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			20 KiB
		
	
	
	
		
			C++
		
	
	
	
	
	
			
		
		
	
	
			562 lines
		
	
	
	
		
			20 KiB
		
	
	
	
		
			C++
		
	
	
	
	
	
| //===- FuzzerMutate.cpp - Mutate a test input -----------------------------===//
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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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| // Mutate a test input.
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| //===----------------------------------------------------------------------===//
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| 
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| #include "FuzzerDefs.h"
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| #include "FuzzerExtFunctions.h"
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| #include "FuzzerIO.h"
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| #include "FuzzerMutate.h"
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| #include "FuzzerOptions.h"
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| #include "FuzzerTracePC.h"
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| 
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| namespace fuzzer {
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| 
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| const size_t Dictionary::kMaxDictSize;
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| 
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| static void PrintASCII(const Word &W, const char *PrintAfter) {
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|   PrintASCII(W.data(), W.size(), PrintAfter);
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| }
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| 
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| MutationDispatcher::MutationDispatcher(Random &Rand,
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|                                        const FuzzingOptions &Options)
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|     : Rand(Rand), Options(Options) {
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|   DefaultMutators.insert(
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|       DefaultMutators.begin(),
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|       {
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|           {&MutationDispatcher::Mutate_EraseBytes, "EraseBytes"},
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|           {&MutationDispatcher::Mutate_InsertByte, "InsertByte"},
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|           {&MutationDispatcher::Mutate_InsertRepeatedBytes,
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|            "InsertRepeatedBytes"},
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|           {&MutationDispatcher::Mutate_ChangeByte, "ChangeByte"},
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|           {&MutationDispatcher::Mutate_ChangeBit, "ChangeBit"},
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|           {&MutationDispatcher::Mutate_ShuffleBytes, "ShuffleBytes"},
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|           {&MutationDispatcher::Mutate_ChangeASCIIInteger, "ChangeASCIIInt"},
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|           {&MutationDispatcher::Mutate_ChangeBinaryInteger, "ChangeBinInt"},
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|           {&MutationDispatcher::Mutate_CopyPart, "CopyPart"},
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|           {&MutationDispatcher::Mutate_CrossOver, "CrossOver"},
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|           {&MutationDispatcher::Mutate_AddWordFromManualDictionary,
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|            "ManualDict"},
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|           {&MutationDispatcher::Mutate_AddWordFromPersistentAutoDictionary,
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|            "PersAutoDict"},
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|       });
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|   if(Options.UseCmp)
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|     DefaultMutators.push_back(
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|         {&MutationDispatcher::Mutate_AddWordFromTORC, "CMP"});
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| 
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|   if (EF->LLVMFuzzerCustomMutator)
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|     Mutators.push_back({&MutationDispatcher::Mutate_Custom, "Custom"});
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|   else
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|     Mutators = DefaultMutators;
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| 
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|   if (EF->LLVMFuzzerCustomCrossOver)
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|     Mutators.push_back(
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|         {&MutationDispatcher::Mutate_CustomCrossOver, "CustomCrossOver"});
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| }
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| 
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| static char RandCh(Random &Rand) {
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|   if (Rand.RandBool()) return Rand(256);
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|   const char Special[] = "!*'();:@&=+$,/?%#[]012Az-`~.\xff\x00";
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|   return Special[Rand(sizeof(Special) - 1)];
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| }
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| 
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| size_t MutationDispatcher::Mutate_Custom(uint8_t *Data, size_t Size,
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|                                          size_t MaxSize) {
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|   return EF->LLVMFuzzerCustomMutator(Data, Size, MaxSize, Rand.Rand());
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| }
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| 
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| size_t MutationDispatcher::Mutate_CustomCrossOver(uint8_t *Data, size_t Size,
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|                                                   size_t MaxSize) {
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|   if (Size == 0)
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|     return 0;
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|   if (!CrossOverWith) return 0;
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|   const Unit &Other = *CrossOverWith;
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|   if (Other.empty())
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|     return 0;
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|   CustomCrossOverInPlaceHere.resize(MaxSize);
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|   auto &U = CustomCrossOverInPlaceHere;
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|   size_t NewSize = EF->LLVMFuzzerCustomCrossOver(
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|       Data, Size, Other.data(), Other.size(), U.data(), U.size(), Rand.Rand());
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|   if (!NewSize)
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|     return 0;
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|   assert(NewSize <= MaxSize && "CustomCrossOver returned overisized unit");
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|   memcpy(Data, U.data(), NewSize);
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|   return NewSize;
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| }
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| 
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| size_t MutationDispatcher::Mutate_ShuffleBytes(uint8_t *Data, size_t Size,
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|                                                size_t MaxSize) {
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|   if (Size > MaxSize || Size == 0) return 0;
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|   size_t ShuffleAmount =
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|       Rand(std::min(Size, (size_t)8)) + 1; // [1,8] and <= Size.
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|   size_t ShuffleStart = Rand(Size - ShuffleAmount);
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|   assert(ShuffleStart + ShuffleAmount <= Size);
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|   std::shuffle(Data + ShuffleStart, Data + ShuffleStart + ShuffleAmount, Rand);
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|   return Size;
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| }
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| 
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| size_t MutationDispatcher::Mutate_EraseBytes(uint8_t *Data, size_t Size,
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|                                              size_t MaxSize) {
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|   if (Size <= 1) return 0;
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|   size_t N = Rand(Size / 2) + 1;
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|   assert(N < Size);
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|   size_t Idx = Rand(Size - N + 1);
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|   // Erase Data[Idx:Idx+N].
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|   memmove(Data + Idx, Data + Idx + N, Size - Idx - N);
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|   // Printf("Erase: %zd %zd => %zd; Idx %zd\n", N, Size, Size - N, Idx);
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|   return Size - N;
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| }
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| 
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| size_t MutationDispatcher::Mutate_InsertByte(uint8_t *Data, size_t Size,
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|                                              size_t MaxSize) {
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|   if (Size >= MaxSize) return 0;
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|   size_t Idx = Rand(Size + 1);
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|   // Insert new value at Data[Idx].
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|   memmove(Data + Idx + 1, Data + Idx, Size - Idx);
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|   Data[Idx] = RandCh(Rand);
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|   return Size + 1;
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| }
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| 
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| size_t MutationDispatcher::Mutate_InsertRepeatedBytes(uint8_t *Data,
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|                                                       size_t Size,
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|                                                       size_t MaxSize) {
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|   const size_t kMinBytesToInsert = 3;
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|   if (Size + kMinBytesToInsert >= MaxSize) return 0;
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|   size_t MaxBytesToInsert = std::min(MaxSize - Size, (size_t)128);
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|   size_t N = Rand(MaxBytesToInsert - kMinBytesToInsert + 1) + kMinBytesToInsert;
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|   assert(Size + N <= MaxSize && N);
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|   size_t Idx = Rand(Size + 1);
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|   // Insert new values at Data[Idx].
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|   memmove(Data + Idx + N, Data + Idx, Size - Idx);
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|   // Give preference to 0x00 and 0xff.
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|   uint8_t Byte = Rand.RandBool() ? Rand(256) : (Rand.RandBool() ? 0 : 255);
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|   for (size_t i = 0; i < N; i++)
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|     Data[Idx + i] = Byte;
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|   return Size + N;
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| }
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| 
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| size_t MutationDispatcher::Mutate_ChangeByte(uint8_t *Data, size_t Size,
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|                                              size_t MaxSize) {
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|   if (Size > MaxSize) return 0;
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|   size_t Idx = Rand(Size);
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|   Data[Idx] = RandCh(Rand);
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|   return Size;
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| }
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| 
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| size_t MutationDispatcher::Mutate_ChangeBit(uint8_t *Data, size_t Size,
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|                                             size_t MaxSize) {
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|   if (Size > MaxSize) return 0;
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|   size_t Idx = Rand(Size);
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|   Data[Idx] ^= 1 << Rand(8);
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|   return Size;
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| }
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| 
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| size_t MutationDispatcher::Mutate_AddWordFromManualDictionary(uint8_t *Data,
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|                                                               size_t Size,
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|                                                               size_t MaxSize) {
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|   return AddWordFromDictionary(ManualDictionary, Data, Size, MaxSize);
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| }
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| 
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| size_t MutationDispatcher::ApplyDictionaryEntry(uint8_t *Data, size_t Size,
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|                                                 size_t MaxSize,
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|                                                 DictionaryEntry &DE) {
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|   const Word &W = DE.GetW();
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|   bool UsePositionHint = DE.HasPositionHint() &&
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|                          DE.GetPositionHint() + W.size() < Size &&
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|                          Rand.RandBool();
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|   if (Rand.RandBool()) {  // Insert W.
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|     if (Size + W.size() > MaxSize) return 0;
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|     size_t Idx = UsePositionHint ? DE.GetPositionHint() : Rand(Size + 1);
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|     memmove(Data + Idx + W.size(), Data + Idx, Size - Idx);
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|     memcpy(Data + Idx, W.data(), W.size());
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|     Size += W.size();
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|   } else {  // Overwrite some bytes with W.
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|     if (W.size() > Size) return 0;
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|     size_t Idx = UsePositionHint ? DE.GetPositionHint() : Rand(Size - W.size());
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|     memcpy(Data + Idx, W.data(), W.size());
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|   }
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|   return Size;
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| }
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| 
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| // Somewhere in the past we have observed a comparison instructions
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| // with arguments Arg1 Arg2. This function tries to guess a dictionary
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| // entry that will satisfy that comparison.
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| // It first tries to find one of the arguments (possibly swapped) in the
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| // input and if it succeeds it creates a DE with a position hint.
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| // Otherwise it creates a DE with one of the arguments w/o a position hint.
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| DictionaryEntry MutationDispatcher::MakeDictionaryEntryFromCMP(
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|     const void *Arg1, const void *Arg2,
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|     const void *Arg1Mutation, const void *Arg2Mutation,
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|     size_t ArgSize, const uint8_t *Data,
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|     size_t Size) {
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|   bool HandleFirst = Rand.RandBool();
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|   const void *ExistingBytes, *DesiredBytes;
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|   Word W;
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|   const uint8_t *End = Data + Size;
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|   for (int Arg = 0; Arg < 2; Arg++) {
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|     ExistingBytes = HandleFirst ? Arg1 : Arg2;
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|     DesiredBytes = HandleFirst ? Arg2Mutation : Arg1Mutation;
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|     HandleFirst = !HandleFirst;
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|     W.Set(reinterpret_cast<const uint8_t*>(DesiredBytes), ArgSize);
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|     const size_t kMaxNumPositions = 8;
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|     size_t Positions[kMaxNumPositions];
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|     size_t NumPositions = 0;
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|     for (const uint8_t *Cur = Data;
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|          Cur < End && NumPositions < kMaxNumPositions; Cur++) {
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|       Cur =
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|           (const uint8_t *)SearchMemory(Cur, End - Cur, ExistingBytes, ArgSize);
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|       if (!Cur) break;
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|       Positions[NumPositions++] = Cur - Data;
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|     }
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|     if (!NumPositions) continue;
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|     return DictionaryEntry(W, Positions[Rand(NumPositions)]);
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|   }
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|   DictionaryEntry DE(W);
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|   return DE;
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| }
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| 
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| 
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| template <class T>
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| DictionaryEntry MutationDispatcher::MakeDictionaryEntryFromCMP(
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|     T Arg1, T Arg2, const uint8_t *Data, size_t Size) {
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|   if (Rand.RandBool()) Arg1 = Bswap(Arg1);
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|   if (Rand.RandBool()) Arg2 = Bswap(Arg2);
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|   T Arg1Mutation = Arg1 + Rand(-1, 1);
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|   T Arg2Mutation = Arg2 + Rand(-1, 1);
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|   return MakeDictionaryEntryFromCMP(&Arg1, &Arg2, &Arg1Mutation, &Arg2Mutation,
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|                                     sizeof(Arg1), Data, Size);
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| }
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| 
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| DictionaryEntry MutationDispatcher::MakeDictionaryEntryFromCMP(
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|     const Word &Arg1, const Word &Arg2, const uint8_t *Data, size_t Size) {
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|   return MakeDictionaryEntryFromCMP(Arg1.data(), Arg2.data(), Arg1.data(),
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|                                     Arg2.data(), Arg1.size(), Data, Size);
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| }
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| 
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| size_t MutationDispatcher::Mutate_AddWordFromTORC(
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|     uint8_t *Data, size_t Size, size_t MaxSize) {
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|   Word W;
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|   DictionaryEntry DE;
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|   switch (Rand(4)) {
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|   case 0: {
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|     auto X = TPC.TORC8.Get(Rand.Rand());
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|     DE = MakeDictionaryEntryFromCMP(X.A, X.B, Data, Size);
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|   } break;
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|   case 1: {
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|     auto X = TPC.TORC4.Get(Rand.Rand());
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|     if ((X.A >> 16) == 0 && (X.B >> 16) == 0 && Rand.RandBool())
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|       DE = MakeDictionaryEntryFromCMP((uint16_t)X.A, (uint16_t)X.B, Data, Size);
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|     else
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|       DE = MakeDictionaryEntryFromCMP(X.A, X.B, Data, Size);
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|   } break;
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|   case 2: {
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|     auto X = TPC.TORCW.Get(Rand.Rand());
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|     DE = MakeDictionaryEntryFromCMP(X.A, X.B, Data, Size);
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|   } break;
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|   case 3: if (Options.UseMemmem) {
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|     auto X = TPC.MMT.Get(Rand.Rand());
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|     DE = DictionaryEntry(X);
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|   } break;
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|   default:
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|     assert(0);
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|   }
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|   if (!DE.GetW().size()) return 0;
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|   Size = ApplyDictionaryEntry(Data, Size, MaxSize, DE);
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|   if (!Size) return 0;
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|   DictionaryEntry &DERef =
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|       CmpDictionaryEntriesDeque[CmpDictionaryEntriesDequeIdx++ %
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|                                 kCmpDictionaryEntriesDequeSize];
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|   DERef = DE;
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|   CurrentDictionaryEntrySequence.push_back(&DERef);
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|   return Size;
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| }
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| 
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| size_t MutationDispatcher::Mutate_AddWordFromPersistentAutoDictionary(
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|     uint8_t *Data, size_t Size, size_t MaxSize) {
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|   return AddWordFromDictionary(PersistentAutoDictionary, Data, Size, MaxSize);
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| }
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| 
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| size_t MutationDispatcher::AddWordFromDictionary(Dictionary &D, uint8_t *Data,
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|                                                  size_t Size, size_t MaxSize) {
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|   if (Size > MaxSize) return 0;
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|   if (D.empty()) return 0;
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|   DictionaryEntry &DE = D[Rand(D.size())];
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|   Size = ApplyDictionaryEntry(Data, Size, MaxSize, DE);
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|   if (!Size) return 0;
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|   DE.IncUseCount();
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|   CurrentDictionaryEntrySequence.push_back(&DE);
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|   return Size;
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| }
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| 
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| // Overwrites part of To[0,ToSize) with a part of From[0,FromSize).
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| // Returns ToSize.
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| size_t MutationDispatcher::CopyPartOf(const uint8_t *From, size_t FromSize,
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|                                       uint8_t *To, size_t ToSize) {
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|   // Copy From[FromBeg, FromBeg + CopySize) into To[ToBeg, ToBeg + CopySize).
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|   size_t ToBeg = Rand(ToSize);
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|   size_t CopySize = Rand(ToSize - ToBeg) + 1;
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|   assert(ToBeg + CopySize <= ToSize);
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|   CopySize = std::min(CopySize, FromSize);
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|   size_t FromBeg = Rand(FromSize - CopySize + 1);
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|   assert(FromBeg + CopySize <= FromSize);
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|   memmove(To + ToBeg, From + FromBeg, CopySize);
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|   return ToSize;
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| }
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| 
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| // Inserts part of From[0,ToSize) into To.
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| // Returns new size of To on success or 0 on failure.
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| size_t MutationDispatcher::InsertPartOf(const uint8_t *From, size_t FromSize,
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|                                         uint8_t *To, size_t ToSize,
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|                                         size_t MaxToSize) {
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|   if (ToSize >= MaxToSize) return 0;
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|   size_t AvailableSpace = MaxToSize - ToSize;
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|   size_t MaxCopySize = std::min(AvailableSpace, FromSize);
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|   size_t CopySize = Rand(MaxCopySize) + 1;
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|   size_t FromBeg = Rand(FromSize - CopySize + 1);
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|   assert(FromBeg + CopySize <= FromSize);
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|   size_t ToInsertPos = Rand(ToSize + 1);
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|   assert(ToInsertPos + CopySize <= MaxToSize);
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|   size_t TailSize = ToSize - ToInsertPos;
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|   if (To == From) {
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|     MutateInPlaceHere.resize(MaxToSize);
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|     memcpy(MutateInPlaceHere.data(), From + FromBeg, CopySize);
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|     memmove(To + ToInsertPos + CopySize, To + ToInsertPos, TailSize);
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|     memmove(To + ToInsertPos, MutateInPlaceHere.data(), CopySize);
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|   } else {
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|     memmove(To + ToInsertPos + CopySize, To + ToInsertPos, TailSize);
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|     memmove(To + ToInsertPos, From + FromBeg, CopySize);
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|   }
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|   return ToSize + CopySize;
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| }
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| 
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| size_t MutationDispatcher::Mutate_CopyPart(uint8_t *Data, size_t Size,
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|                                            size_t MaxSize) {
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|   if (Size > MaxSize || Size == 0) return 0;
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|   // If Size == MaxSize, `InsertPartOf(...)` will
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|   // fail so there's no point using it in this case.
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|   if (Size == MaxSize || Rand.RandBool())
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|     return CopyPartOf(Data, Size, Data, Size);
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|   else
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|     return InsertPartOf(Data, Size, Data, Size, MaxSize);
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| }
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| 
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| size_t MutationDispatcher::Mutate_ChangeASCIIInteger(uint8_t *Data, size_t Size,
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|                                                      size_t MaxSize) {
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|   if (Size > MaxSize) return 0;
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|   size_t B = Rand(Size);
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|   while (B < Size && !isdigit(Data[B])) B++;
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|   if (B == Size) return 0;
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|   size_t E = B;
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|   while (E < Size && isdigit(Data[E])) E++;
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|   assert(B < E);
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|   // now we have digits in [B, E).
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|   // strtol and friends don't accept non-zero-teminated data, parse it manually.
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|   uint64_t Val = Data[B] - '0';
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|   for (size_t i = B + 1; i < E; i++)
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|     Val = Val * 10 + Data[i] - '0';
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| 
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|   // Mutate the integer value.
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|   switch(Rand(5)) {
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|     case 0: Val++; break;
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|     case 1: Val--; break;
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|     case 2: Val /= 2; break;
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|     case 3: Val *= 2; break;
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|     case 4: Val = Rand(Val * Val); break;
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|     default: assert(0);
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|   }
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|   // Just replace the bytes with the new ones, don't bother moving bytes.
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|   for (size_t i = B; i < E; i++) {
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|     size_t Idx = E + B - i - 1;
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|     assert(Idx >= B && Idx < E);
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|     Data[Idx] = (Val % 10) + '0';
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|     Val /= 10;
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|   }
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|   return Size;
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| }
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| 
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| template<class T>
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| size_t ChangeBinaryInteger(uint8_t *Data, size_t Size, Random &Rand) {
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|   if (Size < sizeof(T)) return 0;
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|   size_t Off = Rand(Size - sizeof(T) + 1);
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|   assert(Off + sizeof(T) <= Size);
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|   T Val;
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|   if (Off < 64 && !Rand(4)) {
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|     Val = Size;
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|     if (Rand.RandBool())
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|       Val = Bswap(Val);
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|   } else {
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|     memcpy(&Val, Data + Off, sizeof(Val));
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|     T Add = Rand(21);
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|     Add -= 10;
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|     if (Rand.RandBool())
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|       Val = Bswap(T(Bswap(Val) + Add)); // Add assuming different endiannes.
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|     else
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|       Val = Val + Add;               // Add assuming current endiannes.
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|     if (Add == 0 || Rand.RandBool()) // Maybe negate.
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|       Val = -Val;
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|   }
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|   memcpy(Data + Off, &Val, sizeof(Val));
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|   return Size;
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| }
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| 
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| size_t MutationDispatcher::Mutate_ChangeBinaryInteger(uint8_t *Data,
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|                                                       size_t Size,
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|                                                       size_t MaxSize) {
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|   if (Size > MaxSize) return 0;
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|   switch (Rand(4)) {
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|     case 3: return ChangeBinaryInteger<uint64_t>(Data, Size, Rand);
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|     case 2: return ChangeBinaryInteger<uint32_t>(Data, Size, Rand);
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|     case 1: return ChangeBinaryInteger<uint16_t>(Data, Size, Rand);
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|     case 0: return ChangeBinaryInteger<uint8_t>(Data, Size, Rand);
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|     default: assert(0);
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|   }
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|   return 0;
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| }
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| 
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| size_t MutationDispatcher::Mutate_CrossOver(uint8_t *Data, size_t Size,
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|                                             size_t MaxSize) {
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|   if (Size > MaxSize) return 0;
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|   if (Size == 0) return 0;
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|   if (!CrossOverWith) return 0;
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|   const Unit &O = *CrossOverWith;
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|   if (O.empty()) return 0;
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|   MutateInPlaceHere.resize(MaxSize);
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|   auto &U = MutateInPlaceHere;
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|   size_t NewSize = 0;
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|   switch(Rand(3)) {
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|     case 0:
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|       NewSize = CrossOver(Data, Size, O.data(), O.size(), U.data(), U.size());
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|       break;
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|     case 1:
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|       NewSize = InsertPartOf(O.data(), O.size(), U.data(), U.size(), MaxSize);
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|       if (!NewSize)
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|         NewSize = CopyPartOf(O.data(), O.size(), U.data(), U.size());
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|       break;
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|     case 2:
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|       NewSize = CopyPartOf(O.data(), O.size(), U.data(), U.size());
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|       break;
 | |
|     default: assert(0);
 | |
|   }
 | |
|   assert(NewSize > 0 && "CrossOver returned empty unit");
 | |
|   assert(NewSize <= MaxSize && "CrossOver returned overisized unit");
 | |
|   memcpy(Data, U.data(), NewSize);
 | |
|   return NewSize;
 | |
| }
 | |
| 
 | |
| void MutationDispatcher::StartMutationSequence() {
 | |
|   CurrentMutatorSequence.clear();
 | |
|   CurrentDictionaryEntrySequence.clear();
 | |
| }
 | |
| 
 | |
| // Copy successful dictionary entries to PersistentAutoDictionary.
 | |
| void MutationDispatcher::RecordSuccessfulMutationSequence() {
 | |
|   for (auto DE : CurrentDictionaryEntrySequence) {
 | |
|     // PersistentAutoDictionary.AddWithSuccessCountOne(DE);
 | |
|     DE->IncSuccessCount();
 | |
|     assert(DE->GetW().size());
 | |
|     // Linear search is fine here as this happens seldom.
 | |
|     if (!PersistentAutoDictionary.ContainsWord(DE->GetW()))
 | |
|       PersistentAutoDictionary.push_back({DE->GetW(), 1});
 | |
|   }
 | |
| }
 | |
| 
 | |
| void MutationDispatcher::PrintRecommendedDictionary() {
 | |
|   Vector<DictionaryEntry> V;
 | |
|   for (auto &DE : PersistentAutoDictionary)
 | |
|     if (!ManualDictionary.ContainsWord(DE.GetW()))
 | |
|       V.push_back(DE);
 | |
|   if (V.empty()) return;
 | |
|   Printf("###### Recommended dictionary. ######\n");
 | |
|   for (auto &DE: V) {
 | |
|     assert(DE.GetW().size());
 | |
|     Printf("\"");
 | |
|     PrintASCII(DE.GetW(), "\"");
 | |
|     Printf(" # Uses: %zd\n", DE.GetUseCount());
 | |
|   }
 | |
|   Printf("###### End of recommended dictionary. ######\n");
 | |
| }
 | |
| 
 | |
| void MutationDispatcher::PrintMutationSequence() {
 | |
|   Printf("MS: %zd ", CurrentMutatorSequence.size());
 | |
|   for (auto M : CurrentMutatorSequence)
 | |
|     Printf("%s-", M.Name);
 | |
|   if (!CurrentDictionaryEntrySequence.empty()) {
 | |
|     Printf(" DE: ");
 | |
|     for (auto DE : CurrentDictionaryEntrySequence) {
 | |
|       Printf("\"");
 | |
|       PrintASCII(DE->GetW(), "\"-");
 | |
|     }
 | |
|   }
 | |
| }
 | |
| 
 | |
| size_t MutationDispatcher::Mutate(uint8_t *Data, size_t Size, size_t MaxSize) {
 | |
|   return MutateImpl(Data, Size, MaxSize, Mutators);
 | |
| }
 | |
| 
 | |
| size_t MutationDispatcher::DefaultMutate(uint8_t *Data, size_t Size,
 | |
|                                          size_t MaxSize) {
 | |
|   return MutateImpl(Data, Size, MaxSize, DefaultMutators);
 | |
| }
 | |
| 
 | |
| // Mutates Data in place, returns new size.
 | |
| size_t MutationDispatcher::MutateImpl(uint8_t *Data, size_t Size,
 | |
|                                       size_t MaxSize,
 | |
|                                       Vector<Mutator> &Mutators) {
 | |
|   assert(MaxSize > 0);
 | |
|   // Some mutations may fail (e.g. can't insert more bytes if Size == MaxSize),
 | |
|   // in which case they will return 0.
 | |
|   // Try several times before returning un-mutated data.
 | |
|   for (int Iter = 0; Iter < 100; Iter++) {
 | |
|     auto M = Mutators[Rand(Mutators.size())];
 | |
|     size_t NewSize = (this->*(M.Fn))(Data, Size, MaxSize);
 | |
|     if (NewSize && NewSize <= MaxSize) {
 | |
|       if (Options.OnlyASCII)
 | |
|         ToASCII(Data, NewSize);
 | |
|       CurrentMutatorSequence.push_back(M);
 | |
|       return NewSize;
 | |
|     }
 | |
|   }
 | |
|   *Data = ' ';
 | |
|   return 1;   // Fallback, should not happen frequently.
 | |
| }
 | |
| 
 | |
| // Mask represents the set of Data bytes that are worth mutating.
 | |
| size_t MutationDispatcher::MutateWithMask(uint8_t *Data, size_t Size,
 | |
|                                           size_t MaxSize,
 | |
|                                           const Vector<uint8_t> &Mask) {
 | |
|   size_t MaskedSize = std::min(Size, Mask.size());
 | |
|   // * Copy the worthy bytes into a temporary array T
 | |
|   // * Mutate T
 | |
|   // * Copy T back.
 | |
|   // This is totally unoptimized.
 | |
|   auto &T = MutateWithMaskTemp;
 | |
|   if (T.size() < Size)
 | |
|     T.resize(Size);
 | |
|   size_t OneBits = 0;
 | |
|   for (size_t I = 0; I < MaskedSize; I++)
 | |
|     if (Mask[I])
 | |
|       T[OneBits++] = Data[I];
 | |
| 
 | |
|   if (!OneBits) return 0;
 | |
|   assert(!T.empty());
 | |
|   size_t NewSize = Mutate(T.data(), OneBits, OneBits);
 | |
|   assert(NewSize <= OneBits);
 | |
|   (void)NewSize;
 | |
|   // Even if NewSize < OneBits we still use all OneBits bytes.
 | |
|   for (size_t I = 0, J = 0; I < MaskedSize; I++)
 | |
|     if (Mask[I])
 | |
|       Data[I] = T[J++];
 | |
|   return Size;
 | |
| }
 | |
| 
 | |
| void MutationDispatcher::AddWordToManualDictionary(const Word &W) {
 | |
|   ManualDictionary.push_back(
 | |
|       {W, std::numeric_limits<size_t>::max()});
 | |
| }
 | |
| 
 | |
| }  // namespace fuzzer
 | 
