gecko-dev/extensions/wallet/src/nsBasicStreamGenerator.cpp

100 строки
3.0 KiB
C++

/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*-
*
* The contents of this file are subject to the Netscape 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/NPL/
*
* 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 Netscape are
* Copyright (C) 1998 Netscape Communications Corporation. All
* Rights Reserved.
*
* Contributor(s):
*/
#include "nsBasicStreamGenerator.h"
const char * nsBasicStreamGenerator::mSignature = "Basic Keyed Stream Generator";
NS_IMPL_ISUPPORTS1(nsBasicStreamGenerator, nsIKeyedStreamGenerator)
nsBasicStreamGenerator::nsBasicStreamGenerator()
: mLevel(NS_SECURITY_LEVEL), mSalt(0), mPassword(), mState(0) {
NS_INIT_ISUPPORTS();
}
nsBasicStreamGenerator::~nsBasicStreamGenerator() {
}
NS_IMETHODIMP nsBasicStreamGenerator::GetSignature(char **signature) {
NS_ENSURE_ARG_POINTER(signature);
*signature = nsCRT::strdup(mSignature);
return NS_OK;
}
NS_IMETHODIMP nsBasicStreamGenerator::Setup(PRUint32 salt, nsISupports *consumer) {
nsresult rv = NS_OK;
/* forget about previous setup */
mWeakPasswordSink = nsnull;
mPassword.Truncate(0);
/* reestablish setup */
if (consumer) {
mWeakPasswordSink = getter_AddRefs(NS_GetWeakReference(consumer, &rv));
if (NS_FAILED(rv)) return rv;
}
mSalt = salt;
return NS_OK;
}
NS_IMETHODIMP nsBasicStreamGenerator::GetLevel(float *aLevel) {
NS_ENSURE_ARG_POINTER(aLevel);
*aLevel = mLevel;
return NS_OK;
}
NS_IMETHODIMP nsBasicStreamGenerator::GetByte(PRUint32 offset, PRUint8 *retval) {
NS_ENSURE_ARG_POINTER(retval);
nsresult rv = NS_OK;
if (mPassword.Length() == 0) {
/* this is the first time, so we need to get the password */
nsCOMPtr<nsIPasswordSink> weakPasswordSink = do_QueryReferent(mWeakPasswordSink);
if (!weakPasswordSink) {
return NS_ERROR_FAILURE;
}
PRUnichar *aPassword;
rv = weakPasswordSink->GetPassword(&aPassword);
if (NS_FAILED(rv)) {
return rv;
}
mPassword = aPassword;
nsMemory::Free(aPassword);
mState = 0;
}
/*
* Get the offset byte from the stream. Our stream is just our password
* repeating itself infinite times.
*
* Since mPassword is an nsString, its elements are PRUnichars.
* We want to return either the high-order or low-order 8 bits of the PRUnichar
* depending on whether or not this routine was called an odd or an even number of times
*/
PRUnichar ret16 = mPassword.CharAt((mState>>1) % mPassword.Length());
if (!((mState++) & 1)) {
ret16 = ret16>>8;
}
*retval = (PRUint8)(ret16 & 0xff);
return rv;
}