/js/lib/Socket.IO-node/support/expresso/deps/jscoverage/js/jshash.cpp
C++ | 476 lines | 350 code | 56 blank | 70 comment | 57 complexity | 3fa1df16ff7543d4c526f28746ce1903 MD5 | raw file
Possible License(s): GPL-2.0, LGPL-2.1, MPL-2.0-no-copyleft-exception, BSD-3-Clause
- /* -*- Mode: C; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 4 -*-
- *
- * ***** BEGIN LICENSE BLOCK *****
- * Version: MPL 1.1/GPL 2.0/LGPL 2.1
- *
- * The contents of this file are subject to the Mozilla Public License Version
- * 1.1 (the "License"); you may not use this file except in compliance with
- * the License. You may obtain a copy of the License at
- * http://www.mozilla.org/MPL/
- *
- * Software distributed under the License is distributed on an "AS IS" basis,
- * WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
- * for the specific language governing rights and limitations under the
- * License.
- *
- * The Original Code is Mozilla Communicator client code, released
- * March 31, 1998.
- *
- * The Initial Developer of the Original Code is
- * Netscape Communications Corporation.
- * Portions created by the Initial Developer are Copyright (C) 1998
- * the Initial Developer. All Rights Reserved.
- *
- * Contributor(s):
- *
- * Alternatively, the contents of this file may be used under the terms of
- * either of the GNU General Public License Version 2 or later (the "GPL"),
- * or the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
- * in which case the provisions of the GPL or the LGPL are applicable instead
- * of those above. If you wish to allow use of your version of this file only
- * under the terms of either the GPL or the LGPL, and not to allow others to
- * use your version of this file under the terms of the MPL, indicate your
- * decision by deleting the provisions above and replace them with the notice
- * and other provisions required by the GPL or the LGPL. If you do not delete
- * the provisions above, a recipient may use your version of this file under
- * the terms of any one of the MPL, the GPL or the LGPL.
- *
- * ***** END LICENSE BLOCK ***** */
- /*
- * PR hash table package.
- */
- #include "jsstddef.h"
- #include <stdlib.h>
- #include <string.h>
- #include "jstypes.h"
- #include "jsbit.h"
- #include "jsutil.h" /* Added by JSIFY */
- #include "jshash.h" /* Added by JSIFY */
- /* Compute the number of buckets in ht */
- #define NBUCKETS(ht) JS_BIT(JS_HASH_BITS - (ht)->shift)
- /* The smallest table has 16 buckets */
- #define MINBUCKETSLOG2 4
- #define MINBUCKETS JS_BIT(MINBUCKETSLOG2)
- /* Compute the maximum entries given n buckets that we will tolerate, ~90% */
- #define OVERLOADED(n) ((n) - ((n) >> 3))
- /* Compute the number of entries below which we shrink the table by half */
- #define UNDERLOADED(n) (((n) > MINBUCKETS) ? ((n) >> 2) : 0)
- /*
- ** Stubs for default hash allocator ops.
- */
- static void *
- DefaultAllocTable(void *pool, size_t size)
- {
- return malloc(size);
- }
- static void
- DefaultFreeTable(void *pool, void *item)
- {
- free(item);
- }
- static JSHashEntry *
- DefaultAllocEntry(void *pool, const void *key)
- {
- return (JSHashEntry*) malloc(sizeof(JSHashEntry));
- }
- static void
- DefaultFreeEntry(void *pool, JSHashEntry *he, uintN flag)
- {
- if (flag == HT_FREE_ENTRY)
- free(he);
- }
- static JSHashAllocOps defaultHashAllocOps = {
- DefaultAllocTable, DefaultFreeTable,
- DefaultAllocEntry, DefaultFreeEntry
- };
- JS_PUBLIC_API(JSHashTable *)
- JS_NewHashTable(uint32 n, JSHashFunction keyHash,
- JSHashComparator keyCompare, JSHashComparator valueCompare,
- JSHashAllocOps *allocOps, void *allocPriv)
- {
- JSHashTable *ht;
- size_t nb;
- if (n <= MINBUCKETS) {
- n = MINBUCKETSLOG2;
- } else {
- n = JS_CeilingLog2(n);
- if ((int32)n < 0)
- return NULL;
- }
- if (!allocOps) allocOps = &defaultHashAllocOps;
- ht = (JSHashTable*) allocOps->allocTable(allocPriv, sizeof *ht);
- if (!ht)
- return NULL;
- memset(ht, 0, sizeof *ht);
- ht->shift = JS_HASH_BITS - n;
- n = JS_BIT(n);
- nb = n * sizeof(JSHashEntry *);
- ht->buckets = (JSHashEntry**) allocOps->allocTable(allocPriv, nb);
- if (!ht->buckets) {
- allocOps->freeTable(allocPriv, ht);
- return NULL;
- }
- memset(ht->buckets, 0, nb);
- ht->keyHash = keyHash;
- ht->keyCompare = keyCompare;
- ht->valueCompare = valueCompare;
- ht->allocOps = allocOps;
- ht->allocPriv = allocPriv;
- return ht;
- }
- JS_PUBLIC_API(void)
- JS_HashTableDestroy(JSHashTable *ht)
- {
- uint32 i, n;
- JSHashEntry *he, **hep;
- JSHashAllocOps *allocOps = ht->allocOps;
- void *allocPriv = ht->allocPriv;
- n = NBUCKETS(ht);
- for (i = 0; i < n; i++) {
- hep = &ht->buckets[i];
- while ((he = *hep) != NULL) {
- *hep = he->next;
- allocOps->freeEntry(allocPriv, he, HT_FREE_ENTRY);
- }
- }
- #ifdef DEBUG
- memset(ht->buckets, 0xDB, n * sizeof ht->buckets[0]);
- #endif
- allocOps->freeTable(allocPriv, ht->buckets);
- #ifdef DEBUG
- memset(ht, 0xDB, sizeof *ht);
- #endif
- allocOps->freeTable(allocPriv, ht);
- }
- /*
- * Multiplicative hash, from Knuth 6.4.
- */
- #define BUCKET_HEAD(ht, keyHash) \
- (&(ht)->buckets[((keyHash) * JS_GOLDEN_RATIO) >> (ht)->shift])
- JS_PUBLIC_API(JSHashEntry **)
- JS_HashTableRawLookup(JSHashTable *ht, JSHashNumber keyHash, const void *key)
- {
- JSHashEntry *he, **hep, **hep0;
- #ifdef JS_HASHMETER
- ht->nlookups++;
- #endif
- hep = hep0 = BUCKET_HEAD(ht, keyHash);
- while ((he = *hep) != NULL) {
- if (he->keyHash == keyHash && ht->keyCompare(key, he->key)) {
- /* Move to front of chain if not already there */
- if (hep != hep0) {
- *hep = he->next;
- he->next = *hep0;
- *hep0 = he;
- }
- return hep0;
- }
- hep = &he->next;
- #ifdef JS_HASHMETER
- ht->nsteps++;
- #endif
- }
- return hep;
- }
- static JSBool
- Resize(JSHashTable *ht, uint32 newshift)
- {
- size_t nb, nentries, i;
- JSHashEntry **oldbuckets, *he, *next, **hep;
- #ifdef DEBUG
- size_t nold = NBUCKETS(ht);
- #endif
- JS_ASSERT(newshift < JS_HASH_BITS);
- nb = (size_t)1 << (JS_HASH_BITS - newshift);
- /* Integer overflow protection. */
- if (nb > (size_t)-1 / sizeof(JSHashEntry*))
- return JS_FALSE;
- nb *= sizeof(JSHashEntry*);
- oldbuckets = ht->buckets;
- ht->buckets = (JSHashEntry**)ht->allocOps->allocTable(ht->allocPriv, nb);
- if (!ht->buckets) {
- ht->buckets = oldbuckets;
- return JS_FALSE;
- }
- memset(ht->buckets, 0, nb);
- ht->shift = newshift;
- nentries = ht->nentries;
- for (i = 0; nentries != 0; i++) {
- for (he = oldbuckets[i]; he; he = next) {
- JS_ASSERT(nentries != 0);
- --nentries;
- next = he->next;
- hep = BUCKET_HEAD(ht, he->keyHash);
- /*
- * Since he comes from the old table, it must be unique and we
- * simply add it to the head of bucket chain without chain lookup.
- */
- he->next = *hep;
- *hep = he;
- }
- }
- #ifdef DEBUG
- memset(oldbuckets, 0xDB, nold * sizeof oldbuckets[0]);
- #endif
- ht->allocOps->freeTable(ht->allocPriv, oldbuckets);
- return JS_TRUE;
- }
- JS_PUBLIC_API(JSHashEntry *)
- JS_HashTableRawAdd(JSHashTable *ht, JSHashEntry **hep,
- JSHashNumber keyHash, const void *key, void *value)
- {
- uint32 n;
- JSHashEntry *he;
- /* Grow the table if it is overloaded */
- n = NBUCKETS(ht);
- if (ht->nentries >= OVERLOADED(n)) {
- if (!Resize(ht, ht->shift - 1))
- return NULL;
- #ifdef JS_HASHMETER
- ht->ngrows++;
- #endif
- hep = JS_HashTableRawLookup(ht, keyHash, key);
- }
- /* Make a new key value entry */
- he = ht->allocOps->allocEntry(ht->allocPriv, key);
- if (!he)
- return NULL;
- he->keyHash = keyHash;
- he->key = key;
- he->value = value;
- he->next = *hep;
- *hep = he;
- ht->nentries++;
- return he;
- }
- JS_PUBLIC_API(JSHashEntry *)
- JS_HashTableAdd(JSHashTable *ht, const void *key, void *value)
- {
- JSHashNumber keyHash;
- JSHashEntry *he, **hep;
- keyHash = ht->keyHash(key);
- hep = JS_HashTableRawLookup(ht, keyHash, key);
- if ((he = *hep) != NULL) {
- /* Hit; see if values match */
- if (ht->valueCompare(he->value, value)) {
- /* key,value pair is already present in table */
- return he;
- }
- if (he->value)
- ht->allocOps->freeEntry(ht->allocPriv, he, HT_FREE_VALUE);
- he->value = value;
- return he;
- }
- return JS_HashTableRawAdd(ht, hep, keyHash, key, value);
- }
- JS_PUBLIC_API(void)
- JS_HashTableRawRemove(JSHashTable *ht, JSHashEntry **hep, JSHashEntry *he)
- {
- uint32 n;
- *hep = he->next;
- ht->allocOps->freeEntry(ht->allocPriv, he, HT_FREE_ENTRY);
- /* Shrink table if it's underloaded */
- n = NBUCKETS(ht);
- if (--ht->nentries < UNDERLOADED(n)) {
- Resize(ht, ht->shift + 1);
- #ifdef JS_HASHMETER
- ht->nshrinks++;
- #endif
- }
- }
- JS_PUBLIC_API(JSBool)
- JS_HashTableRemove(JSHashTable *ht, const void *key)
- {
- JSHashNumber keyHash;
- JSHashEntry *he, **hep;
- keyHash = ht->keyHash(key);
- hep = JS_HashTableRawLookup(ht, keyHash, key);
- if ((he = *hep) == NULL)
- return JS_FALSE;
- /* Hit; remove element */
- JS_HashTableRawRemove(ht, hep, he);
- return JS_TRUE;
- }
- JS_PUBLIC_API(void *)
- JS_HashTableLookup(JSHashTable *ht, const void *key)
- {
- JSHashNumber keyHash;
- JSHashEntry *he, **hep;
- keyHash = ht->keyHash(key);
- hep = JS_HashTableRawLookup(ht, keyHash, key);
- if ((he = *hep) != NULL) {
- return he->value;
- }
- return NULL;
- }
- /*
- ** Iterate over the entries in the hash table calling func for each
- ** entry found. Stop if "f" says to (return value & JS_ENUMERATE_STOP).
- ** Return a count of the number of elements scanned.
- */
- JS_PUBLIC_API(int)
- JS_HashTableEnumerateEntries(JSHashTable *ht, JSHashEnumerator f, void *arg)
- {
- JSHashEntry *he, **hep, **bucket;
- uint32 nlimit, n, nbuckets, newlog2;
- int rv;
- nlimit = ht->nentries;
- n = 0;
- for (bucket = ht->buckets; n != nlimit; ++bucket) {
- hep = bucket;
- while ((he = *hep) != NULL) {
- JS_ASSERT(n < nlimit);
- rv = f(he, n, arg);
- n++;
- if (rv & HT_ENUMERATE_REMOVE) {
- *hep = he->next;
- ht->allocOps->freeEntry(ht->allocPriv, he, HT_FREE_ENTRY);
- --ht->nentries;
- } else {
- hep = &he->next;
- }
- if (rv & HT_ENUMERATE_STOP) {
- goto out;
- }
- }
- }
- out:
- /* Shrink table if removal of entries made it underloaded */
- if (ht->nentries != nlimit) {
- JS_ASSERT(ht->nentries < nlimit);
- nbuckets = NBUCKETS(ht);
- if (MINBUCKETS < nbuckets && ht->nentries < UNDERLOADED(nbuckets)) {
- newlog2 = JS_CeilingLog2(ht->nentries);
- if (newlog2 < MINBUCKETSLOG2)
- newlog2 = MINBUCKETSLOG2;
- /* Check that we really shrink the table. */
- JS_ASSERT(JS_HASH_BITS - ht->shift > newlog2);
- Resize(ht, JS_HASH_BITS - newlog2);
- }
- }
- return (int)n;
- }
- #ifdef JS_HASHMETER
- #include <stdio.h>
- JS_PUBLIC_API(void)
- JS_HashTableDumpMeter(JSHashTable *ht, JSHashEnumerator dump, FILE *fp)
- {
- double sqsum, mean, sigma;
- uint32 nchains, nbuckets;
- uint32 i, n, maxChain, maxChainLen;
- JSHashEntry *he;
- sqsum = 0;
- nchains = 0;
- maxChain = maxChainLen = 0;
- nbuckets = NBUCKETS(ht);
- for (i = 0; i < nbuckets; i++) {
- he = ht->buckets[i];
- if (!he)
- continue;
- nchains++;
- for (n = 0; he; he = he->next)
- n++;
- sqsum += n * n;
- if (n > maxChainLen) {
- maxChainLen = n;
- maxChain = i;
- }
- }
- mean = JS_MeanAndStdDev(nchains, ht->nentries, sqsum, &sigma);
- fprintf(fp, "\nHash table statistics:\n");
- fprintf(fp, " number of lookups: %u\n", ht->nlookups);
- fprintf(fp, " number of entries: %u\n", ht->nentries);
- fprintf(fp, " number of grows: %u\n", ht->ngrows);
- fprintf(fp, " number of shrinks: %u\n", ht->nshrinks);
- fprintf(fp, " mean steps per hash: %g\n", (double)ht->nsteps
- / ht->nlookups);
- fprintf(fp, "mean hash chain length: %g\n", mean);
- fprintf(fp, " standard deviation: %g\n", sigma);
- fprintf(fp, " max hash chain length: %u\n", maxChainLen);
- fprintf(fp, " max hash chain: [%u]\n", maxChain);
- for (he = ht->buckets[maxChain], i = 0; he; he = he->next, i++)
- if (dump(he, i, fp) != HT_ENUMERATE_NEXT)
- break;
- }
- #endif /* JS_HASHMETER */
- JS_PUBLIC_API(int)
- JS_HashTableDump(JSHashTable *ht, JSHashEnumerator dump, FILE *fp)
- {
- int count;
- count = JS_HashTableEnumerateEntries(ht, dump, fp);
- #ifdef JS_HASHMETER
- JS_HashTableDumpMeter(ht, dump, fp);
- #endif
- return count;
- }
- JS_PUBLIC_API(JSHashNumber)
- JS_HashString(const void *key)
- {
- JSHashNumber h;
- const unsigned char *s;
- h = 0;
- for (s = (const unsigned char *)key; *s; s++)
- h = JS_ROTATE_LEFT32(h, 4) ^ *s;
- return h;
- }
- JS_PUBLIC_API(int)
- JS_CompareValues(const void *v1, const void *v2)
- {
- return v1 == v2;
- }