xenocara/xserver/Xext/hashtable.c

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#ifdef HAVE_DIX_CONFIG_H
#include <dix-config.h>
#endif
#include <stdlib.h>
#include "misc.h"
#include "hashtable.h"
/* HashResourceID */
#include "resource.h"
#define INITHASHSIZE 6
#define MAXHASHSIZE 11
struct HashTableRec {
int keySize;
int dataSize;
int elements; /* number of elements inserted */
int bucketBits; /* number of buckets is 1 << bucketBits */
struct xorg_list *buckets; /* array of bucket list heads */
HashFunc hash;
HashCompareFunc compare;
pointer cdata;
};
typedef struct {
struct xorg_list l;
void *key;
void *data;
} BucketRec, *BucketPtr;
HashTable
ht_create(int keySize,
int dataSize,
HashFunc hash,
HashCompareFunc compare,
pointer cdata)
{
int c;
int numBuckets;
HashTable ht = malloc(sizeof(struct HashTableRec));
if (!ht) {
return NULL;
}
ht->keySize = keySize;
ht->dataSize = dataSize;
ht->hash = hash;
ht->compare = compare;
ht->elements = 0;
ht->bucketBits = INITHASHSIZE;
numBuckets = 1 << ht->bucketBits;
ht->buckets = malloc(numBuckets * sizeof(*ht->buckets));
ht->cdata = cdata;
if (ht->buckets) {
for (c = 0; c < numBuckets; ++c) {
xorg_list_init(&ht->buckets[c]);
}
return ht;
} else {
free(ht);
return NULL;
}
}
void
ht_destroy(HashTable ht)
{
int c;
BucketPtr it, tmp;
int numBuckets = 1 << ht->bucketBits;
for (c = 0; c < numBuckets; ++c) {
xorg_list_for_each_entry_safe(it, tmp, &ht->buckets[c], l) {
xorg_list_del(&it->l);
free(it);
}
}
free(ht->buckets);
}
static Bool
double_size(HashTable ht)
{
struct xorg_list *newBuckets;
int numBuckets = 1 << ht->bucketBits;
int newBucketBits = ht->bucketBits + 1;
int newNumBuckets = 1 << newBucketBits;
int c;
newBuckets = malloc(newNumBuckets * sizeof(*ht->buckets));
if (newBuckets) {
for (c = 0; c < newNumBuckets; ++c) {
xorg_list_init(&newBuckets[c]);
}
for (c = 0; c < numBuckets; ++c) {
BucketPtr it, tmp;
xorg_list_for_each_entry_safe(it, tmp, &ht->buckets[c], l) {
struct xorg_list *newBucket =
&newBuckets[ht->hash(ht->cdata, it->key, newBucketBits)];
xorg_list_del(&it->l);
xorg_list_add(&it->l, newBucket);
}
}
free(ht->buckets);
ht->buckets = newBuckets;
ht->bucketBits = newBucketBits;
return TRUE;
} else {
return FALSE;
}
}
pointer
ht_add(HashTable ht, pointer key)
{
unsigned index = ht->hash(ht->cdata, key, ht->bucketBits);
struct xorg_list *bucket = &ht->buckets[index];
BucketRec *elem = calloc(1, sizeof(BucketRec));
if (!elem) {
goto outOfMemory;
}
elem->key = malloc(ht->keySize);
if (!elem->key) {
goto outOfMemory;
}
/* we avoid signaling an out-of-memory error if dataSize is 0 */
elem->data = calloc(1, ht->dataSize);
if (ht->dataSize && !elem->data) {
goto outOfMemory;
}
xorg_list_add(&elem->l, bucket);
++ht->elements;
memcpy(elem->key, key, ht->keySize);
if (ht->elements > 4 * (1 << ht->bucketBits) &&
ht->bucketBits < MAXHASHSIZE) {
if (!double_size(ht)) {
--ht->elements;
xorg_list_del(&elem->l);
goto outOfMemory;
}
}
/* if memory allocation has failed due to dataSize being 0, return
a "dummy" pointer pointing at the of the key */
return elem->data ? elem->data : ((char*) elem->key + ht->keySize);
outOfMemory:
if (elem) {
free(elem->key);
free(elem->data);
free(elem);
}
return NULL;
}
void
ht_remove(HashTable ht, pointer key)
{
unsigned index = ht->hash(ht->cdata, key, ht->bucketBits);
struct xorg_list *bucket = &ht->buckets[index];
BucketPtr it;
xorg_list_for_each_entry(it, bucket, l) {
if (ht->compare(ht->cdata, key, it->key) == 0) {
xorg_list_del(&it->l);
--ht->elements;
free(it->key);
free(it->data);
free(it);
return;
}
}
}
pointer
ht_find(HashTable ht, pointer key)
{
unsigned index = ht->hash(ht->cdata, key, ht->bucketBits);
struct xorg_list *bucket = &ht->buckets[index];
BucketPtr it;
xorg_list_for_each_entry(it, bucket, l) {
if (ht->compare(ht->cdata, key, it->key) == 0) {
return it->data ? it->data : ((char*) it->key + ht->keySize);
}
}
return NULL;
}
void
ht_dump_distribution(HashTable ht)
{
int c;
int numBuckets = 1 << ht->bucketBits;
for (c = 0; c < numBuckets; ++c) {
BucketPtr it;
int n = 0;
xorg_list_for_each_entry(it, &ht->buckets[c], l) {
++n;
}
printf("%d: %d\n", c, n);
}
}
/* Picked the function from http://burtleburtle.net/bob/hash/doobs.html by
Bob Jenkins, which is released in public domain */
static CARD32
one_at_a_time_hash(const void *data, int len)
{
CARD32 hash;
int i;
const char *key = data;
for (hash=0, i=0; i<len; ++i) {
hash += key[i];
hash += (hash << 10);
hash ^= (hash >> 6);
}
hash += (hash << 3);
hash ^= (hash >> 11);
hash += (hash << 15);
return hash;
}
unsigned
ht_generic_hash(void *cdata, const void *ptr, int numBits)
{
HtGenericHashSetupPtr setup = cdata;
return one_at_a_time_hash(ptr, setup->keySize) & ~((~0) << numBits);
}
int
ht_generic_compare(void *cdata, const void *l, const void *r)
{
HtGenericHashSetupPtr setup = cdata;
return memcmp(l, r, setup->keySize);
}
unsigned
ht_resourceid_hash(void * cdata, const void * data, int numBits)
{
const XID* idPtr = data;
XID id = *idPtr & RESOURCE_ID_MASK;
(void) cdata;
return HashResourceID(id, numBits);
}
int
ht_resourceid_compare(void* cdata, const void* a, const void* b)
{
const XID* xa = a;
const XID* xb = b;
(void) cdata;
return
*xa < *xb ? -1 :
*xa > *xb ? 1 :
0;
}
void
ht_dump_contents(HashTable ht,
void (*print_key)(void *opaque, void *key),
void (*print_value)(void *opaque, void *value),
void* opaque)
{
int c;
int numBuckets = 1 << ht->bucketBits;
for (c = 0; c < numBuckets; ++c) {
BucketPtr it;
int n = 0;
printf("%d: ", c);
xorg_list_for_each_entry(it, &ht->buckets[c], l) {
if (n > 0) {
printf(", ");
}
print_key(opaque, it->key);
printf("->");
print_value(opaque, it->data);
++n;
}
printf("\n");
}
}