The Tor Browser: nsprpub/lib/ds/plhash.h@7e26c7da4463

     1 /* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 2 -*- */

     2 /* This Source Code Form is subject to the terms of the Mozilla Public

     3  * License, v. 2.0. If a copy of the MPL was not distributed with this

     4  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */

     6 #ifndef plhash_h___

     7 #define plhash_h___

     8 /*

     9  * API to portable hash table code.

    10  */

    11 #include <stdio.h>

    12 #include "prtypes.h"

    14 PR_BEGIN_EXTERN_C

    16 typedef struct PLHashEntry  PLHashEntry;

    17 typedef struct PLHashTable  PLHashTable;

    18 typedef PRUint32 PLHashNumber;

    19 #define PL_HASH_BITS 32  /* Number of bits in PLHashNumber */

    20 typedef PLHashNumber (PR_CALLBACK *PLHashFunction)(const void *key);

    21 typedef PRIntn (PR_CALLBACK *PLHashComparator)(const void *v1, const void *v2);

    23 typedef PRIntn (PR_CALLBACK *PLHashEnumerator)(PLHashEntry *he, PRIntn i, void *arg);

    25 /* Flag bits in PLHashEnumerator's return value */

    26 #define HT_ENUMERATE_NEXT       0       /* continue enumerating entries */

    27 #define HT_ENUMERATE_STOP       1       /* stop enumerating entries */

    28 #define HT_ENUMERATE_REMOVE     2       /* remove and free the current entry */

    29 #define HT_ENUMERATE_UNHASH     4       /* just unhash the current entry */

    31 typedef struct PLHashAllocOps {

    32     void *              (PR_CALLBACK *allocTable)(void *pool, PRSize size);

    33     void                (PR_CALLBACK *freeTable)(void *pool, void *item);

    34     PLHashEntry *       (PR_CALLBACK *allocEntry)(void *pool, const void *key);

    35     void                (PR_CALLBACK *freeEntry)(void *pool, PLHashEntry *he, PRUintn flag);

    36 } PLHashAllocOps;

    38 #define HT_FREE_VALUE   0               /* just free the entry's value */

    39 #define HT_FREE_ENTRY   1               /* free value and entire entry */

    41 struct PLHashEntry {

    42     PLHashEntry         *next;          /* hash chain linkage */

    43     PLHashNumber        keyHash;        /* key hash function result */

    44     const void          *key;           /* ptr to opaque key */

    45     void                *value;         /* ptr to opaque value */

    46 };

    48 struct PLHashTable {

    49     PLHashEntry         **buckets;      /* vector of hash buckets */

    50     PRUint32              nentries;       /* number of entries in table */

    51     PRUint32              shift;          /* multiplicative hash shift */

    52     PLHashFunction      keyHash;        /* key hash function */

    53     PLHashComparator    keyCompare;     /* key comparison function */

    54     PLHashComparator    valueCompare;   /* value comparison function */

    55     const PLHashAllocOps *allocOps;     /* allocation operations */

    56     void                *allocPriv;     /* allocation private data */

    57 #ifdef HASHMETER

    58     PRUint32              nlookups;       /* total number of lookups */

    59     PRUint32              nsteps;         /* number of hash chains traversed */

    60     PRUint32              ngrows;         /* number of table expansions */

    61     PRUint32              nshrinks;       /* number of table contractions */

    62 #endif

    63 };

    65 /*

    66  * Create a new hash table.

    67  * If allocOps is null, use default allocator ops built on top of malloc().

    68  */

    69 PR_EXTERN(PLHashTable *)

    70 PL_NewHashTable(PRUint32 numBuckets, PLHashFunction keyHash,

    71                 PLHashComparator keyCompare, PLHashComparator valueCompare,

    72                 const PLHashAllocOps *allocOps, void *allocPriv);

    74 PR_EXTERN(void)

    75 PL_HashTableDestroy(PLHashTable *ht);

    77 /* Higher level access methods */

    78 PR_EXTERN(PLHashEntry *)

    79 PL_HashTableAdd(PLHashTable *ht, const void *key, void *value);

    81 PR_EXTERN(PRBool)

    82 PL_HashTableRemove(PLHashTable *ht, const void *key);

    84 PR_EXTERN(void *)

    85 PL_HashTableLookup(PLHashTable *ht, const void *key);

    87 PR_EXTERN(void *)

    88 PL_HashTableLookupConst(PLHashTable *ht, const void *key);

    90 PR_EXTERN(PRIntn)

    91 PL_HashTableEnumerateEntries(PLHashTable *ht, PLHashEnumerator f, void *arg);

    93 /* General-purpose C string hash function. */

    94 PR_EXTERN(PLHashNumber)

    95 PL_HashString(const void *key);

    97 /* Compare strings using strcmp(), return true if equal. */

    98 PR_EXTERN(PRIntn)

    99 PL_CompareStrings(const void *v1, const void *v2);

   101 /* Stub function just returns v1 == v2 */

   102 PR_EXTERN(PRIntn)

   103 PL_CompareValues(const void *v1, const void *v2);

   105 /* Low level access methods */

   106 PR_EXTERN(PLHashEntry **)

   107 PL_HashTableRawLookup(PLHashTable *ht, PLHashNumber keyHash, const void *key);

   109 PR_EXTERN(PLHashEntry **)

   110 PL_HashTableRawLookupConst(PLHashTable *ht, PLHashNumber keyHash,

   111                            const void *key);

   113 PR_EXTERN(PLHashEntry *)

   114 PL_HashTableRawAdd(PLHashTable *ht, PLHashEntry **hep, PLHashNumber keyHash,

   115                    const void *key, void *value);

   117 PR_EXTERN(void)

   118 PL_HashTableRawRemove(PLHashTable *ht, PLHashEntry **hep, PLHashEntry *he);

   120 /* This can be trivially implemented using PL_HashTableEnumerateEntries. */

   121 PR_EXTERN(PRIntn)

   122 PL_HashTableDump(PLHashTable *ht, PLHashEnumerator dump, FILE *fp);

   124 PR_END_EXTERN_C

   126 #endif /* plhash_h___ */

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