js/src/jshash.h

   1 /* -*- Mode: C; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 4 -*-
   2  *
   3  * ***** BEGIN LICENSE BLOCK *****
   4  * Version: MPL 1.1/GPL 2.0/LGPL 2.1
   5  *
   6  * The contents of this file are subject to the Mozilla Public License Version
   7  * 1.1 (the "License"); you may not use this file except in compliance with
   8  * the License. You may obtain a copy of the License at
   9  * http://www.mozilla.org/MPL/
  10  *
  11  * Software distributed under the License is distributed on an "AS IS" basis,
  12  * WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
  13  * for the specific language governing rights and limitations under the
  14  * License.
  15  *
  16  * The Original Code is Mozilla Communicator client code, released
  17  * March 31, 1998.
  18  *
  19  * The Initial Developer of the Original Code is
  20  * Netscape Communications Corporation.
  21  * Portions created by the Initial Developer are Copyright (C) 1998
  22  * the Initial Developer. All Rights Reserved.
  23  *
  24  * Contributor(s):
  25  *
  26  * Alternatively, the contents of this file may be used under the terms of
  27  * either of the GNU General Public License Version 2 or later (the "GPL"),
  28  * or the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
  29  * in which case the provisions of the GPL or the LGPL are applicable instead
  30  * of those above. If you wish to allow use of your version of this file only
  31  * under the terms of either the GPL or the LGPL, and not to allow others to
  32  * use your version of this file under the terms of the MPL, indicate your
  33  * decision by deleting the provisions above and replace them with the notice
  34  * and other provisions required by the GPL or the LGPL. If you do not delete
  35  * the provisions above, a recipient may use your version of this file under
  36  * the terms of any one of the MPL, the GPL or the LGPL.
  37  *
  38  * ***** END LICENSE BLOCK ***** */
  39
  40 #ifndef jshash_h___
  41 #define jshash_h___
  42 /*
  43  * API to portable hash table code.
  44  */
  45 #include <stddef.h>
  46 #include <stdio.h>
  47 #include "jstypes.h"
  48 #include "jscompat.h"
  49
  50 JS_BEGIN_EXTERN_C
  51
  52 typedef uint32 JSHashNumber;
  53 typedef struct JSHashEntry JSHashEntry;
  54 typedef struct JSHashTable JSHashTable;
  55
  56 #define JS_HASH_BITS 32
  57 #define JS_GOLDEN_RATIO 0x9E3779B9U
  58
  59 typedef JSHashNumber (* JSHashFunction)(const void *key);
  60 typedef intN (* JSHashComparator)(const void *v1, const void *v2);
  61 typedef intN (* JSHashEnumerator)(JSHashEntry *he, intN i, void *arg);
  62
  63 /* Flag bits in JSHashEnumerator's return value */
  64 #define HT_ENUMERATE_NEXT       0       /* continue enumerating entries */
  65 #define HT_ENUMERATE_STOP       1       /* stop enumerating entries */
  66 #define HT_ENUMERATE_REMOVE     2       /* remove and free the current entry */
  67
  68 typedef struct JSHashAllocOps {
  69     void *              (*allocTable)(void *pool, size_t size);
  70     void                (*freeTable)(void *pool, void *item);
  71     JSHashEntry *       (*allocEntry)(void *pool, const void *key);
  72     void                (*freeEntry)(void *pool, JSHashEntry *he, uintN flag);
  73 } JSHashAllocOps;
  74
  75 #define HT_FREE_VALUE   0               /* just free the entry's value */
  76 #define HT_FREE_ENTRY   1               /* free value and entire entry */
  77
  78 struct JSHashEntry {
  79     JSHashEntry         *next;          /* hash chain linkage */
  80     JSHashNumber        keyHash;        /* key hash function result */
  81     const void          *key;           /* ptr to opaque key */
  82     void                *value;         /* ptr to opaque value */
  83 };
  84
  85 struct JSHashTable {
  86     JSHashEntry         **buckets;      /* vector of hash buckets */
  87     uint32              nentries;       /* number of entries in table */
  88     uint32              shift;          /* multiplicative hash shift */
  89     JSHashFunction      keyHash;        /* key hash function */
  90     JSHashComparator    keyCompare;     /* key comparison function */
  91     JSHashComparator    valueCompare;   /* value comparison function */
  92     JSHashAllocOps      *allocOps;      /* allocation operations */
  93     void                *allocPriv;     /* allocation private data */
  94 #ifdef JS_HASHMETER
  95     uint32              nlookups;       /* total number of lookups */
  96     uint32              nsteps;         /* number of hash chains traversed */
  97     uint32              ngrows;         /* number of table expansions */
  98     uint32              nshrinks;       /* number of table contractions */
  99 #endif
 100 };
 101
 102 /*
 103  * Create a new hash table.
 104  * If allocOps is null, use default allocator ops built on top of malloc().
 105  */
 106 extern JS_PUBLIC_API(JSHashTable *)
 107 JS_NewHashTable(uint32 n, JSHashFunction keyHash,
 108                 JSHashComparator keyCompare, JSHashComparator valueCompare,
 109                 JSHashAllocOps *allocOps, void *allocPriv);
 110
 111 extern JS_PUBLIC_API(void)
 112 JS_HashTableDestroy(JSHashTable *ht);
 113
 114 /* Low level access methods */
 115 extern JS_PUBLIC_API(JSHashEntry **)
 116 JS_HashTableRawLookup(JSHashTable *ht, JSHashNumber keyHash, const void *key);
 117
 118 extern JS_PUBLIC_API(JSHashEntry *)
 119 JS_HashTableRawAdd(JSHashTable *ht, JSHashEntry **hep, JSHashNumber keyHash,
 120                    const void *key, void *value);
 121
 122 extern JS_PUBLIC_API(void)
 123 JS_HashTableRawRemove(JSHashTable *ht, JSHashEntry **hep, JSHashEntry *he);
 124
 125 /* Higher level access methods */
 126 extern JS_PUBLIC_API(JSHashEntry *)
 127 JS_HashTableAdd(JSHashTable *ht, const void *key, void *value);
 128
 129 extern JS_PUBLIC_API(JSBool)
 130 JS_HashTableRemove(JSHashTable *ht, const void *key);
 131
 132 extern JS_PUBLIC_API(intN)
 133 JS_HashTableEnumerateEntries(JSHashTable *ht, JSHashEnumerator f, void *arg);
 134
 135 extern JS_PUBLIC_API(void *)
 136 JS_HashTableLookup(JSHashTable *ht, const void *key);
 137
 138 extern JS_PUBLIC_API(intN)
 139 JS_HashTableDump(JSHashTable *ht, JSHashEnumerator dump, FILE *fp);
 140
 141 /* General-purpose C string hash function. */
 142 extern JS_PUBLIC_API(JSHashNumber)
 143 JS_HashString(const void *key);
 144
 145 /* Stub function just returns v1 == v2 */
 146 extern JS_PUBLIC_API(intN)
 147 JS_CompareValues(const void *v1, const void *v2);
 148
 149 JS_END_EXTERN_C
 150
 151 #endif /* jshash_h___ */