Tommi | d44c077 | 2016-03-11 17:12:32 -0800 | [diff] [blame] | 1 | /* |
| 2 | * Copyright 2014 The WebRTC Project Authors. All rights reserved. |
| 3 | * |
| 4 | * Use of this source code is governed by a BSD-style license |
| 5 | * that can be found in the LICENSE file in the root of the source |
| 6 | * tree. An additional intellectual property rights grant can be found |
| 7 | * in the file PATENTS. All contributing project authors may |
| 8 | * be found in the AUTHORS file in the root of the source tree. |
| 9 | */ |
| 10 | |
| 11 | // Borrowed from Chromium's src/base/numerics/safe_conversions.h. |
| 12 | |
Mirko Bonadei | 92ea95e | 2017-09-15 06:47:31 +0200 | [diff] [blame] | 13 | #ifndef RTC_BASE_SAFE_CONVERSIONS_H_ |
| 14 | #define RTC_BASE_SAFE_CONVERSIONS_H_ |
Tommi | d44c077 | 2016-03-11 17:12:32 -0800 | [diff] [blame] | 15 | |
Henrik Kjellander | ec78f1c | 2017-06-29 07:52:50 +0200 | [diff] [blame] | 16 | #include <limits> |
Tommi | d44c077 | 2016-03-11 17:12:32 -0800 | [diff] [blame] | 17 | |
Mirko Bonadei | 92ea95e | 2017-09-15 06:47:31 +0200 | [diff] [blame] | 18 | #include "rtc_base/checks.h" |
| 19 | #include "rtc_base/safe_conversions_impl.h" |
Henrik Kjellander | ec78f1c | 2017-06-29 07:52:50 +0200 | [diff] [blame] | 20 | |
| 21 | namespace rtc { |
| 22 | |
| 23 | // Convenience function that returns true if the supplied value is in range |
| 24 | // for the destination type. |
| 25 | template <typename Dst, typename Src> |
| 26 | inline bool IsValueInRangeForNumericType(Src value) { |
| 27 | return internal::RangeCheck<Dst>(value) == internal::TYPE_VALID; |
| 28 | } |
| 29 | |
| 30 | // checked_cast<> and dchecked_cast<> are analogous to static_cast<> for |
| 31 | // numeric types, except that they [D]CHECK that the specified numeric |
| 32 | // conversion will not overflow or underflow. NaN source will always trigger |
| 33 | // the [D]CHECK. |
| 34 | template <typename Dst, typename Src> |
| 35 | inline Dst checked_cast(Src value) { |
| 36 | RTC_CHECK(IsValueInRangeForNumericType<Dst>(value)); |
| 37 | return static_cast<Dst>(value); |
| 38 | } |
| 39 | template <typename Dst, typename Src> |
| 40 | inline Dst dchecked_cast(Src value) { |
| 41 | RTC_DCHECK(IsValueInRangeForNumericType<Dst>(value)); |
| 42 | return static_cast<Dst>(value); |
| 43 | } |
| 44 | |
| 45 | // saturated_cast<> is analogous to static_cast<> for numeric types, except |
| 46 | // that the specified numeric conversion will saturate rather than overflow or |
| 47 | // underflow. NaN assignment to an integral will trigger a RTC_CHECK condition. |
| 48 | template <typename Dst, typename Src> |
| 49 | inline Dst saturated_cast(Src value) { |
| 50 | // Optimization for floating point values, which already saturate. |
| 51 | if (std::numeric_limits<Dst>::is_iec559) |
| 52 | return static_cast<Dst>(value); |
| 53 | |
| 54 | switch (internal::RangeCheck<Dst>(value)) { |
| 55 | case internal::TYPE_VALID: |
| 56 | return static_cast<Dst>(value); |
| 57 | |
| 58 | case internal::TYPE_UNDERFLOW: |
| 59 | return std::numeric_limits<Dst>::min(); |
| 60 | |
| 61 | case internal::TYPE_OVERFLOW: |
| 62 | return std::numeric_limits<Dst>::max(); |
| 63 | |
| 64 | // Should fail only on attempting to assign NaN to a saturated integer. |
| 65 | case internal::TYPE_INVALID: |
| 66 | FATAL(); |
| 67 | return std::numeric_limits<Dst>::max(); |
| 68 | } |
| 69 | |
| 70 | FATAL(); |
| 71 | return static_cast<Dst>(value); |
| 72 | } |
| 73 | |
| 74 | } // namespace rtc |
Tommi | d44c077 | 2016-03-11 17:12:32 -0800 | [diff] [blame] | 75 | |
Mirko Bonadei | 92ea95e | 2017-09-15 06:47:31 +0200 | [diff] [blame] | 76 | #endif // RTC_BASE_SAFE_CONVERSIONS_H_ |