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 13namespace base { 14 15// Convenience function that returns true if the supplied value is in range 16// for the destination type. 17template <typename Dst, typename Src> 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. 26template <typename Dst, typename Src> 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. 35template <typename Dst, typename Src> 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