14b43beb7c
TBR=niklas.enbom@webrtc.org Review URL: https://webrtc-codereview.appspot.com/915006 git-svn-id: http://webrtc.googlecode.com/svn/trunk@2963 4adac7df-926f-26a2-2b94-8c16560cd09d
41 lines
1.2 KiB
C++
41 lines
1.2 KiB
C++
/*
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* Copyright (c) 2012 The WebRTC project authors. All Rights Reserved.
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*
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* Use of this source code is governed by a BSD-style license
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* that can be found in the LICENSE file in the root of the source
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* tree. An additional intellectual property rights grant can be found
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* in the file PATENTS. All contributing project authors may
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* be found in the AUTHORS file in the root of the source tree.
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*/
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#include "test/libtest/include/bit_flip_encryption.h"
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#include <cstdlib>
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float NormalizedRand() {
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return static_cast<float>(rand()) /
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static_cast<float>(RAND_MAX);
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}
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BitFlipEncryption::BitFlipEncryption(unsigned int rand_seed,
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float flip_probability)
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: flip_probability_(flip_probability),
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flip_count_(0) {
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srand(rand_seed);
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}
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void BitFlipEncryption::FlipSomeBitsInData(const unsigned char* in_data,
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unsigned char* out_data,
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int bytes_in, int* bytes_out) {
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for (int i = 0; i < bytes_in; i++) {
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out_data[i] = in_data[i];
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if (NormalizedRand() < flip_probability_) {
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int bit_to_flip = rand() % 8;
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out_data[i] ^= 1 << bit_to_flip;
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flip_count_++;
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}
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}
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*bytes_out = bytes_in;
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}
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