switch_hashtable.c File Reference

#include "switch.h"
#include "private/switch_hashtable_private.h"

Include dependency graph for switch_hashtable.c:

Go to the source code of this file.

Functions
switch_status_t	switch_create_hashtable (switch_hashtable_t **hp, unsigned int minsize, unsigned int(*hashf)(void *), int(*eqf)(void *, void *))
static int	hashtable_expand (switch_hashtable_t *h)
unsigned int	switch_hashtable_count (switch_hashtable_t *h)
static void *	_switch_hashtable_remove (switch_hashtable_t *h, void *k, unsigned int hashvalue, unsigned int index)
int	switch_hashtable_insert_destructor (switch_hashtable_t *h, void *k, void *v, hashtable_flag_t flags, hashtable_destructor_t destructor)
void *	switch_hashtable_search (switch_hashtable_t *h, void *k)
void *	switch_hashtable_remove (switch_hashtable_t *h, void *k)
void	switch_hashtable_destroy (switch_hashtable_t **h)
switch_hashtable_iterator_t *	switch_hashtable_next (switch_hashtable_iterator_t **iP)
switch_hashtable_iterator_t *	switch_hashtable_first_iter (switch_hashtable_t *h, switch_hashtable_iterator_t *it)
void	switch_hashtable_this_val (switch_hashtable_iterator_t *i, void *val)
void	switch_hashtable_this (switch_hashtable_iterator_t *i, const void **key, switch_ssize_t *klen, void **val)

Variables
static const unsigned int	primes []
const unsigned int	prime_table_length = sizeof(primes)/sizeof(primes[0])
const float	max_load_factor = 0.65f

Function Documentation

_switch_hashtable_remove()

static void* _switch_hashtable_remove ( switch_hashtable_t *  h, void *  k, unsigned int  hashvalue, unsigned int  index  )

static

Definition at line 156 of file switch_hashtable.c.

References entry::destructor, switch_hashtable::entrycount, switch_hashtable::eqfn, entry::flags, freekey, entry::h, HASHTABLE_FLAG_FREE_KEY, HASHTABLE_FLAG_FREE_VALUE, index, entry::k, entry::next, SWITCH_DECLARE, switch_safe_free, switch_hashtable::table, and entry::v.

Referenced by switch_hashtable_insert_destructor(), and switch_hashtable_remove().

                                                                                                                   {
        /* TODO: consider compacting the table when the load factor drops enough,
         *       or provide a 'compact' method. */

        struct entry *e;
        struct entry **pE;
        void *v;


        pE = &(h->table[index]);
        e = *pE;
        while (NULL != e) {
                /* Check hash value to short circuit heavier comparison */
                if ((hashvalue == e->h) && (h->eqfn(k, e->k))) {
                        *pE = e->next;
                        h->entrycount--;
                        v = e->v;
                        if (e->flags & HASHTABLE_FLAG_FREE_KEY) {
                                freekey(e->k);
                        }
                        if (e->flags & HASHTABLE_FLAG_FREE_VALUE) {
                                switch_safe_free(e->v);
                                v = NULL;
                        } else if (e->destructor) {
                                e->destructor(e->v);
                                v = e->v = NULL;
                        }
                        switch_safe_free(e);
                        return v;
                }
                pE = &(e->next);
                e = e->next;
        }
        return NULL;
}

hashtable_expand()

static int hashtable_expand ( switch_hashtable_t *  h )

static

Definition at line 94 of file switch_hashtable.c.

References entry::h, index, indexFor(), switch_hashtable::loadlimit, memset(), entry::next, prime_table_length, switch_hashtable::primeindex, primes, SWITCH_DECLARE, switch_safe_free, switch_hashtable::table, and switch_hashtable::tablelength.

Referenced by switch_hashtable_insert_destructor().

{
        /* Double the size of the table to accommodate more entries */
        struct entry **newtable;
        struct entry *e;
        struct entry **pE;
        unsigned int newsize, i, index;
        /* Check we're not hitting max capacity */
        if (h->primeindex == (prime_table_length - 1)) return 0;
        newsize = primes[++(h->primeindex)];

        newtable = (struct entry **)malloc(sizeof(struct entry*) * newsize);
        if (NULL != newtable)
                {
                        memset(newtable, 0, newsize * sizeof(struct entry *));
                        /* This algorithm is not 'stable'. ie. it reverses the list
                         * when it transfers entries between the tables */
                        for (i = 0; i < h->tablelength; i++) {
                                while (NULL != (e = h->table[i])) {
                                        h->table[i] = e->next;
                                        index = indexFor(newsize,e->h);
                                        e->next = newtable[index];
                                        newtable[index] = e;
                                }
                        }
                        switch_safe_free(h->table);
                        h->table = newtable;
                }
        /* Plan B: realloc instead */
        else
                {
                        newtable = (struct entry **)
                                realloc(h->table, newsize * sizeof(struct entry *));
                        if (NULL == newtable) { (h->primeindex)--; return 0; }
                        h->table = newtable;
                        memset(newtable[h->tablelength], 0, newsize - h->tablelength);
                        for (i = 0; i < h->tablelength; i++) {
                                for (pE = &(newtable[i]), e = *pE; e != NULL; e = *pE) {
                                        index = indexFor(newsize,e->h);

                                        if (index == i) {
                                                pE = &(e->next);
                                        } else {
                                                *pE = e->next;
                                                e->next = newtable[index];
                                                newtable[index] = e;
                                        }
                                }
                        }
                }
        h->tablelength = newsize;
        h->loadlimit   = (unsigned int) ceil(newsize * max_load_factor);
        return -1;
}

switch_create_hashtable()

switch_status_t switch_create_hashtable	(	switch_hashtable_t **	hp,
		unsigned int	minsize,
		unsigned int(*)(void *)	hashf,
		int(*)(void *, void *)	eqf
	)

Definition at line 56 of file switch_hashtable.c.

References switch_hashtable::entrycount, switch_hashtable::eqfn, entry::h, switch_frame_geometry::h, switch_hashtable::hashfn, switch_hashtable::loadlimit, memset(), prime_table_length, switch_hashtable::primeindex, primes, SWITCH_STATUS_FALSE, SWITCH_STATUS_SUCCESS, switch_hashtable::table, and switch_hashtable::tablelength.

Referenced by switch_core_hash_init_case(), and switch_core_inthash_init().

{
        switch_hashtable_t *h;
        unsigned int pindex, size = primes[0];

        /* Check requested hashtable isn't too large */
        if (minsize > (1u << 30)) {*hp = NULL; return SWITCH_STATUS_FALSE;}
        /* Enforce size as prime */
        for (pindex=0; pindex < prime_table_length; pindex++) {
                if (primes[pindex] > minsize) {
                        size = primes[pindex];
                        break;
                }
        }
        h = (switch_hashtable_t *) malloc(sizeof(switch_hashtable_t));

        if (NULL == h) abort(); /*oom*/

        h->table = (struct entry **)malloc(sizeof(struct entry*) * size);

        if (NULL == h->table) abort(); /*oom*/

        memset(h->table, 0, size * sizeof(struct entry *));
        h->tablelength  = size;
        h->primeindex   = pindex;
        h->entrycount   = 0;
        h->hashfn       = hashf;
        h->eqfn         = eqf;
        h->loadlimit    = (unsigned int) ceil(size * max_load_factor);

        *hp = h;
        return SWITCH_STATUS_SUCCESS;
}

switch_hashtable_count()

unsigned int switch_hashtable_count

(

switch_hashtable_t *

h

)

Definition at line 151 of file switch_hashtable.c.

Referenced by switch_jb_destroy().

{
        return h->entrycount;
}

switch_hashtable_destroy()

void switch_hashtable_destroy

(

switch_hashtable_t **

h

)

Definition at line 253 of file switch_hashtable.c.

References entry::destructor, entry::flags, freekey, entry::h, HASHTABLE_FLAG_FREE_KEY, HASHTABLE_FLAG_FREE_VALUE, entry::k, entry::next, switch_safe_free, and entry::v.

Referenced by switch_core_hash_destroy(), and switch_core_inthash_destroy().

{
        unsigned int i;
        struct entry *e, *f;
        struct entry **table = (*h)->table;

        for (i = 0; i < (*h)->tablelength; i++) {
                e = table[i];
                while (NULL != e) {
                        f = e; e = e->next;

                        if (f->flags & HASHTABLE_FLAG_FREE_KEY) {
                                freekey(f->k);
                        }

                        if (f->flags & HASHTABLE_FLAG_FREE_VALUE) {
                                switch_safe_free(f->v);
                        } else if (f->destructor) {
                                f->destructor(f->v);
                                f->v = NULL;
                        }
                        switch_safe_free(f);
                }
        }

        switch_safe_free((*h)->table);
        free(*h);
        *h = NULL;
}

switch_hashtable_first_iter()

switch_hashtable_iterator_t* switch_hashtable_first_iter	(	switch_hashtable_t *	h,
		switch_hashtable_iterator_t *	it
	)

Definition at line 316 of file switch_hashtable.c.

References switch_hashtable_iterator::e, entry::h, switch_hashtable_iterator::h, switch_hashtable_iterator::pos, switch_assert, switch_hashtable_next(), and switch_zmalloc.

Referenced by switch_core_hash_first_iter().

{
        switch_hashtable_iterator_t *iterator;

        if (it) {
                iterator = it;
        } else {
                switch_zmalloc(iterator, sizeof(*iterator));
        }

        switch_assert(iterator);

        iterator->pos = 0;
        iterator->e = NULL;
        iterator->h = h;

        return switch_hashtable_next(&iterator);
}

switch_hashtable_insert_destructor()

int switch_hashtable_insert_destructor	(	switch_hashtable_t *	h,
		void *	k,
		void *	v,
		hashtable_flag_t	flags,
		hashtable_destructor_t	destructor
	)

Definition at line 194 of file switch_hashtable.c.

References _switch_hashtable_remove(), entry::destructor, entry::flags, entry::h, hash, HASHTABLE_DUP_CHECK, hashtable_expand(), index, indexFor(), entry::k, entry::next, SWITCH_DECLARE, and entry::v.

Referenced by switch_core_hash_insert_alloc_destructor(), switch_core_hash_insert_auto_free(), switch_core_hash_insert_destructor(), switch_core_hash_insert_dup_auto_free(), switch_core_hash_insert_dup_destructor(), switch_core_hash_insert_pointer(), and switch_core_inthash_insert().

{
        struct entry *e;
        unsigned int hashvalue = hash(h, k);
        unsigned index = indexFor(h->tablelength, hashvalue);

        if (flags & HASHTABLE_DUP_CHECK) {
                _switch_hashtable_remove(h, k, hashvalue, index);
        }

        if (++(h->entrycount) > h->loadlimit)
                {
                        /* Ignore the return value. If expand fails, we should
                         * still try cramming just this value into the existing table
                         * -- we may not have memory for a larger table, but one more
                         * element may be ok. Next time we insert, we'll try expanding again.*/
                        hashtable_expand(h);
                        index = indexFor(h->tablelength, hashvalue);
                }
        e = (struct entry *)malloc(sizeof(struct entry));
        if (NULL == e) { --(h->entrycount); return 0; } /*oom*/
        e->h = hashvalue;
        e->k = k;
        e->v = v;
        e->flags = flags;
        e->destructor = destructor;
        e->next = h->table[index];
        h->table[index] = e;
        return -1;
}

switch_hashtable_next()

switch_hashtable_iterator_t* switch_hashtable_next

(

switch_hashtable_iterator_t **

iP

)

Definition at line 283 of file switch_hashtable.c.

References switch_hashtable_iterator::e, switch_hashtable_iterator::h, entry::next, switch_hashtable_iterator::pos, switch_hashtable::table, and switch_hashtable::tablelength.

Referenced by switch_core_hash_next(), and switch_hashtable_first_iter().

{

        switch_hashtable_iterator_t *i = *iP;

        if (i->e) {
                if ((i->e = i->e->next) != 0) {
                        return i;
                } else {
                        i->pos++;
                }
        }

        while(i->pos < i->h->tablelength && !i->h->table[i->pos]) {
                i->pos++;
        }

        if (i->pos >= i->h->tablelength) {
                goto end;
        }

        if ((i->e = i->h->table[i->pos]) != 0) {
                return i;
        }

 end:

        free(i);
        *iP = NULL;

        return NULL;
}

switch_hashtable_remove()

void* switch_hashtable_remove	(	switch_hashtable_t *	h,
		void *	k
	)

Definition at line 244 of file switch_hashtable.c.

References _switch_hashtable_remove(), entry::h, hash, indexFor(), entry::k, and SWITCH_DECLARE.

Referenced by switch_core_hash_delete(), and switch_core_inthash_delete().

{
        unsigned int hashvalue = hash(h,k);
        return _switch_hashtable_remove(h, k, hashvalue, indexFor(h->tablelength,hashvalue));
}

switch_hashtable_search()

void* switch_hashtable_search	(	switch_hashtable_t *	h,
		void *	k
	)

Definition at line 227 of file switch_hashtable.c.

References entry::h, hash, index, indexFor(), entry::k, entry::next, SWITCH_DECLARE, and entry::v.

Referenced by switch_core_hash_find(), and switch_core_inthash_find().

{
        struct entry *e;
        unsigned int hashvalue, index;
        hashvalue = hash(h,k);
        index = indexFor(h->tablelength,hashvalue);
        e = h->table[index];
        while (NULL != e) {
                /* Check hash value to short circuit heavier comparison */
                if ((hashvalue == e->h) && (h->eqfn(k, e->k))) return e->v;
                e = e->next;
        }
        return NULL;
}

switch_hashtable_this()

void switch_hashtable_this	(	switch_hashtable_iterator_t *	i,
		const void **	key,
		switch_ssize_t *	klen,
		void **	val
	)

Definition at line 342 of file switch_hashtable.c.

References switch_hashtable_iterator::e, entry::k, and entry::v.

Referenced by switch_core_hash_this().

{
        if (i->e) {
                if (key) {
                        *key = i->e->k;
                }
                if (klen) {
                        *klen = (int)strlen(i->e->k);
                }
                if (val) {
                        *val = i->e->v;
                }
        } else {
                if (key) {
                        *key = NULL;
                }
                if (klen) {
                        *klen = 0;
                }
                if (val) {
                        *val = NULL;
                }
        }
}

switch_hashtable_this_val()

void switch_hashtable_this_val	(	switch_hashtable_iterator_t *	i,
		void *	val
	)

Definition at line 335 of file switch_hashtable.c.

References switch_hashtable_iterator::e, and entry::v.

Referenced by switch_core_hash_this_val().

{
        if (i->e) {
                i->e->v = val;
        }
}

Variable Documentation

max_load_factor

const float max_load_factor = 0.65f

Definition at line 52 of file switch_hashtable.c.

prime_table_length

const unsigned int prime_table_length = sizeof(primes)/sizeof(primes[0])

Definition at line 51 of file switch_hashtable.c.

Referenced by hashtable_expand(), and switch_create_hashtable().

primes

const unsigned int primes[]

static

Initial value:

= {
        53, 97, 193, 389,
        769, 1543, 3079, 6151,
        12289, 24593, 49157, 98317,
        196613, 393241, 786433, 1572869,
        3145739, 6291469, 12582917, 25165843,
        50331653, 100663319, 201326611, 402653189,
        805306457, 1610612741
}

Definition at line 42 of file switch_hashtable.c.

Referenced by hashtable_expand(), and switch_create_hashtable().