/* -*- Mode: C; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*-
 *
 * ***** 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 ***** */

/*
 * This is a copy of the NSPR hash-table library, but it has been slightly
 * modified to allow an additional argument to be passed into the hash
 * key-comparison function.  This is used to maintain thread-safety by
 * passing in a JNIEnv pointer to the key-comparison function rather
 * than storing it in a global.  All types,function names, etc. have
 * been renamed from their original NSPR names to protect the innocent.
 */

#ifndef jsj_hash_h___
#define jsj_hash_h___
/*
 * API to portable hash table code.
 */
#include <stddef.h>
#include <stdio.h>
#include "jstypes.h"

JS_BEGIN_EXTERN_C

typedef struct JSJHashEntry  JSJHashEntry;
typedef struct JSJHashTable  JSJHashTable;
typedef JSUint32 JSJHashNumber;
#define JSJ_HASH_BITS 32
typedef JSJHashNumber (* JSJHashFunction)(const void *key, void *arg);
typedef JSIntn (* JSJHashComparator)(const void *v1, const void *v2, void *arg);
typedef JSIntn (* JSJHashEnumerator)(JSJHashEntry *he, JSIntn i, void *arg);

/* Flag bits in JSJHashEnumerator's return value */
#define HT_ENUMERATE_NEXT       0       /* continue enumerating entries */
#define HT_ENUMERATE_STOP       1       /* stop enumerating entries */
#define HT_ENUMERATE_REMOVE     2       /* remove and free the current entry */
#define HT_ENUMERATE_UNHASH     4       /* just unhash the current entry */

typedef struct JSJHashAllocOps {
    void *              (*allocTable)(void *pool, size_t size);
    void                (*freeTable)(void *pool, void *item);
    JSJHashEntry *      (*allocEntry)(void *pool, const void *key);
    void                (*freeEntry)(void *pool, JSJHashEntry *he, JSUintn flag);
} JSJHashAllocOps;

#define HT_FREE_VALUE   0               /* just free the entry's value */
#define HT_FREE_ENTRY   1               /* free value and entire entry */

struct JSJHashEntry {
    JSJHashEntry        *next;          /* hash chain linkage */
    JSJHashNumber       keyHash;        /* key hash function result */
    const void          *key;           /* ptr to opaque key */
    void                *value;         /* ptr to opaque value */
};

struct JSJHashTable {
    JSJHashEntry         **buckets;      /* vector of hash buckets */
    JSUint32              nentries;       /* number of entries in table */
    JSUint32              shift;          /* multiplicative hash shift */
    JSJHashFunction     keyHash;        /* key hash function */
    JSJHashComparator   keyCompare;     /* key comparison function */
    JSJHashComparator   valueCompare;   /* value comparison function */
    JSJHashAllocOps     *allocOps;      /* allocation operations */
    void                *allocPriv;     /* allocation private data */
#ifdef HASHMETER
    JSUint32              nlookups;       /* total number of lookups */
    JSUint32              nsteps;         /* number of hash chains traversed */
    JSUint32              ngrows;         /* number of table expansions */
    JSUint32              nshrinks;       /* number of table contractions */
#endif
};

/*
 * Create a new hash table.
 * If allocOps is null, use default allocator ops built on top of malloc().
 */
JS_EXTERN_API(JSJHashTable *)
JSJ_NewHashTable(JSUint32 n, JSJHashFunction keyHash,
                JSJHashComparator keyCompare, JSJHashComparator valueCompare,
                JSJHashAllocOps *allocOps, void *allocPriv);

JS_EXTERN_API(void)
JSJ_HashTableDestroy(JSJHashTable *ht);

/* Low level access methods */
JS_EXTERN_API(JSJHashEntry **)
JSJ_HashTableRawLookup(JSJHashTable *ht, JSJHashNumber keyHash, const void *key, void *arg);

JS_EXTERN_API(JSJHashEntry *)
JSJ_HashTableRawAdd(JSJHashTable *ht, JSJHashEntry **hep, JSJHashNumber keyHash,
                   const void *key, void *value, void *arg);

JS_EXTERN_API(void)
JSJ_HashTableRawRemove(JSJHashTable *ht, JSJHashEntry **hep, JSJHashEntry *he, void *arg);

/* Higher level access methods */
JS_EXTERN_API(JSJHashEntry *)
JSJ_HashTableAdd(JSJHashTable *ht, const void *key, void *value, void *arg);

JS_EXTERN_API(JSBool)
JSJ_HashTableRemove(JSJHashTable *ht, const void *key, void *arg);

JS_EXTERN_API(JSIntn)
JSJ_HashTableEnumerateEntries(JSJHashTable *ht, JSJHashEnumerator f, void *arg);

JS_EXTERN_API(void *)
JSJ_HashTableLookup(JSJHashTable *ht, const void *key, void *arg);

JS_EXTERN_API(JSIntn)
JSJ_HashTableDump(JSJHashTable *ht, JSJHashEnumerator dump, FILE *fp);

/* General-purpose C string hash function. */
JS_EXTERN_API(JSJHashNumber)
JSJ_HashString(const void *key);

/* Compare strings using strcmp(), return true if equal. */
JS_EXTERN_API(int)
JSJ_CompareStrings(const void *v1, const void *v2);

/* Stub function just returns v1 == v2 */
JS_EXTERN_API(JSIntn)
JSJ_CompareValues(const void *v1, const void *v2);

JS_END_EXTERN_C

#endif /* jsj_hash_h___ */
