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1 /* | |
2 * Copyright 2014 The WebRTC Project Authors. All rights reserved. | |
3 * | |
4 * Use of this source code is governed by a BSD-style license | |
5 * that can be found in the LICENSE file in the root of the source | |
6 * tree. An additional intellectual property rights grant can be found | |
7 * in the file PATENTS. All contributing project authors may | |
8 * be found in the AUTHORS file in the root of the source tree. | |
9 */ | |
10 | |
11 // Borrowed from Chromium's src/base/numerics/safe_conversions.h. | |
12 | |
13 #ifndef WEBRTC_BASE_SAFE_CONVERSIONS_H_ | |
14 #define WEBRTC_BASE_SAFE_CONVERSIONS_H_ | |
15 | |
16 #include <limits> | |
17 | |
18 #include "webrtc/base/checks.h" | |
19 #include "webrtc/base/safe_conversions_impl.h" | |
20 | |
21 namespace rtc { | |
22 | |
23 // Convenience function that returns true if the supplied value is in range | |
24 // for the destination type. | |
25 template <typename Dst, typename Src> | |
26 inline bool IsValueInRangeForNumericType(Src value) { | |
27 return internal::RangeCheck<Dst>(value) == internal::TYPE_VALID; | |
28 } | |
29 | |
30 // checked_cast<> is analogous to static_cast<> for numeric types, | |
31 // except that it CHECKs that the specified numeric conversion will not | |
32 // overflow or underflow. NaN source will always trigger a CHECK. | |
33 template <typename Dst, typename Src> | |
34 inline Dst checked_cast(Src value) { | |
35 RTC_CHECK(IsValueInRangeForNumericType<Dst>(value)); | |
36 return static_cast<Dst>(value); | |
37 } | |
38 | |
39 // saturated_cast<> is analogous to static_cast<> for numeric types, except | |
40 // that the specified numeric conversion will saturate rather than overflow or | |
41 // underflow. NaN assignment to an integral will trigger a RTC_CHECK condition. | |
42 template <typename Dst, typename Src> | |
43 inline Dst saturated_cast(Src value) { | |
44 // Optimization for floating point values, which already saturate. | |
45 if (std::numeric_limits<Dst>::is_iec559) | |
46 return static_cast<Dst>(value); | |
47 | |
48 switch (internal::RangeCheck<Dst>(value)) { | |
49 case internal::TYPE_VALID: | |
50 return static_cast<Dst>(value); | |
51 | |
52 case internal::TYPE_UNDERFLOW: | |
53 return std::numeric_limits<Dst>::min(); | |
54 | |
55 case internal::TYPE_OVERFLOW: | |
56 return std::numeric_limits<Dst>::max(); | |
57 | |
58 // Should fail only on attempting to assign NaN to a saturated integer. | |
59 case internal::TYPE_INVALID: | |
60 FATAL(); | |
61 return std::numeric_limits<Dst>::max(); | |
62 } | |
63 | |
64 FATAL(); | |
65 return static_cast<Dst>(value); | |
66 } | |
67 | |
68 } // namespace rtc | |
69 | |
70 #endif // WEBRTC_BASE_SAFE_CONVERSIONS_H_ | |
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