1*a7c257b0Skamil //===- FuzzerCrossOver.cpp - Cross over two test inputs -------------------===//
2*a7c257b0Skamil //
3*a7c257b0Skamil // The LLVM Compiler Infrastructure
4*a7c257b0Skamil //
5*a7c257b0Skamil // This file is distributed under the University of Illinois Open Source
6*a7c257b0Skamil // License. See LICENSE.TXT for details.
7*a7c257b0Skamil //
8*a7c257b0Skamil //===----------------------------------------------------------------------===//
9*a7c257b0Skamil // Cross over test inputs.
10*a7c257b0Skamil //===----------------------------------------------------------------------===//
11*a7c257b0Skamil
12*a7c257b0Skamil #include "FuzzerDefs.h"
13*a7c257b0Skamil #include "FuzzerMutate.h"
14*a7c257b0Skamil #include "FuzzerRandom.h"
15*a7c257b0Skamil #include <cstring>
16*a7c257b0Skamil
17*a7c257b0Skamil namespace fuzzer {
18*a7c257b0Skamil
19*a7c257b0Skamil // Cross Data1 and Data2, store the result (up to MaxOutSize bytes) in Out.
CrossOver(const uint8_t * Data1,size_t Size1,const uint8_t * Data2,size_t Size2,uint8_t * Out,size_t MaxOutSize)20*a7c257b0Skamil size_t MutationDispatcher::CrossOver(const uint8_t *Data1, size_t Size1,
21*a7c257b0Skamil const uint8_t *Data2, size_t Size2,
22*a7c257b0Skamil uint8_t *Out, size_t MaxOutSize) {
23*a7c257b0Skamil assert(Size1 || Size2);
24*a7c257b0Skamil MaxOutSize = Rand(MaxOutSize) + 1;
25*a7c257b0Skamil size_t OutPos = 0;
26*a7c257b0Skamil size_t Pos1 = 0;
27*a7c257b0Skamil size_t Pos2 = 0;
28*a7c257b0Skamil size_t *InPos = &Pos1;
29*a7c257b0Skamil size_t InSize = Size1;
30*a7c257b0Skamil const uint8_t *Data = Data1;
31*a7c257b0Skamil bool CurrentlyUsingFirstData = true;
32*a7c257b0Skamil while (OutPos < MaxOutSize && (Pos1 < Size1 || Pos2 < Size2)) {
33*a7c257b0Skamil // Merge a part of Data into Out.
34*a7c257b0Skamil size_t OutSizeLeft = MaxOutSize - OutPos;
35*a7c257b0Skamil if (*InPos < InSize) {
36*a7c257b0Skamil size_t InSizeLeft = InSize - *InPos;
37*a7c257b0Skamil size_t MaxExtraSize = std::min(OutSizeLeft, InSizeLeft);
38*a7c257b0Skamil size_t ExtraSize = Rand(MaxExtraSize) + 1;
39*a7c257b0Skamil memcpy(Out + OutPos, Data + *InPos, ExtraSize);
40*a7c257b0Skamil OutPos += ExtraSize;
41*a7c257b0Skamil (*InPos) += ExtraSize;
42*a7c257b0Skamil }
43*a7c257b0Skamil // Use the other input data on the next iteration.
44*a7c257b0Skamil InPos = CurrentlyUsingFirstData ? &Pos2 : &Pos1;
45*a7c257b0Skamil InSize = CurrentlyUsingFirstData ? Size2 : Size1;
46*a7c257b0Skamil Data = CurrentlyUsingFirstData ? Data2 : Data1;
47*a7c257b0Skamil CurrentlyUsingFirstData = !CurrentlyUsingFirstData;
48*a7c257b0Skamil }
49*a7c257b0Skamil return OutPos;
50*a7c257b0Skamil }
51*a7c257b0Skamil
52*a7c257b0Skamil } // namespace fuzzer
53