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_ 68
