52 lines
1.9 KiB
C++
52 lines
1.9 KiB
C++
//===- FuzzerCrossOver.cpp - Cross over two test inputs -------------------===//
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//
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// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
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// See https://llvm.org/LICENSE.txt for license information.
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// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
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//
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//===----------------------------------------------------------------------===//
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// Cross over test inputs.
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//===----------------------------------------------------------------------===//
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#include "FuzzerDefs.h"
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#include "FuzzerMutate.h"
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#include "FuzzerRandom.h"
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#include <cstring>
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namespace fuzzer {
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// Cross Data1 and Data2, store the result (up to MaxOutSize bytes) in Out.
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size_t MutationDispatcher::CrossOver(const uint8_t *Data1, size_t Size1,
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const uint8_t *Data2, size_t Size2,
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uint8_t *Out, size_t MaxOutSize) {
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assert(Size1 || Size2);
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MaxOutSize = Rand(MaxOutSize) + 1;
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size_t OutPos = 0;
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size_t Pos1 = 0;
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size_t Pos2 = 0;
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size_t *InPos = &Pos1;
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size_t InSize = Size1;
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const uint8_t *Data = Data1;
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bool CurrentlyUsingFirstData = true;
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while (OutPos < MaxOutSize && (Pos1 < Size1 || Pos2 < Size2)) {
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// Merge a part of Data into Out.
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size_t OutSizeLeft = MaxOutSize - OutPos;
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if (*InPos < InSize) {
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size_t InSizeLeft = InSize - *InPos;
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size_t MaxExtraSize = std::min(OutSizeLeft, InSizeLeft);
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size_t ExtraSize = Rand(MaxExtraSize) + 1;
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memcpy(Out + OutPos, Data + *InPos, ExtraSize);
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OutPos += ExtraSize;
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(*InPos) += ExtraSize;
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}
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// Use the other input data on the next iteration.
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InPos = CurrentlyUsingFirstData ? &Pos2 : &Pos1;
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InSize = CurrentlyUsingFirstData ? Size2 : Size1;
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Data = CurrentlyUsingFirstData ? Data2 : Data1;
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CurrentlyUsingFirstData = !CurrentlyUsingFirstData;
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}
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return OutPos;
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}
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} // namespace fuzzer
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