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