63 lines
1.5 KiB
C++
63 lines
1.5 KiB
C++
//===- FuzzerMutate.cpp - Mutate a test input -----------------------------===//
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//
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// The LLVM Compiler Infrastructure
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//
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// This file is distributed under the University of Illinois Open Source
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// License. See LICENSE.TXT for details.
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//
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//===----------------------------------------------------------------------===//
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// Mutate a test input.
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//===----------------------------------------------------------------------===//
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#include "FuzzerInternal.h"
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namespace fuzzer {
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static char FlipRandomBit(char X) {
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int Bit = rand() % 8;
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char Mask = 1 << Bit;
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char R;
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if (X & (1 << Bit))
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R = X & ~Mask;
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else
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R = X | Mask;
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assert(R != X);
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return R;
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}
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static char RandCh() {
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if (rand() % 2) return rand();
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const char *Special = "!*'();:@&=+$,/?%#[]123ABCxyz-`~.";
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return Special[rand() % (sizeof(Special) - 1)];
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}
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void Mutate(Unit *U, size_t MaxLen) {
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assert(MaxLen > 0);
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assert(U->size() <= MaxLen);
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switch (rand() % 3) {
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case 0:
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if (U->size())
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U->erase(U->begin() + rand() % U->size());
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break;
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case 1:
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if (U->empty()) {
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U->push_back(RandCh());
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} else if (U->size() < MaxLen) {
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U->insert(U->begin() + rand() % U->size(), RandCh());
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} else { // At MaxLen.
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uint8_t Ch = RandCh();
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size_t Idx = rand() % U->size();
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(*U)[Idx] = Ch;
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}
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break;
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default:
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if (!U->empty()) {
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size_t idx = rand() % U->size();
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(*U)[idx] = FlipRandomBit((*U)[idx]);
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}
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break;
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}
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}
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} // namespace fuzzer
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