RetroZilla/rdf/opendir/hash.c

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2015-10-21 05:03:22 +02:00
/* -*- Mode: C++; tab-width: 4; 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.org code.
*
* 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 file holds a temporary implementation of hash tables. It will
be replaced with STL or NSPR
*/
#include "rdf-int.h"
typedef struct _HashEntryStruct {
struct _HashEntryStruct* next; /* hash chain linkage */
char* key;
void* value;
} HashEntryStruct;
typedef HashEntryStruct* HashEntry;
typedef struct _HashTableStruct {
int size;
HashEntry* buckets; /* vector of hash buckets */
} HashTableStruct;
int
hashKey (HashTable ht, char* key) {
size_t len = strlen(key);
int sum = 0;
size_t n = 0;
int ans;
for (n = 0; n < len; n++) sum = sum + (int)key[n];
ans = sum & ht->size;
if (ans == ht->size) ans = ans-1;
return ans;
}
HashTable
NewHashTable(int size) {
HashTable ht = (HashTable)getMem(sizeof(HashTableStruct));
ht->size = size;
ht->buckets = (HashEntry*)getMem(sizeof(HashEntry) * size);
return ht;
}
void*
HashLookup(HashTable ht, char* key) {
int offset = hashKey(ht, key);
HashEntry he = ht->buckets[offset];
while (he) {
if (strcmp(he->key, key) == 0) return he->value;
he = he->next;
}
return NULL;
}
int catCount = 0;
int itemCount = 0;
void
HashAdd (HashTable ht, char* key, void* value) {
int offset = hashKey(ht, key);
HashEntry he = ht->buckets[offset];
HashEntry prev = he;
while (he) {
if (strcmp(he->key, key) == 0) {
if (value == he->value) {
return;
} else {
he->value = value;
return;
}
}
prev = he;
he = he->next;
}
if (startsWith("http://", key)) {
itemCount++;
} else {
catCount++;
}
he = (HashEntry) fgetMem(sizeof(HashEntryStruct));
he->value = value;
he->key = key;
if (prev) {
prev->next = he;
} else {
ht->buckets[offset] = he;
}
}