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 15namespace v8 { 16namespace base { 17 18// Convenience function that returns true if the supplied value is in range 19// for the destination type. 20template <typename Dst, typename Src> 21inline 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. 29template <typename Dst, typename Src> 30inline 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. 38template <typename Dst, typename Src> 39inline 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