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