Back to index

lightning-sunbird  0.9+nobinonly
hash.c
Go to the documentation of this file.
00001 /* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
00002 /* ***** BEGIN LICENSE BLOCK *****
00003  * Version: MPL 1.1/GPL 2.0/LGPL 2.1
00004  *
00005  * The contents of this file are subject to the Mozilla Public License Version
00006  * 1.1 (the "License"); you may not use this file except in compliance with
00007  * the License. You may obtain a copy of the License at
00008  * http://www.mozilla.org/MPL/
00009  *
00010  * Software distributed under the License is distributed on an "AS IS" basis,
00011  * WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
00012  * for the specific language governing rights and limitations under the
00013  * License.
00014  *
00015  * The Original Code is mozilla.org code.
00016  *
00017  * The Initial Developer of the Original Code is
00018  * Netscape Communications Corporation.
00019  * Portions created by the Initial Developer are Copyright (C) 1998
00020  * the Initial Developer. All Rights Reserved.
00021  *
00022  * Contributor(s):
00023  *
00024  * Alternatively, the contents of this file may be used under the terms of
00025  * either of the GNU General Public License Version 2 or later (the "GPL"),
00026  * or the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
00027  * in which case the provisions of the GPL or the LGPL are applicable instead
00028  * of those above. If you wish to allow use of your version of this file only
00029  * under the terms of either the GPL or the LGPL, and not to allow others to
00030  * use your version of this file under the terms of the MPL, indicate your
00031  * decision by deleting the provisions above and replace them with the notice
00032  * and other provisions required by the GPL or the LGPL. If you do not delete
00033  * the provisions above, a recipient may use your version of this file under
00034  * the terms of any one of the MPL, the GPL or the LGPL.
00035  *
00036  * ***** END LICENSE BLOCK ***** */
00037 
00038 /* This file holds a temporary implementation of hash tables. It will
00039    be replaced with STL or NSPR
00040  */
00041 
00042 #include "rdf-int.h"
00043 
00044 typedef struct _HashEntryStruct {
00045     struct _HashEntryStruct*         next;          /* hash chain linkage */
00046     char*   key;
00047     void* value;
00048 } HashEntryStruct;
00049 
00050 typedef HashEntryStruct* HashEntry;
00051 
00052 typedef struct _HashTableStruct {
00053     int                size;
00054     HashEntry*         buckets;      /* vector of hash buckets */
00055 } HashTableStruct;
00056 
00057 
00058 
00059 int 
00060 hashKey (HashTable ht, char* key) {
00061     size_t len = strlen(key);
00062     int    sum = 0;
00063     size_t    n = 0;
00064        int ans;
00065     for (n = 0; n < len; n++) sum = sum + (int)key[n];
00066     ans = sum & ht->size;
00067        if (ans == ht->size) ans = ans-1;
00068        return ans; 
00069 }
00070 
00071 HashTable 
00072 NewHashTable(int size) {
00073     HashTable ht = (HashTable)getMem(sizeof(HashTableStruct));
00074     ht->size = size;
00075     ht->buckets = (HashEntry*)getMem(sizeof(HashEntry) * size);
00076     return ht;
00077 }
00078 
00079 void*
00080 HashLookup(HashTable ht, char* key) {
00081     int offset = hashKey(ht, key);
00082     HashEntry he = ht->buckets[offset];
00083     while (he) {
00084        if (strcmp(he->key, key) == 0) return he->value;
00085        he = he->next;
00086     }
00087     return NULL;
00088 }
00089 
00090 int catCount = 0;
00091 int itemCount = 0;
00092 
00093 void 
00094 HashAdd (HashTable ht, char* key, void* value) {
00095     int offset = hashKey(ht, key);
00096     HashEntry he = ht->buckets[offset];
00097     HashEntry prev = he;
00098     while (he) {
00099        if (strcmp(he->key, key) == 0) {
00100            if (value == he->value) {
00101               return;
00102            } else {
00103               he->value = value;
00104               return;
00105            }
00106        }
00107        prev = he;
00108        he = he->next;
00109     }
00110        if (startsWith("http://", key)) {
00111               itemCount++;
00112        } else {
00113               catCount++;
00114        }
00115     he = (HashEntry) fgetMem(sizeof(HashEntryStruct));
00116     he->value = value;
00117     he->key   = key;
00118     if (prev) {
00119       prev->next = he;
00120     } else {
00121       ht->buckets[offset] = he;
00122     }
00123 }
00124 
00125        
00126