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enigmail  1.4.3
HashFunctions.cpp
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00001 /* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*-
00002  * vim: set ts=8 sw=4 et tw=99 ft=cpp:
00003  *
00004  * ***** BEGIN LICENSE BLOCK *****
00005  * Version: MPL 1.1/GPL 2.0/LGPL 2.1
00006  *
00007  * The contents of this file are subject to the Mozilla Public License Version
00008  * 1.1 (the "License"); you may not use this file except in compliance with
00009  * the License. You may obtain a copy of the License at:
00010  * http://www.mozilla.org/MPL/
00011  *
00012  * Software distributed under the License is distributed on an "AS IS" basis,
00013  * WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
00014  * for the specific language governing rights and limitations under the
00015  * License.
00016  *
00017  * The Original Code is Mozilla Code.
00018  *
00019  * The Initial Developer of the Original Code is
00020  *   The Mozilla Foundation
00021  * Portions created by the Initial Developer are Copyright (C) 2011
00022  * the Initial Developer. All Rights Reserved.
00023  *
00024  * Contributor(s):
00025  *   Justin Lebar <justin.lebar@gmail.com>
00026  *
00027  * Alternatively, the contents of this file may be used under the terms of
00028  * either the GNU General Public License Version 2 or later (the "GPL"), or
00029  * the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
00030  * in which case the provisions of the GPL or the LGPL are applicable instead
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00038  *
00039  * ***** END LICENSE BLOCK ***** */
00040 
00041 /* Implementations of hash functions */
00042 
00043 #include "mozilla/HashFunctions.h"
00044 #include <string.h>
00045 
00046 namespace mozilla {
00047 
00048 MFBT_API(uint32_t)
00049 HashBytes(const void* bytes, size_t length)
00050 {
00051   uint32_t hash = 0;
00052   const char* b = reinterpret_cast<const char*>(bytes);
00053 
00054   /* Walk word by word. */
00055   size_t i = 0;
00056   for (; i < length - (length % sizeof(size_t)); i += sizeof(size_t)) {
00057     /* Do an explicitly unaligned load of the data. */
00058     size_t data;
00059     memcpy(&data, b + i, sizeof(size_t));
00060 
00061     hash = AddToHash(hash, data, sizeof(data));
00062   }
00063 
00064   /* Get the remaining bytes. */
00065   for (; i < length; i++) {
00066     hash = AddToHash(hash, b[i]);
00067   }
00068 
00069   return hash;
00070 }
00071 
00072 } /* namespace mozilla */