| /* |
| * 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 rtc { |
| |
| // 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: |
| FATAL(); |
| return std::numeric_limits<Dst>::max(); |
| } |
| |
| FATAL(); |
| return static_cast<Dst>(value); |
| } |
| |
| } // namespace rtc |
| |
| #endif // RTC_BASE_NUMERICS_SAFE_CONVERSIONS_H_ |