Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 1 | // Copyright 2014 The Chromium Authors. All rights reserved. |
| 2 | // Use of this source code is governed by a BSD-style license that can be |
| 3 | // found in the LICENSE file. |
| 4 | |
| 5 | // Slightly adapted for inclusion in V8. |
| 6 | // Copyright 2014 the V8 project authors. All rights reserved. |
| 7 | |
| 8 | #ifndef V8_BASE_SAFE_CONVERSIONS_H_ |
| 9 | #define V8_BASE_SAFE_CONVERSIONS_H_ |
| 10 | |
| 11 | #include <limits> |
| 12 | |
| 13 | #include "src/base/safe_conversions_impl.h" |
| 14 | |
| 15 | namespace v8 { |
| 16 | namespace base { |
| 17 | |
| 18 | // Convenience function that returns true if the supplied value is in range |
| 19 | // for the destination type. |
| 20 | template <typename Dst, typename Src> |
| 21 | inline bool IsValueInRangeForNumericType(Src value) { |
| 22 | return internal::DstRangeRelationToSrcRange<Dst>(value) == |
| 23 | internal::RANGE_VALID; |
| 24 | } |
| 25 | |
| 26 | // checked_cast<> is analogous to static_cast<> for numeric types, |
| 27 | // except that it CHECKs that the specified numeric conversion will not |
| 28 | // overflow or underflow. NaN source will always trigger a CHECK. |
| 29 | template <typename Dst, typename Src> |
| 30 | inline Dst checked_cast(Src value) { |
| 31 | CHECK(IsValueInRangeForNumericType<Dst>(value)); |
| 32 | return static_cast<Dst>(value); |
| 33 | } |
| 34 | |
| 35 | // saturated_cast<> is analogous to static_cast<> for numeric types, except |
| 36 | // that the specified numeric conversion will saturate rather than overflow or |
| 37 | // underflow. NaN assignment to an integral will trigger a CHECK condition. |
| 38 | template <typename Dst, typename Src> |
| 39 | inline Dst saturated_cast(Src value) { |
| 40 | // Optimization for floating point values, which already saturate. |
| 41 | if (std::numeric_limits<Dst>::is_iec559) |
| 42 | return static_cast<Dst>(value); |
| 43 | |
| 44 | switch (internal::DstRangeRelationToSrcRange<Dst>(value)) { |
| 45 | case internal::RANGE_VALID: |
| 46 | return static_cast<Dst>(value); |
| 47 | |
| 48 | case internal::RANGE_UNDERFLOW: |
| 49 | return std::numeric_limits<Dst>::min(); |
| 50 | |
| 51 | case internal::RANGE_OVERFLOW: |
| 52 | return std::numeric_limits<Dst>::max(); |
| 53 | |
| 54 | // Should fail only on attempting to assign NaN to a saturated integer. |
| 55 | case internal::RANGE_INVALID: |
| 56 | CHECK(false); |
| 57 | return std::numeric_limits<Dst>::max(); |
| 58 | } |
| 59 | |
| 60 | UNREACHABLE(); |
| 61 | return static_cast<Dst>(value); |
| 62 | } |
| 63 | |
| 64 | } // namespace base |
| 65 | } // namespace v8 |
| 66 | |
| 67 | #endif // V8_BASE_SAFE_CONVERSIONS_H_ |