Safe numeric library: base/numerics (copied from Chromium)

webrtc/base/safe_conversions.h

-/*
- *  Copyright 2014 The WebRTC Project Authors. All rights reserved.
- *
- *  Use of this source code is governed by a BSD-style license
- *  that can be found in the LICENSE file in the root of the source
- *  tree. An additional intellectual property rights grant can be found
- *  in the file PATENTS.  All contributing project authors may
- *  be found in the AUTHORS file in the root of the source tree.
- */
-
-// Borrowed from Chromium's src/base/numerics/safe_conversions.h.
-
-#ifndef WEBRTC_BASE_SAFE_CONVERSIONS_H_
-#define WEBRTC_BASE_SAFE_CONVERSIONS_H_
-
-#include <limits>
-
-#include "webrtc/base/checks.h"
-#include "webrtc/base/safe_conversions_impl.h"
-
-namespace rtc {
-
-// Convenience function that returns true if the supplied value is in range
-// for the destination type.
-template <typename Dst, typename Src>
-inline bool IsValueInRangeForNumericType(Src value) {
-  return internal::RangeCheck<Dst>(value) == internal::TYPE_VALID;
-}
-
-// checked_cast<> is analogous to static_cast<> for numeric types,
-// except that it CHECKs that the specified numeric conversion will not
-// overflow or underflow. NaN source will always trigger a CHECK.
-template <typename Dst, typename Src>
-inline Dst checked_cast(Src value) {
-  RTC_CHECK(IsValueInRangeForNumericType<Dst>(value));
-  return static_cast<Dst>(value);
-}
-
-// saturated_cast<> is analogous to static_cast<> for numeric types, except
-// that the specified numeric conversion will saturate rather than overflow or
-// underflow. NaN assignment to an integral will trigger a RTC_CHECK condition.
-template <typename Dst, typename Src>
-inline Dst saturated_cast(Src value) {
-  // Optimization for floating point values, which already saturate.
-  if (std::numeric_limits<Dst>::is_iec559)
-    return static_cast<Dst>(value);
-
-  switch (internal::RangeCheck<Dst>(value)) {
-    case internal::TYPE_VALID:
-      return static_cast<Dst>(value);
-
-    case internal::TYPE_UNDERFLOW:
-      return std::numeric_limits<Dst>::min();
-
-    case internal::TYPE_OVERFLOW:
-      return std::numeric_limits<Dst>::max();
-
-    // Should fail only on attempting to assign NaN to a saturated integer.
-    case internal::TYPE_INVALID:
-      FATAL();
-      return std::numeric_limits<Dst>::max();
-  }
-
-  FATAL();
-  return static_cast<Dst>(value);
-}
-
-}  // namespace rtc
-
-#endif  // WEBRTC_BASE_SAFE_CONVERSIONS_H_