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/*
* Copyright 2014 The WebRTC Project Authors. All rights reserved.
*
* Use of this source code is governed by a BSD-style license
* that can be found in the LICENSE file in the root of the source
* tree. An additional intellectual property rights grant can be found
* in the file PATENTS. All contributing project authors may
* be found in the AUTHORS file in the root of the source tree.
*/
// Borrowed from Chromium's src/base/numerics/safe_conversions.h.
#ifndef RTC_BASE_NUMERICS_SAFE_CONVERSIONS_H_
#define RTC_BASE_NUMERICS_SAFE_CONVERSIONS_H_
#include <limits>
#include "rtc_base/checks.h"
#include "rtc_base/numerics/safe_conversions_impl.h"
namespace webrtc {
// Convenience function that returns true if the supplied value is in range
// for the destination type.
template <typename Dst, typename Src>
inline constexpr bool IsValueInRangeForNumericType(Src value) {
return internal::RangeCheck<Dst>(value) == internal::TYPE_VALID;
}
// checked_cast<> and dchecked_cast<> are analogous to static_cast<> for
// numeric types, except that they [D]CHECK that the specified numeric
// conversion will not overflow or underflow. NaN source will always trigger
// the [D]CHECK.
template <typename Dst, typename Src>
inline constexpr Dst checked_cast(Src value) {
RTC_CHECK(IsValueInRangeForNumericType<Dst>(value));
return static_cast<Dst>(value);
}
template <typename Dst, typename Src>
inline constexpr Dst dchecked_cast(Src value) {
RTC_DCHECK(IsValueInRangeForNumericType<Dst>(value));
return static_cast<Dst>(value);
}
// saturated_cast<> is analogous to static_cast<> for numeric types, except
// that the specified numeric conversion will saturate rather than overflow or
// underflow. NaN assignment to an integral will trigger a RTC_CHECK condition.
template <typename Dst, typename Src>
inline constexpr Dst saturated_cast(Src value) {
// Optimization for floating point values, which already saturate.
if (std::numeric_limits<Dst>::is_iec559)
return static_cast<Dst>(value);
switch (internal::RangeCheck<Dst>(value)) {
case internal::TYPE_VALID:
return static_cast<Dst>(value);
case internal::TYPE_UNDERFLOW:
return std::numeric_limits<Dst>::min();
case internal::TYPE_OVERFLOW:
return std::numeric_limits<Dst>::max();
// Should fail only on attempting to assign NaN to a saturated integer.
case internal::TYPE_INVALID:
RTC_CHECK_NOTREACHED();
}
RTC_CHECK_NOTREACHED();
}
} // namespace webrtc
// Re-export symbols from the webrtc namespace for backwards compatibility.
// TODO(bugs.webrtc.org/4222596): Remove once all references are updated.
namespace rtc {
using ::webrtc::checked_cast;
using ::webrtc::dchecked_cast;
using ::webrtc::IsValueInRangeForNumericType;
using ::webrtc::saturated_cast;
} // namespace rtc
#endif // RTC_BASE_NUMERICS_SAFE_CONVERSIONS_H_
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