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