// Copyright 2014 The Crashpad Authors. All rights reserved.
|
//
|
// Licensed under the Apache License, Version 2.0 (the "License");
|
// you may not use this file except in compliance with the License.
|
// You may obtain a copy of the License at
|
//
|
// http://www.apache.org/licenses/LICENSE-2.0
|
//
|
// Unless required by applicable law or agreed to in writing, software
|
// distributed under the License is distributed on an "AS IS" BASIS,
|
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
|
// See the License for the specific language governing permissions and
|
// limitations under the License.
|
|
#ifndef CRASHPAD_UTIL_NUMERIC_CHECKED_RANGE_H_
|
#define CRASHPAD_UTIL_NUMERIC_CHECKED_RANGE_H_
|
|
#include <limits>
|
#include <tuple>
|
|
#include "base/check.h"
|
#include "base/numerics/safe_conversions.h"
|
#include "base/numerics/safe_math.h"
|
#include "util/misc/implicit_cast.h"
|
|
namespace crashpad {
|
|
//! \brief Ensures that a range, composed of a base and size, does not overflow
|
//! its data type.
|
template <typename ValueType, typename SizeType = ValueType>
|
class CheckedRange {
|
public:
|
CheckedRange(ValueType base, SizeType size) {
|
static_assert(!std::numeric_limits<SizeType>::is_signed,
|
"SizeType must be unsigned");
|
SetRange(base, size);
|
}
|
|
//! \brief Sets the range’s base and size to \a base and \a size,
|
//! respectively.
|
void SetRange(ValueType base, SizeType size) {
|
base_ = base;
|
size_ = size;
|
}
|
|
//! \brief The range’s base.
|
ValueType base() const { return base_; }
|
|
//! \brief The range’s size.
|
SizeType size() const { return size_; }
|
|
//! \brief The range’s end (its base plus its size).
|
ValueType end() const { return base_ + size_; }
|
|
//! \brief Returns the validity of the range.
|
//!
|
//! \return `true` if the range is valid, `false` otherwise.
|
//!
|
//! A range is valid if its size can be converted to the range’s data type
|
//! without data loss, and if its end (base plus size) can be computed without
|
//! overflowing its data type.
|
bool IsValid() const {
|
if (!base::IsValueInRangeForNumericType<ValueType, SizeType>(size_)) {
|
return false;
|
}
|
base::CheckedNumeric<ValueType> checked_end(base_);
|
checked_end += implicit_cast<ValueType>(size_);
|
return checked_end.IsValid();
|
}
|
|
//! \brief Returns whether the range contains another value.
|
//!
|
//! \param[in] value The (possibly) contained value.
|
//!
|
//! \return `true` if the range contains \a value, `false` otherwise.
|
//!
|
//! A range contains a value if the value is greater than or equal to its
|
//! base, and less than its end (base plus size).
|
//!
|
//! This method must only be called if IsValid() would return `true`.
|
bool ContainsValue(ValueType value) const {
|
DCHECK(IsValid());
|
|
return value >= base() && value < end();
|
}
|
|
//! \brief Returns whether the range contains another range.
|
//!
|
//! \param[in] that The (possibly) contained range.
|
//!
|
//! \return `true` if `this` range, the containing range, contains \a that,
|
//! the contained range. `false` otherwise.
|
//!
|
//! A range contains another range when the contained range’s base is greater
|
//! than or equal to the containing range’s base, and the contained range’s
|
//! end is less than or equal to the containing range’s end.
|
//!
|
//! This method must only be called if IsValid() would return `true` for both
|
//! CheckedRange objects involved.
|
bool ContainsRange(const CheckedRange<ValueType, SizeType>& that) const {
|
DCHECK(IsValid());
|
DCHECK(that.IsValid());
|
|
return that.base() >= base() && that.end() <= end();
|
}
|
|
//! \brief Returns whether the range overlaps another range.
|
//!
|
//! \param[in] that The (possibly) overlapping range.
|
//!
|
//! \return `true` if `this` range, the first range, overlaps \a that,
|
//! the provided range. `false` otherwise.
|
//!
|
//! Ranges are considered to be closed-open [base, end) for this test. Zero
|
//! length ranges are never considered to overlap another range.
|
//!
|
//! This method must only be called if IsValid() would return `true` for both
|
//! CheckedRange objects involved.
|
bool OverlapsRange(const CheckedRange<ValueType, SizeType>& that) const {
|
DCHECK(IsValid());
|
DCHECK(that.IsValid());
|
|
if (size() == 0 || that.size() == 0)
|
return false;
|
|
return base() < that.end() && that.base() < end();
|
}
|
|
bool operator<(const CheckedRange& other) const {
|
return std::tie(base_, size_) < std::tie(other.base_, other.size_);
|
}
|
|
private:
|
ValueType base_;
|
SizeType size_;
|
};
|
|
} // namespace crashpad
|
|
#endif // CRASHPAD_UTIL_NUMERIC_CHECKED_RANGE_H_
|
