Add support for safe math operations in base/numerics

base/numerics/safe_conversions.h

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef BASE_SAFE_CONVERSIONS_H_
 #define BASE_SAFE_CONVERSIONS_H_
 
 #include <limits>
 
 #include "base/logging.h"
 #include "base/numerics/safe_conversions_impl.h"
 
 namespace base {
 
 // 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;
+  return internal::DstRangeRelationToSrcRange<Dst>(value) ==
+         internal::RANGE_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) {
   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 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:
+  switch (internal::DstRangeRelationToSrcRange<Dst>(value)) {
+    case internal::RANGE_VALID:
       return static_cast<Dst>(value);
 
-    case internal::TYPE_UNDERFLOW:
+    case internal::RANGE_UNDERFLOW:
       return std::numeric_limits<Dst>::min();
 
-    case internal::TYPE_OVERFLOW:
+    case internal::RANGE_OVERFLOW:
       return std::numeric_limits<Dst>::max();
 
     // Should fail only on attempting to assign NaN to a saturated integer.
-    case internal::TYPE_INVALID:
+    case internal::RANGE_INVALID:
       CHECK(false);
       return std::numeric_limits<Dst>::max();
   }
 
   NOTREACHED();
   return static_cast<Dst>(value);
 }
 
 }  // namespace base
 
 #endif  // BASE_SAFE_CONVERSIONS_H_