/**************************************************************************
*
* Copyright 2007 VMware, Inc.
* All Rights Reserved.
*
* Permission is hereby granted, free of charge, to any person obtaining a
* copy of this software and associated documentation files (the
* "Software"), to deal in the Software without restriction, including
* without limitation the rights to use, copy, modify, merge, publish,
* distribute, sub license, and/or sell copies of the Software, and to
* permit persons to whom the Software is furnished to do so, subject to
* the following conditions:
*
* The above copyright notice and this permission notice (including the
* next paragraph) shall be included in all copies or substantial portions
* of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
* OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT.
* IN NO EVENT SHALL VMWARE AND/OR ITS SUPPLIERS BE LIABLE FOR
* ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
* TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
* SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
*
**************************************************************************/
/*
* Authors:
* Zack Rusin <zackr@vmware.com>
*/
#include "util/u_debug.h"
#include "util/u_memory.h"
#include "cso_hash.h"
#ifndef MAX
#define MAX(a, b) ((a > b) ? (a) : (b))
#endif
static const int MinNumBits = 4;
static const unsigned char prime_deltas[] = {
0, 0, 1, 3, 1, 5, 3, 3, 1, 9, 7, 5, 3, 9, 25, 3,
1, 21, 3, 21, 7, 15, 9, 5, 3, 29, 15, 0, 0, 0, 0, 0
};
static int primeForNumBits(int numBits)
{
return (1 << numBits) + prime_deltas[numBits];
}
/*
Returns the smallest integer n such that
primeForNumBits(n) >= hint.
*/
static int countBits(int hint)
{
int numBits = 0;
int bits = hint;
while (bits > 1) {
bits >>= 1;
numBits++;
}
if (numBits >= (int)sizeof(prime_deltas)) {
numBits = sizeof(prime_deltas) - 1;
} else if (primeForNumBits(numBits) < hint) {
++numBits;
}
return numBits;
}
struct cso_node {
struct cso_node *next;
unsigned key;
void *value;
};
struct cso_hash_data {
struct cso_node *fakeNext;
struct cso_node **buckets;
int size;
int nodeSize;
short userNumBits;
short numBits;
int numBuckets;
};
struct cso_hash {
union {
struct cso_hash_data *d;
struct cso_node *e;
} data;
};
static void *cso_data_allocate_node(struct cso_hash_data *hash)
{
return MALLOC(hash->nodeSize);
}
static void cso_free_node(struct cso_node *node)
{
FREE(node);
}
static struct cso_node *
cso_hash_create_node(struct cso_hash *hash,
unsigned akey, void *avalue,
struct cso_node **anextNode)
{
struct cso_node *node = cso_data_allocate_node(hash->data.d);
if (!node)
return NULL;
node->key = akey;
node->value = avalue;
node->next = (struct cso_node*)(*anextNode);
*anextNode = node;
++hash->data.d->size;
return node;
}
static void cso_data_rehash(struct cso_hash_data *hash, int hint)
{
if (hint < 0) {
hint = countBits(-hint);
if (hint < MinNumBits)
hint = MinNumBits;
hash->userNumBits = (short)hint;
while (primeForNumBits(hint) < (hash->size >> 1))
++hint;
} else if (hint < MinNumBits) {
hint = MinNumBits;
}
if (hash->numBits != hint) {
struct cso_node *e = (struct cso_node *)(hash);
struct cso_node **oldBuckets = hash->buckets;
int oldNumBuckets = hash->numBuckets;
int i = 0;
hash->numBits = (short)hint;
hash->numBuckets = primeForNumBits(hint);
hash->buckets = MALLOC(sizeof(struct cso_node*) * hash->numBuckets);
for (i = 0; i < hash->numBuckets; ++i)
hash->buckets[i] = e;
for (i = 0; i < oldNumBuckets; ++i) {
struct cso_node *firstNode = oldBuckets[i];
while (firstNode != e) {
unsigned h = firstNode->key;
struct cso_node *lastNode = firstNode;
struct cso_node *afterLastNode;
struct cso_node **beforeFirstNode;
while (lastNode->next != e && lastNode->next->key == h)
lastNode = lastNode->next;
afterLastNode = lastNode->next;
beforeFirstNode = &hash->buckets[h % hash->numBuckets];
while (*beforeFirstNode != e)
beforeFirstNode = &(*beforeFirstNode)->next;
lastNode->next = *beforeFirstNode;
*beforeFirstNode = firstNode;
firstNode = afterLastNode;
}
}
FREE(oldBuckets);
}
}
static void cso_data_might_grow(struct cso_hash_data *hash)
{
if (hash->size >= hash->numBuckets)
cso_data_rehash(hash, hash->numBits + 1);
}
static void cso_data_has_shrunk(struct cso_hash_data *hash)
{
if (hash->size <= (hash->numBuckets >> 3) &&
hash->numBits > hash->userNumBits) {
int max = MAX(hash->numBits-2, hash->userNumBits);
cso_data_rehash(hash, max);
}
}
static struct cso_node *cso_data_first_node(struct cso_hash_data *hash)
{
struct cso_node *e = (struct cso_node *)(hash);
struct cso_node **bucket = hash->buckets;
int n = hash->numBuckets;
while (n--) {
if (*bucket != e)
return *bucket;
++bucket;
}
return e;
}
static struct cso_node **cso_hash_find_node(struct cso_hash *hash, unsigned akey)
{
struct cso_node **node;
if (hash->data.d->numBuckets) {
node = (struct cso_node **)(&hash->data.d->buckets[akey % hash->data.d->numBuckets]);
assert(*node
== hash
->data.
e || (*node
)->next
); while (*node != hash->data.e && (*node)->key != akey)
node = &(*node)->next;
} else {
node = (struct cso_node **)((const struct cso_node * const *)(&hash->data.e));
}
return node;
}
struct cso_hash_iter cso_hash_insert(struct cso_hash *hash,
unsigned key, void *data)
{
cso_data_might_grow(hash->data.d);
{
struct cso_node **nextNode = cso_hash_find_node(hash, key);
struct cso_node *node = cso_hash_create_node(hash, key, data, nextNode);
if (!node) {
struct cso_hash_iter null_iter = {hash, 0};
return null_iter;
}
{
struct cso_hash_iter iter = {hash, node};
return iter;
}
}
}
struct cso_hash * cso_hash_create(void)
{
struct cso_hash *hash = MALLOC_STRUCT(cso_hash);
if (!hash)
return NULL;
hash->data.d = MALLOC_STRUCT(cso_hash_data);
if (!hash->data.d) {
FREE(hash);
return NULL;
}
hash->data.d->fakeNext = 0;
hash->data.d->buckets = 0;
hash->data.d->size = 0;
hash->data.d->nodeSize = sizeof(struct cso_node);
hash->data.d->userNumBits = (short)MinNumBits;
hash->data.d->numBits = 0;
hash->data.d->numBuckets = 0;
return hash;
}
void cso_hash_delete(struct cso_hash *hash)
{
struct cso_node *e_for_x = (struct cso_node *)(hash->data.d);
struct cso_node **bucket = (struct cso_node **)(hash->data.d->buckets);
int n = hash->data.d->numBuckets;
while (n--) {
struct cso_node *cur = *bucket++;
while (cur != e_for_x) {
struct cso_node *next = cur->next;
cso_free_node(cur);
cur = next;
}
}
FREE(hash->data.d->buckets);
FREE(hash->data.d);
FREE(hash);
}
struct cso_hash_iter cso_hash_find(struct cso_hash *hash,
unsigned key)
{
struct cso_node **nextNode = cso_hash_find_node(hash, key);
struct cso_hash_iter iter = {hash, *nextNode};
return iter;
}
unsigned cso_hash_iter_key(struct cso_hash_iter iter)
{
if (!iter.node || iter.hash->data.e == iter.node)
return 0;
return iter.node->key;
}
void * cso_hash_iter_data(struct cso_hash_iter iter)
{
if (!iter.node || iter.hash->data.e == iter.node)
return 0;
return iter.node->value;
}
static struct cso_node *cso_hash_data_next(struct cso_node *node)
{
union {
struct cso_node *next;
struct cso_node *e;
struct cso_hash_data *d;
} a;
int start;
struct cso_node **bucket;
int n;
a.next = node->next;
if (!a.next) {
debug_printf("iterating beyond the last element\n");
return 0;
}
if (a.next->next)
return a.next;
start = (node->key % a.d->numBuckets) + 1;
bucket = a.d->buckets + start;
n = a.d->numBuckets - start;
while (n--) {
if (*bucket != a.e)
return *bucket;
++bucket;
}
return a.e;
}
static struct cso_node *cso_hash_data_prev(struct cso_node *node)
{
union {
struct cso_node *e;
struct cso_hash_data *d;
} a;
int start;
struct cso_node *sentinel;
struct cso_node **bucket;
a.e = node;
while (a.e->next)
a.e = a.e->next;
if (node == a.e)
start = a.d->numBuckets - 1;
else
start = node->key % a.d->numBuckets;
sentinel = node;
bucket = a.d->buckets + start;
while (start >= 0) {
if (*bucket != sentinel) {
struct cso_node *prev = *bucket;
while (prev->next != sentinel)
prev = prev->next;
return prev;
}
sentinel = a.e;
--bucket;
--start;
}
debug_printf("iterating backward beyond first element\n");
return a.e;
}
struct cso_hash_iter cso_hash_iter_next(struct cso_hash_iter iter)
{
struct cso_hash_iter next = {iter.hash, cso_hash_data_next(iter.node)};
return next;
}
int cso_hash_iter_is_null(struct cso_hash_iter iter)
{
if (!iter.node || iter.node == iter.hash->data.e)
return 1;
return 0;
}
void * cso_hash_take(struct cso_hash *hash,
unsigned akey)
{
struct cso_node **node = cso_hash_find_node(hash, akey);
if (*node != hash->data.e) {
void *t = (*node)->value;
struct cso_node *next = (*node)->next;
cso_free_node(*node);
*node = next;
--hash->data.d->size;
cso_data_has_shrunk(hash->data.d);
return t;
}
return 0;
}
struct cso_hash_iter cso_hash_iter_prev(struct cso_hash_iter iter)
{
struct cso_hash_iter prev = {iter.hash,
cso_hash_data_prev(iter.node)};
return prev;
}
struct cso_hash_iter cso_hash_first_node(struct cso_hash *hash)
{
struct cso_hash_iter iter = {hash, cso_data_first_node(hash->data.d)};
return iter;
}
int cso_hash_size(struct cso_hash *hash)
{
return hash->data.d->size;
}
struct cso_hash_iter cso_hash_erase(struct cso_hash *hash, struct cso_hash_iter iter)
{
struct cso_hash_iter ret = iter;
struct cso_node *node = iter.node;
struct cso_node **node_ptr;
if (node == hash->data.e)
return iter;
ret = cso_hash_iter_next(ret);
node_ptr = (struct cso_node**)(&hash->data.d->buckets[node->key % hash->data.d->numBuckets]);
while (*node_ptr != node)
node_ptr = &(*node_ptr)->next;
*node_ptr = node->next;
cso_free_node(node);
--hash->data.d->size;
return ret;
}
boolean cso_hash_contains(struct cso_hash *hash, unsigned key)
{
struct cso_node **node = cso_hash_find_node(hash, key);
return (*node != hash->data.e);
}