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 #ifndef BASE_SAFE_CONVERSIONS_H_ 6 #define BASE_SAFE_CONVERSIONS_H_ 7 8 #include <limits> 9 10 #include "base/logging.h" 11 #include "base/numerics/safe_conversions_impl.h" 12 13 namespace base { 14 15 // Convenience function that returns true if the supplied value is in range 16 // for the destination type. 17 template <typename Dst, typename Src> IsValueInRangeForNumericType(Src value)18inline bool IsValueInRangeForNumericType(Src value) { 19 return internal::DstRangeRelationToSrcRange<Dst>(value) == 20 internal::RANGE_VALID; 21 } 22 23 // checked_cast<> is analogous to static_cast<> for numeric types, 24 // except that it CHECKs that the specified numeric conversion will not 25 // overflow or underflow. NaN source will always trigger a CHECK. 26 template <typename Dst, typename Src> checked_cast(Src value)27inline Dst checked_cast(Src value) { 28 CHECK(IsValueInRangeForNumericType<Dst>(value)); 29 return static_cast<Dst>(value); 30 } 31 32 // saturated_cast<> is analogous to static_cast<> for numeric types, except 33 // that the specified numeric conversion will saturate rather than overflow or 34 // underflow. NaN assignment to an integral will trigger a CHECK condition. 35 template <typename Dst, typename Src> saturated_cast(Src value)36inline Dst saturated_cast(Src value) { 37 // Optimization for floating point values, which already saturate. 38 if (std::numeric_limits<Dst>::is_iec559) 39 return static_cast<Dst>(value); 40 41 switch (internal::DstRangeRelationToSrcRange<Dst>(value)) { 42 case internal::RANGE_VALID: 43 return static_cast<Dst>(value); 44 45 case internal::RANGE_UNDERFLOW: 46 return std::numeric_limits<Dst>::min(); 47 48 case internal::RANGE_OVERFLOW: 49 return std::numeric_limits<Dst>::max(); 50 51 // Should fail only on attempting to assign NaN to a saturated integer. 52 case internal::RANGE_INVALID: 53 CHECK(false); 54 return std::numeric_limits<Dst>::max(); 55 } 56 57 NOTREACHED(); 58 return static_cast<Dst>(value); 59 } 60 61 } // namespace base 62 63 #endif // BASE_SAFE_CONVERSIONS_H_ 64 65