webrtc/rtc_base/numerics/safe_conversions.h
Karl Wiberg e40468ba3d Move some numeric utility code from rtc_base/ to rtc_base/numerics/
Specifically, I'm moving

  safe_compare.h
  safe_conversions.h
  safe_minmax.h

They shouldn't be part of the API, and moving them to an appropriate
subdirectory of rtc_base/ is a good way to keep track of that.

BUG=webrtc:8445

Change-Id: I458531aeb30bcf4291c4bec3bf22a2fffbf054ff
Reviewed-on: https://webrtc-review.googlesource.com/20860
Commit-Queue: Karl Wiberg <kwiberg@webrtc.org>
Reviewed-by: Danil Chapovalov <danilchap@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#20829}
2017-11-22 11:21:47 +00:00

76 lines
2.5 KiB
C++

/*
* 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 RTC_BASE_NUMERICS_SAFE_CONVERSIONS_H_
#define RTC_BASE_NUMERICS_SAFE_CONVERSIONS_H_
#include <limits>
#include "rtc_base/checks.h"
#include "rtc_base/numerics/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<> and dchecked_cast<> are analogous to static_cast<> for
// numeric types, except that they [D]CHECK that the specified numeric
// conversion will not overflow or underflow. NaN source will always trigger
// the [D]CHECK.
template <typename Dst, typename Src>
inline Dst checked_cast(Src value) {
RTC_CHECK(IsValueInRangeForNumericType<Dst>(value));
return static_cast<Dst>(value);
}
template <typename Dst, typename Src>
inline Dst dchecked_cast(Src value) {
RTC_DCHECK(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 // RTC_BASE_NUMERICS_SAFE_CONVERSIONS_H_