c; + unsigned int h; + struct ast_hashtab_bucket *b,*bn; + + /* Since we keep a DLL of all the buckets in tlist, + all we have to do is free the array, malloc a new one, + and then go thru the tlist array and reassign them into + the bucket arrayj. + */ + for (i = 0; i < tab->hash_tab_size; i++) { /* don't absolutely have to do this, but + why leave ptrs laying around */ + tab->array[i] = 0; /* erase old ptrs */ + } + free(tab->array); + if (!(tab->array = ast_calloc(newsize, sizeof(*(tab->array))))) + return; + + /* now sort the buckets into their rightful new slots */ + tab->resize_count++; + tab->hash_tab_size = newsize; + tab->largest_bucket_size = 0; + + for (b = tab->tlist; b; b = bn) { + b->prev = 0; + bn = b->tnext; + h = (*tab->hash)(b->object) % tab->hash_tab_size; + b->next = tab->array[h]; + if (b->next) + b->next->prev = b; + tab->array[h] = b; + } + /* recalc the largest bucket size */ + for (i = 0; i < tab->hash_tab_size; i++) { + for (c = 0, b = tab->array[i]; b; b = b->next) + c++; + if (c > tab->largest_bucket_size) + tab->largest_bucket_size = c; + } +} + +struct ast_hashtab_iter *ast_hashtab_start_traversal(struct ast_hashtab *tab) +{ + /* returns an iterator */ + struct ast_hashtab_iter *it; + + if (!(it = ast_calloc(1, sizeof(*it)))) + return NULL; + + it->next = tab->tlist; + it->tab = tab; + if (tab->do_locking) + ast_rwlock_rdlock(&tab->lock); + + return it; +} + +/* use this function to get a write lock */ +struct ast_hashtab_iter *ast_hashtab_start_write_traversal(struct ast_hashtab *tab) +{ + /* returns an iterator */ + struct ast_hashtab_iter *it; + + if (!(it = ast_calloc(1, sizeof(*it)))) + return NULL; + + it->next = tab->tlist; + it->tab = tab; + if (tab->do_locking) + ast_rwlock_wrlock(&tab->lock); + + return it; +} + +void ast_hashtab_end_traversal(struct ast_hashtab_iter *it) +{ + if (it->tab->do_locking) + ast_rwlock_unlock(&it->tab->lock); + free(it); +} + +void *ast_hashtab_next(struct ast_hashtab_iter *it) +{ + /* returns the next object in the list, advances iter one step */ + struct ast_hashtab_bucket *retval; + + if (it && it->next) { /* there's a next in the bucket list */ + retval = it->next; + it->next = retval->tnext; + return (void *) retval->object; + } + + return NULL; +} + +static void *ast_hashtab_remove_object_internal(struct ast_hashtab *tab, struct ast_hashtab_bucket *b, int h) +{ + const void *obj2; + + if (b->prev) + b->prev->next = b->next; + else + tab->array[h] = b->next; + + if (b->next) + b->next->prev = b->prev; + + tlist_del_item(&(tab->tlist), b); + + obj2 = b->object; + b->object = b->next = (void*)2; + free(b); /* free up the hashbucket */ + tab->hash_tab_elements--; +#ifdef DEBUG + { + int c2; + struct ast_hashtab_bucket *b2; + /* do a little checking */ + for (c2 = 0, b2 = tab->tlist; b2; b2 = b2->tnext) { + c2++; + } + if (c2 != tab->hash_tab_elements) { + printf("Hey! we didn't delete right! there are %d elements in the list, and we expected %d\n", + c2, tab->hash_tab_elements); + } + for (c2 = 0, b2 = tab->tlist; b2; b2 = b2->tnext) { + unsigned int obj3 = (unsigned long) obj2; + unsigned int b3 = (unsigned long) b; + if (b2->object == obj2) + printf("Hey-- you've still got a bucket pointing at ht_element %x\n", obj3); + if (b2->next == b) + printf("Hey-- you've still got a bucket with next ptr pointing to deleted bucket %x\n", b3); + if (b2->prev == b) + printf("Hey-- you've still got a bucket with prev ptr pointing to deleted bucket %x\n", b3); + if (b2->tprev == b) + printf("Hey-- you've still got a bucket with tprev ptr pointing to deleted bucket %x\n", b3); + if (b2->tnext == b) + printf("Hey-- you've still got a bucket with tnext ptr pointing to deleted bucket %x\n", b3); + } + } +#endif + return (void *) obj2; /* inside this code, the obj's are untouchable, but outside, they aren't */ +} + +void *ast_hashtab_remove_object_via_lookup(struct ast_hashtab *tab, void *obj) +{ + /* looks up the object; removes the corresponding bucket */ + const void *obj2; + + if (!tab || !obj) + return 0; + + if (tab->do_locking) + ast_rwlock_wrlock(&tab->lock); + + obj2 = ast_hashtab_remove_object_via_lookup_nolock(tab,obj); + + if (tab->do_locking) + ast_rwlock_unlock(&tab->lock); + + return (void *)obj2; +} + +void *ast_hashtab_remove_object_via_lookup_nolock(struct ast_hashtab *tab, void *obj) +{ + /* looks up the object; removes the corresponding bucket */ + unsigned int h; + struct ast_hashtab_bucket *b; + + if (!tab || !obj) + return 0; + + h = (*tab->hash)(obj) % tab->hash_tab_size; + for (b = tab->array[h]; b; b = b->next) { + + if (!(*tab->compare)(obj, b->object)) { + const void *obj2; + + obj2 = ast_hashtab_remove_object_internal(tab, b, h); + + return (void *) obj2; /* inside this code, the obj's are untouchable, but outside, they aren't */ + } + } + + return 0; +} + +void *ast_hashtab_remove_this_object(struct ast_hashtab *tab, void *obj) +{ + /* looks up the object by hash and then comparing pts in bucket list instead of + calling the compare routine; removes the bucket -- a slightly cheaper operation */ + /* looks up the object; removes the corresponding bucket */ + const void *obj2; + + if (!tab || !obj) + return 0; + + if (tab->do_locking) + ast_rwlock_wrlock(&tab->lock); + + obj2 = ast_hashtab_remove_this_object_nolock(tab,obj); + + if (tab->do_locking) + ast_rwlock_unlock(&tab->lock); + + return (void *)obj2; +} + +void *ast_hashtab_remove_this_object_nolock(struct ast_hashtab *tab, void *obj) +{ + /* looks up the object by hash and then comparing pts in bucket list instead of + calling the compare routine; removes the bucket -- a slightly cheaper operation */ + /* looks up the object; removes the corresponding bucket */ + unsigned int h; + struct ast_hashtab_bucket *b; + + if (!tab || !obj) + return 0; + + h = (*tab->hash)(obj) % tab->hash_tab_size; + for (b = tab->array[h]; b; b = b->next) { + + if (obj == b->object) { + const void *obj2; + obj2 = ast_hashtab_remove_object_internal(tab, b, h); + + return (void *) obj2; /* inside this code, the obj's are untouchable, but outside, they aren't */ + } + } + + return 0; +} |