nsprpub/lib/ds/plhash.h

   1 /* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
   2 /* ***** BEGIN LICENSE BLOCK *****
   3  * Version: MPL 1.1/GPL 2.0/LGPL 2.1
   4  *
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   6  * 1.1 (the "License"); you may not use this file except in compliance with
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  11  * WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
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  14  *
  15  * The Original Code is the Netscape Portable Runtime (NSPR).
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  17  * The Initial Developer of the Original Code is
  18  * Netscape Communications Corporation.
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  36  * ***** END LICENSE BLOCK ***** */
  37
  38 #ifndef plhash_h___
  39 #define plhash_h___
  40 /*
  41  * API to portable hash table code.
  42  */
  43 #include <stdio.h>
  44 #include "prtypes.h"
  45
  46 PR_BEGIN_EXTERN_C
  47
  48 typedef struct PLHashEntry  PLHashEntry;
  49 typedef struct PLHashTable  PLHashTable;
  50 typedef PRUint32 PLHashNumber;
  51 #define PL_HASH_BITS 32  /* Number of bits in PLHashNumber */
  52 typedef PLHashNumber (PR_CALLBACK *PLHashFunction)(const void *key);
  53 typedef PRIntn (PR_CALLBACK *PLHashComparator)(const void *v1, const void *v2);
  54
  55 #if defined(XP_OS2_VACPP) && defined(VACPP_FLIP) /* for nsSpaceManager.cpp */
  56 PR_END_EXTERN_C                                  /* and nsHTMLDocument.cpp */
  57 #endif
  58 typedef PRIntn (PR_CALLBACK *PLHashEnumerator)(PLHashEntry *he, PRIntn i, void *arg);
  59
  60 #if defined(XP_OS2_VACPP) && defined(VACPP_FLIP)
  61 PR_BEGIN_EXTERN_C
  62 #endif
  63
  64 /* Flag bits in PLHashEnumerator's return value */
  65 #define HT_ENUMERATE_NEXT       0       /* continue enumerating entries */
  66 #define HT_ENUMERATE_STOP       1       /* stop enumerating entries */
  67 #define HT_ENUMERATE_REMOVE     2       /* remove and free the current entry */
  68 #define HT_ENUMERATE_UNHASH     4       /* just unhash the current entry */
  69
  70 typedef struct PLHashAllocOps {
  71     void *              (PR_CALLBACK *allocTable)(void *pool, PRSize size);
  72     void                (PR_CALLBACK *freeTable)(void *pool, void *item);
  73     PLHashEntry *       (PR_CALLBACK *allocEntry)(void *pool, const void *key);
  74     void                (PR_CALLBACK *freeEntry)(void *pool, PLHashEntry *he, PRUintn flag);
  75 } PLHashAllocOps;
  76
  77 #define HT_FREE_VALUE   0               /* just free the entry's value */
  78 #define HT_FREE_ENTRY   1               /* free value and entire entry */
  79
  80 struct PLHashEntry {
  81     PLHashEntry         *next;          /* hash chain linkage */
  82     PLHashNumber        keyHash;        /* key hash function result */
  83     const void          *key;           /* ptr to opaque key */
  84     void                *value;         /* ptr to opaque value */
  85 };
  86
  87 struct PLHashTable {
  88     PLHashEntry         **buckets;      /* vector of hash buckets */
  89     PRUint32              nentries;       /* number of entries in table */
  90     PRUint32              shift;          /* multiplicative hash shift */
  91     PLHashFunction      keyHash;        /* key hash function */
  92     PLHashComparator    keyCompare;     /* key comparison function */
  93     PLHashComparator    valueCompare;   /* value comparison function */
  94     const PLHashAllocOps *allocOps;     /* allocation operations */
  95     void                *allocPriv;     /* allocation private data */
  96 #ifdef HASHMETER
  97     PRUint32              nlookups;       /* total number of lookups */
  98     PRUint32              nsteps;         /* number of hash chains traversed */
  99     PRUint32              ngrows;         /* number of table expansions */
 100     PRUint32              nshrinks;       /* number of table contractions */
 101 #endif
 102 };
 103
 104 /*
 105  * Create a new hash table.
 106  * If allocOps is null, use default allocator ops built on top of malloc().
 107  */
 108 PR_EXTERN(PLHashTable *)
 109 PL_NewHashTable(PRUint32 numBuckets, PLHashFunction keyHash,
 110                 PLHashComparator keyCompare, PLHashComparator valueCompare,
 111                 const PLHashAllocOps *allocOps, void *allocPriv);
 112
 113 PR_EXTERN(void)
 114 PL_HashTableDestroy(PLHashTable *ht);
 115
 116 /* Higher level access methods */
 117 PR_EXTERN(PLHashEntry *)
 118 PL_HashTableAdd(PLHashTable *ht, const void *key, void *value);
 119
 120 PR_EXTERN(PRBool)
 121 PL_HashTableRemove(PLHashTable *ht, const void *key);
 122
 123 PR_EXTERN(void *)
 124 PL_HashTableLookup(PLHashTable *ht, const void *key);
 125
 126 PR_EXTERN(void *)
 127 PL_HashTableLookupConst(PLHashTable *ht, const void *key);
 128
 129 PR_EXTERN(PRIntn)
 130 PL_HashTableEnumerateEntries(PLHashTable *ht, PLHashEnumerator f, void *arg);
 131
 132 /* General-purpose C string hash function. */
 133 PR_EXTERN(PLHashNumber)
 134 PL_HashString(const void *key);
 135
 136 /* Compare strings using strcmp(), return true if equal. */
 137 PR_EXTERN(PRIntn)
 138 PL_CompareStrings(const void *v1, const void *v2);
 139
 140 /* Stub function just returns v1 == v2 */
 141 PR_EXTERN(PRIntn)
 142 PL_CompareValues(const void *v1, const void *v2);
 143
 144 /* Low level access methods */
 145 PR_EXTERN(PLHashEntry **)
 146 PL_HashTableRawLookup(PLHashTable *ht, PLHashNumber keyHash, const void *key);
 147
 148 PR_EXTERN(PLHashEntry **)
 149 PL_HashTableRawLookupConst(PLHashTable *ht, PLHashNumber keyHash,
 150                            const void *key);
 151
 152 PR_EXTERN(PLHashEntry *)
 153 PL_HashTableRawAdd(PLHashTable *ht, PLHashEntry **hep, PLHashNumber keyHash,
 154                    const void *key, void *value);
 155
 156 PR_EXTERN(void)
 157 PL_HashTableRawRemove(PLHashTable *ht, PLHashEntry **hep, PLHashEntry *he);
 158
 159 /* This can be trivially implemented using PL_HashTableEnumerateEntries. */
 160 PR_EXTERN(PRIntn)
 161 PL_HashTableDump(PLHashTable *ht, PLHashEnumerator dump, FILE *fp);
 162
 163 PR_END_EXTERN_C
 164
 165 #endif /* plhash_h___ */