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Merge #20740: fuzz: Update FuzzedDataProvider.h from upstream (LLVM)
e3d2ba7c70b13a2165020e45abf02373a1e953f7 fuzz: Update FuzzedDataProvider.h from upstream (LLVM) (practicalswift) Pull request description: Update `FuzzedDataProvider.h` from upstream (LLVM). Upstream revision:6d0488f75b/compiler-rt/include/fuzzer/FuzzedDataProvider.h
Changes since last update: * [[compiler-rt] FuzzedDataProvider: add ConsumeData and method.](20a604d3f5
) * [[compiler-rt] Fix a typo in a comment in FuzzedDataProvider.h.](5517d3b80b
) * [[compiler-rt] Add ConsumeRandomLengthString() version without arguments.](2136d17d8d
) * [[compiler-rt] Refactor FuzzedDataProvider for better readability.](1262db1b6a
) * [[compiler-rt] FuzzedDataProvider: make linter happy.](1e65209e04
) * [[compiler-rt] Mark FDP non-template methods inline to avoid ODR violations.](6d0488f75b
) ACKs for top commit: MarcoFalke: ACK e3d2ba7c70b13a2165020e45abf02373a1e953f7 🌛 Tree-SHA512: 62cb27906f08fd07983f4a8fbbd381c12ed185617a58f1ebc8564c87e638086f952417f4f6481fbd91b9a313aff00e944215393734566c219c074512991f8057
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@ -35,208 +35,47 @@ class FuzzedDataProvider {
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: data_ptr_(data), remaining_bytes_(size) {}
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~FuzzedDataProvider() = default;
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// Returns a std::vector containing |num_bytes| of input data. If fewer than
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// |num_bytes| of data remain, returns a shorter std::vector containing all
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// of the data that's left. Can be used with any byte sized type, such as
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// char, unsigned char, uint8_t, etc.
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template <typename T> std::vector<T> ConsumeBytes(size_t num_bytes) {
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num_bytes = std::min(num_bytes, remaining_bytes_);
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return ConsumeBytes<T>(num_bytes, num_bytes);
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}
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// See the implementation below (after the class definition) for more verbose
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// comments for each of the methods.
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// Similar to |ConsumeBytes|, but also appends the terminator value at the end
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// of the resulting vector. Useful, when a mutable null-terminated C-string is
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// needed, for example. But that is a rare case. Better avoid it, if possible,
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// and prefer using |ConsumeBytes| or |ConsumeBytesAsString| methods.
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// Methods returning std::vector of bytes. These are the most popular choice
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// when splitting fuzzing input into pieces, as every piece is put into a
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// separate buffer (i.e. ASan would catch any under-/overflow) and the memory
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// will be released automatically.
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template <typename T> std::vector<T> ConsumeBytes(size_t num_bytes);
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template <typename T>
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std::vector<T> ConsumeBytesWithTerminator(size_t num_bytes,
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T terminator = 0) {
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num_bytes = std::min(num_bytes, remaining_bytes_);
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std::vector<T> result = ConsumeBytes<T>(num_bytes + 1, num_bytes);
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result.back() = terminator;
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return result;
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}
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std::vector<T> ConsumeBytesWithTerminator(size_t num_bytes, T terminator = 0);
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template <typename T> std::vector<T> ConsumeRemainingBytes();
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// Returns a std::string containing |num_bytes| of input data. Using this and
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// |.c_str()| on the resulting string is the best way to get an immutable
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// null-terminated C string. If fewer than |num_bytes| of data remain, returns
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// a shorter std::string containing all of the data that's left.
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std::string ConsumeBytesAsString(size_t num_bytes) {
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static_assert(sizeof(std::string::value_type) == sizeof(uint8_t),
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"ConsumeBytesAsString cannot convert the data to a string.");
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// Methods returning strings. Use only when you need a std::string or a null
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// terminated C-string. Otherwise, prefer the methods returning std::vector.
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std::string ConsumeBytesAsString(size_t num_bytes);
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std::string ConsumeRandomLengthString(size_t max_length);
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std::string ConsumeRandomLengthString();
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std::string ConsumeRemainingBytesAsString();
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num_bytes = std::min(num_bytes, remaining_bytes_);
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std::string result(
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reinterpret_cast<const std::string::value_type *>(data_ptr_),
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num_bytes);
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Advance(num_bytes);
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return result;
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}
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// Methods returning integer values.
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template <typename T> T ConsumeIntegral();
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template <typename T> T ConsumeIntegralInRange(T min, T max);
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// Returns a number in the range [min, max] by consuming bytes from the
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// input data. The value might not be uniformly distributed in the given
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// range. If there's no input data left, always returns |min|. |min| must
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// be less than or equal to |max|.
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template <typename T> T ConsumeIntegralInRange(T min, T max) {
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static_assert(std::is_integral<T>::value, "An integral type is required.");
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static_assert(sizeof(T) <= sizeof(uint64_t), "Unsupported integral type.");
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// Methods returning floating point values.
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template <typename T> T ConsumeFloatingPoint();
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template <typename T> T ConsumeFloatingPointInRange(T min, T max);
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if (min > max)
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abort();
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// 0 <= return value <= 1.
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template <typename T> T ConsumeProbability();
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// Use the biggest type possible to hold the range and the result.
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uint64_t range = static_cast<uint64_t>(max) - min;
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uint64_t result = 0;
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size_t offset = 0;
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bool ConsumeBool();
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while (offset < sizeof(T) * CHAR_BIT && (range >> offset) > 0 &&
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remaining_bytes_ != 0) {
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// Pull bytes off the end of the seed data. Experimentally, this seems to
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// allow the fuzzer to more easily explore the input space. This makes
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// sense, since it works by modifying inputs that caused new code to run,
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// and this data is often used to encode length of data read by
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// |ConsumeBytes|. Separating out read lengths makes it easier modify the
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// contents of the data that is actually read.
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--remaining_bytes_;
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result = (result << CHAR_BIT) | data_ptr_[remaining_bytes_];
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offset += CHAR_BIT;
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}
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// Returns a value chosen from the given enum.
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template <typename T> T ConsumeEnum();
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// Avoid division by 0, in case |range + 1| results in overflow.
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if (range != std::numeric_limits<decltype(range)>::max())
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result = result % (range + 1);
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// Returns a value from the given array.
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template <typename T, size_t size> T PickValueInArray(const T (&array)[size]);
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template <typename T> T PickValueInArray(std::initializer_list<const T> list);
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return static_cast<T>(min + result);
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}
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// Returns a std::string of length from 0 to |max_length|. When it runs out of
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// input data, returns what remains of the input. Designed to be more stable
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// with respect to a fuzzer inserting characters than just picking a random
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// length and then consuming that many bytes with |ConsumeBytes|.
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std::string ConsumeRandomLengthString(size_t max_length) {
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// Reads bytes from the start of |data_ptr_|. Maps "\\" to "\", and maps "\"
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// followed by anything else to the end of the string. As a result of this
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// logic, a fuzzer can insert characters into the string, and the string
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// will be lengthened to include those new characters, resulting in a more
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// stable fuzzer than picking the length of a string independently from
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// picking its contents.
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std::string result;
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// Reserve the anticipated capaticity to prevent several reallocations.
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result.reserve(std::min(max_length, remaining_bytes_));
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for (size_t i = 0; i < max_length && remaining_bytes_ != 0; ++i) {
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char next = ConvertUnsignedToSigned<char>(data_ptr_[0]);
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Advance(1);
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if (next == '\\' && remaining_bytes_ != 0) {
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next = ConvertUnsignedToSigned<char>(data_ptr_[0]);
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Advance(1);
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if (next != '\\')
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break;
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}
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result += next;
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}
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result.shrink_to_fit();
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return result;
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}
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// Returns a std::vector containing all remaining bytes of the input data.
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template <typename T> std::vector<T> ConsumeRemainingBytes() {
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return ConsumeBytes<T>(remaining_bytes_);
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}
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// Returns a std::string containing all remaining bytes of the input data.
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// Prefer using |ConsumeRemainingBytes| unless you actually need a std::string
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// object.
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std::string ConsumeRemainingBytesAsString() {
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return ConsumeBytesAsString(remaining_bytes_);
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}
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// Returns a number in the range [Type's min, Type's max]. The value might
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// not be uniformly distributed in the given range. If there's no input data
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// left, always returns |min|.
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template <typename T> T ConsumeIntegral() {
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return ConsumeIntegralInRange(std::numeric_limits<T>::min(),
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std::numeric_limits<T>::max());
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}
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// Reads one byte and returns a bool, or false when no data remains.
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bool ConsumeBool() { return 1 & ConsumeIntegral<uint8_t>(); }
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// Returns a copy of the value selected from the given fixed-size |array|.
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template <typename T, size_t size>
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T PickValueInArray(const T (&array)[size]) {
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static_assert(size > 0, "The array must be non empty.");
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return array[ConsumeIntegralInRange<size_t>(0, size - 1)];
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}
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template <typename T>
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T PickValueInArray(std::initializer_list<const T> list) {
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// TODO(Dor1s): switch to static_assert once C++14 is allowed.
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if (!list.size())
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abort();
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return *(list.begin() + ConsumeIntegralInRange<size_t>(0, list.size() - 1));
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}
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// Returns an enum value. The enum must start at 0 and be contiguous. It must
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// also contain |kMaxValue| aliased to its largest (inclusive) value. Such as:
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// enum class Foo { SomeValue, OtherValue, kMaxValue = OtherValue };
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template <typename T> T ConsumeEnum() {
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static_assert(std::is_enum<T>::value, "|T| must be an enum type.");
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return static_cast<T>(ConsumeIntegralInRange<uint32_t>(
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0, static_cast<uint32_t>(T::kMaxValue)));
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}
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// Returns a floating point number in the range [0.0, 1.0]. If there's no
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// input data left, always returns 0.
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template <typename T> T ConsumeProbability() {
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static_assert(std::is_floating_point<T>::value,
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"A floating point type is required.");
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// Use different integral types for different floating point types in order
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// to provide better density of the resulting values.
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using IntegralType =
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typename std::conditional<(sizeof(T) <= sizeof(uint32_t)), uint32_t,
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uint64_t>::type;
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T result = static_cast<T>(ConsumeIntegral<IntegralType>());
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result /= static_cast<T>(std::numeric_limits<IntegralType>::max());
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return result;
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}
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// Returns a floating point value in the range [Type's lowest, Type's max] by
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// consuming bytes from the input data. If there's no input data left, always
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// returns approximately 0.
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template <typename T> T ConsumeFloatingPoint() {
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return ConsumeFloatingPointInRange<T>(std::numeric_limits<T>::lowest(),
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std::numeric_limits<T>::max());
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}
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// Returns a floating point value in the given range by consuming bytes from
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// the input data. If there's no input data left, returns |min|. Note that
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// |min| must be less than or equal to |max|.
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template <typename T> T ConsumeFloatingPointInRange(T min, T max) {
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if (min > max)
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abort();
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T range = .0;
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T result = min;
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constexpr T zero(.0);
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if (max > zero && min < zero && max > min + std::numeric_limits<T>::max()) {
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// The diff |max - min| would overflow the given floating point type. Use
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// the half of the diff as the range and consume a bool to decide whether
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// the result is in the first of the second part of the diff.
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range = (max / 2.0) - (min / 2.0);
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if (ConsumeBool()) {
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result += range;
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}
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} else {
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range = max - min;
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}
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return result + range * ConsumeProbability<T>();
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}
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// Writes data to the given destination and returns number of bytes written.
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size_t ConsumeData(void *destination, size_t num_bytes);
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// Reports the remaining bytes available for fuzzed input.
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size_t remaining_bytes() { return remaining_bytes_; }
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@ -245,62 +84,305 @@ class FuzzedDataProvider {
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FuzzedDataProvider(const FuzzedDataProvider &) = delete;
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FuzzedDataProvider &operator=(const FuzzedDataProvider &) = delete;
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void Advance(size_t num_bytes) {
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if (num_bytes > remaining_bytes_)
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abort();
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void CopyAndAdvance(void *destination, size_t num_bytes);
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data_ptr_ += num_bytes;
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remaining_bytes_ -= num_bytes;
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}
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void Advance(size_t num_bytes);
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template <typename T>
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std::vector<T> ConsumeBytes(size_t size, size_t num_bytes_to_consume) {
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static_assert(sizeof(T) == sizeof(uint8_t), "Incompatible data type.");
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std::vector<T> ConsumeBytes(size_t size, size_t num_bytes);
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// The point of using the size-based constructor below is to increase the
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// odds of having a vector object with capacity being equal to the length.
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// That part is always implementation specific, but at least both libc++ and
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// libstdc++ allocate the requested number of bytes in that constructor,
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// which seems to be a natural choice for other implementations as well.
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// To increase the odds even more, we also call |shrink_to_fit| below.
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std::vector<T> result(size);
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if (size == 0) {
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if (num_bytes_to_consume != 0)
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abort();
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return result;
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}
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std::memcpy(result.data(), data_ptr_, num_bytes_to_consume);
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Advance(num_bytes_to_consume);
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// Even though |shrink_to_fit| is also implementation specific, we expect it
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// to provide an additional assurance in case vector's constructor allocated
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// a buffer which is larger than the actual amount of data we put inside it.
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result.shrink_to_fit();
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return result;
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}
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template <typename TS, typename TU> TS ConvertUnsignedToSigned(TU value) {
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static_assert(sizeof(TS) == sizeof(TU), "Incompatible data types.");
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static_assert(!std::numeric_limits<TU>::is_signed,
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"Source type must be unsigned.");
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// TODO(Dor1s): change to `if constexpr` once C++17 becomes mainstream.
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if (std::numeric_limits<TS>::is_modulo)
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return static_cast<TS>(value);
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// Avoid using implementation-defined unsigned to signer conversions.
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// To learn more, see https://stackoverflow.com/questions/13150449.
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if (value <= std::numeric_limits<TS>::max()) {
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return static_cast<TS>(value);
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} else {
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constexpr auto TS_min = std::numeric_limits<TS>::min();
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return TS_min + static_cast<char>(value - TS_min);
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}
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}
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template <typename TS, typename TU> TS ConvertUnsignedToSigned(TU value);
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const uint8_t *data_ptr_;
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size_t remaining_bytes_;
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};
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// Returns a std::vector containing |num_bytes| of input data. If fewer than
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// |num_bytes| of data remain, returns a shorter std::vector containing all
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// of the data that's left. Can be used with any byte sized type, such as
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// char, unsigned char, uint8_t, etc.
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template <typename T>
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std::vector<T> FuzzedDataProvider::ConsumeBytes(size_t num_bytes) {
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num_bytes = std::min(num_bytes, remaining_bytes_);
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return ConsumeBytes<T>(num_bytes, num_bytes);
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}
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// Similar to |ConsumeBytes|, but also appends the terminator value at the end
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// of the resulting vector. Useful, when a mutable null-terminated C-string is
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// needed, for example. But that is a rare case. Better avoid it, if possible,
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// and prefer using |ConsumeBytes| or |ConsumeBytesAsString| methods.
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template <typename T>
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std::vector<T> FuzzedDataProvider::ConsumeBytesWithTerminator(size_t num_bytes,
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T terminator) {
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num_bytes = std::min(num_bytes, remaining_bytes_);
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std::vector<T> result = ConsumeBytes<T>(num_bytes + 1, num_bytes);
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result.back() = terminator;
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return result;
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}
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// Returns a std::vector containing all remaining bytes of the input data.
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template <typename T>
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std::vector<T> FuzzedDataProvider::ConsumeRemainingBytes() {
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return ConsumeBytes<T>(remaining_bytes_);
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}
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// Returns a std::string containing |num_bytes| of input data. Using this and
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// |.c_str()| on the resulting string is the best way to get an immutable
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// null-terminated C string. If fewer than |num_bytes| of data remain, returns
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// a shorter std::string containing all of the data that's left.
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inline std::string FuzzedDataProvider::ConsumeBytesAsString(size_t num_bytes) {
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static_assert(sizeof(std::string::value_type) == sizeof(uint8_t),
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"ConsumeBytesAsString cannot convert the data to a string.");
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num_bytes = std::min(num_bytes, remaining_bytes_);
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std::string result(
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reinterpret_cast<const std::string::value_type *>(data_ptr_), num_bytes);
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Advance(num_bytes);
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return result;
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}
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// Returns a std::string of length from 0 to |max_length|. When it runs out of
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// input data, returns what remains of the input. Designed to be more stable
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// with respect to a fuzzer inserting characters than just picking a random
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// length and then consuming that many bytes with |ConsumeBytes|.
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inline std::string
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FuzzedDataProvider::ConsumeRandomLengthString(size_t max_length) {
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// Reads bytes from the start of |data_ptr_|. Maps "\\" to "\", and maps "\"
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// followed by anything else to the end of the string. As a result of this
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// logic, a fuzzer can insert characters into the string, and the string
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// will be lengthened to include those new characters, resulting in a more
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// stable fuzzer than picking the length of a string independently from
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// picking its contents.
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std::string result;
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// Reserve the anticipated capaticity to prevent several reallocations.
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result.reserve(std::min(max_length, remaining_bytes_));
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for (size_t i = 0; i < max_length && remaining_bytes_ != 0; ++i) {
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char next = ConvertUnsignedToSigned<char>(data_ptr_[0]);
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Advance(1);
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if (next == '\\' && remaining_bytes_ != 0) {
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next = ConvertUnsignedToSigned<char>(data_ptr_[0]);
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Advance(1);
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if (next != '\\')
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break;
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}
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result += next;
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}
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result.shrink_to_fit();
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return result;
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}
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// Returns a std::string of length from 0 to |remaining_bytes_|.
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inline std::string FuzzedDataProvider::ConsumeRandomLengthString() {
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return ConsumeRandomLengthString(remaining_bytes_);
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}
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|
||||
// Returns a std::string containing all remaining bytes of the input data.
|
||||
// Prefer using |ConsumeRemainingBytes| unless you actually need a std::string
|
||||
// object.
|
||||
inline std::string FuzzedDataProvider::ConsumeRemainingBytesAsString() {
|
||||
return ConsumeBytesAsString(remaining_bytes_);
|
||||
}
|
||||
|
||||
// Returns a number in the range [Type's min, Type's max]. The value might
|
||||
// not be uniformly distributed in the given range. If there's no input data
|
||||
// left, always returns |min|.
|
||||
template <typename T> T FuzzedDataProvider::ConsumeIntegral() {
|
||||
return ConsumeIntegralInRange(std::numeric_limits<T>::min(),
|
||||
std::numeric_limits<T>::max());
|
||||
}
|
||||
|
||||
// Returns a number in the range [min, max] by consuming bytes from the
|
||||
// input data. The value might not be uniformly distributed in the given
|
||||
// range. If there's no input data left, always returns |min|. |min| must
|
||||
// be less than or equal to |max|.
|
||||
template <typename T>
|
||||
T FuzzedDataProvider::ConsumeIntegralInRange(T min, T max) {
|
||||
static_assert(std::is_integral<T>::value, "An integral type is required.");
|
||||
static_assert(sizeof(T) <= sizeof(uint64_t), "Unsupported integral type.");
|
||||
|
||||
if (min > max)
|
||||
abort();
|
||||
|
||||
// Use the biggest type possible to hold the range and the result.
|
||||
uint64_t range = static_cast<uint64_t>(max) - min;
|
||||
uint64_t result = 0;
|
||||
size_t offset = 0;
|
||||
|
||||
while (offset < sizeof(T) * CHAR_BIT && (range >> offset) > 0 &&
|
||||
remaining_bytes_ != 0) {
|
||||
// Pull bytes off the end of the seed data. Experimentally, this seems to
|
||||
// allow the fuzzer to more easily explore the input space. This makes
|
||||
// sense, since it works by modifying inputs that caused new code to run,
|
||||
// and this data is often used to encode length of data read by
|
||||
// |ConsumeBytes|. Separating out read lengths makes it easier modify the
|
||||
// contents of the data that is actually read.
|
||||
--remaining_bytes_;
|
||||
result = (result << CHAR_BIT) | data_ptr_[remaining_bytes_];
|
||||
offset += CHAR_BIT;
|
||||
}
|
||||
|
||||
// Avoid division by 0, in case |range + 1| results in overflow.
|
||||
if (range != std::numeric_limits<decltype(range)>::max())
|
||||
result = result % (range + 1);
|
||||
|
||||
return static_cast<T>(min + result);
|
||||
}
|
||||
|
||||
// Returns a floating point value in the range [Type's lowest, Type's max] by
|
||||
// consuming bytes from the input data. If there's no input data left, always
|
||||
// returns approximately 0.
|
||||
template <typename T> T FuzzedDataProvider::ConsumeFloatingPoint() {
|
||||
return ConsumeFloatingPointInRange<T>(std::numeric_limits<T>::lowest(),
|
||||
std::numeric_limits<T>::max());
|
||||
}
|
||||
|
||||
// Returns a floating point value in the given range by consuming bytes from
|
||||
// the input data. If there's no input data left, returns |min|. Note that
|
||||
// |min| must be less than or equal to |max|.
|
||||
template <typename T>
|
||||
T FuzzedDataProvider::ConsumeFloatingPointInRange(T min, T max) {
|
||||
if (min > max)
|
||||
abort();
|
||||
|
||||
T range = .0;
|
||||
T result = min;
|
||||
constexpr T zero(.0);
|
||||
if (max > zero && min < zero && max > min + std::numeric_limits<T>::max()) {
|
||||
// The diff |max - min| would overflow the given floating point type. Use
|
||||
// the half of the diff as the range and consume a bool to decide whether
|
||||
// the result is in the first of the second part of the diff.
|
||||
range = (max / 2.0) - (min / 2.0);
|
||||
if (ConsumeBool()) {
|
||||
result += range;
|
||||
}
|
||||
} else {
|
||||
range = max - min;
|
||||
}
|
||||
|
||||
return result + range * ConsumeProbability<T>();
|
||||
}
|
||||
|
||||
// Returns a floating point number in the range [0.0, 1.0]. If there's no
|
||||
// input data left, always returns 0.
|
||||
template <typename T> T FuzzedDataProvider::ConsumeProbability() {
|
||||
static_assert(std::is_floating_point<T>::value,
|
||||
"A floating point type is required.");
|
||||
|
||||
// Use different integral types for different floating point types in order
|
||||
// to provide better density of the resulting values.
|
||||
using IntegralType =
|
||||
typename std::conditional<(sizeof(T) <= sizeof(uint32_t)), uint32_t,
|
||||
uint64_t>::type;
|
||||
|
||||
T result = static_cast<T>(ConsumeIntegral<IntegralType>());
|
||||
result /= static_cast<T>(std::numeric_limits<IntegralType>::max());
|
||||
return result;
|
||||
}
|
||||
|
||||
// Reads one byte and returns a bool, or false when no data remains.
|
||||
inline bool FuzzedDataProvider::ConsumeBool() {
|
||||
return 1 & ConsumeIntegral<uint8_t>();
|
||||
}
|
||||
|
||||
// Returns an enum value. The enum must start at 0 and be contiguous. It must
|
||||
// also contain |kMaxValue| aliased to its largest (inclusive) value. Such as:
|
||||
// enum class Foo { SomeValue, OtherValue, kMaxValue = OtherValue };
|
||||
template <typename T> T FuzzedDataProvider::ConsumeEnum() {
|
||||
static_assert(std::is_enum<T>::value, "|T| must be an enum type.");
|
||||
return static_cast<T>(
|
||||
ConsumeIntegralInRange<uint32_t>(0, static_cast<uint32_t>(T::kMaxValue)));
|
||||
}
|
||||
|
||||
// Returns a copy of the value selected from the given fixed-size |array|.
|
||||
template <typename T, size_t size>
|
||||
T FuzzedDataProvider::PickValueInArray(const T (&array)[size]) {
|
||||
static_assert(size > 0, "The array must be non empty.");
|
||||
return array[ConsumeIntegralInRange<size_t>(0, size - 1)];
|
||||
}
|
||||
|
||||
template <typename T>
|
||||
T FuzzedDataProvider::PickValueInArray(std::initializer_list<const T> list) {
|
||||
// TODO(Dor1s): switch to static_assert once C++14 is allowed.
|
||||
if (!list.size())
|
||||
abort();
|
||||
|
||||
return *(list.begin() + ConsumeIntegralInRange<size_t>(0, list.size() - 1));
|
||||
}
|
||||
|
||||
// Writes |num_bytes| of input data to the given destination pointer. If there
|
||||
// is not enough data left, writes all remaining bytes. Return value is the
|
||||
// number of bytes written.
|
||||
// In general, it's better to avoid using this function, but it may be useful
|
||||
// in cases when it's necessary to fill a certain buffer or object with
|
||||
// fuzzing data.
|
||||
inline size_t FuzzedDataProvider::ConsumeData(void *destination,
|
||||
size_t num_bytes) {
|
||||
num_bytes = std::min(num_bytes, remaining_bytes_);
|
||||
CopyAndAdvance(destination, num_bytes);
|
||||
return num_bytes;
|
||||
}
|
||||
|
||||
// Private methods.
|
||||
inline void FuzzedDataProvider::CopyAndAdvance(void *destination,
|
||||
size_t num_bytes) {
|
||||
std::memcpy(destination, data_ptr_, num_bytes);
|
||||
Advance(num_bytes);
|
||||
}
|
||||
|
||||
inline void FuzzedDataProvider::Advance(size_t num_bytes) {
|
||||
if (num_bytes > remaining_bytes_)
|
||||
abort();
|
||||
|
||||
data_ptr_ += num_bytes;
|
||||
remaining_bytes_ -= num_bytes;
|
||||
}
|
||||
|
||||
template <typename T>
|
||||
std::vector<T> FuzzedDataProvider::ConsumeBytes(size_t size, size_t num_bytes) {
|
||||
static_assert(sizeof(T) == sizeof(uint8_t), "Incompatible data type.");
|
||||
|
||||
// The point of using the size-based constructor below is to increase the
|
||||
// odds of having a vector object with capacity being equal to the length.
|
||||
// That part is always implementation specific, but at least both libc++ and
|
||||
// libstdc++ allocate the requested number of bytes in that constructor,
|
||||
// which seems to be a natural choice for other implementations as well.
|
||||
// To increase the odds even more, we also call |shrink_to_fit| below.
|
||||
std::vector<T> result(size);
|
||||
if (size == 0) {
|
||||
if (num_bytes != 0)
|
||||
abort();
|
||||
return result;
|
||||
}
|
||||
|
||||
CopyAndAdvance(result.data(), num_bytes);
|
||||
|
||||
// Even though |shrink_to_fit| is also implementation specific, we expect it
|
||||
// to provide an additional assurance in case vector's constructor allocated
|
||||
// a buffer which is larger than the actual amount of data we put inside it.
|
||||
result.shrink_to_fit();
|
||||
return result;
|
||||
}
|
||||
|
||||
template <typename TS, typename TU>
|
||||
TS FuzzedDataProvider::ConvertUnsignedToSigned(TU value) {
|
||||
static_assert(sizeof(TS) == sizeof(TU), "Incompatible data types.");
|
||||
static_assert(!std::numeric_limits<TU>::is_signed,
|
||||
"Source type must be unsigned.");
|
||||
|
||||
// TODO(Dor1s): change to `if constexpr` once C++17 becomes mainstream.
|
||||
if (std::numeric_limits<TS>::is_modulo)
|
||||
return static_cast<TS>(value);
|
||||
|
||||
// Avoid using implementation-defined unsigned to signed conversions.
|
||||
// To learn more, see https://stackoverflow.com/questions/13150449.
|
||||
if (value <= std::numeric_limits<TS>::max()) {
|
||||
return static_cast<TS>(value);
|
||||
} else {
|
||||
constexpr auto TS_min = std::numeric_limits<TS>::min();
|
||||
return TS_min + static_cast<char>(value - TS_min);
|
||||
}
|
||||
}
|
||||
|
||||
#endif // LLVM_FUZZER_FUZZED_DATA_PROVIDER_H_
|
||||
|
Loading…
Reference in New Issue
Block a user