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}diff --git a/rtc_base/numerics/safe_conversions.h b/rtc_base/numerics/safe_conversions.h
new file mode 100644
index 0000000..58efcaa
--- /dev/null
+++ b/rtc_base/numerics/safe_conversions.h
@@ -0,0 +1,76 @@
+/*
+ * 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_