| // Copyright (c) 2019, Paul Dreik |
| // For the license information refer to format.h. |
| |
| #ifndef FUZZER_COMMON_H |
| #define FUZZER_COMMON_H |
| |
| #include <cstdint> // std::uint8_t |
| #include <cstring> // memcpy |
| #include <vector> |
| |
| #include <fmt/core.h> |
| |
| // One can format to either a string, or a buffer. The latter is faster, but |
| // one may be interested in formatting to a string instead to verify it works |
| // as intended. To avoid a combinatoric explosion, select this at compile time |
| // instead of dynamically from the fuzz data. |
| #define FMT_FUZZ_FORMAT_TO_STRING 0 |
| |
| // If {fmt} is given a buffer that is separately allocated, chances that address |
| // sanitizer detects out of bound reads is much higher. However, it slows down |
| // the fuzzing. |
| #define FMT_FUZZ_SEPARATE_ALLOCATION 1 |
| |
| // The size of the largest possible type in use. |
| // To let the the fuzzer mutation be efficient at cross pollinating between |
| // different types, use a fixed size format. The same bit pattern, interpreted |
| // as another type, is likely interesting. |
| constexpr auto fixed_size = 16; |
| |
| // Casts data to a char pointer. |
| template <typename T> inline const char* as_chars(const T* data) { |
| return reinterpret_cast<const char*>(data); |
| } |
| |
| // Casts data to a byte pointer. |
| template <typename T> inline const std::uint8_t* as_bytes(const T* data) { |
| return reinterpret_cast<const std::uint8_t*>(data); |
| } |
| |
| // Blits bytes from data to form an (assumed trivially constructible) object |
| // of type Item. |
| template <class Item> inline Item assign_from_buf(const std::uint8_t* data) { |
| auto item = Item(); |
| std::memcpy(&item, data, sizeof(Item)); |
| return item; |
| } |
| |
| // Reads a boolean value by looking at the first byte from data. |
| template <> inline bool assign_from_buf<bool>(const std::uint8_t* data) { |
| return *data != 0; |
| } |
| |
| struct data_to_string { |
| #if FMT_FUZZ_SEPARATE_ALLOCATION |
| std::vector<char> buffer; |
| |
| data_to_string(const uint8_t* data, size_t size, bool add_terminator = false) |
| : buffer(size + (add_terminator ? 1 : 0)) { |
| std::memcpy(buffer.data(), data, size); |
| } |
| |
| fmt::string_view get() const { return {buffer.data(), buffer.size()}; } |
| #else |
| fmt::string_view sv; |
| |
| data_to_string(const uint8_t* data, size_t size, bool = false) |
| : str(as_chars(data), size) {} |
| |
| fmt::string_view get() const { return sv; } |
| #endif |
| |
| const char* data() const { return get().data(); } |
| }; |
| |
| #endif // FUZZER_COMMON_H |