[asterisk-commits] seanbright: trunk r177884 - in /trunk: include/asterisk/hashtab.h main/hashtab.c
SVN commits to the Asterisk project
asterisk-commits at lists.digium.com
Sat Feb 21 08:16:44 CST 2009
Author: seanbright
Date: Sat Feb 21 08:16:44 2009
New Revision: 177884
URL: http://svn.digium.com/svn-view/asterisk?view=rev&rev=177884
Log:
Trailing whitespace, minor coding guideline fixes, and start beefing up the
hashtab documentation a bit.
Modified:
trunk/include/asterisk/hashtab.h
trunk/main/hashtab.c
Modified: trunk/include/asterisk/hashtab.h
URL: http://svn.digium.com/svn-view/asterisk/trunk/include/asterisk/hashtab.h?view=diff&rev=177884&r1=177883&r2=177884
==============================================================================
--- trunk/include/asterisk/hashtab.h (original)
+++ trunk/include/asterisk/hashtab.h Sat Feb 21 08:16:44 2009
@@ -81,12 +81,12 @@
{
struct ast_hashtab_bucket **array;
struct ast_hashtab_bucket *tlist; /*!< the head of a DLList of all the hashbuckets in the table (for traversal). */
-
- int (*compare) (const void *a, const void *b); /*!< a ptr to func that returns int, and take two void* ptrs, compares them,
+
+ int (*compare) (const void *a, const void *b); /*!< a ptr to func that returns int, and take two void* ptrs, compares them,
rets -1 if a < b; rets 0 if a==b; rets 1 if a>b */
int (*newsize) (struct ast_hashtab *tab); /*!< a ptr to func that returns int, a new size for hash tab, based on curr_size */
int (*resize) (struct ast_hashtab *tab); /*!< a function to decide whether this hashtable should be resized now */
- unsigned int (*hash) (const void *obj); /*!< a hash func ptr for this table. Given a raw ptr to an obj,
+ unsigned int (*hash) (const void *obj); /*!< a hash func ptr for this table. Given a raw ptr to an obj,
it calcs a hash.*/
int hash_tab_size; /*!< the size of the bucket array */
int hash_tab_elements; /*!< the number of objects currently stored in the table */
@@ -108,47 +108,87 @@
/* some standard, default routines for general use */
-/*! \brief For sizing the hash table, tells if num is prime or not */
+/*!
+ * \brief Determines if the specified number is prime.
+ *
+ * \param num the number to test
+ * \retval 0 if the number is not prime
+ * \retval 1 if the number is prime
+ */
int ast_is_prime(int num);
-/*!
- * \brief assumes a and b are char *
- * \return 0 if they match
-*/
+/*!
+ * \brief Compares two strings for equality.
+ *
+ * \param a a character string
+ * \param b a character string
+ * \retval 0 if the strings match
+ * \retval <0 if string a is less than string b
+ * \retval >0 if string a is greather than string b
+ */
int ast_hashtab_compare_strings(const void *a, const void *b);
/*!
- * \brief assumes a & b are strings
- * \return 0 if they match (strcasecmp)
-*/
+ * \brief Compares two strings for equality, ignoring case.
+ *
+ * \param a a character string
+ * \param b a character string
+ * \retval 0 if the strings match
+ * \retval <0 if string a is less than string b
+ * \retval >0 if string a is greather than string b
+ */
int ast_hashtab_compare_strings_nocase(const void *a, const void *b);
/*!
- * \brief assumes a & b are int *
- * \retval 0 if match
- * \retval 1 a > b
- * \retval -1 a < b
-*/
+ * \brief Compares two integers for equality.
+ *
+ * \param a an integer pointer (int *)
+ * \param b an integer pointer (int *)
+ * \retval 0 if the integers pointed to are equal
+ * \retval 1 if a is greater than b
+ * \retval -1 if a is less than b
+ */
int ast_hashtab_compare_ints(const void *a, const void *b);
/*!
- * \brief assumes a & b are short *
- * \retval 0 if match
- * \retval 1 a > b
- * \retval -1 a < b
-*/
+ * \brief Compares two shorts for equality.
+ *
+ * \param a a short pointer (short *)
+ * \param b a short pointer (short *)
+ * \retval 0 if the shorts pointed to are equal
+ * \retval 1 if a is greater than b
+ * \retval -1 if a is less than b
+ */
int ast_hashtab_compare_shorts(const void *a, const void *b);
/*!
- * \brief determine if resize should occur
- * \returns 1 if the table is 75% full or more
-*/
+ * \brief Determines if a table resize should occur using the Java algorithm
+ * (if the table load factor is 75% or higher).
+ *
+ * \param tab the hash table to operate on
+ * \retval 0 if the table load factor is less than or equal to 75%
+ * \retval 1 if the table load factor is greater than 75%
+ */
int ast_hashtab_resize_java(struct ast_hashtab *tab);
-/*! \brief no resizing; always return 0 */
+/*! \brief Causes a resize whenever the number of elements stored in the table
+ * exceeds the number of buckets in the table.
+ *
+ * \param tab the hash table to operate on
+ * \retval 0 if the number of elements in the table is less than or equal to
+ * the number of buckets
+ * \retval 1 if the number of elements in the table exceeds the number of
+ * buckets
+ */
int ast_hashtab_resize_tight(struct ast_hashtab *tab);
-/*! \brief no resizing; always return 0 */
+/*!
+ * \brief Effectively disables resizing by always returning 0, regardless of
+ * of load factor.
+ *
+ * \param tab the hash table to operate on
+ * \return 0 is always returned
+ */
int ast_hashtab_resize_none(struct ast_hashtab *tab);
/*! \brief Create a prime number roughly 2x the current table size */
@@ -160,18 +200,37 @@
/*! \brief always return current size -- no resizing */
int ast_hashtab_newsize_none(struct ast_hashtab *tab);
-/*!
+/*!
* \brief Hashes a string to a number
- * \param obj
- * \note A modulus is applied so it in the range 0 to mod-1
-*/
+ *
+ * \param obj the string to hash
+ * \return Integer hash of the specified string
+ * \sa ast_hashtable_hash_string_nocase
+ * \sa ast_hashtab_hash_string_sax
+ * \note A modulus will be applied to the return value of this function
+ */
unsigned int ast_hashtab_hash_string(const void *obj);
-/*! \brief Upperases each char before using them for a hash */
+/*!
+ * \brief Hashes a string to a number ignoring case
+ *
+ * \param obj the string to hash
+ * \return Integer hash of the specified string
+ * \sa ast_hashtable_hash_string
+ * \sa ast_hashtab_hash_string_sax
+ * \note A modulus will be applied to the return value of this function
+ */
unsigned int ast_hashtab_hash_string_nocase(const void *obj);
-
-unsigned int ast_hashtab_hash_string_sax(const void *obj); /* from Josh */
+/*!
+ * \brief Hashes a string to a number using a modified Shift-And-XOR algorithm
+ *
+ * \param obj the string to hash
+ * \return Integer has of the specified string
+ * \sa ast_hastable_hash_string
+ * \sa ast_hastable_hash_string_nocase
+ */
+unsigned int ast_hashtab_hash_string_sax(const void *obj);
unsigned int ast_hashtab_hash_int(const int num); /* right now, both these funcs are just result = num%modulus; */
@@ -183,7 +242,7 @@
/*!
* \brief Create the hashtable list
* \param initial_buckets starting number of buckets
- * \param compare a func ptr to compare two elements in the hash -- cannot be null
+ * \param compare a func ptr to compare two elements in the hash -- cannot be null
* \param resize a func ptr to decide if the table needs to be resized, a NULL ptr here will cause a default to be used
* \param newsize a func ptr that returns a new size of the array. A NULL will cause a default to be used
* \param hash a func ptr to do the hashing
@@ -191,23 +250,23 @@
*/
#if (defined(MALLOC_DEBUG) && !defined(STANDALONE))
struct ast_hashtab * _ast_hashtab_create(int initial_buckets,
- int (*compare)(const void *a, const void *b),
- int (*resize)(struct ast_hashtab *),
+ 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),
+ unsigned int (*hash)(const void *obj),
int do_locking, const char *file, int lineno, const char *function);
#define ast_hashtab_create(a,b,c,d,e,f) _ast_hashtab_create(a,b,c,d,e,f,__FILE__,__LINE__,__PRETTY_FUNCTION__)
#else
struct ast_hashtab * ast_hashtab_create(int initial_buckets,
- int (*compare)(const void *a, const void *b),
- int (*resize)(struct ast_hashtab *),
+ 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),
+ unsigned int (*hash)(const void *obj),
int do_locking );
#endif
/*!
- * \brief This func will free the hash table and all its memory.
+ * \brief This func will free the hash table and all its memory.
* \note It doesn't touch the objects stored in it, unless you
* specify a destroy func; it will call that func for each
* object in the hashtab, remove all the objects, and then
@@ -220,14 +279,14 @@
/*!
- * \brief Insert without checking
+ * \brief Insert without checking
* \param tab
* \param obj
*
* Normally, you'd insert "safely" by checking to see if the element is
* already there; in this case, you must already have checked. If an element
* is already in the hashtable, that matches this one, most likely this one
- * will be found first.
+ * will be found first.
* \note will force a resize if the resize func returns 1
* \retval 1 on success
* \retval 0 if there's a problem
@@ -239,7 +298,7 @@
* \param tab
* \param obj
* \param h hashed index value
- *
+ *
* \note Will force a resize if the resize func returns 1
* \retval 1 on success
* \retval 0 if there's a problem
@@ -250,14 +309,14 @@
* \brief Check and insert new object only if it is not there.
* \note Will force a resize if the resize func returns 1
* \retval 1 on success
- * \retval 0 if there's a problem, or it's already there.
+ * \retval 0 if there's a problem, or it's already there.
*/
int ast_hashtab_insert_safe(struct ast_hashtab *tab, const void *obj);
/*!
- * \brief Lookup this object in the hash table.
- * \param tab
- * \param obj
+ * \brief Lookup this object in the hash table.
+ * \param tab
+ * \param obj
* \retval a ptr if found
* \retval NULL if not found
*/
@@ -324,15 +383,15 @@
following locking routines yourself to lock the table between threads. */
/*! \brief Call this after you create the table to init the lock */
-void ast_hashtab_initlock(struct ast_hashtab *tab);
+void ast_hashtab_initlock(struct ast_hashtab *tab);
/*! \brief Request a write-lock on the table. */
-void ast_hashtab_wrlock(struct ast_hashtab *tab);
+void ast_hashtab_wrlock(struct ast_hashtab *tab);
/*! \brief Request a read-lock on the table -- don't change anything! */
-void ast_hashtab_rdlock(struct ast_hashtab *tab);
+void ast_hashtab_rdlock(struct ast_hashtab *tab);
/*! \brief release a read- or write- lock. */
-void ast_hashtab_unlock(struct ast_hashtab *tab);
+void ast_hashtab_unlock(struct ast_hashtab *tab);
/*! \brief Call this before you destroy the table. */
-void ast_hashtab_destroylock(struct ast_hashtab *tab);
+void ast_hashtab_destroylock(struct ast_hashtab *tab);
#endif
Modified: trunk/main/hashtab.c
URL: http://svn.digium.com/svn-view/asterisk/trunk/main/hashtab.c?view=diff&rev=177884&r1=177883&r2=177884
==============================================================================
--- trunk/main/hashtab.c (original)
+++ trunk/main/hashtab.c Sat Feb 21 08:16:44 2009
@@ -38,7 +38,7 @@
#include "asterisk/linkedlists.h"
#include "asterisk/hashtab.h"
-static void ast_hashtab_resize( struct ast_hashtab *tab);
+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 */
@@ -60,7 +60,7 @@
if (ai < bi)
return -1;
-
+
return !(ai == bi);
}
@@ -68,7 +68,7 @@
{
short as = *((short *) a);
short bs = *((short *) b);
-
+
if (as < bs)
return -1;
@@ -95,10 +95,10 @@
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;
@@ -109,20 +109,19 @@
/* 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++;
@@ -133,7 +132,7 @@
{
int x = (tab->hash_tab_size << 1);
int i = (tab->hash_tab_size + x);
-
+
while (!ast_is_prime(i))
i++;
@@ -150,14 +149,13 @@
unsigned char *str = (unsigned char *) obj;
unsigned int total;
- for (total = 0; *str; str++)
- {
+ 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;
@@ -184,14 +182,14 @@
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
+ /* 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);
}
@@ -215,11 +213,11 @@
#else
ast_hashtab_create
#endif
-(int initial_buckets,
- int (*compare)(const void *a, const void *b),
- int (*resize)(struct ast_hashtab *),
+(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),
+ unsigned int (*hash)(const void *obj),
int do_locking
#if (defined(MALLOC_DEBUG) && !defined(STANDALONE))
, const char *file, int lineno, const char *function
@@ -363,12 +361,12 @@
ast_rwlock_unlock(&tab->lock);
}
-void ast_hashtab_destroy( struct ast_hashtab *tab, void (*objdestroyfunc)(void *obj))
+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);
@@ -376,19 +374,24 @@
/* 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 */
-
+ if (t->object && objdestroyfunc) {
+ /* I cast this because I'm not going to MOD it, I'm going to DESTROY
+ * it.
+ */
+ (*objdestroyfunc)((void *) t->object);
+ }
+
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 */
-
+
+ for (i = 0; i < tab->hash_tab_size; i++) {
+ /* Not totally necessary, but best to destroy old pointers */
+ tab->array[i] = NULL;
+ }
free(tab->array);
}
if (tab->do_locking) {
@@ -403,7 +406,7 @@
{
unsigned int h;
int res=0;
-
+
if (!tab || !obj)
return res;
@@ -424,10 +427,10 @@
{
int c;
struct ast_hashtab_bucket *b;
-
+
if (!tab || !obj)
return 0;
-
+
for (c = 0, b = tab->array[h]; b; b= b->next)
c++;
@@ -469,13 +472,13 @@
if (tab->do_locking)
ast_rwlock_unlock(&tab->lock);
-
+
return ret2;
}
if (tab->do_locking)
ast_rwlock_unlock(&tab->lock);
-
+
return 0;
}
@@ -487,7 +490,7 @@
if (!tab || !obj)
return 0;
-
+
if (tab->do_locking)
ast_rwlock_rdlock(&tab->lock);
@@ -510,14 +513,14 @@
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);
@@ -532,13 +535,13 @@
if (!tab || !obj)
return 0;
-
+
h = (*tab->hash)(obj) % tab->hash_tab_size;
-
+
ret = ast_hashtab_lookup_internal(tab,obj,h);
-
- *bucket = h;
-
+
+ *bucket = h;
+
return ret;
}
@@ -548,14 +551,15 @@
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 */
+ /* I can't touch obj in this func, but the outside world is welcome to */
+ return (void*) b->object;
}
}
return NULL;
}
-void ast_hashtab_get_stats( struct ast_hashtab *tab, int *biggest_bucket_size, int *resize_count, int *num_objects, int *num_buckets)
+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)
@@ -568,23 +572,20 @@
ast_rwlock_unlock(&tab->lock);
}
- /* this function returns the number of elements stored in the hashtab */
-int ast_hashtab_size( struct ast_hashtab *tab)
+/* 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)
+/* 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)
{
@@ -593,10 +594,10 @@
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
+ 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
@@ -634,7 +635,7 @@
{
/* returns an iterator */
struct ast_hashtab_iter *it;
-
+
if (!(it = ast_calloc(1, sizeof(*it))))
return NULL;
@@ -651,7 +652,7 @@
{
/* returns an iterator */
struct ast_hashtab_iter *it;
-
+
if (!(it = ast_calloc(1, sizeof(*it))))
return NULL;
@@ -674,7 +675,7 @@
{
/* 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;
@@ -687,17 +688,17 @@
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 */
@@ -763,12 +764,12 @@
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 */
}
}
@@ -785,12 +786,12 @@
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);
@@ -807,14 +808,14 @@
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 */
}
}
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