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plhash.h (4834B)

      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/. */
      5 
      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"
     13 
     14 PR_BEGIN_EXTERN_C
     15 
     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);
     22 
     23 typedef PRIntn (PR_CALLBACK *PLHashEnumerator)(PLHashEntry *he, PRIntn i, void *arg);
     24 
     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 */
     30 
     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;
     37 
     38 #define HT_FREE_VALUE   0               /* just free the entry's value */
     39 #define HT_FREE_ENTRY   1               /* free value and entire entry */
     40 
     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 };
     47 
     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 };
     64 
     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);
     73 
     74 PR_EXTERN(void)
     75 PL_HashTableDestroy(PLHashTable *ht);
     76 
     77 /* Higher level access methods */
     78 PR_EXTERN(PLHashEntry *)
     79 PL_HashTableAdd(PLHashTable *ht, const void *key, void *value);
     80 
     81 PR_EXTERN(PRBool)
     82 PL_HashTableRemove(PLHashTable *ht, const void *key);
     83 
     84 PR_EXTERN(void *)
     85 PL_HashTableLookup(PLHashTable *ht, const void *key);
     86 
     87 PR_EXTERN(void *)
     88 PL_HashTableLookupConst(PLHashTable *ht, const void *key);
     89 
     90 PR_EXTERN(PRIntn)
     91 PL_HashTableEnumerateEntries(PLHashTable *ht, PLHashEnumerator f, void *arg);
     92 
     93 /* General-purpose C string hash function. */
     94 PR_EXTERN(PLHashNumber)
     95 PL_HashString(const void *key);
     96 
     97 /* Compare strings using strcmp(), return true if equal. */
     98 PR_EXTERN(PRIntn)
     99 PL_CompareStrings(const void *v1, const void *v2);
    100 
    101 /* Stub function just returns v1 == v2 */
    102 PR_EXTERN(PRIntn)
    103 PL_CompareValues(const void *v1, const void *v2);
    104 
    105 /* Low level access methods */
    106 PR_EXTERN(PLHashEntry **)
    107 PL_HashTableRawLookup(PLHashTable *ht, PLHashNumber keyHash, const void *key);
    108 
    109 PR_EXTERN(PLHashEntry **)
    110 PL_HashTableRawLookupConst(PLHashTable *ht, PLHashNumber keyHash,
    111                           const void *key);
    112 
    113 PR_EXTERN(PLHashEntry *)
    114 PL_HashTableRawAdd(PLHashTable *ht, PLHashEntry **hep, PLHashNumber keyHash,
    115                   const void *key, void *value);
    116 
    117 PR_EXTERN(void)
    118 PL_HashTableRawRemove(PLHashTable *ht, PLHashEntry **hep, PLHashEntry *he);
    119 
    120 /* This can be trivially implemented using PL_HashTableEnumerateEntries. */
    121 PR_EXTERN(PRIntn)
    122 PL_HashTableDump(PLHashTable *ht, PLHashEnumerator dump, FILE *fp);
    123 
    124 PR_END_EXTERN_C
    125 
    126 #endif /* plhash_h___ */