libweave: Added base/ files required by libweave
These files cloned from
https://android.googlesource.com/platform/external/libchrome/+/3ca9d0096f5618f5bbad8b1363a069d13fc3026e
They are unchanged and not included into build yet.
BUG=brillo:1256
TEST=`FEATURES=test emerge-gizmo libweave buffet`
Change-Id: I91ccf741ffa3f8fc09f83ae7f6adfa279845434c
111
Change-Id: I27ef0b115216f9fd9865abecaf9e63749ec7a35c
Reviewed-on: https://chromium-review.googlesource.com/294331
Reviewed-by: Vitaly Buka <vitalybuka@chromium.org>
Commit-Queue: Vitaly Buka <vitalybuka@chromium.org>
Tested-by: Vitaly Buka <vitalybuka@chromium.org>
diff --git a/libweave/external/base/numerics/safe_math.h b/libweave/external/base/numerics/safe_math.h
new file mode 100644
index 0000000..1fab032
--- /dev/null
+++ b/libweave/external/base/numerics/safe_math.h
@@ -0,0 +1,279 @@
+// Copyright 2014 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#ifndef BASE_NUMERICS_SAFE_MATH_H_
+#define BASE_NUMERICS_SAFE_MATH_H_
+
+#include "base/numerics/safe_math_impl.h"
+
+namespace base {
+
+namespace internal {
+
+// CheckedNumeric implements all the logic and operators for detecting integer
+// boundary conditions such as overflow, underflow, and invalid conversions.
+// The CheckedNumeric type implicitly converts from floating point and integer
+// data types, and contains overloads for basic arithmetic operations (i.e.: +,
+// -, *, /, %).
+//
+// The following methods convert from CheckedNumeric to standard numeric values:
+// IsValid() - Returns true if the underlying numeric value is valid (i.e. has
+// has not wrapped and is not the result of an invalid conversion).
+// ValueOrDie() - Returns the underlying value. If the state is not valid this
+// call will crash on a CHECK.
+// ValueOrDefault() - Returns the current value, or the supplied default if the
+// state is not valid.
+// ValueFloating() - Returns the underlying floating point value (valid only
+// only for floating point CheckedNumeric types).
+//
+// Bitwise operations are explicitly not supported, because correct
+// handling of some cases (e.g. sign manipulation) is ambiguous. Comparison
+// operations are explicitly not supported because they could result in a crash
+// on a CHECK condition. You should use patterns like the following for these
+// operations:
+// Bitwise operation:
+// CheckedNumeric<int> checked_int = untrusted_input_value;
+// int x = checked_int.ValueOrDefault(0) | kFlagValues;
+// Comparison:
+// CheckedNumeric<size_t> checked_size;
+// CheckedNumeric<int> checked_size = untrusted_input_value;
+// checked_size = checked_size + HEADER LENGTH;
+// if (checked_size.IsValid() && checked_size.ValueOrDie() < buffer_size)
+// Do stuff...
+template <typename T>
+class CheckedNumeric {
+ public:
+ typedef T type;
+
+ CheckedNumeric() {}
+
+ // Copy constructor.
+ template <typename Src>
+ CheckedNumeric(const CheckedNumeric<Src>& rhs)
+ : state_(rhs.ValueUnsafe(), rhs.validity()) {}
+
+ template <typename Src>
+ CheckedNumeric(Src value, RangeConstraint validity)
+ : state_(value, validity) {}
+
+ // This is not an explicit constructor because we implicitly upgrade regular
+ // numerics to CheckedNumerics to make them easier to use.
+ template <typename Src>
+ CheckedNumeric(Src value)
+ : state_(value) {
+ static_assert(std::numeric_limits<Src>::is_specialized,
+ "Argument must be numeric.");
+ }
+
+ // This is not an explicit constructor because we want a seamless conversion
+ // from StrictNumeric types.
+ template <typename Src>
+ CheckedNumeric(StrictNumeric<Src> value)
+ : state_(static_cast<Src>(value)) {
+ }
+
+ // IsValid() is the public API to test if a CheckedNumeric is currently valid.
+ bool IsValid() const { return validity() == RANGE_VALID; }
+
+ // ValueOrDie() The primary accessor for the underlying value. If the current
+ // state is not valid it will CHECK and crash.
+ T ValueOrDie() const {
+ CHECK(IsValid());
+ return state_.value();
+ }
+
+ // ValueOrDefault(T default_value) A convenience method that returns the
+ // current value if the state is valid, and the supplied default_value for
+ // any other state.
+ T ValueOrDefault(T default_value) const {
+ return IsValid() ? state_.value() : default_value;
+ }
+
+ // ValueFloating() - Since floating point values include their validity state,
+ // we provide an easy method for extracting them directly, without a risk of
+ // crashing on a CHECK.
+ T ValueFloating() const {
+ static_assert(std::numeric_limits<T>::is_iec559, "Argument must be float.");
+ return CheckedNumeric<T>::cast(*this).ValueUnsafe();
+ }
+
+ // validity() - DO NOT USE THIS IN EXTERNAL CODE - It is public right now for
+ // tests and to avoid a big matrix of friend operator overloads. But the
+ // values it returns are likely to change in the future.
+ // Returns: current validity state (i.e. valid, overflow, underflow, nan).
+ // TODO(jschuh): crbug.com/332611 Figure out and implement semantics for
+ // saturation/wrapping so we can expose this state consistently and implement
+ // saturated arithmetic.
+ RangeConstraint validity() const { return state_.validity(); }
+
+ // ValueUnsafe() - DO NOT USE THIS IN EXTERNAL CODE - It is public right now
+ // for tests and to avoid a big matrix of friend operator overloads. But the
+ // values it returns are likely to change in the future.
+ // Returns: the raw numeric value, regardless of the current state.
+ // TODO(jschuh): crbug.com/332611 Figure out and implement semantics for
+ // saturation/wrapping so we can expose this state consistently and implement
+ // saturated arithmetic.
+ T ValueUnsafe() const { return state_.value(); }
+
+ // Prototypes for the supported arithmetic operator overloads.
+ template <typename Src> CheckedNumeric& operator+=(Src rhs);
+ template <typename Src> CheckedNumeric& operator-=(Src rhs);
+ template <typename Src> CheckedNumeric& operator*=(Src rhs);
+ template <typename Src> CheckedNumeric& operator/=(Src rhs);
+ template <typename Src> CheckedNumeric& operator%=(Src rhs);
+
+ CheckedNumeric operator-() const {
+ RangeConstraint validity;
+ T value = CheckedNeg(state_.value(), &validity);
+ // Negation is always valid for floating point.
+ if (std::numeric_limits<T>::is_iec559)
+ return CheckedNumeric<T>(value);
+
+ validity = GetRangeConstraint(state_.validity() | validity);
+ return CheckedNumeric<T>(value, validity);
+ }
+
+ CheckedNumeric Abs() const {
+ RangeConstraint validity;
+ T value = CheckedAbs(state_.value(), &validity);
+ // Absolute value is always valid for floating point.
+ if (std::numeric_limits<T>::is_iec559)
+ return CheckedNumeric<T>(value);
+
+ validity = GetRangeConstraint(state_.validity() | validity);
+ return CheckedNumeric<T>(value, validity);
+ }
+
+ CheckedNumeric& operator++() {
+ *this += 1;
+ return *this;
+ }
+
+ CheckedNumeric operator++(int) {
+ CheckedNumeric value = *this;
+ *this += 1;
+ return value;
+ }
+
+ CheckedNumeric& operator--() {
+ *this -= 1;
+ return *this;
+ }
+
+ CheckedNumeric operator--(int) {
+ CheckedNumeric value = *this;
+ *this -= 1;
+ return value;
+ }
+
+ // These static methods behave like a convenience cast operator targeting
+ // the desired CheckedNumeric type. As an optimization, a reference is
+ // returned when Src is the same type as T.
+ template <typename Src>
+ static CheckedNumeric<T> cast(
+ Src u,
+ typename enable_if<std::numeric_limits<Src>::is_specialized, int>::type =
+ 0) {
+ return u;
+ }
+
+ template <typename Src>
+ static CheckedNumeric<T> cast(
+ const CheckedNumeric<Src>& u,
+ typename enable_if<!is_same<Src, T>::value, int>::type = 0) {
+ return u;
+ }
+
+ static const CheckedNumeric<T>& cast(const CheckedNumeric<T>& u) { return u; }
+
+ private:
+ CheckedNumericState<T> state_;
+};
+
+// This is the boilerplate for the standard arithmetic operator overloads. A
+// macro isn't the prettiest solution, but it beats rewriting these five times.
+// Some details worth noting are:
+// * We apply the standard arithmetic promotions.
+// * We skip range checks for floating points.
+// * We skip range checks for destination integers with sufficient range.
+// TODO(jschuh): extract these out into templates.
+#define BASE_NUMERIC_ARITHMETIC_OPERATORS(NAME, OP, COMPOUND_OP) \
+ /* Binary arithmetic operator for CheckedNumerics of the same type. */ \
+ template <typename T> \
+ CheckedNumeric<typename ArithmeticPromotion<T>::type> operator OP( \
+ const CheckedNumeric<T>& lhs, const CheckedNumeric<T>& rhs) { \
+ typedef typename ArithmeticPromotion<T>::type Promotion; \
+ /* Floating point always takes the fast path */ \
+ if (std::numeric_limits<T>::is_iec559) \
+ return CheckedNumeric<T>(lhs.ValueUnsafe() OP rhs.ValueUnsafe()); \
+ if (IsIntegerArithmeticSafe<Promotion, T, T>::value) \
+ return CheckedNumeric<Promotion>( \
+ lhs.ValueUnsafe() OP rhs.ValueUnsafe(), \
+ GetRangeConstraint(rhs.validity() | lhs.validity())); \
+ RangeConstraint validity = RANGE_VALID; \
+ T result = static_cast<T>(Checked##NAME( \
+ static_cast<Promotion>(lhs.ValueUnsafe()), \
+ static_cast<Promotion>(rhs.ValueUnsafe()), \
+ &validity)); \
+ return CheckedNumeric<Promotion>( \
+ result, \
+ GetRangeConstraint(validity | lhs.validity() | rhs.validity())); \
+ } \
+ /* Assignment arithmetic operator implementation from CheckedNumeric. */ \
+ template <typename T> \
+ template <typename Src> \
+ CheckedNumeric<T>& CheckedNumeric<T>::operator COMPOUND_OP(Src rhs) { \
+ *this = CheckedNumeric<T>::cast(*this) OP CheckedNumeric<Src>::cast(rhs); \
+ return *this; \
+ } \
+ /* Binary arithmetic operator for CheckedNumeric of different type. */ \
+ template <typename T, typename Src> \
+ CheckedNumeric<typename ArithmeticPromotion<T, Src>::type> operator OP( \
+ const CheckedNumeric<Src>& lhs, const CheckedNumeric<T>& rhs) { \
+ typedef typename ArithmeticPromotion<T, Src>::type Promotion; \
+ if (IsIntegerArithmeticSafe<Promotion, T, Src>::value) \
+ return CheckedNumeric<Promotion>( \
+ lhs.ValueUnsafe() OP rhs.ValueUnsafe(), \
+ GetRangeConstraint(rhs.validity() | lhs.validity())); \
+ return CheckedNumeric<Promotion>::cast(lhs) \
+ OP CheckedNumeric<Promotion>::cast(rhs); \
+ } \
+ /* Binary arithmetic operator for left CheckedNumeric and right numeric. */ \
+ template <typename T, typename Src> \
+ CheckedNumeric<typename ArithmeticPromotion<T, Src>::type> operator OP( \
+ const CheckedNumeric<T>& lhs, Src rhs) { \
+ typedef typename ArithmeticPromotion<T, Src>::type Promotion; \
+ if (IsIntegerArithmeticSafe<Promotion, T, Src>::value) \
+ return CheckedNumeric<Promotion>(lhs.ValueUnsafe() OP rhs, \
+ lhs.validity()); \
+ return CheckedNumeric<Promotion>::cast(lhs) \
+ OP CheckedNumeric<Promotion>::cast(rhs); \
+ } \
+ /* Binary arithmetic operator for right numeric and left CheckedNumeric. */ \
+ template <typename T, typename Src> \
+ CheckedNumeric<typename ArithmeticPromotion<T, Src>::type> operator OP( \
+ Src lhs, const CheckedNumeric<T>& rhs) { \
+ typedef typename ArithmeticPromotion<T, Src>::type Promotion; \
+ if (IsIntegerArithmeticSafe<Promotion, T, Src>::value) \
+ return CheckedNumeric<Promotion>(lhs OP rhs.ValueUnsafe(), \
+ rhs.validity()); \
+ return CheckedNumeric<Promotion>::cast(lhs) \
+ OP CheckedNumeric<Promotion>::cast(rhs); \
+ }
+
+BASE_NUMERIC_ARITHMETIC_OPERATORS(Add, +, += )
+BASE_NUMERIC_ARITHMETIC_OPERATORS(Sub, -, -= )
+BASE_NUMERIC_ARITHMETIC_OPERATORS(Mul, *, *= )
+BASE_NUMERIC_ARITHMETIC_OPERATORS(Div, /, /= )
+BASE_NUMERIC_ARITHMETIC_OPERATORS(Mod, %, %= )
+
+#undef BASE_NUMERIC_ARITHMETIC_OPERATORS
+
+} // namespace internal
+
+using internal::CheckedNumeric;
+
+} // namespace base
+
+#endif // BASE_NUMERICS_SAFE_MATH_H_
